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Factcheck: Trump’s false claims about the IPCC and ‘RCP8.5’ climate scenario (Carbon Brief)

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US president Donald Trump.

US president Donald Trump. Credit: Associated Press / Alamy Stock Photo

FACTCHECKS – Original post

Multiple Authors 

19.05.2026 | 5:22pm

Among a flurry of posts on social media last weekend, US president Donald Trump declared “good riddance” to a specific emissions scenario used in global climate projections.

The “RCP8.5” scenario, which envisages a future of very high carbon emissions, was “wrong, wrong, wrong”, the president wrote in block capitals.

This was “just admitted” by the UN’s “top climate committee”, he falsely claimed, referring to the Intergovernmental Panel on Climate Change (IPCC).

The post was quickly picked up by right-leaning media, amplifying Trump’s misrepresentation of emissions scenarios and the role of the IPCC.

His claim follows the publication of a new set of emissions scenarios that will feed into the next IPCC reports. 

While the new scenarios no longer include such high emissions as in RCP8.5, they also show it is “not possible” to limit global warming to 1.5C above pre-industrial levels without significant “overshoot”, one of the authors tells Carbon Brief.

Moreover, projections suggest that the world is still on course for between 2.5C and 3C of warming, another author says.

This level of warming was previously described as “catastrophic” by the UN.

In this factcheck, Carbon Brief looks at Trump’s comments, the debate around RCP8.5 and the “good” and “bad” news within the latest scenarios.

What did Trump say?

In the late evening of Saturday 16 May, Trump posted the following message on his Truth Social social-media platform:

Social media post by US president Donald Trump that says: "GOOD RIDDANCE! After 15 years of Dumocrats promising that “Climate Change” is going to destroy the Planet, the United Nations TOP Climate Committee just admitted that its own projections (RCP8.5) were WRONG! WRONG! WRONG! For far too long Climate Activism has been used by Dumocrats to scare Americans, push horrible Energy Polices, and fund BILLIONS into their bogus research programs. Unlike the Dumocrats, who use Climate Alarmism nonsense to push their GREEN NEW SCAM, my Administration will always be based on TRUTH, SCIENCE, and FACT! President DONALD J. TRUMP"

“Dumocrats” is a derogatory nickname for Democrat politicians, debuted by the president in a televised Fox News interview on Thursday 14 May, according to the Independent.

By “top climate committee”, the president was presumably referring to the IPCC, the UN body responsible for assessing science about human-caused climate change. 

However, the IPCC does not develop, control or own climate scenarios. Moreover, it has not published anything stating that any climate scenario is “wrong”. (For more, see: How is the IPCC involved?)

Nevertheless, right-leaning media outlets have reported on Trump’s comments, in many instances repeating his false assertion that the RCP8.5 climate scenario had been developed by the IPCC. 

The New York Post misleadingly claimed that the IPCC “had quietly adjusted” its framework of emission scenarios. The Daily Caller, a pro-Trump conspiratorial US outlet, adds its own falsehoods stating that “IPCC researchers revised their modelling approach last month, swapping the extreme pathway for seven alternative scenarios”. The climate-sceptic Australian claimed that scientists had “quietly scrapped the apocalyptic forecasts that have terrified policymakers and the public”.

With Fox News also covering Trump’s comments, along with an earlier article by the Times, much of the reporting around RCP8.5 in recent days has been driven by media controlled by the climate-sceptic mogul Rupert Murdoch.

It is not the first time the Trump administration has attacked RCP8.5. In an executive order  issued in May 2025 – entitled, “Restoring gold-standard science” – the White House included the climate scenario in a list of examples of how the previous government had “used or promoted scientific information in a highly misleading manner”.

Excerpt from White House executive order, saying: "Similarly, agencies have used Representative Concentration Pathway (RCP) scenario 8.5 to assess the potential effects of climate change in a “higher” warming scenario. RCP 8.5 is a worst-case scenario based on highly unlikely assumptions like end-of-century coal use exceeding estimates of recoverable coal reserves. Scientists have warned that presenting RCP 8.5 as a likely outcome is misleading."
Excerpt from White House executive order, issued in May 2025.

Federal agencies, it claimed, had been using RCP8.5 to “assess the potential effects of climate change in a higher warming scenario”, despite scientists warning that “presenting RCP8.5 as a likely outcome is misleading”.

The executive order came after Project 2025 – a policy wishlist for Trump’s second term published in 2023 by the Heritage Foundation, an influential rightwing, climate-sceptic thinktank in the US  – criticised the climate scenario.

The manifesto said a “day-one” priority for the new government should be to “eliminate” the US Environmental Protection Agency’s “use of unauthorised regulatory inputs”, such as “unrealistic climate scenarios, including those based on RCP8.5”.

What is RCP8.5?

Scientists use emissions scenarios to explore potential future climates, based on how global energy and land use could change in the decades to come. 

These scenarios are not predictions or forecasts of what will happen in the future. Therefore, Trump’s declaration that projections under RCP8.5 were “wrong, wrong, wrong” misrepresents the purpose of emissions scenarios.

Different modelling groups have produced thousands of different scenarios over the years. RCP8.5 was developed by scientists back in the early 2010s as one of a set of four consistent “representative concentration pathways”, or RCPs, for climate modellers to use. 

As their name suggests, the RCPs were representative of the vast array of scenarios in the scientific literature.

Their corresponding numbers – 2.6, 4.5, 6.0 and 8.5 – do not describe temperature rise (as some mistakenly assume), but the level of “radiative forcing” that each pathway reaches by 2100. This forcing level is a measure of the change in the Earth’s “energy balance” (in watts per square metre) caused by human-caused greenhouse gas emissions.

As the highest forcing of the set, RCP8.5 was a scenario of very high emissions and extensive global warming. 

When it was originally published in 2011, RCP8.5 was intended to reflect the high end – roughly the 90th percentile – of the baseline scenarios available in the scientific literature at the time. 

A “baseline” scenario is one that assumes no climate mitigation, explains Dr Chris Smith, senior research scholar at the International Institute for Applied Systems Analysis (IIASA) in Austria. He tells Carbon Brief:

“RCP8.5 was developed as a no-climate-policy scenario, often called ‘reference’ or ‘baseline’ scenarios. These are used to benchmark the actions of climate policy.”

Under RCP8.5, the IPCC’s fifth assessment report (AR5) in 2013 projected a best estimate of 4.3C of temperature rise by 2081-2100, compared to the pre-industrial period, with a “likely” range of 3.2C to 5.4C.

The RCPs were succeeded in 2017 by the “shared socioeconomic pathways”, or SSPs. The SSPs included a set of five socioeconomic “narratives”, which described factors such as population change, economic growth and the rate of technological development.

The SSPs were then used in the IPCC’s sixth assessment (AR6) cycle, which ran over 2015-23. The upper end of the AR6 temperature projections was provided by the successor to RCP8.5, known as SSP5-8.5, which indicated warming of 4.4C by 2081-2100, with a “very likely” range of 3.3C to 5.7C.

Why is RCP8.5 so hotly debated?

Prof Detlef van Vuuren from Utrecht University, a leading figure in the development of emissions scenarios for many years, tells Carbon Brief that RCP8.5 is a “low-probability, high-risk scenario and it was always meant like that”.

The scenario assumed a world without climate policy and was designed to explore the consequences of high levels of greenhouse gases and global warming. It was not, van Vueren says, a “best-guess scenario” of what the future held in store.

However, in some research papers, RCP8.5 was characterised as “business as usual”, suggesting that it was the likely outcome if society did not pursue climate action.

This was “incorrect”, says van Vuuren, noting that RCP8.5 “is not a likely outcome”. He adds: “It’s never been a likely outcome.”

Over time, RCP8.5 became hotly debated in academic circles, with some scientists arguing that such high emissions were becoming increasingly unlikely and others claiming that RCP8.5 was still consistent with historical cumulative carbon dioxide (CO2) emissions. 

Carbon Brief unpacked the arguments in this debate in a detailed explainer in 2019.

The charts below, originally included in a 2012 Nature commentary and then updated each year by the authors, shows how projected CO2 emissions under RCP8.5 (red line) compares with the other RCPs (bold coloured lines) and observations (black line).

The left-hand chart shows total CO2 emissions, including land-use change, while the right-hand chart shows CO2 emissions from burning fossil fuels and producing cement – the dominant drivers of 21st century emissions. 

Global total CO2 emissions from fossil fuels and land use
Global total CO2 emissions from fossil fuels and land use (left) and global fossil CO2 emissions (left) for historical observations (black lines) and the four RCP (coloured bold lines) for 1980-2050. Originally produced as part of Peters et al. (2012) and since updated by Glen Peters and Robbie Andrew.

While emission trends up to the early 2010s approximately tracked RCP8.5, a flattening of emissions growth in the years since has meant they have not kept pace with the sustained rises that were assumed in the scenario.

Over the past decade, global emissions have more closely tracked RCP4.5, one of the two “medium stabilisation scenarios” of the original four RCPs.

The debate around RCP8.5 has not just focused on current emissions, but also on the scenario’s underlying assumptions for the future. 

When it was published in 2011, the world had just seen unprecedented growth in global CO2 emissions, which had increased by 30% over the previous decade. Global coal use had increased by nearly 50% over the same period. Cleaner alternatives remained expensive in most countries and the idea of continued rapid growth in coal use seemed realistic.

Critics of RCP8.5 point to its assumptions for a dramatic expansion of coal use in the future, as well as high growth in global population.

For example, in a 2017 paper, two scientists argued that the “return to coal” envisaged in RCP8.5 would require an unprecedented five-fold increase in global coal use by the end of the century. Such an outcome was “exceptionally unlikely”, the authors wrote.

However, others have argued that while high-emissions scenarios are becoming increasingly unlikely, they still have an important role to play. For example, they highlight risks that only emerge under higher levels of warming. 

In addition, research has shown that feedbacks in the climate system – where warming triggers the release of more CO2 and methane, which warms the planet further – could mean that human-caused emissions lead to a higher radiative forcing and have a greater climate impact than initially assumed.

How has RCP8.5 been replaced?

As the IPCC heads into its seventh assessment cycle (AR7), scientists have been developing the emissions scenarios and climate model projections that will – eventually – feed into its reports.

For the emissions scenarios, that process – known as ScenarioMIP – started back in 2023 at a meeting in Reading, UK. This involved scientists representing “different climate research communities”, explains van Vuuren.

This “brainstorming” session devised the outlines for the new scenarios, he says. After more meetings, these were subsequently developed into a proposal that was – after review – translated into a journal paper. After review from scientists and the public, the final paper was published in April. 

The paper sets out seven all-new emissions scenarios, replacing the SSPs (and its predecessors, the RCPs). For simplicity, the new scenarios are named according to their levels of greenhouse gas emissions.

The figures below show the emissions (left) and the estimated global temperature changes (right) under the proposed scenarios, from the “low-to-negative” emissions scenario (turquoise) up to a “high-emissions” scenario (brown). 

The greenhouse gas emissions for each of the CMIP7 climate scenarios (left) and the associated estimated average temperature change over 2000-2150 from a 1850-1900 baseline (right) using the FaIR emulator. Source: Adapted from Van Vuuren et al. (2026)
The greenhouse gas emissions for each of the CMIP7 climate scenarios (left) and the associated estimated average temperature change over 2000-2150 from a 1850-1900 baseline (right) using the FaIR emulator. Source: Adapted from Van Vuuren et al. (2026)

(It should be noted that, while the ScenarioMIP paper has been published, there remains an embargo on using the scenario data produced by integrated assessment models – often referred to as IAMs – to publish academic papers, analysis or even social media posts until 1 September this year. Carbon Brief will publish a detailed explainer on the new scenarios once the embargo lifts.)

When compared to the SSPs that came before, the range in future emissions in the new scenarios “will be smaller”, the authors say in the paper:

“On the high-end of the range, the…high emission levels (quantified by SSP5-8.5) have become implausible, based on trends in the costs of renewables, the emergence of climate policy and recent emission trends…At the low end, many…emission trajectories have become inconsistent with observed trends during the 2020-30 period.”

In other words, the combination of technological progress and action on climate change that, to date, remains insufficient, means that scenarios of very high or very low emissions are now not considered plausible. 

Another way of looking at it is that the “range of potential futures has narrowed”, explains Smith, one of the authors on the paper.

If you “draw a fan or plume of potential future emissions that start in 2025”, it lies entirely within the spread of scenarios from a decade ago, he says:

“So you’ve ruled out futures at the high end. You’ve also ruled out futures at the low end – so it’s now not possible to limit warming to 1.5C, at least in the short term or the medium term.” 

This is a mix of “good” and “bad” news, Smith adds. 

“In the latest set of scenarios, the lowest [scenario sees] peaking at about 1.7C, so we’ve also lost that low end, but the good news is we’ve lost the high end…Back in 2010, RCP8.5 wasn’t an implausible future, we’ve now made it an implausible future, because we’ve actually bent the curve [on emissions] enough to eliminate that possibility.”

The new “high” scenario projects warming in 2100 of closer to 3.2C (with a range of 2.5C to 4.3C).

To be clear, this “high” scenario would still come with catastrophic climate impacts, even if the level of warming would remain slightly below what was set out in RCP8.5.

Van Vuuren adds that the world is “now on a trajectory to 2.5-3C of warming”. As a result, “we don’t have any scenario anymore that can reach 1.5C with limited overshoot – we will have a significant overshoot”. 

How is the IPCC involved?

Contrary to Trump’s claims, the common set of future emissions scenarios used by climate scientists are not developed by the IPCC, the UN climate-science body that produces landmark reports about climate change.

Instead, the development process described above is driven by a group of Earth system modelling experts convened by the Coupled Model Intercomparison Project (CMIP).

CMIP – an initiative of another UN body, the World Climate Research Programme – coordinates the work of dozens of climate modelling centres around the world.

Working in six-to-eight year cycles, CMIP asks modelling centres around the world to run a common set of climate-model experiments – simulations that use the same inputs and conditions – that allows for results to be collected together and more easily compared. 

For experiments that explore how the climate might change in the future, modelling centres are instructed to run simulations against a fixed set of future climate scenarios, each with different levels of concentrations of greenhouse gases, aerosols and other drivers of climate change. 

These future emissions scenarios are revisited each time CMIP embarks on a new “phase” of climate-modelling coordination, to reflect advances in scientific understanding and the pace of real-world climate action. 

The group tasked with producing the design of future scenarios, as well as the “input files” for climate models, is the “scenario model intercomparison project”, or ScenarioMIP.

CMIP aligns its work with the schedule of the IPCC, coordinating a new set of model runs for each IPCC assessment cycle. 

For example, the IPCC’s AR5 in 2013 featured climate models from the fifth phase of CMIP (CMIP5), whereas AR6 in 2021 used climate models from CMIP’s sixth phase (CMIP6).

AR7 will feature models from CMIP’s ongoing seventh phase (CMIP7). The first results from CMIP7 model runs are expected later this year. 

The IPCC is consulted during the CMIP process, van Vuuren tells Carbon Brief, but its input is “no different from any other review comment” that the ScenarioMIP team received. 

Thus, while the IPCC relies on model runs coordinated by CMIP in its landmark reports, it does not play a role in designing future emissions scenarios, nor in deciding when they should be retired. 

Dr Robert Vautard, co-chair of IPCC AR7 Working Group I, tells Carbon Brief that the IPCC does not “do or coordinate research”. Its role, he says, is to “synthesise existing knowledge” and produce “regular” reviews of climate-science literature. 

He adds that ScenarioMIP is just one set of scenarios the climate-science body assesses in its reports:

“IPCC assesses all scenarios, or sets of scenarios, that the scientific community produces. IPCC does not produce scenarios. CMIP7 will be [one] set of scenarios assessed by IPCC [for AR7] – but there will be many others.”

India’s first ‘heat lounges’ (Carbon Brief)

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Chennai’s gig workers race against the heat

Aruna Chandrasekhar

Original post

15.05.2026 | 2:50pm

This week, Carbon Brief visits one of India’s first air-conditioned lounges designed to help gig workers deal with extreme heat.

An air-conditioned lounge for gig workers in Chennai’s T Nagar shopping district. Credit: Ishan Tankha / Scorched
An air-conditioned lounge for gig workers in Chennai’s T Nagar shopping district. Credit: Ishan Tankha / Scorched

On a single day in late April, 20 of the world’s hottest cities were all in India.

Chennai was not on the list this time, but is no stranger to high temperatures. In the south-eastern coastal capital of Tamil Nadu, extreme humidity and heat are inescapable facts of life.

“The heat is by no means manageable, but we have no choice but to deal with it,” said Mohammed S, a 29-year-old grocery platform delivery worker, speaking to Carbon Brief. 

Last year, Chennai became India’s first ever city to roll out air-conditioned lounges for millions of gig workers, like Mohammed, navigating India’s increasingly hotter cities. 

Lounge access

In the dense shopping district of T Nagar – recognised as an “urban heat island” – studded with silk sari and jewellery shops, an unassuming oblong container-like structure stands out.

Gig workers leave their slippers outside the lounge. Credit: Ishan Tankha / Scorched
Gig workers leave their slippers outside the lounge. Credit: Ishan Tankha / Scorched

Through the building’s tinted windows, workers wearing synthetic jerseys emblazoned with food delivery app logos are stretched out on wooden benches meant to seat 25 people. 

The lounge has charging points for phones, a water cooler and a unisex toilet. It might not seem like much, but workers tell Carbon Brief that it has made a “huge difference” to their lives – even on a day when the air conditioner stopped working. 

“Before this, life was very difficult,” said Mohammed. He continued:

“We would park our [electric] bikes and try to find a tree to sleep under, stop for tea and tea shop owners would tell us we couldn’t sit there for more than 10 minutes, try to rest in a building’s stairwell and be chased away, then try to find shade under a flyover. Now we can sit in the AC and avoid the worst of the heat.”

Dinesh, 27, said his day starts at dawn before the sun is up, picking up packages from companies in north Chennai – another critical heat hotspot.

For the next seven hours, there is no “off point” or breaks for Dinesh as apps rush deliveries. 

Some of Chennai’s gig workers told Carbon Brief they try to avoid the worst of afternoon temperatures from noon to 3pm, but for many – especially migrant workers – sitting back in the lounge is not a choice they can afford. One of them explained:

“If you don’t have cash to cover your bills or have to send money back home, you head out into the heat for a 12-hour shift and hope for the best.”

Dinesh checks his orders in the gig worker’s lounge. Credit: Ishan Tankha / Scorched
Dinesh checks his orders in the gig worker’s lounge. Credit: Ishan Tankha / Scorched

Feeling ‘gear’

In Chennai, heat might be normalised, but it has its own vocabulary. Speaking to Carbon Brief, the city’s gig workers, auto rickshaw drivers and fish sellers used an all-encompassing term – “gear” – to describe their symptoms, including dizziness, exhaustion and nausea. 

Last summer, researchers offered Delhi’s gig workers a Rs 200 (roughly £2) cash transfer on the first day of a heatwave, to provide them with a means to achieve “real-time” adaptation to heat risk. Workers who received a cash transfer reported fewer heat-related symptoms, according to the study.  

Asked if they would accept similar incentives to stay home on 40C days, workers in the T Nagar lounge expressed disbelief. Dinesh – who also trains technicians on how to repair air conditioners to support his income – told Carbon Brief:

“They [the apps] offer us incentives to go out in the heat when there are fewer riders.” 

Barring a few, none of the dozens of outdoor workers Carbon Brief spoke to had an air conditioner at home or in their hostels, making the lounge the only place they could cool down. 

Declare climate crisis a global public health emergency, experts tell WHO (The Guardian)

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Exclusive: Commission says alert would trigger coordinated international response that could help avoid millions dying

Original article

Anna Bawden Health and social affairs correspondent

Sat 16 May 2026 05.00 BST

The climate crisis should be declared a global public health emergency by the World Health Organization, or millions more people will die unnecessarily, leading international experts have said.

The independent pan-European commission on climate and health, which was convened by the WHO, concluded the climate crisis was such a worldwide threat to health that the WHO should declare it “a public health emergency of international concern” (Pheic).

The international spread of vector-borne disease, such as dengue and chikungunya, as well as the health impacts of extreme weather events, global heating, food insecurity and air pollution make a Pheic necessary, said the commission’s report, which will be presented to European ministers on Sunday before the WHO’s world health assembly starts on Monday.

Pheics are the highest level of health alert. Previous declarations include infectious diseases such as Covid and Mpox. While declaring one would not on its own reverse climate change, it would trigger the kind of coordinated international response that the scale of the health crisis demands but has not yet materialised.

The 11-strong independent commission, which includes former health and climate ministers, said: “Far from being a fading priority or fake news, climate change poses an immediate and long-term threat to health, economic, food, water, environmental, personal, community and national security.”

Andrew Haines and Katrin Jakobsdóttir pose for a photo standing in a London street
Andrew Haines and Katrin Jakobsdóttir, the commission’s chief scientific adviser and chair respectively. Photograph: WHO/Hedinn Halldorsson

In an interview with the Guardian, Katrín Jakobsdóttir, a former prime minister of Iceland who chaired the commission, said: “The climate crisis may not be a pandemic, but it’s still a public health emergency that threatens humanity’s very health and survival. And if we don’t act more quickly and comprehensively, many millions more people could die or face life-changing illness.”

Sir Andrew Haines, a professor of environmental change and public health at the London School of Hygiene & Tropical Medicine, and the commission’s chief scientific adviser, said: “WHO has already recognised that climate change is a major threat to global health. What we’re asking for is a step further.”

He added: “If we carry on emitting at current rates, that will accelerate the risks to health for both current and future generations including: more people suffering and dying from excess heat, floods and infectious diseases, air pollution from wildfires, more preterm births and more food insecurity.”

The commission also urged governments to stop subsidising fossil fuels, which are directly responsible for 600,000 premature deaths a year in Europe alone. The region spends about €444bn (£387bn) a year on subsidies for oil and gas production, the report said. In 12 European countries, fossil fuel subsidies exceeded 10% of national health expenditure in 2023 and in four exceeded the entire health budget, the report observed.

“This is not a sustainable energy policy. It’s really more of a public health failure,” Jakobsdóttir said. “And it’s one that could get a lot worse. New subsidies for fossil fuels as well as countries considering redrilling in the wake of the Iran crisis would be catastrophic for health.

“European governments are subsidising the very industries responsible for their own citizens’ premature deaths. We need health leaders to really step into the climate debate and not just be on the receiving end of it.”

