Arquivo da tag: Meteorologia

The Coming California Megastorm (New York Times)

Raymond Zhong

A different ‘Big One’ is approaching. Climate change is hastening its arrival.

Aug. 12, 2022

California, where earthquakes, droughts and wildfires have shaped life for generations, also faces the growing threat of another kind of calamity, one whose fury would be felt across the entire state.

This one will come from the sky.

According to new research, it will very likely take shape one winter in the Pacific, near Hawaii. No one knows exactly when, but from the vast expanse of tropical air around the Equator, atmospheric currents will pluck out a long tendril of water vapor and funnel it toward the West Coast.

This vapor plume will be enormous, hundreds of miles wide and more than 1,200 miles long, and seething with ferocious winds. It will be carrying so much water that if you converted it all to liquid, its flow would be about 26 times what the Mississippi River discharges into the Gulf of Mexico at any given moment.

When this torpedo of moisture reaches California, it will crash into the mountains and be forced upward. This will cool its payload of vapor and kick off weeks and waves of rain and snow.

The coming superstorm — really, a rapid procession of what scientists call atmospheric rivers — will be the ultimate test of the dams, levees and bypasses California has built to impound nature’s might.

But in a state where scarcity of water has long been the central fact of existence, global warming is not only worsening droughts and wildfires. Because warmer air can hold more moisture, atmospheric rivers can carry bigger cargoes of precipitation. The infrastructure design standards, hazard maps and disaster response plans that protected California from flooding in the past might soon be out of date.

As humans burn fossil fuels and heat up the planet, we have already increased the chances each year that California will experience a monthlong, statewide megastorm of this severity to roughly 1 in 50, according to a new study published Friday. (The hypothetical storm visualized here is based on computer modeling from this study.)

In the coming decades, if global average temperatures climb by another 1.8 degrees Fahrenheit, or 1 degree Celsius — and current trends suggest they might — then the likelihood of such storms will go up further, to nearly 1 in 30.

At the same time, the risk of megastorms that are rarer but even stronger, with much fiercer downpours, will rise as well.

These are alarming possibilities. But geological evidence suggests the West has been struck by cataclysmic floods several times over the past millennium, and the new study provides the most advanced look yet at how this threat is evolving in the age of human-caused global warming.

The researchers specifically considered hypothetical storms that are extreme but realistic, and which would probably strain California’s flood preparations. According to their findings, powerful storms that once would not have been expected to occur in an average human lifetime are fast becoming ones with significant risks of happening during the span of a home mortgage.

“We got kind of lucky to avoid it in the 20th century,” said Daniel L. Swain, a climate scientist at the University of California, Los Angeles, who prepared the new study with Xingying Huang of the National Center for Atmospheric Research in Boulder, Colo. “I would be very surprised to avoid it occurring in the 21st.”

Unlike a giant earthquake, the other “Big One” threatening California, an atmospheric river superstorm will not sneak up on the state. Forecasters can now spot incoming atmospheric rivers five days to a week in advance, though they don’t always know exactly where they’ll hit or how intense they’ll be.

Using Dr. Huang and Dr. Swain’s findings, California hopes to be ready even earlier. Aided by supercomputers, state officials plan to map out how all that precipitation will work its way through rivers and over land. They will hunt for gaps in evacuation plans and emergency services.

The last time government agencies studied a hypothetical California megaflood, more than a decade ago, they estimated it could cause $725 billion in property damage and economic disruption. That was three times the projected fallout from a severe San Andreas Fault earthquake, and five times the economic damage from Hurricane Katrina, which left much of New Orleans underwater for weeks in 2005.

Dr. Swain and Dr. Huang have handed California a new script for what could be one of its most challenging months in history. Now begin the dress rehearsals.

“Mother Nature has no obligation to wait for us,” said Michael Anderson, California’s state climatologist.

In fact, nature has not been wasting any time testing California’s defenses. And when it comes to risks to the water system, carbon dioxide in the atmosphere is hardly the state’s only foe.


On Feb. 12, 2017, almost 190,000 people living north of Sacramento received an urgent order: Get out. Now. Part of the tallest dam in America was verging on collapse.

That day, Ronald Stork was in another part of the state, where he was worrying about precisely this kind of disaster — at a different dam.