The sun rises over Lindsey oil refinery in North Lincolnshire
The commission urged governments to stop subsidising fossil fuels, which are responsible for 600,000 premature deaths a year in Europe. Photograph: Christopher Furlong/Getty Images

The report also called for measures to tackle disinformation, greater use of national climate health impact assessments, as well as recognition that climate change was also a mental health crisis.

Jakobsdóttir said: “The way to challenge climate scepticism and misinformation is simple: make it personal. Climate change is not happening somewhere else, to someone else, in the future. It is shortening lives in European cities right now. It is filling hospitals. It is driving anxiety and stress and other mental health issues. And the policies that would fix it – clean air, active travel, insulated homes, sustainable food – are exactly the policies that make people healthier and happier today.

“When the health argument and the climate argument are the same argument, it becomes very hard to oppose.”

The report also recommended that countries’ healthcare systems needed to become more resilient to the rapidly changing environment in order to try to adapt as much as possible.

“Every country needs to be aware of where its health facilities are situated, how likely it is to be flooded and how they would deal with an extreme and prolonged heatwave,” Haines said, pointing out that hospitals were often built on floodplains and frequently were not energy efficient.

“Even in the UK, which is a temperate country, we know that many hospitals struggle when it comes to extreme heat,” he added. “Many of the buildings were designed before climate change.”

The healthcare sector accounts for 5% of global emissions worldwide, so needs to prioritise adaptation to become more resilient, the report concluded.

Members of the emergency military unit try to extinguish a wildfire in Ourense province, Spain, in August 2025.
Members of the emergency military unit try to extinguish a wildfire in Ourense province, Spain, in August 2025. Photograph: Pablo Blázquez Domínguez/Getty Images

Responding to the recommendations, Dr Hans Kluge, the WHO’s regional director for Europe, said: “The conflicts in Ukraine and the Middle East have clearly shown what fossil fuel dependency really means – not just higher bills, but strained or broken health systems, disrupted food and fuel supplies and societies under pressure.

“The case for acting on climate now is not just environmental. It is a security argument, a health argument and an economic argument, all at once. And it is a moral imperative.”

Kluge added: “The decisions taken by governments today will determine the disease burden carried by people who are currently in primary school. It now falls to the rest of us to act on their recommendations and protect future generations. I commit to ensuring that climate change is treated as the health emergency it is across the 53 member states of the WHO European region.”

Johan Rockström, the director of the Potsdam Institute for Climate Impact Research, welcomed the report. He said: “The current state of the planet, where we are breaching multiple planetary boundaries, and which manifests itself as public health threats impacting millions of people across the world, provides ample scientific evidence that climate change should be declared a public health emergency of international concern.”

AI Is Changing the Way We Predict the Weather. It’s More Perilous Than We Think (Gizmodo)

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AI forecast models offer some clear benefits over traditional physical models, but they are ill-equipped to handle the increasing volatility of a warming climate.

By Ellyn Lapointe

Published April 27, 2026, 6:00 am ET

Original article

 On November 12, 1970, the Bhola cyclone slammed into the coast of what was then East Pakistan. The storm brought maximum sustained wind speeds of 130 miles per hour (205 kilometers per hour) and a 35-foot (10.5-meter) storm surge, killing an estimated 300,000 to 500,000 people.

Today, the Bhola cyclone remains the deadliest tropical storm on record. But if it had struck a decade later, it might not have been so devastating. Weather forecasting changed dramatically in the 1970s as meteorologists adopted physics-based computer models that improved storm prediction. With the rise of AI, forecasting is evolving again—but this time, experts worry the new models may be less reliable when it comes to predicting unprecedented weather events.

Researchers are calling this the “gray swan” problem. Gray swan weather extremes are physically plausible but so rare that they are poorly represented in training datasets. The trouble is, climate change is leading to more first-of-their-kind weather extremes. Think: the 2021 Pacific Northwest heatwave. This event was so severe that it would have been virtually impossible without climate change.

Physical forecast models can simulate gray swan events like the Pacific Northwest heatwave, though they are labeled extremely rare. They can do that because they are built on the laws of physics. AI models are trained on past weather data, wherein gray swans are practically nonexistent.

“They fail on gray swans,” Pedram Hassanzadeh, an associate professor of geophysical sciences at the University of Chicago, told Gizmodo. He and his colleagues published a study last April that removed all Category 3 through 5 hurricanes from an AI model’s training dataset, then tested it on Category 5 storms. The results showed that AI models cannot accurately forecast previously unseen events, as this would require extrapolation.

“The concern isn’t occasional misses. It’s that AI models can miss silently, producing confident forecasts of unremarkable weather while a record-breaking event is unfolding,” Rose Yu, an associate professor of computer science and engineering at the University of California San Diego, told Gizmodo in an email.

“Other risks matter too,” she said. “AI models can violate conservation laws in subtle ways that don’t show up in standard metrics. When they bust a forecast, diagnosing why is harder. They depend on stable observing systems, which is a real concern given current pressure on satellite programs. And institutionally, if we consolidate around AI too quickly and let physics-based infrastructure atrophy, we lose the redundancy that currently catches AI’s failures.”

The case for AI forecasting

Despite these pitfalls, meteorologists are rapidly adopting AI forecast models, and it’s actually easy to understand why. They’re faster, cheaper, and require far less computational infrastructure than physical models. When it comes to predicting typical weather patterns and events (not gray swans), their accuracy is comparable and improving rapidly.

“The typical rate of progress for most state-of-the-art physical models has been something like a day more accurate per decade, which doesn’t sound like a lot, but that’s consequential,” Andrew Charlton-Perez, a professor of meteorology and head of the School of Mathematical, Physical, and Computational Sciences at the University of Reading, told Gizmodo.

“The rate of accuracy growth for machine learning models has vastly exceeded that,” he said. “They are now competitive, and two-three years ago, they were not even in the same ballpark.”

During the 2025 Atlantic hurricane season, for example, Google DeepMind’s model outperformed nearly every physical model on storm track and intensity. In fact, since 2023, leading AI models such as GraphCast, Pangu-Weather, and the ECMWF’s AIFS have matched or outperformed the best physical models on medium-range forecasting metrics, according to Yu.

AI models are proving especially valuable in parts of the world that lack traditional forecasting resources—regions that are often on the frontlines of climate change. Hassanzadeh co-directed an initiative that provided 38 million farmers across India with AI-based monsoon forecasts, giving them up to four weeks’ advance notice of the rainy season’s onset.

“​​A lot of countries were left behind in that first revolution of weather forecasting, because [traditional] weather forecasting requires a supercomputer, hundreds of millions of dollars, various fields, workforce, and experts,” Hassanzadeh explained. AI models, by comparison, are far more accessible to lower-income countries.

Filling the knowledge gaps

Still, rapidly adopting these models without addressing the risks would be dangerous, especially in parts of the world highly vulnerable to the impacts of climate change. Shruti Nath, a postdoctoral research associate at the University of Oxford, recently co-authored an editorial calling for more rigorous testing of AI forecast models before public agencies widely adopt them.

“There is still a lot of work to be done in understanding the limits of these models, alongside where they could supplement physical models and why,” she told Gizmodo in an email.

Nath’s editorial outlines a framework for testing AI forecast models that would deliberately withhold a designated set of “iconic” extreme events (like the Pacific Northwest heat wave, for example) from the training dataset. These events would be reserved solely for testing in order to assess the models’ ability to extrapolate unprecedented weather extremes, or gray swans.

Actually implementing this AI Retraining Without Iconic Events (AIRWIE) protocol “would require the meteorological community to agree on which high-impact events constitute a rigorous benchmark,” the editorial states. This would be a great undertaking, but Nath believes most researchers agree that there is an urgent need for this kind of testing.

“We need to be a bit more organized, however, in ensuring that proper protocols can be followed and that robust safeguards are put in place and maintained by the community,” Nath said. “This is difficult when things are in such a hype phase and no one wants to miss out on the bandwagon.”

Other researchers, like Hassanzadeh, are developing ways to teach AI forecast models to predict gray swans. He and his colleagues are investigating whether combining AI systems with “relevant sampling” methods—which allow them to generate samples of gray swan events—can improve the models’ ability to extrapolate unprecedented extremes.

Efforts to understand and address the limitations of AI forecasting will be critical, because there’s no turning back now. AI is already reshaping the way we predict the weather, and as the climate becomes increasingly volatile, meteorologists will need every tool in their arsenal to be sharp and reliable. Despite their current limitations, there is much to gain from continuing to push these systems forward and figuring out how to best integrate them with physical forecasting.

“The research agenda is about making AI models physically consistent, well-calibrated, and robust to distribution shift,” Yu said. “Abandoning this approach because of the gray swan problem means giving up the biggest improvement in forecasting in a generation.”

Por que previsões de terremotos falham tanto (BBC/Folha de S.Paulo)

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Nas redes sociais, um autoproclamado ‘previsor’ de terremotos diz que consegue prever grandes tremores, mas especialistas afirmam que é pura sorte

Artigo original (Folha de S.Paulo)

26.mar.2025 às 15h22

Ana Faguy, Christal Hayes e Max Matza

BBC News

Brent Dmitruk se autodenomina um “previsor” de terremotos.

Em meados de outubro, ele disse às suas dezenas de milhares de seguidores nas redes sociais que um terremoto atingiria em breve o ponto mais ocidental da Califórnia, ao sul da pequena cidade costeira de Eureka, nos EUA.

Dois meses depois, um tremor de magnitude 7,3 atingiu o local ao norte da Califórnia–colocando milhões de pessoas sob alerta de tsunami, e aumentando o número de seguidores de Dmitruk, que confiaram nele para prever o próximo abalo sísmico.

“Então, para as pessoas que menosprezam o que eu faço: como vocês podem argumentar que é apenas uma coincidência? É preciso ter muita habilidade para descobrir para onde os terremotos vão”, afirmou ele na véspera do Ano Novo.

A imagem mostra uma torre de alto-falantes em primeiro plano, com três alto-falantes brancos montados em um suporte. Ao fundo, é visível a Ponte Golden Gate, com suas torres vermelhas e cabos suspensos, sobre um corpo d'água. O céu está claro e azul, e a paisagem é montanhosa.
Por que previsões de terremotos falham tanto – Getty Images via BBC

Mas há um problema: os terremotos não podem ser previstos, dizem os cientistas que estudam o fenômeno.

É exatamente essa imprevisibilidade que os torna tão perturbadores. Milhões de pessoas que vivem na costa oeste da América do Norte temem que o “Big One” (que significa “O Grande”) possa acontecer a qualquer momento, alterando paisagens e inúmeras vidas.

A imagem mostra uma estrutura de ponte parcialmente destruída, com um pilar quebrado e carros estacionados nas proximidades. O cenário é de destruição, com destroços de concreto espalhados pelo chão e uma paisagem árida ao fundo.
O terremoto de Northridge, em Los Angeles, que matou 57 pessoas e feriu milhares de outras, em 1994, foi o abalo sísmico mais mortal nos EUA na memória recente – Getty Images via BBC

Lucy Jones, sismóloga que trabalhou para o Serviço Geológico dos EUA (USGS, na sigla em inglês) por mais de três décadas, e é autora de um livro chamado The Big Ones, concentrou grande parte de sua pesquisa nas probabilidades de terremotos e na melhoria da resiliência para resistir a esses eventos cataclísmicos.

Desde que começou a estudar terremotos, Jones conta que sempre houve pessoas querendo uma resposta para quando o “Big One”–que significa coisas diferentes, em regiões diferentes–vai acontecer, e alegando ter desvendado a questão.

“A necessidade humana de criar um padrão diante do perigo é extremamente forte, é uma resposta humana bastante normal ao medo”, diz ela à BBC. “No entanto, isso não tem nenhum poder de previsão.”

Com cerca de 100 mil terremotos registrados no mundo todo a cada ano, de acordo com o USGS, é compreensível que as pessoas queiram ser avisadas.

A região de Eureka, uma cidade costeira a 434 quilômetros ao norte de San Francisco, onde ocorreu o terremoto de dezembro, registrou mais de 700 terremotos somente no último ano–incluindo mais de 10 apenas na última semana, segundo os dados.

A região, onde Dmitruk adivinhou corretamente que haveria um terremoto, é uma das “áreas sismicamente mais ativas” dos EUA, de acordo com o USGS. Sua volatilidade se deve ao encontro de três placas tectônicas, uma área conhecida como Junção Tripla de Mendocino.

É o movimento das placas em relação umas às outras – seja acima, abaixo ou ao lado – que causa o acúmulo de estresse. Quando a tensão é liberada, pode ocorrer um terremoto.

Adivinhar que um tremor aconteceria aqui é uma aposta fácil, diz Jones, embora um terremoto forte, de magnitude sete, seja bastante raro.

O USGS destaca que houve apenas 11 terremotos deste tipo ou mais fortes desde 1900. Cinco deles, incluindo o que Dmitruk promoveu nas redes sociais, ocorreram na mesma região.

Embora o palpite estivesse correto, Jones afirma à BBC que é improvável que qualquer terremoto– inclusive os maiores, que devastam a sociedade–possa ser previsto com precisão.

Segundo ela, há um conjunto complexo e “dinâmico” de fatores geológicos que levam a um terremoto.

A magnitude de um terremoto é provavelmente formada à medida que o evento está ocorrendo, Jones explica, usando o ato de rasgar um pedaço de papel como analogia: o rasgo vai continuar a menos que haja algo que o interrompa ou retarde–como marcas de água que deixam o papel molhado.

Os cientistas sabem por que ocorre um terremoto – movimentos repentinos ao longo de falhas geológicas–, mas prever este evento é algo que, segundo o USGS, não pode ser feito, e algo que “não esperamos descobrir em um futuro próximo”.

A imagem mostra um cenário de destruição urbana, com edifícios em ruínas e escombros visíveis. No fundo, há prédios parcialmente intactos, enquanto a área em primeiro plano exibe paredes de tijolos danificadas e destroços. A cena é em preto e branco, sugerindo um período histórico anterior.
San Francisco ficou em ruínas após o terremoto de 1906 – Getty Images via BBC

A agência observa que pode calcular a probabilidade de terremotos em uma região específica dentro de um determinado número de anos – mas isso é o mais próximo que eles conseguem chegar.

Os registros geológicos mostram que alguns dos terremotos de maiores proporções, conhecidos como “Big Ones” pelos moradores locais, acontecem com certa regularidade. Sabe-se que a zona de subducção de Cascadia desliza a cada 300 a 500 anos, devastando regularmente a costa noroeste do Pacífico com megatsunamis de 30,5 metros de altura.

A falha de San Andreas, no sul da Califórnia, também é fonte de outro potencial “Big One”, com terremotos devastadores ocorrendo a cada 200 a 300 anos. Especialistas afirmam que o “Big One” pode acontecer a qualquer momento em qualquer uma das regiões.

Jones conta que, ao longo de sua carreira, milhares de pessoas a alertaram com previsões de um grande terremoto–inclusive indivíduos na década de 1990, que enviavam faxes para seu escritório na esperança de fazer um alerta.

“Quando você recebe uma previsão toda semana, alguém vai ter sorte, certo?”, diz ela rindo. “Mas isso geralmente subia à cabeça deles, e eles faziam mais 10 previsões que não estavam certas.”

Esta situação parece ter acontecido com Dmitruk, que não tem formação científica. Há muito tempo ele prevê que um terremoto incrivelmente grande atingiria o sudoeste do Alasca, o Japão ou as ilhas da costa da Nova Zelândia, com uma magnitude tão forte que, segundo ele, poderia interromper o comércio global.

O USGS afirma que uma previsão de terremoto precisa ter três elementos definidos – uma data e hora, o local e a magnitude do tremor – para ser útil.

Mas o cronograma de Dmitruk continua mudando.

Em um determinado momento, ele disse que o terremoto ocorreria imediatamente antes ou depois da posse do presidente dos EUA, Donald Trump.

Depois, ele anunciou que aconteceria, sem dúvida, antes de 2030.

Embora esse terremoto de grandes proporções ainda não tenha ocorrido, Dmitruk afirma que ainda acredita que vai acontecer.

“Não acredito que seja apenas por acaso”, diz Dmitruk à BBC. “Não é aleatório ou sorte.”

Este tipo de pensamento é comum quando se trata de terremotos, de acordo com Jones.

“Distribuições aleatórias podem parecer ter padrões, vemos constelações nas estrelas”, ela observa.

“Muita gente tem muito medo de terremoto, e a maneira de lidar com isso é prever [quando] eles vão acontecer.”

Como você pode se preparar diante da incerteza de um terremoto

No entanto, o fato de não ser possível prever quando vai acontecer um terremoto, não significa que você deva estar despreparado, segundo especialistas.

Todos os anos, na terceira quinta-feira de outubro, milhões de americanos participam da maior simulação de terremoto do planeta: The Great Shake Out, que pode ser traduzida como “a grande sacudida”.

O exercício foi criado por um grupo do Centro de Terremotos do Sul da Califórnia, que incluía Jones.

Durante a simulação, as pessoas praticam a orientação de “se abaixar, se cobrir e aguardar”: elas se ajoelham, se protegem sob um objeto resistente, como uma mesa, e se mantêm assim por um minuto.

O exercício se tornou tão popular desde sua criação que se espalhou pela costa propensa a terremotos para outros Estados e países.

Se estiverem ao ar livre, as pessoas são aconselhadas a ir para um espaço aberto longe de árvores, edifícios ou linhas de transmissão de energia. Perto do oceano, os moradores praticam fugir para terrenos mais altos depois que o tremor cessa, para se preparar para a possibilidade de um tsunami.

“Agora, enquanto o solo não está tremendo, enquanto não é uma situação muito estressante, é realmente o melhor momento para praticar”, afirma Brian Terbush, gerente do Programa de Terremotos e Vulcões da Divisão de Gerenciamento de Emergências do Estado de Washington, nos EUA.

Além das simulações, os moradores dos Estados da Costa Oeste americana usam um sistema de alerta telefônico mantido pelo USGS, chamado ShakeAlert.

O sistema funciona por meio da detecção de ondas de pressão emitidas por um terremoto. Embora não possa prever quando um terremoto vai ocorrer em um futuro distante, ele fornece um alerta com segundos de antecedência que podem salvar vidas. É a coisa mais próxima de um “previsor” de terremotos que foi inventada até agora.

Este texto foi publicado inicialmente aqui.

Scientists have a new explanation for the last two years of record heat (Washington Post)

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washingtonpost.com

Shannon Osaka

Feb 16, 2025

For the past few years, scientists have watched, aghast, as global temperatures have surged — with both 2023 and 2024 reachingaround 1.5 degrees Celsius above the preindustrial average. In some ways, that record heat was expected: Scientists predicted that El Niño, combined with decreasing air pollution that cools the earth, would cause temperatures to skyrocket.

But even those factors, scientists say, are not sufficient to explain the world’s recent record heat.

Earth’s overall energy imbalance — the amount of heat the planet is taking in minus the amount of heat it is releasing — also continues to rise, worrying scientists. The energy imbalance drives global warming. If it rises, scientists expect global temperatures to follow.

Two new studies offer a potential explanation: fewer clouds. And the decline in cloud cover, researchers say, could signal the start of a feedback loop that leads to more warming.

“We have added a new piece to the puzzle of where we are headed,” Helge Goessling, a climate physicist at the Alfred Wegener Institute in Germany and the author of one of the studies,saidin a video interview.

For years, scientists have struggled to incorporate clouds’ influence into the large-scale climate models that help them predict the planet’s future. Clouds can affect the climate system in two ways: First, their white surfaces reflect the sun’s light, cooling the planet. But clouds also act as a kind of blanket, reflecting infrared radiation back to the surface of the planet, just like greenhouse gases.

Which factor wins out depends on the type of cloud and its altitude. High, thin cirrus clouds tend to have more of a warming effect on the planet. Low, fluffy cumulus clouds have more of a cooling effect.

“Clouds are a huge lever on the climate system,” said Andrew Gettelman, an affiliate scientist at the University of Colorado at Boulder. “A small change in clouds could be a large change in how we warm the planet.”

Researchers are beginning to pinpoint how clouds are changing as the world warms. In Goessling’s study, published in December in the journal Science, researchers analyzed how clouds have changed over the past decade. They found that low-altitude cloud cover has fallen dramatically — which has also reduced the reflectivity of the planet. The year 2023 — which was 1.48 degrees Celsius above the preindustrial average — had the lowest albedo since 1940.

In short, the Earth is getting darker.

That low albedo, Goessling and his co-authors calculated, contributed 0.2 degrees Celsius of warming to 2023’s record-high temperatures — an amount roughly equivalent to the warming that has so far been unexplained. “This number of about 0.2 degrees fairly well fits this ‘missing warming,’” Goessling said.

Researchers are still unsure exactly what accounts for this decrease. Some believe that it could be due to less air pollution: When particulates are in the air, it can make it easier for water droplets to stick to them and form clouds.

Another possibility, Goessling said, is a feedback loop from warming temperatures. Clouds require moisture to form, and moist stratocumulus clouds sit just underneath a dry layer of air about one mile high. If temperatures warm, hot air from below can disturb that dry layer, mixing with it and making it harder for wet clouds to form.

But those changes are difficult to predict — and not all climate models show the same changes. “It’s really tricky,” Goessling said.

Other scientists have also found decliningcloud cover. In a preprint study presented at a science conference in December, a group of researchers at NASA found that some of the Earth’s cloudiest zones have been shrinking over the past two decades. Three areas of clouds — one that stretches around the Earth’s equator, and two around the stormy midlatitude zones in the Northern and Southern Hemispheres — have narrowed since 2000, decreasing the reflectivity of the Earth and warming the planet.

George Tselioudis, a climate scientist at NASA’s Goddard Institute for Space Studies and the lead author of the preprint, said this decrease in cloud cover can help explain why the Earth’s energy imbalance has been growing over the past two decades. Overall, the cloud cover in these regions is shrinking by about 1.5 percent per decade, he said, warming the Earth.

Tselioudis said that warming could be constraining these cloud-heavy regions — thus heatingthe planet.“We’ve always understood that the cloud feedback is positive — and it very well could be strong,” he said. “This seems to explain a big part of why clouds are changing the way they are.”

If the cloud changes are part of a feedback loop, scientists warn, that could indicate more warming coming, with extreme heat for billions of people around the globe. Every hot year buttresses the idea that some researchers have now embraced, that global temperature rise will reach the high end of what models had predicted. If so, the planet could pass 1.5 degrees Celsius later this decade.

Researchers now say that they are rushing to understand these effects as the planet continues to warm. “We are kind of in crunch time,” Goessling said. “We have a really strong climate signal — and from year to year it’s getting stronger.”

Superfreak pivot: When climate engineering came to South Africa (Daily Maverick)

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Our Burning Planet

Superfreak pivot: When climate engineering came to South Africa

 Illustrative image. Photo by Andy Hutchinson on Unsplash

By Kevin Bloom

22 Jan 2019 

Cooling the earth by blocking out the sun, although potentially disastrous, is now a real answer to climate change. As a Harvard research paper published late last year proved, solar geo-engineering is both technically feasible and relatively cheap. With governments and international bodies considering the technology, a South African university has just announced a study. But how convenient is this answer for our politicians and heavy emitters?

I.Global Hollywood

In his book The Planet Remade: How Geo-engineering Could Change the World, Oliver Morton laid down a potential scenario from the not-too-distant future. As briefings editor at The Economist and former chief news and features editor at the scientific journal Nature, it was a given that this scenario—a thought experiment on the deployment into the stratosphere of “climate engineering” aerosols—would be based more in science fact than science fiction. Which is exactly what made it, like the best work of Robert Heinlein or Charlie Brooker, truly terrifying.

According to a Harvard study published in November 2018, three years after the release of Morton’s book, it would work in practice like this: a fleet of purpose-built aircraft, with disproportionately large wings relative to their fuselages, so as to allow “level flight at an altitude of 20 kilometres while carrying a 25-ton payload,” would inject 0.2 million tons of sulphur dioxide into the lower stratosphere per year—thereby reflecting enough solar radiation back out into space to cut the rate of global warming progressively in half. Pre-launch costs in 2018 values would come in at $3.5 billion, with yearly operating costs at $2.25 billion. Given that in 2017 around 50 nations had military budgets of $3 billion or more, noted the Harvard scientists, the barriers to entry would be remarkably low.

“It is not a large nation that does it—indeed, it is not a single nation’s action at all,” speculated Morton back in 2015. “Sometime in the 2020s, there is a small group of them, two of which are in a position to host the runways. They call themselves the Concert; once they go public, others call them the Affront. None of them is a rich nation, but nor are they among the least developed. All of them already have low carbon-dioxide emissions, and all of them are on pathways to no emissions at all. In climate terms, they look like the good guys. But their low emissions and the esteem of the environmentally conscious part of the international community are doing nothing to reduce the climate-related risks their citizens face.”

So why “truly terrifying”?

Because, as Morton went on to explain, solar geo-engineering—otherwise known as solar radiation management, or SRM—was not (or at least was no longer) a conceptual absurdity. When he wrote his book, its probability of deployment was already based on two of the most urgent existential questions in the history of humanity: 1) Are the risks of climate change great enough to warrant serious action aimed at mitigating them? 2) Will the world’s largest industrial economies be able to lower their carbon emissions to net zero by the middle of the century?

But terrifying more specifically because, by 2018, the answer to the first question was a scientifically unqualified “yes” and to the second a statistically implausible “no”—and yet the effect of SRM on the biosphere was still unknown. With the results from the Harvard study leading to the scheduling of tests as early as the first half of 2019, the Berlin-based climate science and policy institute Climate Analytics wasted no time in recommending a global ban on the technology.

“Solar radiation management aims at limiting temperature increase by deflecting sunlight, mostly through injection of particles into the atmosphere,” the institute noted. “At best, SRM would mask warming temporarily, but more fundamentally is itself a potentially dangerous interference with the climate system.”

SRM, argued the scientists at Climate Analytics, would “alter the global hydrological cycle as well as fundamentally affect global circulation patterns such as monsoons.” It would not “halt, reverse or address in any other way the profound and dangerous problem of ocean acidification which threatens coral reefs and marine life as it does not reduce CO2 emissions and hence influence atmospheric C02 concentration.” Also, the scientists pointed out, the approach was “unlikely to attenuate the effects of global warming on global agricultural production” as its “potentially positive effect due to cooling” was projected to be counterbalanced by “negative effects on crop production of reducing solar radiation at the earth’s surface.”

In other words, according to Climate Analytics, while cooler temperatures would be helpful to the world’s farmers, the crops would still need sunlight to grow. And none of the above even counted as the number one reason that the institute was raising the alarm—SRM’s gravest danger, these scientists and policy experts insisted, was that it would divert attention from the core problem, which remained the unprecedented amount of carbon being spewed daily into the atmosphere by the extraction of coal, crude oil and natural gas.

For Morton, this was the predicament known as the “superfreak pivot”—the turning of large masses of humanity from the position that “global warming requires no emissions reduction because it isn’t a real problem” to the position that “the Concert has it all covered”. It was a predicament highlighted too by Harvard scientist David Keith, who told the Guardian in 2017:

“One of the main concerns I and everyone involved in this have is that Trump might tweet ‘geoengineering solves everything—we don’t have to bother about emissions.’ That would break the slow-moving agreement among many environmental groups that sound research in this field makes sense.”

As for South Africa, less than two months after publication of the seminal Harvard paper of late 2018, a press release was issued by the African Climate and Development Initiative of the University of Cape Town.

“UCT researchers to embark on pioneering study on potential impacts of solar geoengineering in southern Africa,” it stated.

II. Local Hollywood

As the recipient of a grant from the international DECIMALS Fund (Developing Country Impacts Modelling Analysis for SRM), the UCT team cited two reasons for going ahead with the study—and both of them had to do with the social and economic havoc that anthropogenic climate change had so far wrought in our corner of the world. First, the 2015/16 summer rainfall failure over southern Africa, which led to 30 million people becoming food insecure in South Africa, Mozambique, Botswana and Zimbabwe. Second, Cape Town almost running out of water in 2018. If SRM could be done in a safe and reliable manner, so the rationale went, it was “the only known way” to quickly offset the temperature increases that were behind the droughts.

“We want to understand the impact of solar radiation management on drought conditions,” Dr Romaric Odoulami, the project’s leader, told Daily Maverick, “that’s our motivation. What will the implications be for regional agriculture? But I want to make one thing clear: SRM has never been implemented in the real world… and we are not going to do it either.”

What the African Climate and Development Initiative was going to do, said Odoulami, was climate modelling. The project, he added, would run for the next “one or two years”—as soon as he got “something interesting,” he promised, he would let Daily Maverick know. For the moment, he wanted to leave us with this:

“Solar radiation management doesn’t stop climate change. It doesn’t stop global emissions of greenhouse gases. The only thing it does is help to reduce the global temperature by reducing the amount of solar radiation reaching the earth’s surface.”

This caution in the face of the sheer unprecedented scale of the thing was also detectable in the words of Andy Parker, project director of the Solar Radiation Management Governance Initiative, the UK-based organisation—founded in 2010 by, among others, The World Academy of Sciences and the Royal Society—that set up the DECIMALS Fund in 2018. Speaking to Daily Maverick from a conference in Bangladesh, Parker was vague yet morbidly fascinating on the legislative context that could eventually give the green light to SRM.

“That’s really tricky to predict,” he said. “We can imagine various different deployment scenarios. There’s the desperation scenario, where a country or perhaps a coalition of countries that are really suffering from climate change decide that they are going to use solar geo-engineering to stop the temperature from rising. That could be seen as unilateral and illegitimate deployment. At the other end of things, it’s possible that through the United Nations—the UN General Assembly or one of the UN conventions—there’s a much broader coalition that comes together with much more legitimacy to develop a decision-making infrastructure for if we were to ever use this, or indeed, for how we would reject it.

“Really, at this stage, we don’t know what’s going to happen. We don’t know what’s going to happen with the research, we don’t know how governments are going to deal with this, and we don’t know how quickly and how deeply the impacts of climate change are going to bite.”

In South Africa, unfortunately, all indications are that the bite is going to be serious. As Daily Maverick learned from the country’s leading land-based climate scientist in October last year, we are warming at twice the global average. At 3°C of global warming, which is 6°C regionally—and which at current emission rates we are steaming towards, as per the most conservative estimates, before the end of the century—there will be a total collapse of the maize crop and livestock industry. This is something that the Department of Environmental Affairs seems to understand well, as evidenced by their “Third National Communication” under the United Nations Framework Convention on Climate Change, submitted in March 2018.

But the other unknown factor in this general SRM universe of “unknown unknowns” is the person that currently sits atop the DEA. Has Nomvula Mokonyane, who was named at the State Capture inquiry on Monday for allegedly accepting bribes in the form of monthly cash payments, even read the Third National Communication? Does President Cyril Ramaphosa plan on replacing her with someone who will? Aside from Tito Mboweni at treasury, does anyone in the upper echelons of the ANC get the urgency of the situation?

These are the questions that highlight the possibility of South Africa one day performing the superfreak pivot. Because it might not only suit the government to defer to technology when the food and water shortages get real, it might also suit Sasol, the coal mining companies and the country’s heavy emitters at large. DM

Injetar partículas na atmosfera poderia reduzir temporariamente o aquecimento global (Pesquisa Fapesp)

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Polêmica, a liberação de aerossóis diminuiria a quantidade de luz solar que chega à Terra, mas seus efeitos colaterais negativos poderiam ser maiores que os positivos

Aumentar a quantidade de aerossóis na atmosfera poderia barrar a chegada à Terra de uma pequena fração da luz solar e resfriar provisoriamente o planeta. Cadan Cummings / Jacobs / JETS / NASA-JSC

Marcos Pivetta

Atualizado em 6 set 2024

Edição 343, set 2024

Depois de ter permanecido em silêncio por 600 anos, o monte Pinatubo, nas Filipinas, acordou em 1991. Uma série de pequenas explosões ao longo de dois meses culminou em uma grande erupção em meados de junho daquele ano, considerada a segunda maior do século passado. Cerca de 200 mil pessoas tiveram de deixar suas casas e mais de 700 morreram no arquipélago filipino como consequência da eclosão. A explosão produziu uma coluna de fumaça e cinzas vulcânicas que se elevou até 40 quilômetros (km) acima da superfície e invadiu a estratosfera, a segunda das cinco camadas da atmosfera que envolve a Terra. Esse manto de partículas em suspensão, geralmente com tamanhos micrométricos, atrapalhou o tráfego aéreo, queimou plantas e cultivos e produziu outros danos locais.

Apesar de ter causado grandes prejuízos materiais e a perda de vidas humanas nas Filipinas, a erupção do Pinatubo é lembrada hoje no meio científico por ter tido uma consequência surpreendente no clima global: a temperatura média da Terra reduziu-se cerca de 0,5 grau Celsius (°C) nos dois anos seguintes à sua atividade vulcânica. A enorme quantidade de partículas em suspensão, os chamados aerossóis, lançada pelo vulcão entrou no sistema de circulação de ar da estratosfera, espalhou-se pelo planeta e atuou por meses como uma espécie de filtro solar: parte dos raios do Sol que chegariam normalmente à superfície terrestre foi refletida ao incidir sobre essa quantidade extra de partículas de aerossóis injetados no sistema. Essa ação produziu um resfriamento temporário do planeta.

Os aerossóis também resfriam a Terra quando estão na troposfera, a camada mais baixa da atmosfera, mas sua ação é mais intensa na estratosfera. O efeito Pinatubo serve de inspiração para uma linha de pesquisa polêmica, cercada de incertezas científicas e riscos ambientais e geopolíticos: a geoengenharia solar ou modificação da radiação solar (SRM, na sigla derivada do inglês). Ela começou a tomar corpo lentamente nos últimos 20 anos em algumas universidades dos Estados Unidos e da Europa à medida que o aquecimento global se tornou mais pronunciado. A ideia central dessa abordagem é aumentar deliberadamente o albedo da Terra, sobretudo na estratosfera, para que ela passe a refletir mais radiação de volta ao espaço e, assim, torne-se um pouco menos quente.

Glauco Lara

O albedo é a fração da luz refletida em relação à absorvida por um corpo ou superfície. Quanto maior o albedo, como em superfícies claras ou brancas, menor a quantidade de calor absorvida. Injetar aerossóis na atmosfera é uma das formas de tentar aumentar o albedo terrestre. Alguns cálculos indicam que uma redução de 1% a 2% da quantidade de radiação solar que normalmente chega à Terra seria suficiente para diminuir sua temperatura média em um 1 °C.

A possibilidade de reduzir a quantidade de radiação solar sobre a Terra começou a ser aventada ainda na década de 1960. Mas sempre foi vista como uma excentricidade perigosa, quase um devaneio. A ideia só ganhou alguma relevância científica depois da erupção do Pinatubo e, mais recentemente, com a emergência da crise climática, causada pelo aumento significativo da temperatua global decorrente da emissão de gases de efeito estufa. Ainda assim, a pesquisa experimental – que envolveria a soltura de alguns quilos de aerossóis na estratosfera para observar seus eventuais efeitos em âmbito local (não global, como ocorreu na gigantesca erupção do vulcão nas Filipinas) – pouco progrediu até hoje em razão da oposição de parte da comunidade científica e de grupos ambientalistas.

“Até agora, existem poucos trabalhos de modelagem climática envolvendo as técnicas de geoengenharia solar”, comenta o físico Paulo Artaxo, do Instituto de Física da Universidade de São Paulo (IF-USP), especialista no estudo de aerossóis atmosféricos. “Nenhum experimento mais significativo foi feito em campo.” Duas abordagens que visam à modificação da radiação solar dominam as discussões. A principal delas é a injeção de aerossóis na estratosfera, a 15 ou 20 km de altitude, conhecida pela sigla SAI, que tenta reproduzir de forma artificial o que as grandes erupções fazem de maneira natural.

Glauco Lara

A outra, vista como de impacto mais localizado, é o clareamento de nuvens marítimas (marine cloud brightening ou MCB). Ela também envolve a liberação de aerossóis (nesse caso, partículas de sal marinho), que funcionam como núcleos de condensação das nuvens. Mas a soltura dessas partículas ocorre em altitudes bem mais baixas, de no máximo 2 km, ainda na troposfera. Com mais aerossóis, as gotas de nuvens ficam menores, refletem mais radiação solar de volta ao espaço e resfriam a superfície. Há outras técnicas cogitadas, como aumentar o albedo em grandes superfícies brancas do planeta, como o Ártico, mas as duas primeiras propostas dominam o debate.

Artaxo colabora com um grupo da Universidade Harvard, dos Estados Unidos, em estudos de modelagem computacional para tentar entender se o comportamento dos aerossóis na estratosfera é realmente similar à sua ação na troposfera. “Precisamos de mais pesquisas sobre esse tema antes de sequer pensarmos em implementar alguma intervenção desse tipo”, comenta o físico da USP, um dos coordenadores do Programa FAPESP de Pesquisa sobre Mudanças Climáticas Globais. “Não temos condições de garantir que a injeção de mais aerossóis não vá, por exemplo, diminuir as chuvas de monções no Sudeste Asiático e colocar em risco uma população de bilhões de pessoas. Se isso ocorrer, quem decide se essa injeção de aerossóis para ou continua? Esse tipo de decisão não pode ficar na mão de um pequeno grupo de países ou de um bilionário que financie um experimento desse tipo.”

Também há indícios de que uma dose extra de aerossóis na estratosfera poderia afetar a camada de ozônio, que protege a vida terrestre da ação nociva da radiação ultravioleta vinda do Sol. Isso sem falar que essas partículas em suspensão são uma forma de poluição do ar. Elas naturalmente se depositam, descem da estratosfera para a troposfera, onde podem causar ou agravar problemas de saúde, sobretudo os respiratórios. Por ora, essas e outras questões não têm respostas satisfatórias.

A posição do físico da USP é partilhada por muitos colegas. “A modificação da radiação solar é um tema sensível e o IPCC [Painel Intergovernamental sobre Mudanças Climáticas, da ONU]reconhece que ainda há muitas incertezas sobre seus potenciais efeitos”, comenta a matemática Thelma Krug, que foi vice-presidente do painel entre 2015 e 2023 e representou o Brasil em negociações internacionais sobre o clima por uma década. “Pessoalmente, sou a favor da pesquisa na área. Mas é preciso ir passo a passo com os experimentos, ter transparência e estabelecer uma governança para esse processo.”

Erupção do vulcão Pinatubo, em 1991, é considerada a segunda maior do século passadoArlan Naeg / AFP via Getty Images

O tema é tão controverso que alguns pesquisadores são contra até que se faça pesquisa sobre as técnicas de geoengenharia solar. Isso porque elas não têm impacto na redução das emissões de gases de efeito estufa, que causam o aumento da temperatura da Terra. Ainda que se mostrem relativamente seguras e eficientes em esfriar temporariamente a Terra, objetivo que hoje é apenas uma hipótese, técnicas como a SAI seriam, no máximo, paliativas. No fundo, dizem os críticos dessa abordagem, os trabalhos nessa área desviariam recursos e tomariam um tempo que poderia ser mais bem empregado na busca por ações que reduzissem a emissão de gases como dióxido de carbono (CO2) e metano (CH4). “Os estudos sobre geoengenharia solar também poderiam ser usados como a desculpa perfeita para que os grandes produtores de gases de efeito estufa não reduzissem suas emissões”, pondera o climatologista Carlos Nobre, do Instituto de Estudos Avançados (IEA) da USP.

Além de ser encarada como um diversionismo em relação à meta central de zerar as emissões de gases de efeito estufa nas próximas décadas, a adoção das técnicas de SRM poderia tornar o planeta refém desse tipo de intervenção climática por um prazo muito longo e indefinido, de décadas ou séculos. Isso criaria um problema extra: o risco de promover o chamado termination shock. Quando o planeta abandonasse o emprego das técnicas de SRM, a temperatura subiria novamente – só que dessa vez de forma muito mais rápida do que no cenário atual de aquecimento global. Isso tornaria quase impossível a adaptação a essa brusca elevação de temperatura. Qualquer oscilação significativa da temperatura, para cima ou para baixo, em um curto período, representa um desafio adaptativo.

Alguns estudos de modelagem climática têm sugerido cenários preocupantes em simulações de possíveis impactos do emprego de técnicas de geoengenharia solar. Esses trabalhos costumam averiguar que outros efeitos (colaterais) essas técnicas de intervenção no clima poderiam induzir, além da redução temporária da temperatura terrestre. Um dos problemas é que a maioria desses estudos se concentra em possíveis consequências no hemisfério Norte, onde ficam os países mais ricos e vive e trabalha a maior parte dos pesquisadores do clima.

Começam, no entanto, a surgir pesquisas com foco em outras partes do planeta. Trabalho publicado em junho deste ano na revista Environmental Research Climate sugere que a adoção da SAI ao longo deste século alteraria os prováveis impactos do aquecimento global sobre a formação de ciclones extratropicais no hemisfério Sul, como aqueles que se formam com certa regularidade na região Sul do Brasil. A previsão é de que, até o fim deste século, o aumento da temperatura global reduza o número de ciclones gerados nessa parte do globo terrestre, mas aumente a intensidade dos fenômenos produzidos. Ou seja, menos ciclones, mas mais fortes.

Glauco Lara

Quando diferentes regimes de injeção de aerossóis na estratosfera são simulados em três modelos climáticos internacionais até 2100, os resultados sinalizam um aumento na frequência de ciclones, mas uma redução em sua força em relação aos prognósticos obtidos em cenários de aquecimento global sem a adoção de qualquer protocolo da SAI. “Não somos contra nem a favor da geoengenharia solar”, diz a pesquisadora Michelle Reboita, da Universidade Federal de Itajubá (Unifei), de Minas Gerais, coordenadora do estudo. “Precisamos é estudá-la. Ela pode produzir resultados positivos em uma parte do mundo e negativos em outra.”

Há também estudos de simulação que tentam prever os possíveis impactos da SAI sobre a biodiversidade. “Nosso objetivo é entender como a SAI pode afetar as espécies de vertebrados terrestres no cenário das mudanças climáticas”, conta o biólogo brasileiro Andreas Schwarz Meyer, que faz estágio de pós-doutorado na Universidade da Cidade do Cabo, na África do Sul, e coordena um projeto de pesquisa sobre o tema. “Em outras palavras, queremos saber quais seriam as espécies ‘vencedoras’ e ‘perdedoras’ no globo caso o emprego dessas técnicas para diminuir a temperatura do planeta venha a se tornar uma realidade.”

No projeto, que ainda está em andamento, Meyer adota uma abordagem chamada perfis horizontais de biodiversidade, que usa dados climáticos históricos para estimar o intervalo térmico (a temperatura máxima e a mínima) e o grau de umidade em que as espécies ocorrem. A técnica é normalmente usada para estimar o impacto sobre as espécies de diferentes cenários de aquecimento global previstos pelo IPCC ao longo deste século.

“Assim, temos uma ideia de quantas espécies serão expostas a essas mudanças, quando e o quão rapidamente isso poderá ocorrer”, comenta o biólogo. Em 2022, o brasileiro publicou um artigo no periódico científico Philosophical Transactions of the Royal Society B em que simulou os efeitos sobre mais de 30 mil espécies de vertebrados marinhos e terrestres de um cenário particular ao longo deste século: primeiro haveria um aquecimento global superior a 2 °C e, em seguida, ocorreria uma redução de temperatura da Terra de forma artificial, por meio da remoção direta de dióxido de carbono da atmosfera. A retirada do principal gás de efeito estufa é hoje ensaiada por um conjunto de técnicas que, por ora, são muito caras e ineficientes em perseguir esse objetivo.

Trilhas de nuvens criadas no mar pela emissão de partículas de poeira por navios

A conclusão geral do estudo é que a subida e a posterior queda artificial da temperatura terrestre poderiam inviabilizar a sobrevivência de muitas espécies e produziriam danos a essas comunidades décadas após se ter atingido uma hipotética estabilização da temperatura do planeta. Meyer está fazendo um estudo semelhante agora, mas com o emprego da SAI no lugar da remoção direta de carbono.

Os trabalhos de Reboita e Meyer se dão no âmbito de uma iniciativa internacional, a Developing country governance research and evaluation for SRM, ou simplesmente Degrees. Seu objetivo é estimular estudos e formar recursos humanos especializados nas técnicas de modificação da radiação solar em países da África, América Latina e sul da Ásia. A Degrees nasceu na década passada dentro da Academia Mundial de Ciências (TWAS) e posteriormente foi assumida por uma organização não governamental britânica, a homônima Degrees. Ela financia quase 40 projetos. No Brasil, além das pesquisas da meteorologista da Unifei, duas linhas de estudo de professores da Universidade Federal de Santa Catarina (UFSC) passaram a ser apoiadas em julho passado.