Standing with binoculars near California’s New Exchequer Dam, he dreaded what might happen if large amounts of water were ever sent through the dam’s spillways. Mr. Stork, a policy expert with the conservation group Friends of the River, had seen on a previous visit to Exchequer that the nearby earth was fractured and could be easily eroded. If enough water rushed through, it might cause major erosion and destabilize the spillways.

He only learned later that his fears were playing out in real time, 150 miles north. At the Oroville Dam, a 770-foot-tall facility built in the 1960s, water from atmospheric rivers was washing away the soil and rock beneath the dam’s emergency spillway, which is essentially a hillside next to the main chute that acts like an overflow drain in a bathtub. The top of the emergency spillway looked like it might buckle, which would send a wall of water cascading toward the cities below.

Mr. Stork had no idea this was happening until he got home to Sacramento and found his neighbor in a panic. The neighbor’s mother lived downriver from Oroville. She didn’t drive anymore. How was he going to get her out?

Mr. Stork had filed motions and written letters to officials, starting in 2001, about vulnerabilities at Oroville. People were now in danger because nobody had listened. “It was nearly soul crushing,” he said.

“With flood hazard, it’s never the fastball that hits you,” said Nicholas Pinter, an earth scientist at the University of California, Davis. “It’s the curveball that comes from a direction you don’t anticipate. And Oroville was one of those.”

Ronald Stork in his office at Friends of the River in Sacramento.

The spillway of the New Exchequer Dam.

Such perils had lurked at Oroville for so long because California’s Department of Water Resources had been “overconfident and complacent” about its infrastructure, tending to react to problems rather than pre-empt them, independent investigators later wrote in a report. It is not clear this culture is changing, even as the 21st-century climate threatens to test the state’s aging dams in new ways. One recent study estimated that climate change had boosted precipitation from the 2017 storms at Oroville by up to 15 percent.

A year and a half after the crisis, crews were busy rebuilding Oroville’s emergency spillway when the federal hydropower regulator wrote to the state with some unsettling news: The reconstructed emergency spillway will not be big enough to safely handle the “probable maximum flood,” or the largest amount of water that might ever fall there.

Sources: Global Historical Climatology Network, Huang and Swain (2022) Measurements taken from the Oroville weather station and the nearest modeled data point

This is the standard most major hydroelectric projects in the United States have to meet. The idea is that spillways should basically never fail because of excessive rain.

Today, scientists say they believe climate change might be increasing “probable maximum” precipitation levels at many dams. When the Oroville evacuation was ordered in 2017, nowhere near that much water had been flowing through the dam’s emergency spillway.

Yet California officials have downplayed these concerns about the capacity of Oroville’s emergency spillway, which were raised by the Federal Energy Regulatory Commission. Such extreme flows are a “remote” possibility, they argued in a letter last year. Therefore, further upgrades at Oroville aren’t urgently needed.

In a curt reply last month, the commission said this position was “not acceptable.” It gave the state until mid-September to submit a plan for addressing the issue.

The Department of Water Resources told The Times it would continue studying the matter. The Federal Energy Regulatory Commission declined to comment.

“People could die,” Mr. Stork said. “And it bothers the hell out of me.”


Donald G. Sullivan was lying in bed one night, early in his career as a scientist, when he realized his data might hold a startling secret.

For his master’s research at the University of California, Berkeley, he had sampled the sediment beneath a remote lake in the Sacramento Valley and was hoping to study the history of vegetation in the area. But a lot of the pollen in his sediment cores didn’t seem to be from nearby. How had it gotten there?

When he X-rayed the cores, he found layers where the sediment was denser. Maybe, he surmised, these layers were filled with sand and silt that had washed in during floods.

It was only late that night that he tried to estimate the ages of the layers. They lined up neatly with other records of West Coast megafloods.

“That’s when it clicked,” said Dr. Sullivan, who is now at the University of Denver.

His findings, from 1982, showed that major floods hadn’t been exceptionally rare occurrences over the past eight centuries. They took place every 100 to 200 years. And in the decades since, advancements in modeling have helped scientists evaluate how quickly the risks are rising because of climate change.