Com parceiros no exterior, a equipe do engenheiro Mauricio Uriona, do Departamento de Engenharia de Produção e Sistemas da UFSC, pretende estudar como é a percepção do setor produtivo, do governo e da comunidade científica de três países (Brasil, Índia e África do Sul) sobre os potenciais riscos das técnicas de SRM. “Trabalhamos no passado com o tema da transição energética com uma abordagem de cunho socioeconômico e vimos agora uma boa oportunidade de fazer um estudo semelhante sobre geoengenharia solar”, afirma Uriona.

A socióloga ambiental Julia S. Guivant, do Instituto de Pesquisa em Riscos e Sustentabilidade (Iris), da UFSC, vai estudar como diversos atores-chave do país, como a comunidade científica, reguladores políticos, agricultores e representantes de organizações não governamentais, posicionam-se diante dos desafios de governança da geoengenharia solar. “Não temos uma posição sobre se a SRM deve ser usada ou como seu eventual emprego deve ser governado. Somos a favor das pesquisas e do debate democrático sobre o tema, diante dos problemas para atingir as metas de mitigação e adaptação às mudanças climáticas”, diz a socióloga. Colegas da USP e da Universidade Federal de São Paulo (Unifesp) vão colaborar na pesquisa coordenada por Guivant.

Há preocupação de que a geoengenharia solar possa afetar o regime das chuvas de monções na ÍndiaAmarjeet Kumar Singh / Anadolu Agency via Getty Images

As técnicas de SRM são tão polêmicas e sem qualquer tipo de regulação em acordos internacionais que mesmo grupos de pesquisas de instituições renomadas enfrentam dificuldades extremas de realizar pequenos experimentos de campo. Esses trabalhos não têm o potencial de influenciar o clima global, no máximo produzir ciência para se entender os processos envolvidos, com alguma alteração localmente. Ainda assim, os obstáculos práticos à sua realização são quase intransponíveis.

Em março deste ano, foi abandonado o Stratospheric Controlled Perturbation Experiment (SCoPEx), experimento concebido na década passada pelo grupo do físico-químico Frank Keutsch, da Universidade Harvard. A ideia da iniciativa era usar um balão de alta altitude para injetar 2 quilos de aerossóis (no caso, carbonato de cálcio) cerca de 20 km acima da superfície. “Essa quantidade de partículas é ínfima. Equivale à poluição expelida por um jato comercial durante apenas 1 minuto de voo”, disse Keutsch em entrevista dada em 2021 (ver Pesquisa FAPESP nº 303). O balão do SCoPEx era para ter ganho inicialmente os ares dos Estados Unidos em 2018. Mas isso não ocorreu. Em seguida, sua soltura foi prevista para a Suécia, também sem sucesso. Devido a protestos de ambientalistas e de grupos indígenas, o projeto nunca decolou de fato.

Alguns testes de campo com a técnica de clareamento de nuvens marinhas, uma abordagem menos ambiciosa do que a SAI, têm sido feitos, quase sempre a duras penas e diante de críticas de vários setores da sociedade. Em abril deste ano, um grupo da Universidade de Washington, dos Estados Unidos, usou um tipo de ventilador para espalhar partículas de sal marinho na pista de um navio porta-aviões aposentado que estava estacionado no litoral da cidade de Alameda, na Califórnia. A ideia da iniciativa era apenas ver se as partículas poderiam causar algum mal à saúde. Dois meses mais tarde, o município californiano proibiu esse tipo de experimento em seu território.

Na Austrália, pesquisadores da Southern Cross University e organizações locais tocam desde 2020 um projeto-piloto em que tentam aferir se a técnica de MCB pode ser útil para diminuir o branqueamento de corais na região de Townsville. O objetivo do experimento é averiguar se o método diminuiria localmente a temperatura do oceano no centro da Grande Barreira de Corais. O aquecimento das águas marinhas é a principal causa do branqueamento.

Alterar a capacidade de o Ártico refletir a luz do Sol poderia, em tese, minorar o aquecimento globalsodar99 via Getty Images

A desconfiança dos experimentos de campo deriva, em parte, do surgimento periódico de iniciativas pouco transparentes, geridas às vezes por empresas privadas obscuras. Em 2022, a Make Sunsets, uma startup norte-americana, soltou sem autorização no norte do México dois balões com aerossóis destinados à estratosfera. Pouco depois, o governo mexicano proibiu esse tipo de iniciativa em seu território. Agora, a empresa anunciou que está fazendo esse tipo de experimento nos Estados Unidos, mas os resultados dessas iniciativas são desconhecidos.

Para o físico norte-americano David Keith, da Universidade de Chicago, nos Estados Unidos, o interesse em estimular as pesquisas sobre geoengenharia solar tem aumentado, a despeito das incertezas científicas que cercam o emprego dessas técnicas. “Isso é visível nos principais relatórios internacionais, como os do Programa das Nações Unidas para o Meio Ambiente, do Programa Mundial de Pesquisa do Clima, também da ONU, e de grandes grupos ambientalistas, como Environmental Defense”, comenta Keith, em entrevista por e-mail a Pesquisa FAPESP. “Não há dúvida de que a oposição à investigação enfraqueceu, mas é difícil dizer por quê. Talvez seja por causa do aumento das temperaturas ou porque [acredito que] o mundo esteja fazendo agora esforços substanciais para reduzir as emissões de gases de efeito estufa.”

Keith foi membro do programa de geoengenharia solar de Harvard por 12 anos. Hoje ele é a favor da adoção de uma moratória internacional em experimentos de campo até que a ciência sobre o tema esteja mais bem estabelecida e haja alguma forma de governança internacional. Se esse cenário se materializar algum dia, ele diz que a humanidade deveria considerar a realização de um teste no qual se injetaria por uma década na estratosfera cerca de 10% da quantidade necessária de aerossóis para baixar em 1 °C a temperatura global. Dessa forma, seria possível conferir claramente os efeitos dessa abordagem sem correr muitos riscos.

A operação envolveria transportar cerca de 100 mil toneladas de enxofre por ano para a estratosfera – equivalente a 0,3% da quantidade de poluição por enxofre que chega anualmente à atmosfera – por uma frota de 15 jatinhos capazes de voar em altas altitudes. A operação custaria aproximadamente US$ 500 milhões ao ano. É mais uma ideia polêmica. Para alguns, é possível que a única parte boa da sugestão seja a adoção de uma moratória para esse tipo de experimento.

A reportagem acima foi publicada com o título “Controlando o sol” na edição impressa nº 343, de setembro de 2024.

Artigos científicos
REBOITA, M. S. et al. Response of the Southern Hemisphere extratropical cyclone climatology to climate intervention with stratospheric aerosol injection. Environmental Research: Climate. 20 jun. 2024.
MEYER. A.  L. S. et al. Risks to biodiversity from temperature overshoot pathways. Philosophical Transactions of the Royal Society B. 27 jun. 2022.

Andrew Ng’s new model lets you play around with solar geoengineering to see what would happen (MIT Technology Review)

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technologyreview.com

The climate emulator invites you to explore the controversial climate intervention. I gave it a whirl.

August 23, 2024

James Temple

AI pioneer Andrew Ng has released a simple online tool that allows anyone to tinker with the dials of a solar geoengineering model, exploring what might happen if nations attempt to counteract climate change by spraying reflective particles into the atmosphere.

The concept of solar geoengineering was born from the realization that the planet has cooled in the months following massive volcanic eruptions, including one that occurred in 1991, when Mt. Pinatubo blasted some 20 million tons of sulfur dioxide into the stratosphere. But critics fear that deliberately releasing such materials could harm certain regions of the world, discourage efforts to cut greenhouse-gas emissions, or spark conflicts between nations, among other counterproductive consequences.

The goal of Ng’s emulator, called Planet Parasol, is to invite more people to think about solar geoengineering, explore the potential trade-offs involved in such interventions, and use the results to discuss and debate our options for climate action. The tool, developed in partnership with researchers at Cornell, the University of California, San Diego, and other institutions, also highlights how AI could help advance our understanding of solar geoengineering. 

The current version is bare-bones. It allows users to select different emissions scenarios and various quantities of particles that would be released each year, from 25% of a Pinatubo eruption to 125%. 

Planet Parasol then displays a pair of diverging lines that represent warming levels globally through 2100. One shows the steady rise in temperatures that would occur without solar geoengineering, and the other indicates how much warming could be reduced under your selected scenario. The model can also highlight regional temperature differences on heat maps.

You can also scribble your own rising, falling, or squiggling line representing different levels of intervention across the decades to see what might happen as reflective aerosols are released.

I tried to simulate what’s known as the “termination shock” scenario, exploring how much temperatures would rise if, for some reason, the world had to suddenly halt or cut back on solar geoengineering after using it at high levels. The sudden surge of warming that could occur afterward is often cited as a risk of geoengineering. The model projects that global temperatures would quickly rise over the following years, though they might take several decades to fully rebound to the curve they would have been on if the nations in this simulation hadn’t conducted such an intervention in the first place. 

To be clear, this is an exaggerated scenario, in which I maxed out the warming and the geoengineering. No one is proposing anything like this. I was playing around to see what would happen because, well, that’s what an emulator lets you do.

You can give it a try yourself here. 

Emulators are effectively stripped-down climate models. They’re not as precise, since they don’t simulate as many of the planet’s complex, interconnected processes. But they don’t require nearly as much time and computing power to run.

International negotiators and policymakers often use climate emulators, like En-ROADS, to get a quick, rough sense of the impact that potential rules or commitments on greenhouse-gas emissions could have. 

The Parasol team wanted to develop a similar tool specifically to allow people to evaluate the potential effects of various solar geoengineering scenarios, says Daniele Visioni, a climate scientist focused on solar geoengineering at Cornell, who contributed to Planet Parasol (as well as an earlier emulator).

Climate models are steadily becoming more powerful, simulating more Earth system processes at higher resolutions, and spitting out more and more information as they do. AI is well suited to help draw meaning and understanding from that data. It’s getting ever better at spotting patterns within huge data sets and predicting outcomes based on them.

Ng’s machine-learning group at Stanford has applied AI to a growing list of climate-related subjects. Among other projects, it has developed tools to identify sources of methane emissions, recognize the drivers of deforestation, and forecast the availability of solar energy. Ng also helps oversee the AI for Climate Change bootcamp at the university.

But he says he’s been spending more and more of his time exploring the potential of solar geoengineering (sometimes referred to as solar radiation management, or SRM), given the threat of climate change and the role that AI can play in advancing the research field. 

There are “many things one can do—and that society broadly should work on—to help address climate change, first and foremost decarbonization,” he wrote in an email. “And SRM is where I’m focusing most of my climate-related efforts right now, given that this is one of the places where engineers and researchers can make a big difference (in addition to decarbonization).”

In a 2022 piece, Ng noted that AI could play several important roles in geoengineering research, including “autonomously piloting high-altitude drones” that would disperse reflective particles, modeling effects of geoengineering across specific regions, and optimizing techniques. 

Planet Parasol itself is built on top of another climate emulator, developed by researchers at the University of Leeds and the University of Oxford, that relies on the rules of physics to project global average temperatures under various scenarios. Ng’s team then harnessed machine learning to estimate the local cooling effects that could result from varying levels of solar geoengineering, says Jeremy Irvin, a grad student in his research group at Stanford.

One of the clearest limits of the current version of the tool, however, is that the results look dazzling. In the scenarios I tested, solar geoengineering cleanly cuts off the predicted rise in temperatures over the coming decades, which it may well do. 

That might lead the casual user of such a tool to conclude: Cool, let’s do it!

But even if solar geoengineering does help the world on average, it could still have negative effects, such as harming the protective ozone layer, disturbing regional rainfall patterns, undermining agriculture productivity, and changing the distribution of infectious diseases. 

None of that is incorporated in the results as yet. Plus, a climate emulator isn’t equipped to address deeply complex societal concerns. For instance, does researching such possibilities ease pressure to address the root causes of climate change? Can a tool that works at the scale of the planet ever be managed in a globally equitable way? Planet Parasol won’t be able to answer either of those questions.

Holly Buck, an environmental social scientist at the University at Buffalo and author of After Geoengineering, questioned the broader value of such a tool along similar lines.

In focus groups that she has conducted on the topic of solar geoengineering, she’s found that people easily grok the concept that it can curb warming, even without seeing the results plotted out in a model.

“They want to hear about what can go wrong, the impact on precipitation and extreme weather, who will control it, what it means existentially to fail to deal with the root of the problem, and so on,” she said in an email. “So it is hard to imagine who would actually use this and how.”

Visioni explained that the group did make a point of highlighting major challenges and concerns at the top of the page. He added that they intend to improve the tool over time in ways that will provide a fuller sense of the uncertainties, trade-offs, and regional impacts.

“This is hard, and I struggled a lot with your same observation,” Visioni wrote in an email. “But at the same time … I came to the conclusion it’s worth putting something down and work[ing] to improve it with user feedback, rather than wait until we have the perfect, nuanced version.”

As to the value of the tool, Irvin added that seeing the temperature reduction laid out clearly can make a “stronger, lasting impression.” 

“We are calling for more research to push the science forward about other areas of concern prior to potential implementation, and we hope the tool helps people understand the capabilities of SAI and support future research on it,” he said.

How Close Are the Planet’s Climate Tipping Points? (New York Times)

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Raymond Zhong, Mira Rojanasakul

12 Aug 2024

Right now, every moment of every day, we humans are reconfiguring Earth’s climate bit by bit. Hotter summers and wetter storms. Higher seas and fiercer wildfires. The steady, upward turn of the dial on a host of threats to our homes, our societies and the environment around us.

We might also be changing the climate in an even bigger way.

For the past two decades, scientists have been raising alarms about great systems in the natural world that warming, caused by carbon emissions, might be pushing toward collapse. These systems are so vast that they can stay somewhat in balance even as temperatures rise. But only to a point.

Once we warm the planet beyond certain levels, this balance might be lost, scientists say. The effects would be sweeping and hard to reverse. Not like the turning of a dial, but the flipping of a switch. One that wouldn’t be easily flipped back.

Mass Death of Coral Reefs

When corals go ghostly white, they aren’t necessarily dead, and their reefs aren’t necessarily gone forever. Too much heat in the water causes the corals to expel the symbiotic algae living inside their tissues. If conditions improve, they can survive this bleaching. In time, the reefs can bounce back. As the world gets warmer, though, occasional bleaching is becoming regular bleaching. Mild bleaching is becoming severe bleaching.

Scientists’ latest predictions are grim. Even if humanity moves swiftly to rein in global warming, 70 percent to 90 percent of today’s reef-building corals could die in the coming decades. If we don’t, the toll could be 99 percent or more. A reef can look healthy right up until its corals start bleaching and dying. Eventually, it is a graveyard.

This doesn’t necessarily mean reef-building corals will go extinct. Hardier ones might endure in pockets. But the vibrant ecosystems these creatures support will be unrecognizable. There is no bouncing back anytime soon, not in the places corals live today, not at any scale.

When it might happen: It could already be underway.

Abrupt Thawing of Permafrost

In the ground beneath the world’s cold places, the accumulated remains of long-dead plants and animals contain a lot of carbon, roughly twice the amount that’s currently in the atmosphere. As heat, wildfires and rains thaw and destabilize the frozen ground, microbes get to work, converting this carbon into carbon dioxide and methane. These greenhouse gasses worsen the heat and the fire and the rain, which intensifies the thawing.

Like many of these vast, self-propelling shifts in our climate, permafrost thaw is complicated to predict. Large areas have already come unfrozen, in Western Canada, in Alaska, in Siberia. But how quickly the rest of it might defrost, how much that would add to global warming, how much of the carbon might stay trapped down there because the thawing causes new vegetation to sprout up on top of it — all of that is tricky to pin down.

“Because these things are very uncertain, there’s a bias toward not talking about it or dismissing the possibility, even,” said Tapio Schneider, a climate scientist at the California Institute of Technology. “That, I think, is a mistake,” he said. “It’s still important to explore the risks, even if the probability of occurrence in the near future is relatively small.”

When it might happen: The timing will vary place to place. The effects on global warming could accumulate over a century or more.

Collapse of Greenland Ice

The colossal ice sheets that blanket Earth’s poles aren’t melting the way an ice cube melts. Because of their sheer bigness and geometric complexity, a host of factors shapes how quickly the ice sheds its bulk and adds to the rising oceans. Among these factors, scientists are particularly concerned about ones that could start feeding on themselves, causing the melting to accelerate in a way that would be very hard to stop.

In Greenland, the issue is elevation. As the surface of the ice loses height, more of it sits at a balmier altitude, exposed to warmer air. That makes it melt even faster.

Scientists know, from geological evidence, that large parts of Greenland have been ice-free before. They also know that the consequences of another great melt could reverberate worldwide, affecting ocean currents and rainfall down into the tropics and beyond.

When it might happen: Irreversible melting could begin this century and unfold over hundreds, even thousands, of years.

Breakup of West Antarctic Ice

At the other end of the world from Greenland, the ice of western Antarctica is threatened less by warm air than by warm water.

Many West Antarctic glaciers flow out to sea, which means their undersides are exposed to constant bathing by ocean currents. As the water warms, these floating ice shelves melt and weaken from below, particularly where they sit on the seafloor. Like a dancer holding a difficult pose, the shelf starts to lose its footing. With less floating ice to hold it back, more ice from the continent’s interior would slide into the ocean. Eventually, the ice at the water’s edge might fail to support its own weight and crack into pieces.

The West Antarctic ice sheet has probably collapsed before, in Earth’s deep past. How close today’s ice is to suffering the same fate is something scientists are still trying to figure out.

“If you think about the future of the world’s coastlines, 50 percent of the story is going to be the melt of Antarctica,” said David Holland, a New York University scientist who studies polar regions. And yet, he said, when it comes to understanding how the continent’s ice might break apart, “we are at Day Zero.”

When it might happen: As in Greenland, the ice sheet could begin to recede irreversibly in this century.

Sudden Shift in the West African Monsoon

Around 15,000 years ago, the Sahara started turning green. It began when small shifts in Earth’s orbit caused North Africa to be sunnier each summer. This warmed the land, causing the winds to shift and draw in more moist air from over the Atlantic. The moisture fell as monsoon rain, which fed grasses and filled lakes, some as large as the Caspian Sea. Animals flourished: elephants, giraffes, ancestral cattle. So did humans, as engravings and rock paintings from the era attest. Only about 5,000 years ago did the region transform back into the harsh desert we know today.

Scientists now understand that the Sahara has flipped several times over the ages between arid and humid, between barren and temperate. They are less sure about how, and whether, the West African monsoon might shift or intensify in response to today’s warming. (Despite its name, the region’s monsoon unleashes rain over parts of East Africa as well.)

Whatever happens will matter hugely to an area of the world where many people’s nutrition and livelihoods depend on the skies.

When it might happen: Hard to predict.

Loss of Amazon Rainforest

Besides being home to hundreds of Indigenous communities, millions of animal and plant species and 400 billion trees; besides containing untold numbers of other living things that have yet to be discovered, named and described; and besides storing an abundance of carbon that might otherwise be warming the planet, the Amazon rainforest plays another big role. It is a living, churning, breathing engine of weather.

The combined exhalations of all those trees give rise to clouds fat with moisture. When this moisture falls, it helps keep the region lush and forested.

Now, though, ranchers and farmers are clearing the trees, and global warming is worsening wildfires and droughts. Scientists worry that once too much more of the forest is gone, this rain machine could break down, causing the rest of the forest to wither and degrade into grassy savanna.

By 2050, as much of half of today’s Amazon forest could be at risk of undergoing this kind of degradation, researchers recently estimated.

When it might happen: Will depend on how rapidly people clear, or protect, the remaining forest.

Shutdown of Atlantic Currents

Sweeping across the Atlantic Ocean, from the western coasts of Africa, round through the Caribbean and up toward Europe before heading down again, a colossal loop of seawater sets temperatures and rainfall for a big part of the globe. Saltier, denser water sinks to the ocean depths while fresher, lighter water rises, keeping this conveyor belt turning.

Now, though, Greenland’s melting ice is upsetting this balance by infusing the North Atlantic with immense new flows of freshwater. Scientists fear that if the motor slows too much, it could stall, upending weather patterns for billions of people in Europe and the tropics.

Scientists have already seen signs of a slowdown in these currents, which go by an unwieldy name: the Atlantic Meridional Overturning Circulation, or AMOC. The hard part is predicting when a slowdown might become a shutdown. At the moment, our data and records are just too limited, said Niklas Boers, a climate scientist at the Technical University of Munich and the Potsdam Institute for Climate Impact Research.

Already, though, we know enough to be sure about one thing, Dr. Boers said. “With every gram of additional CO2 in the atmosphere, we are increasing the likelihood of tipping events,” he said. “The longer we wait” to slash emissions, he said, “the farther we go into dangerous territory.”

When it might happen: Very hard to predict.

Methodology

The range of warming levels at which each tipping point might potentially be triggered is from David I. Armstrong McKay et al., Science.

The shaded areas on the maps [see here] show the present-day extent of relevant areas for each natural system. They don’t necessarily indicate precisely where large-scale changes could occur if a tipping point is reached.

Hashtag: Chove em Paris e nas redes chovem memes de abertura morna (Folha de S.Paulo)

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Internautas culpam o prefeito da cidade-luz por não ter encontrado um ‘caciqueux cobraint coral’

26 de julho de 2024

Chove chuva, chove sem parar em Paris. A cerimônia de abertura das Olimpíadas de Paris-2024 está debaixo de chuva desde seu início, às 14h30, horário de Brasília. Isso não impediu, porém, as apresentações, e muito menos os memes. Quem curte de casa esperava imagens avassaladoras do pôr do sol parisiense, enquanto os que estão presencialmente esperavam assistir à cerimônia, secos.

No X (ex-Twitter), entrou para os assuntos mais comentados “cacique cobra coral”, meme de uma fundação que tem como propósito minimizar ou impedir eventos climáticos, como catástrofes ou, no caso de Paris, a chuva. Internautas reclamam que a prefeita esqueceu de contratar a Fundação Cacique Cobra Coral (FCCC).

Galvão Bueno protagonizou um momento “Parasita” ao elogiar a chuva.

Celine Dion entra só depois de um barco afundar?

Paris sob chuva.

‘Cerimônia de abertura poderia ter sido sem chuva, mas não fomos chamados’, diz Fundação Cacique Cobra Coral (Folha de S.Paulo)

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Delegações desfilaram debaixo d’água na abertura das Olimpíadas de Paris

Anahi Martinho

26.jul.2024 às 17h37

Espectadores tomam chuva na cerimônia de abertura das Olimpíadas, em Paris – AFP

São Paulo

Osmar Santos, um dos diretores da Fundação Cacique Cobra Coral, lamentou a chuva intensa que atingiu a cerimônia de abertura das Olimpíadas nesta sexta-feira (26), em Paris.