For their new study, which was published in the journal Science Advances, Dr. Huang and Dr. Swain replayed portions of the 20th and 21st centuries using 40 simulations of the global climate. Extreme weather events, by definition, don’t occur very often. So by using computer models to create realistic alternate histories of the past, present and future climate, scientists can study a longer record of events than the real world offers.

Dr. Swain and Dr. Huang looked at all the monthlong California storms that took place during two time segments in the simulations, one in the recent past and the other in a future with high global warming, and chose one of the most intense events from each period. They then used a weather model to produce detailed play-by-plays of where and when the storms dump their water.

Those details matter. There are “so many different factors” that make an atmospheric river deadly or benign, Dr. Huang said.

Xingying Huang of the National Center for Atmospheric Research in Boulder, Colo. Rachel Woolf for The New York Times

The New Don Pedro Dam spillway.

Wes Monier, a hydrologist, with a 1997 photo of water rushing through the New Don Pedro Reservoir spillway.

In the high Sierras, for example, atmospheric rivers today largely bring snow. But higher temperatures are shifting the balance toward rain. Some of this rain can fall on snowpack that accumulated earlier, melting it and sending even more water toward towns and cities below.

Climate change might be affecting atmospheric rivers in other ways, too, said F. Martin Ralph of the Scripps Institution of Oceanography at the University of California, San Diego. How strong their winds are, for instance. Or how long they last: Some storms stall, barraging an area for days on end, while others blow through quickly.

Scientists are also working to improve atmospheric river forecasts, which is no easy task as the West experiences increasingly sharp shifts from very dry conditions to very wet and back again. In October, strong storms broke records in Sacramento and other places. Yet this January through March was the driest in the Sierra Nevada in more than a century.

“My scientific gut says there’s change happening,” Dr. Ralph said. “And we just haven’t quite pinned down how to detect it adequately.”

Better forecasting is already helping California run some of its reservoirs more efficiently, a crucial step toward coping with wetter wet years and drier dry ones.

On the last day of 2016, Wes Monier was looking at forecasts on his iPad and getting a sinking feeling.

Mr. Monier is chief hydrologist for the Turlock Irrigation District, which operates the New Don Pedro Reservoir near Modesto. The Tuolumne River, where the Don Pedro sits, was coming out of its driest four years in a millennium. Now, some terrifying rainfall projections were rolling in.

First, 23.2 inches over the next 16 days. A day later: 28.8 inches. Then 37.1 inches, roughly what the area normally received in a full year.

If Mr. Monier started releasing Don Pedro’s water too quickly, homes and farms downstream would flood. Release too much and he would be accused of squandering water that would be precious come summer.

But the forecasts helped him time his flood releases precisely enough that, after weeks of rain, the water in the dam ended up just shy of capacity. Barely a drop was wasted, although some orchards were flooded, and growers took a financial hit.

The next storm might be even bigger, though. And even the best data and forecasts might not allow Mr. Monier to stop it from causing destruction. “There’s a point there where I can’t do anything,” he said.


How do you protect a place as vast as California from a storm as colossal as that? Two ways, said David Peterson, a veteran engineer. Change where the water goes, or change where the people are. Ideally, both. But neither is easy.

Firebaugh is a quiet, mostly Hispanic city of 8,100 people, one of many small communities that power the Central Valley’s prodigious agricultural economy. Many residents work at nearby facilities that process almonds, pistachios, garlic and tomatoes.

Firebaugh also sits right on the San Joaquin River.

For a sleepless stretch of early 2017, Ben Gallegos, Firebaugh’s city manager, did little but watch the river rise and debate whether to evacuate half the town. Water from winter storms had already turned the town’s cherished rodeo grounds into a swamp. Now it was threatening homes, schools, churches and the wastewater treatment plant. If that flooded, people would be unable to flush their toilets. Raw sewage would flow down the San Joaquin.

Luckily, the river stopped rising. Still, the experience led Mr. Gallegos to apply for tens of millions in funding for new and improved levees around Firebaugh.

Levees change where the water goes, giving rivers more room to swell before they inundate the land. Levee failures in New Orleans were what turned Katrina into an epochal catastrophe, and after that storm, California toughened levee standards in urbanized areas of the Sacramento and San Joaquin Valleys, two major river basins of the Central Valley.

The idea is to keep people out of places where the levees don’t protect against 200-year storms, or those with a 0.5 percent chance of occurring in any year. To account for rising seas and the shifting climate, California requires that levees be recertified as providing this level of defense at least every 20 years.

Firebaugh, Calif., on the San Joaquin River, is home to 8,100 people and helps power the Central Valley’s agricultural economy.

Ben Gallegos, the Firebaugh city manager.

A 6-year-old’s birthday celebration in Firebaugh.

The problem is that once levees are strengthened, the areas behind them often become particularly attractive for development: fancier homes, bigger buildings, more people. The likelihood of a disaster is reduced, but the consequences, should one strike, are increased.

Federal agencies try to stop this by not funding infrastructure projects that induce growth in flood zones. But “it’s almost impossible to generate the local funds to raise that levee if you don’t facilitate some sort of growth behind the levee,” Mr. Peterson said. “You need that economic activity to pay for the project,” he said. “It puts you in a Catch-22.”

A project to provide 200-year protection to the Mossdale Tract, a large area south of Stockton, one of the San Joaquin Valley’s major cities, has been on pause for years because the Army Corps of Engineers fears it would spur growth, said Chris Elias, executive director of the San Joaquin Area Flood Control Agency, which is leading the project. City planners have agreed to freeze development across thousands of acres, but the Corps still hasn’t given its final blessing.

The Corps and state and local agencies will begin studying how best to protect the area this fall, said Tyler M. Stalker, a spokesman for the Corps’s Sacramento District.

The plodding pace of work in the San Joaquin Valley has set people on edge. At a recent public hearing in Stockton on flood risk, Mr. Elias stood up and highlighted some troubling math.

The Department of Water Resources says up to $30 billion in investment is needed over the next 30 years to keep the Central Valley safe. Yet over the past 15 years, the state managed to spend only $3.5 billion.

“We have to find ways to get ahead of the curve,” Mr. Elias said. “We don’t want to have a Katrina 2.0 play out right here in the heart of Stockton.”

As Mr. Elias waits for projects to be approved and budgets to come through, heat and moisture will continue to churn over the Pacific. Government agencies, battling the forces of inertia, indifference and delay, will make plans and update policies. And Stockton and the Central Valley, which runs through the heart of California, will count down the days and years until the inevitable storm.

T​​he Sacramento-San Joaquin Delta near Stockton, Calif.


The megastorm simulation is based on the “ARkHist” storm modeled by Huang and Swain, Science Advances (2022), a hypothetical statewide, 30-day atmospheric river storm sequence over California with an approximately 2 percent likelihood of occurring each year in the present climate. Data was generated using the Weather Research and Forecasting model and global climate simulations from the Community Earth System Model Large Ensemble.

The chart of precipitation at Oroville compares cumulative rainfall at the Oroville weather station before the 2017 crisis with cumulative rainfall at the closest data point in ARkHist.

The rainfall visualization compares observed hourly rainfall in December 2016 from the Los Angeles Downtown weather station with rainfall at the closest data point in a hypothetical future megastorm, the ARkFuture scenario in Huang and Swain (2022). This storm would be a rare but plausible event in the second half of the 21st century if nations continue on a path of high greenhouse-gas emissions.

Additional credits

The 3D rainfall visualization and augmented reality effect by Nia Adurogbola, Jeffrey Gray, Evan Grothjan, Lydia Jessup, Max Lauter, Daniel Mangosing, Noah Pisner, James Surdam and Raymond Zhong.

Photo editing by Matt McCann.

Produced by Sarah Graham, Claire O’Neill, Jesse Pesta and Nadja Popovich.

Audio produced by Kate Winslett.

Cloud Wars: Mideast Rivalries Rise Along a New Front (New York Times)

Alissa J. Rubin, Bryan Denton

Artificial lakes like this one in Dubai are helping fuel an insatiable demand for water in the United Arab Emirates.
Artificial lakes like this one in Dubai are helping fuel an insatiable demand for water in the United Arab Emirates.

As climate change makes the region hotter and drier, the U.A.E. is leading the effort to squeeze more rain out of the clouds, and other countries are rushing to keep up.