A fundação, que afirma intervir misticamente no clima, não foi contratada para os Jogos de 2024. Em Tóquio, porém, eles estiveram presentes e asseguraram o tempo firme. Nos Jogos de Londres, em 2012, desviaram uma chuva torrencial que estava prevista para cair bem na hora da cerimônia de abertura.

Segundo Osmar, o evento em si é apenas um detalhe. A entidade só desvia a chuva quando há motivo sério para isso. A equipe conta com cientistas e meterologistas que estudam para onde as chuvas podem ir.

Na ocasião de Londres, a água foi desviada para regiões de Portugal e Espanha que sofriam com queimadas.

“Paris poderia ter sido diferente, mas não fomos chamados e não temos tempo de ficar atrás de quem precisa”, disse Osmar ao F5. Segundo ele, a fundação está com muita demanda e não houve procura do COI neste ano, diferente do que já ocorreu em outras edições das Olimpíadas.

O diretor ainda lamentou o descaso com as mudanças climáticas a nível mundial. “Não é só em Paris, o clima está muito estável em todo o planeta”, afirmou.

97% dos brasileiros percebem mudanças climáticas no dia a dia, aponta Datafolha (Folha de S.Paulo)

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Jéssica Maes

02.julho.2024

Em meio a fenômenos de proporções históricas, como os alagamentos que devastaram o Rio Grande do Sul e a seca que vem causando incêndios florestais recordes no pantanal, 97% dos brasileiros afirmam que percebem no dia a dia que o planeta está passando por mudanças climáticas.

O dado pertence a uma nova pesquisa Datafolha, divulgada nesta segunda-feira (1º), que aponta que apenas 2% dos entrevistados negam a existência das alterações no clima, enquanto 1% não soube responder.

O levantamento foi realizado presencialmente, com 2.457 pessoas de 16 anos ou mais em 130 municípios pelo Brasil, entre os dias 17 e 22 de junho. A margem de erro é de dois pontos percentuais, com taxa de confiança de 95%.

Os resultados mostram que essa percepção quase unânime se repete mesmo considerando diferentes recortes, como gênero, nível de escolaridade e faixa etária —chegando, por exemplo, a 100% de concordância sobre a ocorrência das mudanças climáticas entre os mais jovens, de 16 a 24 anos.

Os índices caem, porém, quando questionados sobre os agentes que provocam essa transformação. São 77% quem acha que as mudanças climáticas são causadas principalmente pelas ações humanas, enquanto 20% defendem que a causa delas é a oscilação natural da temperatura.

Conforme aponta o consenso científico, a crise do clima atual é provocada pelos gases de efeito estufa emitidos pelas atividades humanas, principalmente a queima de combustíveis fósseis e o desmatamento, que aquecem o planeta. Em 2021, uma análise de quase 90 mil artigos científicos mostrou que mais de 99,9% dos pesquisadores do mundo concordam sobre essas causas e efeitos.

Os altos índices gerais de reconhecimento da mudança do clima podem estar relacionados ao aumento da intensidade, frequência e exposição a eventos climáticos extremos. A pesquisa perguntou se nas últimas semanas o lugar onde o entrevistado mora passou por diferentes tipos de fenômenos desta natureza, e 77% disseram que sim.

Entre esses, o número mais expressivo foi o de pessoas que passaram por calor extremo (65%), seguido de chuva intensa ou tempestade (33%), e seca extrema (29%). Enchentes atingiram 20% dos entrevistados e deslizamentos de terra, 7%.

Um quarto dos respondentes (23%) afirmou não ter vivenciado nenhum destes eventos recentemente.

Para Paulo Artaxo, professor de física da USP (Universidade de São Paulo) e membro do IPCC (Painel Intergovernamental sobre Mudanças Climáticas), vinculado à ONU, no mundo inteiro a população está percebendo que o clima mudou para pior, o que é reforçado pela ocorrência de fenômenos extremos.

“As mudanças climáticas se dão em dois níveis. Primeiro, um lento e gradual: degradação ambiental com o aumento lento da temperatura, redução ou aumento lento da precipitação, o aumento do nível do mar que afeta as áreas costeiras e assim por diante”, explica.

“Um segundo componente é a intensificação dos eventos climáticos extremos, que cada vez mais se tornam muito perceptíveis para a população em geral, causando enormes danos na saúde, na economia e na sociedade em geral”.

Marcio Astrini, secretário-executivo do Observatório do Clima, que reúne mais de uma centena de organizações ambientais, concorda.

“As pessoas não precisam mais procurar um relatório científico para se informar. Elas abrem a janela de casa, ligam a televisão e as mudanças climáticas estão acontecendo —não são mais uma previsão, são o presente”, diz. “Isso, obviamente, faz com que as pessoas tenham mais capacidade de compreender o que está acontecendo”.

O Datafolha mostra que a escolaridade é um fator que impacta a percepção dos brasileiros sobre o clima. Entre pessoas com educação de nível fundamental, 67% acreditam que as mudanças climáticas são causadas pela humanidade, 26% dizem que elas fazem parte da natureza e 4%, que não existem, Entre aquelas com ensino superior, os números são, respectivamente, 87%, 13% e 1%.

Astrini afirma que os resultados estão relacionados à falta de acesso à informação qualificada e à abundância de fake news disseminadas sobre o tema.

“Nós vivemos em um mundo em que existe desinformação em larga escala e alguns setores são alvos preferenciais de quem provoca a desinformação. O meio ambiente é um deles”, diz. “Em meio ambiente há muito, muito tempo, a gente enfrenta um verdadeiro batalhão —que vem enfraquecendo, mas ainda existe— de negacionismo, de desinformação”.

Também é entre os que passaram menos tempo na educação formal que está a taxa mais alta de descrença nas previsões da ciência sobre as consequências do aquecimento global. Daqueles que estudaram até o ensino fundamental, 43% dizem acreditar que cientistas e ambientalistas exageram sobre os impactos das mudanças climáticas, enquanto na população geral o índice é de 31%.

O nível mais alto de confiança nos especialistas está entre os mais jovens, com 77% dos que têm entre 16 e 24 anos afirmando que não há exagero a respeito do tema; 21% dizem o contrário.

Já entre aqueles com 60 anos ou mais o patamar de descrença está acima da média nacional, com mais de um terço (36%) concordando com a afirmação de que cientistas e ambientalistas exageram ao tratar dos impactos da crise do clima.

“É esperado que os mais jovens e os com mais acesso à informação mostrem maior concordância com as avaliações científicas. Os mais velhos têm a memória de condições mais estáveis e se formaram em um ambiente onde o tema não estava tão difundido, estudado ou documentado”, avalia Mercedes Bustamante, professora do departamento de ecologia da UnB (Universidade de Brasília).

Cruzando os dados da pesquisa, é possível notar, ainda, que aqueles que relatam não terem vivenciado um evento climático extremo no local onde moram são mais propensos a duvidar do parecer científico sobre os impactos do aquecimento global. Neste grupo, 36% das pessoas acham que os especialistas exageram, 61% acham que não e 3% não souberam responder.

A taxa de descrédito cai para 29% entre aqueles que passaram por alguma situação climática extrema recentemente, enquanto 69% deste estrato acha que não há exagero e 2% não soube responder.

Mais da metade dos brasileiros diz que crise do clima representa ameaça imediata, mostra Datafolha (Folha de S.Paulo)

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Jéssica Maes

02.julho.2024

Mais da metade (52%) dos brasileiros acha que as mudanças climáticas são um risco imediato para a população do planeta, enquanto 43% opinam que elas só representarão perigo para quem viverá daqui a muitos anos. Apenas 5% dizem que a crise do clima não representa risco algum.

Os números são da pesquisa Datafolha divulgada nesta segunda-feira (1º), que trata das percepções e opiniões sobre as alterações no clima. O levantamento ouviu 2.457 pessoas de 16 anos ou mais em 130 municípios pelo Brasil, entre os dias 17 e 22 de junho. A margem de erro é de dois pontos percentuais, com taxa de confiança de 95%.

“O percentual de brasileiros que compreende a mudança climática é elevado em comparação a outros países (por exemplo, os Estados Unidos)”, analisa Mercedes Bustamante, professora do departamento de Ecologia da Universidade de Brasília. Ela se refere a outros dados da pesquisa, que mostram que 77% das pessoas dizem acreditar que as mudanças climáticas são provocadas principalmente pelas atividades humanas.

A pesquisadora pondera, porém, que é interessante comparar esses índices com a divisão que aparece quando os entrevistados são questionados sobre os efeitos do aquecimento global. “Isso talvez seja uma indicação [de que há uma] percepção da existência do problema, mas ainda não [percebe-se] como seus mais variados efeitos já estão no dia a dia.”

Estudos mostram que o planeta já aqueceu mais de 1,2°C desde o período pré-industrial (1850-1900), que marca o grande aumento na emissão de carbono pela humanidade, e que fenômenos climáticos extremos, como tempestades e ondas de calor, já estão mais intensos e frequentes.

O Datafolha aponta ainda que, para 58% dos entrevistados, a humanidade não conseguirá agir para reverter os impactos das mudanças climáticas. Menos de um terço da população (31%) acha que será possível retornar a um clima mais ameno, enquanto 7% dizem que isso não faz diferença para a humanidade e o planeta.

O patamar de descrença na capacidade da humanidade de reverter as mudanças climáticas varia de acordo com a escolaridade, sendo mais alto entre aqueles que têm ensino de nível médio (60%). No estrato da população com ensino superior, 36% acreditam na possibilidade dos humanos conseguirem frear a crise climática.

Apesar disso, a pesquisa mostra que a disposição dos próprios brasileiros para mudar atitudes que têm o poder de potencializar o aquecimento global é alta.

Quase a totalidade diz que concordaria em adotar atitudes simples, como trocar as lâmpadas de casa por modelos mais econômicos (99%) e reduzir o uso de plástico (94%), e os índices de aceitação são altos mesmo diante de uma atitude custosa, como colocar paineis solares em casa (89%) e pagar mais caro por produtos com baixa emissão de carbono (74%) ou para ter um carro elétrico (63%).

Para especialistas, o que pode parecer uma contradição pode ser, na verdade, apenas desesperança com a inação de governantes e grandes corporações –que são os maiores culpados pelas emissões de gases de efeito estufa e, portanto, os principais responsáveis por reduzi-las.

“A ciência mostra caminhos para a resolução da mudança do clima. No entanto, creio que a percepção de que não haverá reversão indica a avaliação da morosidade ou mesmo falta de ações políticas concretas e robustas para abordar as soluções”, afirma Bustamante.

“A falta de ação das indústrias do petróleo e dos governos que são associados a elas, que financiam uma enorme quantidade de governos no mundo todo, está fazendo com que o planeta esteja indo por uma trajetória de aumento de temperatura médio da ordem de 3°C”, afirma o físico Paulo Artaxo, pesquisador da USP.

“Isto pode comprometer muito a qualidade de vida das próximas gerações, e isso não é para o final do século, já é para as próximas décadas”, acrescenta ele.

Para Marcio Astrini, secretário-executivo do Observatório do Clima, rede que reúne mais de uma centena de organizações ambientais, o impacto dessa desesperança da população em reverter as mudanças climáticas pode ter um efeito nocivo, de diminuir esforços nesse sentido.

“Quando o ser humano pensa, ‘olha, já que não tem jeito, então para que que eu vou me esforçar? Para resolver algo que não tem solução?’. Isso, inclusive, se reflete no voto, na escolha dos governantes que vão gerenciar a máquina estatal, que é quem vai resolver o problema”, explica.

“Isso desencadeia um problema em cima do outro, porque é uma imobilização. E quanto mais passa o tempo, mais estreita vai ficar a janela para termos alguma esperança de solução”, diz Astrini.

Análise: Fatalismo domina percepção sobre mudança climática (Folha de S.Paulo)

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Marcelo Leite

02.julho.2024

Talvez o fator mais determinante para essa opinião unânime decorra da repetição de eventos extremos, como secas incendiárias, ondas de calor mortíferas e tempestades avassaladoras. Em 2020 o fogo já devastara o pantanal, e o Sul fora açoitado por sucessivas chuvas torrenciais no segundo semestre de 2023.

Com a reincidência e o porte desses desastres, muita gente passou a ter experiência direta com flagelos. Ao Datafolha, 65% relataram ter enfrentado calor extremo, assim como 33% apontaram chuva intensa ou tempestade e 29%, seca extrema. Só um quarto (23%) afirmou não ter vivido nenhum desses eventos.

Eram favas contadas que a maioria dos 2.457 brasileiros entrevistados pelo Datafolha, de 17 a 22 de junho, acusaria os golpes seguidos do aquecimento global, diante da avalanche de imagens dantescas a cada noite na TV. Poucos ainda negam a mudança climática, mas isso não significa que o negacionismo morreu.

Só 77% dos ouvidos atribuem as alterações aos gases do efeito estufa produzidos pela atividade humana, como a queima de combustíveis fósseis (derivados de petróleo, carvão e gás natural), o desmatamento e a agropecuária. Um contingente expressivo de 20% prefere enxergar causas naturais para a crise.

Menos gente ainda, 53%, diz acreditar que o fim da normalidade seja um risco imediato para a população da Terra. Outros 43% afirmam que o impacto afetará apenas as gerações futuras.

Quase um terço dos entrevistados (31%) avalia haver exagero de pesquisadores e ambientalistas quanto a impactos da mudança climática. Esse grupo de céticos alcança 43% entre pessoas que têm nível fundamental de escolaridade.

O dado da pesquisa que causa mais alarme aponta um excesso de fatalismo: 58% dos brasileiros opinam que a humanidade será incapaz de reverter a crise do clima. Meros 31% consideram possível manter o clima sob relativo controle, e 7% dizem que não faz diferença para a humanidade ou a natureza.

Esses bolsões remanescentes de ceticismo climático refletem o sucesso parcial da propaganda negacionista em sua tática de semear dúvidas múltiplas e variadas. Quando se torna impossível contradizer a existência do aquecimento global, dado o acúmulo de evidências e medições, lança-se suspeita sobre a contribuição humana para o fenômeno.

No mesmo diapasão, argumenta-se que a sociedade humana não tem meios para contra-arrestar fenômenos em escala planetária. Em paralelo, assegura-se que os impactos não serão tão graves assim, quem sabe até benéficos.

E pensar que há supostos cientistas dispostos a propagar tais fake news, em realidade pesquisadores argentários, aposentados ou desacreditados. Essa traição à ciência tem consequências, porém.

Embora tenha muito a perder com o desvario climático, a banda atrasada do agronegócio aplaude os mercadores de dúvidas e ajuda a eleger parlamentares, sobretudo no centrão, que tanto retrocesso impuseram à pauta ambiental no governo Bolsonaro (PL) e ainda dão suas mordidas sob a ambivalência de Lula (PT).

The Weather Man (Stanford Magazine)

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Daniel Swain studies extreme floods. And droughts. And wildfires. Then he explains them to the rest of us.

February 6, 2024

    

An illustration of Daniel Swain walking through the mountains and clouds.

By Tracie White

Illustrations by Tim O’Brien

7:00 a.m., 45 degrees F

The moment Daniel Swain wakes up, he gets whipped about by hurricane-force winds. “A Category 5, literally overnight, hits Acapulco,” says the 34-year-old climate scientist and self-described weather geek, who gets battered daily by the onslaught of catastrophic weather headlines: wildfires, megafloods, haboobs (an intense dust storm), atmospheric rivers, bomb cyclones. Everyone’s asking: Did climate change cause these disasters? And, more and more, they want Swain to answer.

Swain, PhD ’16, rolls over in bed in Boulder, Colo., and checks his cell phone for emails. Then, retainer still in his mouth, he calls back the first reporter of the day. It’s October 25, and Isabella Kwai at the New York Times wants to know whether climate change is responsible for the record-breaking speed and ferocity of Hurricane Otis, which rapidly intensified and made landfall in Acapulco as the eastern Pacific’s strongest hurricane on record. It caught everyone off guard. Swain posted on X (formerly known as Twitter) just hours before the storm hit: “A tropical cyclone undergoing explosive intensification unexpectedly on final approach to a major urban area . . . is up there on list of nightmare weather scenarios becoming more likely in a warming #climate.”

Swain is simultaneously 1,600 miles away from the tempest and at the eye of the storm. His ability to explain science to the masses—think the Carl Sagan of weather—has made him one of the media’s go-to climate experts. He’s a staff research scientist at UCLA’s Institute of the Environment and Sustainability who spends more than 1,100 hours each year on public-facing climate and weather communication, explaining whether (often, yes) and how climate change is raising the number and exacer­bating the viciousness of weather disasters. “I’m a physical scientist, but I not only study how the physics and thermo­dynamics of weather evolve but how they affect people,” says Swain. “I lead investigations into how extreme events like floods and droughts and wildfires are changing in a warming climate, and what we might do about it.”

He translates that science to everyday people, even as the number of weather-disaster headlines grows each year. “To be quite honest, it’s nerve-racking,” says Swain. “There’s such a demand. But there’s a climate emergency, and we need climate scientists to talk to the world about it.”

No bells, no whistles. No fancy clothes, makeup, or vitriolic speech. Sometimes he doesn’t even shave for the camera. Just a calm, matter-of-fact voice talking about science on the radio, online, on TV. In 2023, he gave nearly 300 media interviews—sometimes at midnight or in his car. The New York Times, CNN, and BBC keep him on speed dial. Social media is Swain’s home base. His Weather West blog reaches millions. His weekly Weather West “office hours” on YouTube are public and interactive, doubling as de facto press conferences. His tweets reach 40 million people per year. “I don’t think that he appreciates fully how influential he is of the public understanding of weather events, certainly in California but increasingly around the world,” says Stanford professor of earth system science Noah Diffenbaugh, ’96, MS ’97, Swain’s doctoral adviser and mentor. “He’s such a recognizable presence in newspapers and radio and television. Daniel’s the only climate scientist I know who’s been able to do that.”

Illustration of Daniel Swain's reflection in a puddle.

There’s no established job description for climate communicator—what Swain calls himself—and no traditional source of funding. He’s not particularly a high-energy person, nor is he naturally gregarious; in fact, he has a chronic medical condition that often saps his energy. But his work is needed, he says. “Climate change is an increasingly big part of what’s driving weather extremes today,” Swain says. “I connect the dots between the two. There’s a lot of misunderstanding about how a warming climate affects day-to-day variations in weather, but my goal is to push public perception toward what the science actually says.” So when reporters call him, he does his best to call them back. 

Decoration

7:30 a.m., winds at 5 mph from the east northeast

Swain finishes the phone call with the Times reporter and schedules a Zoom interview with Reuters for noon. Then he brushes his teeth. He’s used to a barrage of requests when there’s a catastrophic weather event. Take August 2020, when, over three days, California experienced 14,000 lightning strikes from “dry” thunderstorms. More than 650 reported wildfires followed, eventually turning the skies over San Francisco a dystopian orange. “In a matter of weeks, I did more than 100 interviews with television, radio, and newspaper outlets, and walked a social media audience of millions through the disaster unfolding in their own backyards,” he wrote in a recent essay for Nature.

Swain’s desire to understand the physics of weather stretches back to his preschool years. In 1993, his family moved from San Francisco across the Golden Gate Bridge to San Rafael, and the 4-year-old found himself wondering where all that Bay City fog had gone. Two years later, Swain spent the first big storm of his life under his parents’ bed. He lay listening to screeching 100 mile-per-hour winds around his family’s home, perched on a ridge east of Mount Tamalpais. But he was more excited than scared. The huge winter storm of 1995 that blew northward from San Francisco and destroyed the historic Conservatory of Flowers just got 6-year-old Swain wired.

‘Climate change is an increasingly big part of what’s driving weather extremes today. I connect the dots between the two.’

“To this day, it’s the strongest winds I’ve ever experienced,” he says. “It sent a wind tunnel through our house.” It broke windows. Shards of glass embedded in one of his little brother’s stuffies, which was sitting in an empty bedroom. “I remember being fascinated,” he says. So naturally, when he got a little older, he put a weather station on top of that house. And then, in high school, he launched his Weather West blog. “It was read by about 10 people,” Swain says, laughing. “I was a weather geek. It didn’t exactly make me popular.” Two decades, 550 posts, and 2 million readers later, well, who’s popular now?

Swain graduated from UC Davis with a bachelor’s degree in atmospheric science. He knew then that something big was happening on the weather front, and he wanted to understand how climate change was influencing the daily forecast. So at Stanford, he studied earth system science and set about using physics to understand the causes of changing North Pacific climate extremes. “From the beginning, Daniel had a clear sense of wanting to show how climate change was affecting the weather conditions that matter for people,” says Diffenbaugh. “A lot of that is extreme weather.” Swain focused on the causes of persistent patterns in the atmosphere—long periods of drought or exceptionally rainy winters—and how climate change might be exacerbating them.

The first extreme weather event he studied was the record-setting California drought that began in 2012. He caught the attention of both the media and the scientific community after he coined the term Ridiculously Resilient Ridge, referring to a persistent ridge of high pressure caused by unusual oceanic warmth in the western tropical Pacific Ocean. That ridge was blocking weather fronts from bringing rain into California. The term was initially tongue-in-cheek. Today the Ridiculously Resilient Ridge (aka RRR or Triple R) has a Wikipedia page.

“One day, I was sitting in my car, waiting to pick up one of my kids, reading the news on my phone,” says Diffenbaugh. “And I saw this article in the Economist about the drought. It mentioned this Ridiculously Resilient Ridge. I thought, ‘Oh, wow, that’s interesting. That’s quite a branding success.’ I click on the page and there’s a picture of Daniel Swain.”

Diffenbaugh recommended that Swain write a scientific paper about the Ridiculously Resilient Ridge, and Swain did, in 2014. By then, the phrase was all over the internet. “Journalists started calling while I was still at Stanford,” says Swain. “I gave into it initially, and the demand just kept growing from there.”

Decoration

11:45 a.m., precipitation 0 inches

Swain’s long, lanky frame is seated ramrod straight in front of his computer screen, scrolling for the latest updates about Hurricane Otis. At noon, he signs in to Zoom and starts answering questions again.

Reuters: “Hurricane Otis wasn’t in the forecast until about six to 10 hours before it occurred. What would you say were the factors that played into its fierce intensification?”