Aug. 28, 2022

ABU DHABI, United Arab Emirates — Iranian officials have worried for years that other nations have been depriving them of one of their vital water sources. But it was not an upstream dam that they were worrying about, or an aquifer being bled dry.

In 2018, amid a searing drought and rising temperatures, some senior officials concluded that someone was stealing their water from the clouds.

“Both Israel and another country are working to make Iranian clouds not rain,” Brig. Gen. Gholam Reza Jalali, a senior official in the country’s powerful Revolutionary Guards Corps, said in a 2018 speech.

The unnamed country was the United Arab Emirates, which had begun an ambitious cloud-seeding program, injecting chemicals into clouds to try to force precipitation. Iran’s suspicions are not surprising, given its tense relations with most Persian Gulf nations, but the real purpose of these efforts is not to steal water, but simply to make it rain on parched lands.

As the Middle East and North Africa dry up, countries in the region have embarked on a race to develop the chemicals and techniques that they hope will enable them to squeeze rain drops out of clouds that would otherwise float fruitlessly overhead.

With 12 of the 19 regional countries averaging less than 10 inches of rainfall a year, a decline of 20 percent over the past 30 years, their governments are desperate for any increment of fresh water, and cloud seeding is seen by many as a quick way to tackle the problem.

The tawny mountain range that rises above Khor Fakkan in the United Arab Emirates is where summer updrafts often create clouds that make excellent candidates for seeding.

And as wealthy countries like the emirates pump hundreds of millions of dollars into the effort, other nations are joining the race, trying to ensure that they do not miss out on their fair share of rainfall before others drain the heavens dry — despite serious questions about whether the technique generates enough rainfall to be worth the effort and expense.

Morocco and Ethiopia have cloud-seeding programs, as does Iran. Saudi Arabia just started a large-scale program, and a half-dozen other Middle Eastern and North African countries are considering it.

China has the most ambitious program worldwide, with the aim of either stimulating rain or halting hail across half the country. It is trying to force clouds to rain over the Yangtze River, which is running dry in some spots.

While cloud seeding has been around for 75 years, experts say the science has yet to be proven. And they are especially dismissive of worries about one country draining clouds dry at the expense of others downwind.

The life span of a cloud, in particular the type of cumulus clouds most likely to produce rain, is rarely more than a couple of hours, atmospheric scientists say. Occasionally, clouds can last longer, but rarely long enough to reach another country, even in the Persian Gulf, where seven countries are jammed close together.

But several Middle Eastern countries have brushed aside the experts’ doubts and are pushing ahead with plans to wring any moisture they can from otherwise stingy clouds.

Today, the unquestioned regional leader is the United Arab Emirates. As early as the 1990s, the country’s ruling family recognized that maintaining a plentiful supply of water would be as important as the nation’s huge oil and gas reserves in sustaining its status as the financial and business capital of the Persian Gulf.

While there had been enough water to sustain the tiny country’s population in 1960, when there were fewer than 100,000 people, by 2020 the population had ballooned to nearly 10 million. And the demand for water soared, as well. United Arab Emirates residents now use roughly 147 gallons per person a day, compared with the world average of 47 gallons, according to a 2021 research paper funded by the emirates.

Currently, that demand is being met by desalination plants. Each facility, however, costs $1 billion or more to build and requires prodigious amounts of energy to run, especially when compared with cloud seeding, said Abdulla Al Mandous, the director of the National Center of Meteorology and Seismology in the emirates and the leader of its cloud-seeding program.

After 20 years of research and experimentation, the center runs its cloud-seeding program with near military protocols. Nine pilots rotate on standby, ready to bolt into the sky as soon as meteorologists focusing on the country’s mountainous regions spot a promising weather formation — ideally, the types of clouds that can build to heights of as much as 40,000 feet.

They have to be ready on a moment’s notice because promising clouds are not as common in the Middle East as in many other parts of the world.

“We are on 24-hour availability — we live within 30 to 40 minutes of the airport — and from arrival here, it takes us 25 minutes to be airborne,” said Capt. Mark Newman, a South African senior cloud-seeding pilot. In the event of multiple, potentially rain-bearing clouds, the center will send more than one aircraft.