Swain: “Tropical cyclones, or hurricanes, require a few different ingredients. I think the most unusual one was the warmth of water temperature in the Pacific Ocean off the west coast of Mexico. It’s much higher than usual. This provided a lot of extra potential intensity to this storm. We expect to see increases in intensification of storms like this in a warming climate.”

Swain’s dog, Luna, bored by the topic, snores softly. She’s asleep just behind him, next to a bookshelf filled with weather disaster titles: The Terror by Dan Simmons; The Water Will Come by Jeff Goodell; Fire Weather by John Vaillant. And the deceptively hopeful-sounding Paradise by Lizzie Johnson, which tells the story of the 2018 Camp Fire that burned the town of Paradise, Calif., to the ground. Swain was interviewed by Johnson for the book. The day of the fire, he found himself glued to the comment section of his blog, warning anyone who asked about evacuation to get out.

“During the Camp Fire, people were commenting, ‘I’m afraid. What should we do? Do we stay or do we go?’ Literally life or death,” he says. He wrote them back: “There is a huge fire coming toward you very fast. Leave now.” As they fled, they sent him progressively more horrifying images of burning homes and trees like huge, flaming matchsticks. “This makes me extremely uncomfortable—that I was their best bet for help,” says Swain.

Swain doesn’t socialize much. He doesn’t have time. His world revolves around his home life, his work, and taking care of his health. He has posted online about his chronic health condition, Ehlers-Danlos syndrome, a heritable connective tissue disease that, for him, results in fatigue, gastrointestinal problems, and injuries—he can partially dislocate a wrist mopping the kitchen floor. He works to keep his health condition under control when he has down time, traveling to specialists in Utah, taking medications and supplements, and being cautious about any physical activity. When he hikes in the Colorado Rocky Mountains, he’s careful and tries to keep his wobbly ankles from giving out. Doctors don’t have a full understanding of EDS. So, Swain researches his illness himself, much like he does climate science, constantly looking for and sifting through new data, analyzing it, and sometimes sharing what he discovers online with the public. “If it’s this difficult to parse even as a professional scientist and science communicator, I can only imagine how challenging this task is for most other folks struggling with complex/chronic illnesses,” he wrote on Twitter. 

‘“There is a huge fire coming toward you very fast. Leave now.” This makes me extremely uncomfortable—that I was their best bet for help. ’

It helps if he can exert some control over his own schedule to minimize fatigue. The virtual world has helped him do that. He mostly works from a small, extra bedroom in an aging rental home perched at an elevation of 5,400 feet in Boulder, where he lives with his partner, Jilmarie Stephens, a research scientist at the University of Colorado Boulder.

When Swain was hired at UCLA in 2018, Peter Kareiva, the then director of the Institute of the Environment and Sustainability, supported a nontraditional career path that would allow Swain to split his time between research and climate communication, with the proviso that he find grants to fund much of his work. That same year, Swain was invited to join a group at the National Center for Atmospheric Research (NCAR) located in Boulder, which has two labs located at the base of the Rocky Mountains. 

“Daniel had a very clear vision about how he wanted to contribute to science and the world, using social media and his website,” says Kareiva, a research professor at UCLA. “We will not solve climate change without a movement, and communication and social media are key to that. Most science papers are never even read. What we do as scientists only matters if it has an impact on the world. We need at least 100 more Daniels.”

And yet financial support for this type of work is never assured. In a recent essay in Nature, Swain writes about what he says is a desperate need for more institutions to fund climate communication by scientists. “Having a foot firmly planted in both research and public-engagement worlds has been crucial,” he writes. “Even as I write this, it’s unclear whether there will be funding to extend my present role beyond the next six months.”

Decoration

4:00 p.m., 67 degrees F

“Ready?” says the NBC reporter on the computer screen. “Can we just have you count to 10, please?”

“Yep. One, two, three, four, five, six, seven, eight, nine, 10,” Swain says.

“Walk me through in a really concise way why we saw this tropical storm, literally overnight, turn into a Category 5 hurricane, when it comes to climate change,” the reporter says.

“So, as the Earth warms, not only does the atmosphere warm or air temperatures increase, but the oceans are warming as well. And because warm tropical oceans are hurricane fuel, the maximum potential intensity of hurricanes is set by how warm the oceans are,” Swain says.

An hour later, Swain lets Luna out and prepares for the second half of his day: He’ll spend the next five hours on a paper for a science journal. It’s a review of research on weather whiplash in California—the phenomenon of rapid swings between extremes, such as the 2023 floods that came on the heels of a severe drought. Using atmospheric modeling, Swain predicted in a 2018 Nature Climate Change study that there would be a 25 percent to 100 percent increase in extreme dry-to-wet precipitation events in the years ahead. Recent weather events support that hypothesis, and Swain’s follow-up research analyzes the ways those events are seriously stressing California’s water storage and flood control infrastructure.

“What’s remarkable about this summer is that the record-shattering heat has occurred not only over land but also in the oceans,” Swain explained in an interview with Katie Couric on YouTube in August, “like the hot tub [temperature] water in certain parts of the shallow coastal regions off the Gulf of Mexico.” In a warming climate, the atmosphere acts as a kitchen sponge, he explains later. It soaks up water but also wrings it out. The more rapid the evaporation, the more intense the 
precipitation. When it rains, there are heavier downpours and more extreme flood events.

‘What we do as scientists only matters if it has an impact on the world. We need at least 100 more Daniels.’

“It really comes down to thermo­dynamics,” he says. The increasing temperatures caused by greenhouse gases lead to more droughts, but they also cause more intense precipitation. The atmosphere is thirstier, so it takes more water from the land and from plants. The sponge holds more water vapor. That’s why California is experiencing these wild alternations, he says, from extremely dry to extremely wet. “It explains the role climate change plays in turning a tropical storm overnight into hurricane forces,” he says.

Decoration

October 26, expected high of 45 degrees F

In 2023, things got “ludicrously crazy” for both Swain and the world. It was the hottest year in recorded history. Summer temperatures broke records worldwide. The National Oceanic and Atmospheric Administration reported 28 confirmed weather/climate disaster events with losses exceeding $1 billion—among them a drought, four flooding events, 19 severe storm events, two tropical cyclones, and a killer wildfire. Overall, catastrophic weather events resulted in the deaths of 492 people in the United States. “Next year may well be worse than that,” Swain says. “It’s mind-blowing when you think about that.” 

“There have always been floods and wildfires, hurricanes and storms,” Swain continues. “It’s just that now, climate change plays a role in most weather disasters”—pumped-up storms, more intense and longer droughts and wildfire seasons, and heavier rains and flooding. It also plays a role in our ability to manage those disasters, Swain says. In a 2023 paper he published in Communications Earth & Environment, for example, he provides evidence that climate change is shifting the ideal timing of prescribed burns (which help mitigate wildfire risk) from spring and autumn to winter.

The day after Hurricane Otis strikes, Swain’s schedule has calmed down, so he takes time to make the short drive from his home up to the NCAR Mesa Lab, situated in a majestic spot where the Rocky Mountains meet the plains. Sometimes he’ll sit in his Hyundai in the parking lot, looking out his windshield at the movements of the clouds while doing media interviews on his cell phone. Today he scrolls through weather news updates on the aftermath of Hurricane Otis, keeping informed for the next interview that pops up, or his next blog post. In total, 52 people will be reported dead due to the disaster. The hurricane destroyed homes and hotels, high-rises and hospitals. Swain’s name will appear in at least a dozen stories on Hurricane Otis, including one by David Wallace-Wells, an opinion writer for the New York Times, columnist for the New York Times Magazine, and bestselling author of The Uninhabitable Earth: Life After Warming. “It’s easy to get pulled into overly dramatic ways of looking at where the world is going,” says Wallace-Wells, who routinely listens to Swain’s office hours and considers him a key source when he needs information on weather events. “Daniel helps people know how we can better calibrate those fears with the use of scientific rigor. He’s incredibly valuable.”

From the parking lot in the mountains, Swain often watches the weather that blows across the wide-open plains that stretch for hundreds of miles, all the way to the Mississippi River. He never tires of examining weather in real time, learning from it. He studies the interplay between the weather and the clouds at this spot where storms continually roll in and roll out.

“After all these years,” he says, “I’m still a weather geek.” 

Tracie White is a senior writer at Stanford. Email her at traciew@stanford.edu.

With the World Stumbling Past 1.5 Degrees of Warming, Scientists Warn Climate Shocks Could Trigger Unrest and Authoritarian Backlash (Inside Climate News)

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Science

With the World Stumbling Past 1.5 Degrees of Warming, Scientists Warn Climate Shocks Could Trigger Unrest and Authoritarian Backlash

Most of the public seems unaware that global temperatures will soon push past the target to which the U.N. hoped to limit warming, but researchers see social and psychological crises brewing.

By Bob Berwyn

January 28, 2024

Activists march in protest on day nine of the COP28 Climate Conference on Dec. 9, 2023 in Dubai, United Arab Emirates. Credit: Sean Gallup/Getty Images
Activists march in protest on day nine of the COP28 Climate Conference on Dec. 9, 2023 in Dubai, United Arab Emirates. Credit: Sean Gallup/Getty Images

As Earth’s annual average temperature pushes against the 1.5 degree Celsius limit beyond which climatologists expect the impacts of global warming to intensify, social scientists warn that humanity may be about to sleepwalk into a dangerous new era in human history. Research shows the increasing climate shocks could trigger more social unrest and authoritarian, nationalist backlashes.

Established by the 2015 Paris Agreement and affirmed by a 2018 report from the Intergovernmental Panel on Climate Change, the 1.5 degree mark has been a cliff edge that climate action has endeavored to avoid, but the latest analyses of global temperature data showed 2023 teetering on that red line. 

One major dataset suggested that the threshold was already crossed in 2023, and most projections say 2024 will be even warmer. Current global climate policies have the world on a path to heat by about 2.7 degrees Celsius by 2100, which would threaten modern human civilization within the lifespan of children born today.

Paris negotiators were intentionally vague about the endeavor to limit warming to 1.5 degrees, and the Intergovernmental Panel on Climate Change put the goal in the context of 30-year global averages. Earlier this month, the Berkeley Earth annual climate report showed Earth’s average temperature in 2023 at 1.54 degrees Celsius above the 1850-1900 pre-industrial average, marking the first step past the target. 

But it’s barely registering with people who are being bombarded with inaccurate climate propaganda and distracted by the rising cost of living and regional wars, said Reinhard Steurer, a climate researcher at the University of Natural Resources and Life Sciences, Vienna.

“The real danger is that there are so many other crises around us that there is no effort left for the climate crisis,” he said. “We will find all kinds of reasons not to put more effort into climate protection, because we are overburdened with other things like inflation and wars all around us.”

Steurer said he doesn’t expect any official announcement from major climate institutions until long after the 1.5 degree threshold is actually crossed, when some years will probably already be edging toward 2 degrees Celsius. “I think most scientists recognize that 1.5 is gone,” he said.

“We’ll be doing this for a very long time,” he added, “not accepting facts, pretending that we are doing a good job, pretending that it’s not going to be that bad.” 

In retrospect, using the 1.5 degree temperature rise as the key metric of whether climate action was working may have been a bad idea, he said.

“It’s language nobody really understands, unfortunately, outside of science,” he said. ”You always have to explain that 1.5 means a climate we can adapt to and manage the consequences, 2 degrees of heating is really dangerous, and 3 means collapse of civilization.”

Absent any formal notification of breaching the 1.5 goal, he hopes more scientists talk publicly about worst-case outcomes.

“It would really make a difference if scientists talked more about societal collapse and how to prepare for that because it would signal, now it’s getting real,” he said. “It’s much more tangible than 1.5 degrees.”

Instead, recent public climate discourse was dominated by feel-good announcements about how COP28 kept the 1.5 goal alive, he added.

“This is classic performative politics,” he said. “If the fossil fuel industry can celebrate the outcome of the COP, that’s not a good sign.”

Like many social scientists, Steurer is worried that the increasingly severe climate shocks that warming greater than 1.5 degrees brings will reverberate politically as people reach for easy answers.

“That is usually denial, in particular when it comes to right-wing parties,” he said. “That’s the easiest answer you can find.” 

“Global warming will be catastrophic sooner or later, but for now, denial works,” he said. “And that’s all that matters for the next election.”

‘Fear, Terror and Anxiety’

Social policy researcher Paul Hoggett, professor emeritus at the University of the West of England in Bristol, said the scientific roots of 1.5-degree target date back to research in the early 2000s that culminated in a University of Exeter climate conference at which scientists first spelled out the risks of triggering irreversible climate tipping points above that level of warming.

“I think it’s still seen very much as that key marker of where we move from something which is incremental, perhaps to something which ceases to be incremental,” he said. “But there’s a second reality, which is the reality of politics and policymaking.” 

The first reality is “profoundly disturbing,” but in the political world, 1.5 is a symbolic maker, he said. 

“It’s more rhetorical; it’s a narrative of 1.5,” he said, noting the disconnect of science and policy. “You almost just shrug your shoulders. As the first reality worsens, the political and cultural response becomes more perverse.” 

A major announcement about breaching the 1.5 mark in today’s political and social climate could be met with extreme denial in a political climate marked by “a remorseless rise of authoritarian forms of nationalism,” he said. “Even an announcement from the Pope himself would be taken as just another sign of a global elite trying to pull the wool over our eyes.” 

An increasing number of right-wing narratives simply see this as a set of lies, he added.

“I think this is a huge issue that is going to become more and more important in the coming years,” he said. “We’re going backwards to where we were 20 years ago, when there was a real attempt to portray climate science as misinformation,” he said. “More and more right wing commentators will portray what comes out of the IPCC, for example, as just a pack of lies.”

The IPCC’s reports represent a basic tenet of modernity—the idea that there is no problem for which a solution cannot be found, he said.

“Even an announcement from the Pope himself would be taken as just another sign of a global elite trying to pull the wool over our eyes.”

“However, over the last 100 years, this assumption has periodically been put to the test and has been found wanting,” Hoggett wrote in a 2023 paper. The climate crisis is one of those situations with no obvious solution, he wrote. 

In a new book, Paradise Lost? The Climate Crisis and the Human Condition, Hoggett says the climate emergency is one of the big drivers of authoritarian nationalism, which plays on the terror and anxiety the crisis inspires.

“Those are crucial political and individual emotions,” he said. “And it’s those things that drive this non-rational refusal to see what’s in front of your eyes.”

“At times of such huge uncertainty, a veritable plague of toxic public feelings can be unleashed, which provide the effective underpinning for political movements such as populism, authoritarianism, and totalitarianism,” he said.

“When climate reality starts to get tough, you secure your borders, you secure your own sources of food and energy, and you keep out the rest of them. That’s the politics of the armed lifeboat.” 

The Emotional Climate

“I don’t think people like facing things they can’t affect,” said psychotherapist Rebecca Weston, co-president of the Climate Psychology Alliance of North America. “And in trauma, people do everything that they possibly can to stop feeling what is unbearable to feel.”

That may be one reason why the imminent breaching of the 1.5 degree limit may not stir the public, she said.

“We protect ourselves from fear, we protect ourselves from deep grief on behalf of future generations and we protect ourselves from guilt and shame. And I think that the fossil fuel industry knows that,” she said. “We can be told something over and over and over again, but if we have an identity and a sense of ourselves tied up in something else, we will almost always refer to that, even if it’s at the cost of pretending that something that is true is not true.”

Such deep disavowal is part of an elaborate psychological system for coping with the unbearable. “It’s not something we can just snap our fingers and get ourselves out of,” she said.

People who point out the importance of the 1.5-degree warming limit are resented because they are intruding on peoples’ psychological safety, she said, and they become pariahs. “The way societies enforce this emotionally is really very striking,” she added. 

But how people will react to passing the 1.5 target is hard to predict, Weston said.

“I do think it revolves around the question of agency and the question of meaning in one’s life,” she said. “And I think that’s competing with so many other things that are going on in the world at the same time, not coincidentally, like the political crises that are happening globally, the shift to the far right in Europe, the shift to the far right in the U.S. and the shift in Argentina.”

Those are not unrelated, she said, because a lack of agency produces a yearning for false, exclusionary solutions and authoritarianism. 

“If there’s going to be something that keeps me up at night, it’s not the 1.5. It’s the political implications of that feeling of helplessness,” she said. “People will do an awful lot to avoid feeling helpless. That can mean they deny the problem in the first place. Or it could mean that they blame people who are easier targets, and there is plenty of that to witness happening in the world. Or it can be utter and total despair, and a turning inward and into a defeatist place.”

She said reaching the 1.5 limit will sharpen questions about addressing the problem politically and socially. 

“I don’t think most people who are really tracking climate change believe it’s a question of technology or science,” she said. “The people who are in the know, know deeply that these are political and social and emotional questions. And my sense is that it will deepen a sense of cynicism and rage, and intensify the polarization.”

Unimpressed by Science

Watching the global temperature surging past the 1.5 degree mark without much reaction from the public reinforces the idea that the focus on the physical science of climate change in recent decades came at the expense of studying how people and communities will be affected and react to global warming, said sociologist and author Dana Fisher, a professor in the School of International Service at American University and director of its Center for Environment, Community, and Equity.

“It’s a fool’s errand to continue down that road right now,” she said. “It’s been an abysmal ratio of funds that are going to understand the social conflict that’s going to come from climate shocks, the climate migration and the ways that social processes will have to shift. None of that has been done.”

Passing the 1.5 degree threshold will “add fuel to the fire of the vanguard of the climate movement,” she said. “Groups that are calling for systemic change, that are railing against incremental policy making and against business as usual are going to be empowered by this information, and we’re going to see those people get more involved and be more confrontational.”

And based on the historical record, a rise in climate activism is likely to trigger a backlash, a dangerous chain reaction that she outlined in her new book, Saving Ourselves: From Climate Shocks to Climate Action. 

“When you see a big cycle of activism growing, you get a rise in counter-movements, particularly as activism becomes more confrontational, even if it’s nonviolent, like we saw during the Civil Rights period,” she said. “And it will lead to clashes.”

Looking at the historic record, she said, shows that repressive crackdowns on civil disobedience is often where the violence starts. There are signs that pattern will repeat, with police raids and even pre-emptive arrests of climate activists in Germany, and similar repressive measures in the United Kingdom and other countries.

“I think that’s an important story to talk about, that people are going to push back against climate action just as much as they’re going to push for it,” she said. “There are those that are going to feel like they’re losing privileged access to resources and funding and subsidies.”

“When you see a big cycle of activism growing, you get a rise in counter-movements, particularly as activism becomes more confrontational, even if it’s nonviolent, like we saw during the Civil Rights period.”

A government dealing effectively with climate change would try to deal with that by making sure there were no clear winners and losers, she said, but the climate shocks that come with passing the 1.5 degree mark will worsen and intensify social tensions.

“There will be more places where you can’t go outside during certain times of the year because of either smoke from fires, or extreme heat, or flooding, or all the other things that we know are coming,” she said. “That’s just going to empower more people to get off their couches and become activists.”

‘A Life or Death Task For Humanity’

Public ignorance of the planet’s passing the 1.5 degree mark depends on “how long the powers-that-be can get away with throwing up smokescreens and pretending that they are doing something significant,” said famed climate researcher James Hansen, who recently co-authored a paper showing that warming is accelerating at a pace that will result in 2 degrees of warming within a couple of decades.

“As long as they can maintain the 1.5C fiction, they can claim that they are doing their job,” he said. “They will keep faking it as long as the scientific community lets them get away with it.”

But even once the realization of passing 1.5 is widespread, it might not change the social and political responses much, said Peter Kalmus, a climate scientist and activist in California.

“Not enough people care,” he said. “I’ve been a climate activist since 2006. I’ve tried so many things, I’ve had so many conversations, and I still don’t know what it will take for people to care. Maybe they never will.”

Hovering on the brink of this important climate threshold has left Kalmus feeling “deep frustration, sadness, helplessness, and anger,” he said. “I’ve been feeling that for a long time. Now, though, things feel even more surreal, as we go even deeper into this irreversible place, seeming not to care.”

“No one really knows for sure, but it may still be just physically possible for Earth to stay under 1.5C,” he said, “if humanity magically stopped burning fossil fuels today. But we can’t stop fossil fuels that fast even if everyone wanted to. People would die. The transition takes preparation.”

And there are a lot of people who just don’t want to make that transition, he said.

“We have a few people with inordinate power who actively want to continue expanding fossil fuels,” he said. “They are the main beneficiaries of extractive capitalism; billionaires, politicians, CEOs, lobbyists and bankers. And the few people who want to stop those powerful people haven’t figured out how to get enough power to do so.”

Kalmus said he was not a big fan of setting a global temperature threshold to begin with. 

“For me it’s excruciatingly clear that every molecule of fossil fuel CO2 or methane humanity adds to the atmosphere makes irreversible global heating that much worse, like a planet-sized ratchet turning molecule by molecule,” he said. “I think the target framing lends itself to a cycle of procrastination and failure and target moving.”

Meanwhile, climate impacts will continue to worsen into the future, he said.

“There is no upper bound, until either we choose to end fossil fuels or until we simply aren’t organized enough anymore as a civilization to burn much fossil fuel,” he said. “I think it’s time for the movement to get even more radical. Stopping fossil-fueled global heating is a life-or-death task for humanity and the planet, just most people haven’t realized it yet.”

Bob Berwyn – Reporter, Austria

Bob Berwyn an Austria-based reporter who has covered climate science and international climate policy for more than a decade. Previously, he reported on the environment, endangered species and public lands for several Colorado newspapers, and also worked as editor and assistant editor at community newspapers in the Colorado Rockies.

U.N. Chief’s Test: Shaming Without Naming the World’s Climate Delinquents (New York Times)

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nytimes.com

Somini Sengupta

Sept. 19, 2023

António Guterres told world leaders gathered in New York that their efforts to address the climate crisis had come up “abysmally short.”

António Guterres, in dark suit and light blue necktie, speaks at a microphone and gestures with his left hand. Behind him, a blue background with the United Nations logo and the words “United Nations” in several languages.
António Guterres in India this month. “History is coming for the planet-wreckers,” he has said. Credit: Arun Sankar/Agence France-Presse — Getty Images

Somini Sengupta

The world’s top diplomat, António Guterres, the United Nations secretary general, on Tuesday told world leaders their efforts to address the climate crisis had come up “abysmally short” and called on them to do what even climate-ambitious countries have been reluctant to do: stop expanding coal, oil and gas production.

“Every continent, every region and every country is feeling the heat, but I’m not sure all leaders are feeling that heat,” he said in his opening remarks to presidents and prime ministers assembled for their annual gathering in the General Assembly. “The fossil fuel age has failed.”

Mr. Guterres, now in his second and last term, has made climate action his centerpiece issue and has become unusually blunt in his language about the need to rein in the production of fossil fuels and not just focus on reducing greenhouse gas emissions from their use.

As always, he pointed to the world’s 20 largest economies for not moving fast enough. As always, he stopped short of calling on specific countries.

Not China, the world’s coal behemoth. Not Britain or the United States, who both have ambitious climate laws but continue to issue new oil and gas permits. Not the United Arab Emirates, a petrostate where a state-owned oil company executive is hosting the upcoming United Nations climate negotiations — a move that activists have decried as undermining the very legitimacy of the talks.

The contradictions show not only the constraints on Mr. Guterres, a 74-year-old politician from Portugal, but also the shortcomings of the diplomatic playbook on a problem as urgent as global warming.

“The rules of multilateral diplomacy and multilateral summitry are not fit for the speedy and effective response that we need,” said Richard Gowan, who decodes the rituals of the United Nations for the International Crisis Group.

The 2015 Paris climate accord asks only that countries set voluntary targets to address climate pollution. The agreements that come out of annual climate negotiations routinely get watered down, because every country, including champions of coal, oil and gas, must agree on every word and comma.

The secretary general can cajole but not command, urge but not enforce. He doesn’t name specific countries, though nothing in the United Nations Charter prevents him from doing so.

Despite his exhortations, governments have only increased their fossil fuel subsidies, to a record $7 trillion in 2022. Few nations have concrete plans to move their economies away from fossil fuels, and many depend directly or indirectly on revenues from coal, oil and gas. The human toll of climate change continues to mount.

“He has interpreted his role as a sort of truth teller,” said Rachel Kyte, a former United Nations climate diplomat and a professor at the Fletcher School at Tufts University. “The powers available to him as secretary general are awesome but limited.”

On Wednesday, he is deploying a bit of a diplomatic wink-nod. At a Climate Ambition Summit he is hosting , he is giving the mic only to those countries that have done as he has urged, and only if they send a high-level leader, to show that they take the summit seriously. “A naming and shaming device that doesn’t actually require naming and shaming anyone,” Mr. Gowan said.

Diplomatic jockeying around who will get on the list has been intense. More than 100 countries sent in requests to speak, and Mr. Guterres’s aides have in turn requested more information to prove they deserve to be on the list. What have you done on coal phaseout, some have been asked. How much climate funding have you offered? Are you still issuing new oil and gas permits? And so on.

“It’s good to see Guterres trying to hold their feet to the fire,” said Mohamed Adow, a Kenyan activist.

Mr. Guterres has waited until the last possible minute to make public the list of speakers.

The Secretary General has invited neither the United States nor China, the worlds biggest climate polluters, to speak at the summit on Wednesday. Nor has India secured a speaking invitation. Brazil, South Africa and the European Union have.

Expect the awkward.

John Kerry, the United States climate envoy, is expected to attend but not speak. (Mr. Guterres is giving the mic only to high-level national leaders.) It’s unclear whether the head of the Chinese delegation this year, Vice President Han Zheng, will have a speaking role. The European Commission president, Ursula von der Leyen, has secured the mic. Britain’s prime minister, Rishi Sunak, isn’t coming to the General Assembly conclave at all. Sultan al-Jaber, the head of the Emirati oil company, and host of the next climate talks, is scheduled to speak.

Mr. Guterres will also invite companies with what he calls “credible” targets to reduce their climate emissions to participate. Expect to count them with the fingers of one hand.

“If fossil fuel companies want to be part of the solution, they must lead the transition to renewable energy,” he said Tuesday.

Mr. Guterres, who had led the United Nations refugee agency for 10 years before being selected for the top job, didn’t always make climate change his centerpiece issue.

In fact, he didn’t talk about it when he was chosen to head the United Nations in 2016. Climate was seen as the signature issue of his predecessor, Ban Ki-moon, who shepherded through the Paris Agreement in 2015. Mr. Guterres spoke instead about the war in Syria, terrorism, and gender parity in the United Nations. (His choice disappointed those who had pressed for a woman to lead the world body for the first time in its 70-year history.)

In 2018 came a shift. At that year’s General Assembly, he called climate change “the defining issue of our time.” In 2019, he invited the climate activist Greta Thunberg to the General Assembly, whose raw anger at world leaders (“How dare you?” she railed at world leaders) spurred a social media clash with President Donald J. Trump, who was pulling the United States out of the Paris Accord.

Mr. Guterres, for his part, studiously avoided criticism of the United States by name.

By 2022, as oil companies were raking in record profits in the aftermath of the Russian invasion of Ukraine, he amped up his language. “We need to hold fossil fuel companies and their enablers to account,” he told world leaders at the General Assembly. He called for a windfall-profit tax, urged countries to suspend subsidies for fossil fuels and appointed a committee to issue guidelines for private companies on what counts as “greenwashing.”

This year, he stepped into the contentious debate between those who want greenhouse gas emissions from oil and gas projects captured and stored away, or “abated,” and those who want to keep oil and gas tucked in the ground altogether. “The problem is not simply fossil fuel emissions. It’s fossil fuels, period,” Mr. Guterres said in June.

The reactions from the private sector are mixed, said Paul Simpson, a founder and former head of CDP, a nongovernmental group that works with companies to address their climate pollution. Some executives privately say Mr. Guterres is right to call for a swift phaseout of fossil fuels, while others note that most national governments still lack concrete energy transition plans, no matter what he says.

“The question really is, how effective is the United Nations?” Mr. Simpson said. “It has the ability to get governments to focus and plan. But the U.N. itself doesn’t have any teeth, so national governments and companies must act.”

Somini Sengupta is The Times’s international climate correspondent. She has also covered the Middle East, West Africa and South Asia and is the author of the book, “The End of Karma: Hope and Fury Among India’s Young.”

A version of this article appears in print on  , Section A, Page 11 of the New York edition with the headline: U.N. Chief Implores Leaders to Improve on Climate.

Atividade humana coloca sistemas de suporte à vida na Terra em risco, diz estudo (Folha de S.Paulo)

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Riham Alkousaa, David Stanway

14 de setembro de 2023

Mundo já ultrapassou 6 das 9 fronteiras planetárias, como são chamados os limites seguros para a existência no planeta

Os sistemas de suporte à vida na Terra enfrentam riscos e incertezas maiores do que nunca, e a maioria dos principais limites de segurança já foram ultrapassados como resultado de intervenções humanas em todo o planeta, apontou estudo científico divulgado nesta quarta-feira (13).

Em uma espécie de “check-up de saúde” do planeta publicado na revista Science Advances, uma equipe internacional de 29 especialistas concluiu que a Terra atualmente está “bem fora do espaço operacional seguro para a humanidade” devido à atividade humana.

O estudo, que amplia um relatório de 2015, afirma que o mundo já ultrapassou 6 das 9 “fronteiras planetárias” —limites seguros para a vida humana em áreas como a integridade da biosfera, mudanças climáticas e a utilização e disponibilidade de água doce.

Ao todo, afirma o estudo, 8 das 9 fronteiras estão sob pressão maior do que a verificada na avaliação de 2015, aumentando o risco de mudanças dramáticas nas condições de vida da Terra. A camada de ozônio é o único dos quesitos a melhorar.

“Não sabemos se podemos prosperar sob grandes e dramáticas alterações das nossas condições”, disse a principal autora do estudo, Katherine Richardson, da Universidade de Copenhague.

Os autores afirmam que cruzar as fronteiras não representa um ponto de inflexão no qual a civilização humana simplesmente entrará em colapso, mas pode trazer mudanças irreversíveis nos sistemas de suporte à vida na Terra.

“Podemos pensar na Terra como um corpo humano e nos limites planetários como a pressão sanguínea. Acima de 120/80 [na medição da pressão sanguínea] não necessariamente indica um ataque cardíaco, mas aumenta o risco”, disse Richardson.

Os cientistas soaram o alarme sobre o aumento do desmatamento, o consumo excessivo de plantas como combustível, a proliferação de produtos como o plástico, organismos geneticamente modificados e produtos químicos sintéticos.

Dos nove limites avaliados, apenas a acidificação dos oceanos, a destruição da camada de ozônio e a poluição atmosférica —principalmente com partículas semelhantes à fuligem— foram consideradas ainda dentro de limites seguros. O teto da acidificação dos oceanos, no entanto, está perto de ser ultrapassado.

A concentração atmosférica de dióxido de carbono, o principal gás causador do efeito estufa, aumentou para cerca de 417 ppm (partes por milhão), significativamente superior ao nível seguro de 350 ppm.

Estima-se também que a atual taxa de extinção de espécies seja pelo menos dezenas de vezes mais rápida do que a taxa média dos últimos 10 milhões de anos, o que significa que o planeta já ultrapassou a fronteira segura para a diversidade genética.

“Na minha carreira nunca me baseei em tantas evidências como hoje”, disse Johan Rockström, coautor do estudo e diretor do Instituto Potsdam para Pesquisa de Impacto Climático.

Como é calculada chance de chuva que serviços de meteorologia divulgam (Folha de SP/BBC)

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Quanto mais específicos e precisos forem os dados atmosféricos coletados na área observada, mais precisa será a probabilidade.

Rafael Abuchaibe

29 de abril de 2023

Se você é daqueles que não sai de casa sem antes conferir a previsão do tempo, certamente já se perguntou por que a porcentagem de chuva oferecida pela maioria dos serviços de meteorologia nem sempre corresponde ao que você vê pela janela.

“Porque representa as chances de chover na sua cidade“, alguém já deve ter respondido, quase surpreso com o quão básica parecia ser a resposta à sua pergunta:

“E as estatísticas nunca são 100% precisas.”

Outros, tendo indagado um pouco mais sobre o assunto, podem ter dito que o que o percentual representa é a área do território em que vai chover durante um determinado período de tempo (por exemplo, “das 9h às 12h”).

E para colocar mais lenha na fogueira, você deve ter visto alguns vídeos do TikTok explicando que o que a porcentagem reflete é a certeza dos meteorologistas de que vai chover em uma determinada área, com base em medições de fatores como temperatura, pressão atmosférica e velocidade do vento.

Diante de explicações tão variadas e distintas para algo que parece ser tão simples, a BBC News Mundo, serviço de notícias em espanhol da BBC, resolveu buscar uma explicação mais exata para o que aquele número representa —e percebeu que, de certa forma, todo mundo tem razão.

Probabilidade de precipitação

Para poder estabelecer o que essa porcentagem realmente significa, vamos começar revisando a definição dada pelo Serviço Meteorológico dos EUA:

“A probabilidade de precipitação representa simplesmente a probabilidade estatística de que haja 0,01 polegadas [0,25 mm] ou mais de precipitação [seja chuva, neve ou granizo] em uma determinada área dentro do período de tempo especificado.”

A porcentagem leva em consideração diferentes fatores para expressar em um valor estatístico a probabilidade de ocorrer precipitação em um determinado ponto.

“Vejamos um exemplo do que essa probabilidade significa”, diz o serviço meteorológico em sua definição.

“Se a previsão para um determinado distrito diz que há 40% de probabilidade de chuva para esta tarde, isso significa que há 40% de chance de chover em algum lugar do distrito entre meio-dia e 18h”, acrescenta.

Com base nessa definição, quanto mais específicos e precisos forem os dados atmosféricos coletados na área observada, mais preciso será o percentual de probabilidade.

Isso explica por que os dados fornecidos por diferentes serviços meteorológicos variam (embora não muito).

Duas medições, mesmo resultado

Para poder fazer uma previsão, um analista meteorológico multiplica dois fatores: a certeza que tem de que um sistema de precipitação vai se formar ou se aproximar, calculado por meio de medições atmosféricas, pela extensão —área física— que se espera que tal precipitação tenha no território analisado.

A esse resultado, basta mover duas casas decimais, e a probabilidade de precipitação é obtida.

Isso indica que é possível chegar à mesma porcentagem de precipitação tendo valores diferentes para cada fator.

Para ver essa ideia na prática, vamos voltar ao nosso exemplo do distrito com 40% de probabilidade de precipitação: se um analista tivesse 80% de certeza de que vai chover naquele distrito (medindo a velocidade do vento, a temperatura do ar, a umidade etc.), mas só espera que o sistema de precipitação cubra 50% da área, ele dirá que há uma “probabilidade de 40% de chuva” durante esse período de tempo.

Por outro lado, se outro analista estimasse que a precipitação iria cobrir 100% da área analisada, mas só tivesse 40% de certeza de que essa precipitação iria atingir o distrito, ele obteria o mesmo resultado: “40% de probabilidade de chuva em qualquer ponto do distrito durante esse período de tempo.”

Pequenas variações entre os sistemas

Cada meteorologista terá seus próprios modelos de medição e coleta de dados para calcular a probabilidade de precipitação nos locais que analisa —e alguns serão mais precisos que outros.

O importante é identificar o quão precisos são os métodos de coleta de dados atmosféricos que cada serviço possui na área específica em que você se encontra, algo que pode ser feito comparando-os e analisando qual deles se adequa melhor à realidade que você observa pela janela.

E, claro, não se pode esquecer que, por se basear em modelos probabilísticos, a meteorologia está longe de ser infalível.

Se você confiar apenas na previsão do tempo, é inevitável que um dia, por melhor que seja o sistema que usa, você saia de casa sem guarda-chuva com base na previsão do aplicativo —e seja pego na rua por um temporal.

Este texto foi originalmente publicado aqui.

The Problem With Weather Apps (The Atlantic)

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theatlantic.com

Charlie Warzel

April 10, 2023

How are we still getting caught in the rain?

An illustration of a guy on his phone standing in rain showers.
Illustration by Daniel Zender. Source: Getty.

Technologically speaking, we live in a time of plenty. Today, I can ask a chatbot to render The Canterbury Tales as if written by Taylor Swift or to help me write a factually inaccurate autobiography. With three swipes, I can summon almost everyone listed in my phone and see their confused faces via an impromptu video chat. My life is a gluttonous smorgasbord of information, and I am on the all-you-can-eat plan. But there is one specific corner where technological advances haven’t kept up: weather apps.

Weather forecasts are always a game of prediction and probabilities, but these apps seem to fail more often than they should. At best, they perform about as well as meteorologists, but some of the most popular ones fare much worse. The cult favorite Dark Sky, for example, which shut down earlier this year and was rolled into the Apple Weather app, accurately predicted the high temperature in my zip code only 39 percent of the time, according to ForecastAdvisor, which evaluates online weather providers. The Weather Channel’s app, by comparison, comes in at 83 percent. The Apple app, although not rated by ForecastAdvisor, has a reputation for off-the-mark forecasts and has been consistently criticized for presenting faulty radar screens, mixing up precipitation totals, or, as it did last week, breaking altogether. Dozens of times, the Apple Weather app has lulled me into a false sense of security, leaving me wet and betrayed after a run, bike ride, or round of golf.

People love to complain about weather forecasts, dating back to when local-news meteorologists were the primary source for those planning their morning commutes. But the apps have produced a new level of frustration, at least judging by hundreds of cranky tweets over the past decade. Nearly two decades into the smartphone era—when anyone can theoretically harness the power of government weather data and dissect dozens of complex, real-time charts and models—we are still getting caught in the rain.

Weather apps are not all the same. There are tens of thousands of them, from the simply designed Apple Weather to the expensive, complex, data-rich Windy.App. But all of these forecasts are working off of similar data, which are pulled from places such as the National Oceanic and Atmospheric Administration (NOAA) and the European Centre for Medium-Range Weather Forecasts. Traditional meteorologists interpret these models based on their training as well as their gut instinct and past regional weather patterns, and different weather apps and services tend to use their own secret sauce of algorithms to divine their predictions. On an average day, you’re probably going to see a similar forecast from app to app and on television. But when it comes to how people feel about weather apps, these edge cases—which usually take place during severe weather events—are what stick in a person’s mind. “Eighty percent of the year, a weather app is going to work fine,” Matt Lanza, a forecaster who runs Houston’s Space City Weather, told me. “But it’s that 20 percent where people get burned that’s a problem.”

No people on the planet have a more tortured and conflicted relationship with weather apps than those who interpret forecasting models for a living. “My wife is married to a meteorologist, and she will straight up question me if her favorite weather app says something different than my forecast,” Lanza told me. “That’s how ingrained these services have become in most peoples’ lives.” The basic issue with weather apps, he argues, is that many of them remove a crucial component of a good, reliable forecast: a human interpreter who can relay caveats about models or offer a range of outcomes instead of a definitive forecast.

Lanza explained the human touch of a meteorologist using the example of a so-called high-resolution forecasting model that can predict only 18 hours out. It is generally quite good, he told me, at predicting rain and thunderstorms—“but every so often it runs too hot and over-indexes the chances of a bad storm.” This model, if left to its own devices, will project showers and thunderstorms blanketing the region for hours when, in reality, the storm might only cause 30 minutes of rain in an isolated area of the mapped region. “The problem is when you take the model data and push it directly into the app with no human interpretation,” he said. “Because you’re not going to get nuance from these apps at all. And that can mean a difference between a chance of rain all day and it’s going to rain all day.”

But even this explanation has caveats; all weather apps are different, and their forecasts have varying levels of sophistication. Some pipe model data right in, whereas others are curated using artificial intelligence. Peter Neilley, the Weather Channel’s director of weather forecasting sciences and technologies, said in an email that the company’s app incorporates “billions of weather data points,” adding that “our expert team of meteorologists does oversee and correct the process as needed.”

Weather apps might be less reliable for another reason too. When it comes to predicting severe weather such as snow, small changes in atmospheric moisture—the type of change an experienced forecaster might notice—can cause huge variances in precipitation outcomes. An app with no human curation might choose to average the model’s range of outcomes, producing a forecast that doesn’t reflect the dynamic situation on the ground. Or consider cities with microclimates: “Today, in Chicago, the lakefront will sit in the lower 40s, and the suburbs will be 50-plus degrees,” Greg Dutra, a meteorologist at ABC 7 Chicago, told me. “Often, the difference is even more stark—20-degree swings over just miles.” These sometimes subtle temperature disparities can mean very different forecasts for people living in the same region—something that one-size-fits-all weather apps don’t always pick up.

Naturally, meteorologists think that what they do is superior to forecasting by algorithm alone, but even weather-app creators told me that the challenges are real. “It’s impossible for a weather-data provider to be accurate everywhere in the world,” Brian Mueller, the founder of the app Carrot Weather, told me. His solution to the problem of app-based imprecision is to give users more ability to choose what they see when they open Carrot, letting them customize what specific weather information the app surfaces as well as what data sources the app will draw from. Mueller said that he learned from Dark Sky’s success how important beautiful, detailed radar maps were—both as a source of weather data and for entertainment purposes. In fact, meteorology seems to be only part of the allure when it comes to building a beloved weather app. Carrot has a pleasant design interface, with bright colors and Easter eggs scattered throughout, such as geography challenges based off of its weather maps. He’s also hooked Carrot up to ChatGPT to allow people to chat with the app’s fictional personality.

But what if these detailed models and dizzying maps, in the hands of weather rubes like myself,  are the real problem? “The general public has access to more weather information than ever, and I’d posit that that’s a bad thing,” Chris Misenis, a weather-forecasting consultant in North Carolina who goes by the name “Weather Moose,” told me. “You can go to PivotalWeather.com right now and pull up just about any model simulation you want.” He argues that these data are fine to look at if you know how to interpret them, but for people who aren’t trained to analyze them, they are at best worthless and at worst dangerous.

In fact, forecasts are better than ever, Andrew Blum, a journalist and the author of the book The Weather Machine: A Journey Inside the Forecast, told me. “But arguably, we are less prepared to understand,” he said, “and act upon that improvement—and a forecast is only as good as our ability to make decisions with it.” Indeed, even academic research around weather apps suggests that apps fail worst when they give users a false sense of certainty around forecasting. A 2016 paper for the Royal Meteorological Society argued that “the current way of conveying forecasts in the most common apps is guilty of ‘immodesty’ (‘not admitting that sometimes predictions may fail’) and ‘impoverishment’ (‘not addressing the broader context in which forecasts … are made’).”

The conflicted relationship that people have with weather apps may simply be a manifestation of the information overload that dominates all facets of modern life. These products grant anyone with a phone access to an overwhelming amount of information that can be wildly complex. Greg Dutra shared one such public high-resolution model from the NOAA with me that was full of indecipherable links to jargony terms such as “0-2 km max vertical vorticity.” Weather apps seem to respond mostly to this fire hose of data in two ways: By boiling them down to a reductive “partly sunny” icon, or by bombarding the user with information they might not need or understand. At its worst, a modern weather app seems to flatter people, entrusting them to do their own research even if they’re not equipped. I’m not too proud to admit that some of the fun of toying around with Dark Sky’s beautiful radar or Windy.App’s endless array of models is the feeling of role-playing as a meteorologist. But the truth is that I don’t really know what I’m looking at.

What people seem to be looking for in a weather app is something they can justify blindly trusting and letting into their lives—after all, it’s often the first thing you check when you roll over in bed in the morning. According to the 56,400 ratings of Carrot in Apple’s App Store, its die-hard fans find the app entertaining and even endearing. “Love my psychotic, yet surprisingly accurate weather app,” one five-star review reads. Although many people need reliable forecasting, true loyalty comes from a weather app that makes people feel good when they open it.

Our weather-app ambivalence is a strange pull between feeling grateful for instant access to information and simultaneously navigating a sense of guilt and confusion about how the experience is also, somehow, dissatisfying—a bit like staring down Netflix’s endless library and feeling as if there’s nothing to watch. Weather apps aren’t getting worse. In fact they’re only getting more advanced, inputting more and more data and offering them to us to consume. Which, of course, might be why they feel worse.

Governo de SP foi alertado de risco no Sahy 48 horas antes, diz centro federal (Folha de S.Paulo)

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OUTRO LADO: Defesa Civil diz que enviou SMS para 34 mil celulares cadastrados na região do litoral norte

Isabela Palhares

22 de fevereiro de 2023

O Cemaden (Centro Nacional de Monitoramento e Alerta para Desastres Naturais) afirma ter alertado o Governo de São Paulo cerca de 48 horas antes sobre o alto risco de desastre no litoral paulista.

Ao menos 48 pessoas morreram, sendo 47 em São Sebastião e 1 em Ubatuba —a última atualização foi feita nesta quarta (22) pela Defesa Civil.