The United Arab Emirates uses two seeding substances: the traditional material made of silver iodide and a newly patented substance developed at Khalifa University in Abu Dhabi that uses nanotechnology that researchers there say is better adapted to the hot, dry conditions in the Persian Gulf. The pilots inject the seeding materials into the base of the cloud, allowing it to be lofted tens of thousands of feet by powerful updrafts.

And then, in theory, the seeding material, made up of hygroscopic (water attracting) molecules, bonds to the water vapor particles that make up a cloud. That combined particle is a little bigger and in turn attracts more water vapor particles until they form droplets, which eventually become heavy enough to fall as rain — with no appreciable environmental impact from the seeding materials, scientists say.

That is in theory. But many in the scientific community doubt the efficacy of cloud seeding altogether. A major stumbling block for many atmospheric scientists is the difficulty, perhaps the impossibility, of documenting net increases in rainfall.

“The problem is that once you seed, you can’t tell if the cloud would have rained anyway,” said Alan Robock, an atmospheric scientist at Rutgers University and an expert in evaluating climate engineering strategies.

Another problem is that the tall cumulus clouds most common in summer in the emirates and nearby areas can be so turbulent that it is difficult to determine if the seeding has any effect, said Roy Rasmussen, a senior scientist and an expert in cloud physics at the National Center for Atmospheric Research in Boulder, Colo.

Israel, a pioneer in cloud seeding, halted its program in 2021 after 50 years because it seemed to yield at best only marginal gains in precipitation. It was “not economically efficient,” said Pinhas Alpert, an emeritus professor at the University of Tel Aviv who did one of the most comprehensive studies of the program.

Cloud seeding got its start in 1947, with General Electric scientists working under a military contract to find a way to de-ice planes in cold weather and create fog to obscure troop movements. Some of the techniques were later used in Vietnam to prolong the monsoon season, in an effort to make it harder for the North Vietnamese to supply their troops.

While the underlying science of cloud seeding seems straightforward, in practice, there are numerous problems. Not all clouds have the potential to produce rain, and even a cloud seemingly suitable for seeding may not have enough moisture. Another challenge in hot climates is that raindrops may evaporate before they reach the ground.

Sometimes the effect of seeding can be larger than expected, producing too much rain or snow. Or the winds can shift, carrying the clouds away from the area where the seeding was done, raising the possibility of “unintended consequences,” notes a statement from the American Meteorological Society.

“You can modify a cloud, but you can’t tell it what to do after you modify it,” said James Fleming, an atmospheric scientist and historian of science at Colby College in Maine.

“It might snow; it might dissipate. It might go downstream; it might cause a storm in Boston,” he said, referring to an early cloud-seeding experiment over Mount Greylock in the Berkshire Mountains of western Massachusetts.

This seems to be what happened in the emirates in the summer of 2019, when cloud seeding apparently generated such heavy rains in Dubai that water had to be pumped out of flooded residential neighborhoods and the upscale Dubai mall.

Despite the difficulties of gathering data on the efficacy of cloud seeding, Mr. Al Mandous said the emirates’ methods were yielding at least a 5 percent increase in rain annually — and almost certainly far more. But he acknowledged the need for data covering many more years to satisfy the scientific community.

Over last New Year’s weekend, said Mr. Al Mandous, cloud seeding coincided with a storm that produced 5.6 inches of rain in three days — more precipitation than the United Arab Emirates often gets in a year.

In the tradition of many scientists who have tried to modify the weather, he is ever optimistic. There is the new cloud-seeding nanosubstance, and if the emirates just had more clouds to seed, he said, maybe they could make more rain for the country.

And where would those extra clouds come from?

“Making clouds is very difficult,” he acknowledged. “But, who knows, maybe God will send us somebody who will have the idea of how to make clouds.”

Cobra Coral: Rock in Rio dispensa médium e tem previsão de chuva em shows (Splash)

Fernanda Talarico De Splash, em São Paulo 29/08/2022 04h00

O Rock in Rio está chegando! Depois de três anos, o evento de música voltará a acontecer no Parque Olímpico, Rio de Janeiro. Ao todo, serão sete dias de shows: 2, 3, 4, 8, 9, 10 e 11 de setembro. As apresentações acontecem em diferentes palcos, todos a céu aberto, o que gera uma grande preocupação: será que vai chover?