Segundo o Cemaden, que é um órgão federal, a Defesa Civil estadual foi alertada sobre a ocorrência de chuvas fortes na região e o alto risco de desastres em uma reunião online na manhã de sexta (17). A vila do Sahy, o ponto em que mais pessoas morreram, foi citada como uma área de alto risco para deslizamento.

Em nota, a Defesa Civil diz que emitiu alertas preventivos à população desde que foi informada da previsão de fortes chuvas.

“Nós alertamos e avisamos a Defesa Civil na sexta, foram quase 48 horas antes de o desastre acontecer. Seguimos o protocolo que é estabelecido, alertando a Defesa Civil estadual para que ela se organizasse com os municípios”, disse Osvaldo Moraes, presidente do Cemaden.

O Cemaden é ligado ao Ministério da Ciência, Tecnologia e Inovação. O centro é responsável por monitorar índices meteorológicos e geológicos e alertar, caso necessário, os órgãos de prevenção.

Moraes diz que, ainda na quinta-feira (16), um boletim meteorológico já indicava as fortes chuvas na região. Esse boletim foi repassado para a Defesa Civil do estado.

Depois desse primeiro alerta, o Cemaden se reuniu com um representante da Defesa Civil estadual na sexta de manhã. “Nós emitimos boletins diários, o de quinta já indicava o risco. Mas o de sexta-feira aumentou o nível de alerta para essa região.”

A Defesa Civil disse que enviou 14 alertas de mensagem de texto (SMS) para mais de 34 mil celulares cadastrados na região do litoral norte. O órgão informou ainda que começou a articular ações as defesas civis municipais na quinta-feira quando recebeu a previsão de fortes chuvas na região.

“Os primeiros avisos divulgados pela Defesa Civil do Estado, que ocorreram ainda de forma preventiva, foram publicados por volta das 15 horas de quinta-feira, nas redes sociais da Defesa Civil e do Governo com informações sobre o volume de chuvas estimado para o período, bem como as medidas de segurança que poderiam ser adotadas pela população em áreas de risco”, diz a nota.

O órgão disse ainda que à 00h52 de sexta, ao acompanhar imagens de radares e satélites, enviou a primeira mensagem de SMS com o alerta.

Nas redes sociais da Defesa Civil, a primeira mensagem de alertas para chuvas fortes no sábado foi feita às 12h22. A mensagem, no entanto, não fala sobre os riscos de desmoronamento.

Durante a noite, outros alertas foram postados pelo órgão e nenhum deles faz menção ao risco de desmoronamento de terra. Foi só às 19h49 uma mensagem recomendou que as pessoas deixassem o local se precisassem.

Para os especialistas, a proporção do desastre e o elevado número de vítimas mostram que apenas a estratégia de envio de SMS aos moradores não é eficiente. Além de não ser possível saber se as pessoas viram os alertas, não havia um plano ou orientação sobre o que fazer na situação.

“Você cria um sistema de aviso, as pessoas podem até receber a mensagem, mas não sabem o que fazer com aquela informação. Não há uma orientação para onde devem ir, quando sair de casa, o que levar”, diz Eduardo Mario Mendiondo, coordenador científico do Ceped (Centro de Estudos e Pesquisas sobre Desastres) da USP.

Para ele, a estratégias devem pensar também criação de rotas de fugas em áreas de risco e na orientação aos moradores. “A população precisa saber qual o risco está correndo e como se proteger. É injusto depois dizer que eles não queriam sair de casa, eles não tinham orientação correta do que fazer.”

Segundo ele, em diversas cidades do país, como Petrópolis e Salvador, o alerta ocorre por uma sirene.

“Você garante que todo mundo vai ouvir a qualquer momento do dia. É o instrumento mais antigo, mas que funciona. Uma sirene dá o recado claro do risco iminente”, diz.

Para Fernando Rocha Nogueira, coordenador do LabGRIS (Laboratório Gestão de Riscos) da UFABC, as autoridade brasileiras assistem de forma inerte aos desastres que ocorrem no país. Segundo ele, o Brasil conta com bons sistemas de monitoramento, mas não desenvolve estratégias para proteger a população.

“Temos um problema grave de comunicação no país. Tinha o mapeamento de que iria chover muito, que havia um alto risco e não se deu a atenção devida. Milhares de pessoas desceram para o litoral, ignorando a previsão. Nós não temos conscientização do risco, nós vivemos um negacionismo das informações climáticas”, diz.

Como foram os avisos

Quinta-feira (16)
Boletim do Cemaden alerta para a ocorrência de chuvas fortes e volumosas no litoral paulista durante o Carnaval

Sexta-feira (17)
Em reunião virtual, o Cemaden faz alerta sobre a previsão de chuvas fortes e o risco de deslizamentos de terra para integrantes da Defesa Civil do estado. A vila do Sahy estava entre as áreas apontadas como de maior risco

Sábado (18)

12h22: Defesa Civil do Estado avisa nas redes sociais que a chuva estava se espalhando pela região de Ubatuba e Caraguatatuba. “Tem vento e raios. Atinge municípios vizinhos. Tenha cuidado nas próximas horas”, diz a mensagem

18h33: Uma nova mensagem da Defesa Civil é postada alertando para chuva persistente na região.

19h49: Outra mensagem é postada pela Defesa Civil diz que a “chuva está se espalhando” pelo Litoral Norte e pede para que as pessoas “tenham cuidado nas próximas horas”

23h13: A Defesa Civil alerta que a chuva persiste na região e recomenda “não enfrente alagamentos. Fique atento a inclinação de muros e a rachaduras. Se precisar saia do local”

03h15: O órgão volta a alerta sobre a chuva forte e persistente no litoral norte e diz “não enfrente alagamentos. Fique atento a inclinação de muros e a rachaduras. Se precisar saia do local.”

Tragédia no litoral norte indica necessidade de aprimorar previsão de chuvas (Folha de S.Paulo)

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www1.folha.uol.com.br

Especialistas apontam falta de investimento e defasagem do modelo; temporal foi agravado por ciclone extratropical, diz meteorologista

Carlos Petrocilo

22 de fevereiro de 2023

A falta de investimento em novas tecnologias, aliada à aceleração das mudanças climáticas, torna a previsão do tempo mais imprecisa no Brasil, segundo especialistas ouvidos pela Folha.

O serviço de meteorologia é essencial para que órgãos públicos, como Defesa Civil, se preparem com antecedência na tentativa de mitigar os efeitos de um temporal.

No litoral norte, a Defesa Civil havia emitido alerta na quinta-feira (16) para a possibilidade de registrar um acumulado de 250 milímetros no final de semana. Porém, o volume de chuva chegou a 682 mm, de acordo com o Governo de São Paulo.

Como consequência do temporal, 48 pessoas morreram, sendo 47 em São Sebastião e uma em Ubatuba, conforme os dados desta quarta (22).

Segundo o professor Eduardo Mario Mendiondo, coordenador científico do Ceped (Centro de Educação e Pesquisa de Desastres) da USP, os modelos atuais de previsão utilizam parâmetros atmosféricos calibrados por condições históricas e precisam ser atualizados.

“O clima está mudando, com maior magnitude e com maior frequência de ocorrência de extremos. Os modelos precisam ser atualizados de forma constante, em escala global e em regiões específicas, com microclima e dinâmicas peculiares, como é o caso da Serra do Mar e da Baixada Santista”, afirma Mendiondo.

O professor chama atenção para falta de investimentos públicos. Segundo ele, o governo precisa reforçar o quadro de servidores e investir em novas ferramentas para Cemaden (Centro Nacional de Monitoramento e Alertas de Desastres Naturais), Inpe (Instituto Nacional de Pesquisas Espaciais) e Inmet (Instituto Nacional de Meteorologia).

“Falta aumentar em 20 vezes o potencial de supercomputadores atuais em território nacional, falta contratar até 20 vezes o número servidores de manutenção e operação de supercomputadores e falta contratar até em dez vezes o número atual de técnicos operadores”, afirma o professor da USP.

Para suprir tais necessidades, Mendiondo estima que é necessário investimentos de R$ 25 bilhões por ano. “Isto para converter essas novas evidências científicas, melhorando as previsões, seguindo exemplos como Japão, Europa e Estados Unidos.”

O meteorologista Mamedes Luiz Melo afirma que o volume de chuva foi agravado pela ação do ciclone extratropical associado a uma frente fria que passou pelo Sul do país e por São Paulo. “A tecnologia vinha alertando, mas estamos lidando com algo móvel na atmosfera”, afirma Melo.

A Defesa Civil diz, em nota, que os boletins especiais e de aviso de risco meteorológicos são emitidos com base em simulações numéricas de previsão do tempo. “Tais limiares baseiam-se no histórico da chuva da região em que a chuva acumulada representa risco para transtornos, como deslizamentos, desabamentos, alagamentos, enchentes e ocorrências relacionadas a raios e ventos”, disse a Defesa Civil.

As projeções do Inmet, que emite alertas sobre riscos de deslizamentos para órgãos públicos, previram volumes de chuva menores do que um modelo usado pela empresa de meteorologia MetSul.

O modelo da empresa, chamado WRF, apontou que algumas áreas poderiam ter chuva acima de 600 mm em alguns pontos do terreno, o que acabou se confirmando. As previsões mais graves do instituto federal falavam em chuvas no patamar de 400 mm.

A previsão do Inmet para a chuva no litoral norte utilizou seis modelos numéricos diferentes. O instituto também usa o WRF, mas com uma resolução menor do que a da MetSul. Ou seja, a empresa conseguiu fazer os cálculos a partir de detalhes mais precisos do relevo do que o órgão público.

“O WRF tem se mostrado uma ferramenta muito importante na identificação de eventos extremos de chuva”, diz a meteorologista Estael Sias, da MetSul. “É importante assinalar que o modelo WRF é meramente uma ferramenta de trabalho, um produto, e não a previsão, e que o prognóstico final divulgado ao público e clientes leva em conta outros modelos e também a experiência do meteorologista para eventos extremos.”

Segundo o meteorologista Franco Nadal Villela, da equipe do Inmet em São Paulo, a resolução não é o fator mais decisivo na previsão de chuvas. Ele diz que os modelos usados pelo instituto deram conta de prever que o temporal em São Sebastião seria muito grave, embora não tenham chegado ao valor de 600 mm.

“Há modelos de menor resolução que pontualmente previram menos precipitação”, diz Villela. “As previsões modeladas estavam prevendo bem este evento e as variações na quantificação de precipitação [volume de chuva por hora] são mais uma das varáveis que ponderamos para emitir alertas.”

A Folha enviou perguntas através de email ao Inpe, que coordena o Centro de Previsão de Tempo e Estudos Climáticos (Cptec), mas não obteve resposta até a publicação deste texto.

Para José Marengo, climatologista e coordenador do Cemaden, defende mudanças [sic]. Ele explica que o modelo de previsão do tempo divide a região em áreas de até 200 quilômetros quadrados. Com isso, não é possível prever a quantidade de chuva aproximada em toda a região.

“O Brasil não está preparado tecnologicamente. É como se dividisse o Brasil em caixas grandes de 200 quilômetros quadrados, por isso há distorções dentro da mesma região. Pode ter áreas em que chove menos e outras que superaram os 600 milímetros, a modelagem não é perfeita”, afirma Marengo.

Ele também alerta para a falta de novas tecnologias. “O supercomputador do Inpe, o Tupã, que resolve as equações matemáticas em alta velocidade, é de 2010 e considerado obsoleto”, afirma o climatologista.

O professor Pedro Côrtes, do Instituto de Energia e Ambiente da USP, concorda que é área precise de mais recursos, mas pondera que as previsões dos órgãos do governo foram suficientes para apontar que uma tempestade grave se aproximava.

“A espera pelo investimento não pode postergar a solução do problema, as previsões já funcionam.”

A Folha publicou, no dia 28 de dezembro de 2010, a inauguração do supercomputador. Na ocasião, o Tupã custou R$ 31 milhões e era utilizado em países como Estados Unidos, China, Alemanha e Rússia. Para operá-lo, o Inpe precisou construir uma nova central elétrica, de mil quilowatts —antes tinha só 280 quilowatts disponíveis no instituto.

Até hoje os especialistas apontam o Tupã como o melhor equipamento que o Brasil possui para prever, além de enchentes, ondas de calor e frio e os períodos de seca.

Unknowns Swirl Around How Plastic Particles Impact the Climate (Undark)

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Original article

Microplastics found washed up on a beach. About 11 percent of microplastics in the atmosphere over the western U.S. come from the ocean. Visual: Alistair Berg/DigitalVision via Getty Images

Airborne microplastics can absorb or reflect sunlight and seed clouds. How might that change the planet’s trajectory?

By Nicola Jones

02.14.2023

Plastic has become an obvious pollutant over recent decades, choking turtles and seabirds, clogging up our landfills and waterways. But in just the past few years, a less obvious problem has emerged. Researchers are starting to get concerned about how tiny bits of plastic in the air, lofted into the skies from seafoam bubbles or spinning tires on the highway, might potentially change our future climate.

“Here’s something that people just didn’t think about — another aspect of plastic pollution,” says environmental analytical chemist Denise Mitrano of ETH Zürich University, in Switzerland, who co-wrote an article last November highlighting what researchers know — and don’t yet know — about how plastics can change clouds, potentially altering temperature and rainfall patterns.

This story was originally published by the Yale Environment 360 and is reproduced here as part of the Climate Desk collaboration.

Clouds form when water or ice condenses on “seeds” in the air: usually tiny particles of dust, salt, sand, soot, or other material thrown up by burning fossil fuels, forest fires, cooking, or volcanoes. There are plenty of these fine particles, or aerosols, in the skies — a lot more since the Industrial Revolution — and they affect everything from the quality of the air we breathe, to the color of sunsets, to the number and type of clouds in our skies.

Until recently, when chemists thought of the gunk in our air, plastics did not leap to mind. Concentrations were low, they thought, and plastic is often designed to be water repellent for applications like bags or clothing, which presumably made them unlikely to seed cloud droplets. But in recent years, studies have confirmed not only that microscopic pieces of plastic can seed clouds — sometimes powerfully — but they also travel thousands of miles from their source. And there are a lot more particles in the air than scientists originally thought. All this has opened researchers’ eyes to their potential contribution to atmospheric murk — and, possibly, to future climate change.

“The people who invented plastics all those decades ago, who were very proud of inventions that transformed society in many ways — I doubt they envisaged that plastics were going to end up floating around in the atmosphere and potentially influencing the global climate system,” says Laura Revell, an atmospheric scientist at the University of Canterbury in New Zealand. “We are still learning what the impacts are for humans, ecosystems, and climate. But certainly, from what we know so far, it doesn’t look good.”

Global annual production of plastics has skyrocketed from 2 million tons in 1950 to more than 450 million tons today. And despite growing concerns about this waste accumulating in the environment, production is ramping up rather than slowing down — some oil companies are building up their plastic production capacity as the demand for fossil fuel declines. To date, more than 9 billion tons of plastic has been produced, and about half of it has gone to landfills or been otherwise discarded. Some project that by 2025, 11 billion tons of plastic will have accumulated in the environment.

Plastic has been found in soils, water, crops, and on the ocean floor. And in recent years, several studies have suggested that microplastics (pieces less than 5 millimeters in length) and nanoplastics (smaller than approximately 1,000 nanometers) were being transported long distances through the air. In 2019, for example, researchers found microplastics in the Pyrenees that had arrived via rain or snowfall. In 2020, Janice Brahney of Utah State University and four co-authors published a high-profile Science paper revealing high amounts of plastic in federally protected areas of the United States. Brahney had found the plastic by accident; she had been looking for phosphorus, but was surprised by all the colorful bits of gunk in her ground-based filters. Her study led to a slew of headlines warning, “It’s raining plastic.”

Brahney’s extensive U.S. dataset also opened the door for modelers to figure out where, exactly, all this plastic was coming from. “It’s a really beautiful data set,” says Cornell University’s Natalie Mahowald, who did the modeling work.

Mahowald took the plastic concentrations Brahney had cataloged and mapped them against atmospheric patterns and known sources of plastics, including roads, agricultural dust, and oceans. On roadways, tires and brakes hurl microplastics into the air. Plastic winds up in agricultural dust, notes Mahowald, in part from plastics used on farm fields and in part because people toss fleece clothing into washing machines: The wastewater flows to treatment plants that separate solids from liquids, and about half the resulting biosolids get sent to farms for use as fertilizer. As for the ocean, Mahowald says, big globs of plastic in places like the Pacific Gyre degrade into microscopic pieces, which then float to the surface and are whipped up into the air by chopping waters and bursting air bubbles.

Mahowald’s model concluded that over the western U.S., 84 percent of microplastics were coming from roads, 5 percent from agricultural dust, and 11 percent from the oceans. Plastic is so lightweight that even chunks tens of micrometers across — the width of a human hair — can be lofted and blown great distances. The model revealed that some of this plastic was found thousands of miles from its presumed source. The smaller the pieces, the longer they can stay aloft.

While individual bits of plastic may stay in the air for only hours, days, or weeks, there’s so much being kicked up so consistently that there’s always some in the air: enough that plastic bits are now also found in human lungs. “We’re definitely breathing them right now,” says Mahowald.

Working out exactly how much plastic is in our skies is extremely difficult. Most of these studies are done by painstakingly teasing bits of plastic out of filters and examining them under a microscope to get an estimate of shape and color, then using spectroscopic techniques to confirm their source material. The smaller the pieces, the harder they are to identify. Studies can also be plagued by contamination: Walking into a lab wearing a fleece sweater, for example, can skew results with shedding plastic microfibers.

Nearly a dozen studies have shown airborne microplastic concentrations ranging from between 0.01 particles per cubic meter over the western Pacific Ocean to several thousand particles per cubic meter in London and Beijing. The cities showing higher levels are probably genuinely more polluted, says Revell, but it’s also true that those studies used a more-sensitive technique that could identify smaller bits of plastic (under 10 micrometers in size). The other studies would have missed such smaller pieces, which made up about half the plastic found in the London and Beijing studies.

Plastic bits are now found in human lungs. “We’re definitely breathing them right now,” says Mahowald.

Concentrations of airborne nanoplastics are understood even less. The numbers floating around today, says atmospheric chemist Zamin Kanji, Mitrano’s colleague at ETH Zürich, are likely to be “significantly underestimated.”

For now, the proportion of plastics to total airborne aerosols is tiny, so plastics aren’t contributing much to aerosol climate impacts, says Mahowald. Even in London and Beijing, plastic may account for only a millionth of the total aerosols. But plastic production, and the accumulation of plastic in the environment, keeps going up. Says Mahowald, “It’s only going to get worse.”

That’s especially true in less polluted regions — like over the oceans of the Southern Hemisphere, Kanji says. Since plastic can likely travel farther than other, denser aerosols, it could become a dominant airborne pollutant in more pristine areas. Brahney and Mahowald’s paper concludes that plastic currently makes up less than 1 percent of anthropogenic aerosols landing on the ground but they could, “alarmingly,” make up more than 50 percent of the aerosols landing on some parts of the ocean downwind from plastic sources.

Exactly how aerosols affect climate has been a critical sticking point in climate models, and many of the details are still unknown. Different aerosols can change the climate by either reflecting or absorbing sunlight, which can depend, in part, on their color. Black soot, for example, tends to have a warming effect, while salt reflects and cools. Aerosols can land on the ground and change the albedo, or reflectivity, of ice and snow.

Aerosols also affect cloud formation: Different bits and pieces can seed more and smaller droplets of water or ice, making for different types of clouds at different elevations that last for different amounts of time. High-altitude, thin, icy clouds tend to warm the Earth’s surface like a blanket, while low-altitude, bright and fluffy clouds tend to reflect sunlight and cool the Earth.

Though tiny, aerosols have an oversized influence on climate. The murk of anthropogenic aerosols in the sky has, overall, had a dramatic cooling effect since the Industrial Revolution (without them, global warming would be 30 to 50 percent greater than it is today). And they have more sway on extreme weather than greenhouse gases do: A world warmed by removing aerosols would have more floods and droughts, for example, than a world warmed the same amount by CO2.

Revell and her colleagues took a stab at trying to model how microplastics might affect temperature by either reflecting or absorbing sunlight, a calculation of what’s known as “radiative forcing.” For simplicity’s sake, they assumed that plastic is always clear, even though that’s not true (and darker material tends to absorb more sunlight), and that the global concentration is uniformly one particle per cubic meter, which is on the order of 1,000 times lower than concentrations measured in, say, London.

With those assumptions, Revell found that plastic’s direct impact on radiative forcing is “so small as to be insignificant.” But, importantly, if concentrations reach 100 particles per cubic meter (which they already have in many spots), plastics could have about the same magnitude of radiative forcing as some aerosols already included in Intergovernmental Panel on Climate Change assessments. In other words, plastics become noteworthy. But whether they would warm, or cool, the Earth is unknown.

Though tiny, aerosols have an oversized influence on climate.

Aerosols often have a greater impact on the climate through their influence on clouds. Pristine plastic beads, Kanji notes, repel water and so are unlikely to affect clouds. But plastic can “age” in a matter of hours, says Kanji, during its transit to the sky: It can be abraded, or it can accumulate salt from the ocean and other chemicals from the atmosphere, all of which can make the particles more water-loving. Plastic pieces can also contain nooks and crannies, which aid in the formation of ice.

In the lab, Kanji’s student Omar Girlanda has run preliminary tests showing that under such battered conditions, plastic pieces can be potent cloudmakers. “Some of them are as good as mineral dust particles,” says Kanji, “which is the most well-known, effective ice nucleus out there.”

Kanji says skies heavily polluted with plastic will probably make both more high-altitude ice clouds, which tend to warm the Earth’s surface, and more low-altitude water clouds, which tend to cool the Earth. Which effect will dominate is unknown. “It doesn’t make sense to model it at the moment, given the poor estimates we have of [atmospheric] plastic,” says Kanji. Plastic could also affect precipitation patterns: In general, Kanji says, clouds that are more polluted tend to last longer before bursting into rain than do less polluted clouds, and then they rain more heavily.

Revell and her colleagues are now whittling down the assumptions in their paper, working out more detailed calculations for more realistic estimates of plastic concentrations, colors, and sizes. “All we know is that the problem is not going to go away anytime soon,” she says. “These plastics are incredibly long lived. They’re breaking down, and they’re going to be forming new microplastics for centuries. We just don’t know how big the problem is that we’ve committed ourselves to.”

Nicola Jones is a freelance journalist based in Pemberton, British Columbia. Her work can be found in Nature, Scientific American, Globe and Mail, and New Scientist.