O Rock in Rio 2022 será a segunda edição seguida do evento que não contará com a parceria da produção com a Fundação Cacique Cobra Coral (FCCC), entidade esotérica que diz controlar o clima.

Ana Avila, meteorologista da Cepagri/Unicamp, afirma a Splash, assim como em 2019, quem for ao evento pode precisar separar o dinheiro da capa de chuva.

Ana explicou que os primeiros três dias de festival devem ter um clima mais seco. “O tempo é bom, ensolarado.” No entanto, a partir do dia 8, pode ser que o público enfrente momentos não tão agradáveis.

“Há a possibilidade de pancadas de chuvas. De fazer sol, mas com pancadas de chuvas. Não tem como cravar se será de dia ou de noite, mas elas podem acontecer.”

“De forma geral, não há nada que possa impedir a atividade ou qualquer evento. O que pode acontecer são pancadas de chuvas. Quanto mais próximos chegarmos dos dias do Rock in Rio, podemos saber melhor as intensidades.”

Se a previsão da especialista se concretizar, os shows de Iron Maiden, Post Malone, Jason Derulo, Dream Theater, Demi Lovato, Justin Bieber e outros que tocam nos primeiros dias de festival, acontecerão em uma noite sem chuva. Porém, os fãs de Guns N’ Roses, Green Day, Billy Idol, Coldplay, Dua Lipa e mais podem acabar se molhando durante as apresentações.

Quanto às temperaturas, Avila explica que nos primeiros dias elas podem variar entre 18ºC e 27ºC e, depois, a partir do dia 8 de setembro, em decorrência de nebulosidade e pancadas de chuvas, elas tendem a diminuir um pouco. “Ou seja, vai continuar calor, não vai haver uma amplitude muito grande. De noite, as mínimas serão de 19ºC e máxima de 22ºC.”

Sem parceria com Fundação Cacique Cobra Coral

Comandada pela médium Adelaide Scritori, que diz incorporar o espírito do Cacique Cobra Coral, entidade capaz de controlar o tempo, a fundação foi uma parceira histórica do Rock in Rio, além de ter mantido diversas colaborações com a prefeitura do Rio de Janeiro desde 2015 para, por exemplo, evitar fortes chuvas nas viradas de ano em Copacabana.

Procurada por Splash, a assessoria do Rock in Rio confirmou que não há mais a parceria com a FCCC. Ela foi questionada sobre o motivo do rompimento, mas até a publicação desta reportagem, não respondeu. A Fundação Cacique Cobra Coral também foi procurada, mas não respondeu nenhuma tentativa de contato.

Segundo reportagem do jornal Extra, Roberto Medina, o empresário responsável pelo evento, se desentendeu com a fundação depois que um grande temporal aconteceu em um dos dias do Rock in Rio de 2015.

À época, um representante da FCCC explicou que a médium se atrasou 30 minutos para chegar ao local do evento pois houve uma confusão com o adesivo do estacionamento. Quando finalmente conseguiram entrar, a chuva já tinha começado.

Em 2019, já sem a parceria, o festival foi novamente castigado pelo mau tempo e houve dias em que atrações como montanha-russa e roda gigante nem mesmo chegaram a abrir.

Governo nacionalista da Hungria demite meteorologistas após previsão cancelar show (Folha de S.Paulo)

24.ago.2022 às 23h01

Risco de tempestades não se confirmou, e mídia ligada a Orbán liderou críticas a agência

Dirigentes do Serviço Nacional de Meteorologia da Hungria foram demitidas depois de uma previsão de chuvas fortes levar o governo nacionalista de Viktor Orbán a cancelar um tradicional show de fogos de artifício em Budapeste no último fim de semana.

As informações são da agência de notícias Associated Press. O espetáculo, realizado anualmente em homenagem ao Dia de Santo Estevão, estava marcado para a noite do sábado (20). O show húngaro nessa data é tido como um dos maiores da Europa, o que explica o apreço do premiê pelo evento.

Naquela tarde, no entanto, o governo anunciou o cancelamento da festividade por orientação do serviço de meteorologia, que previa “condições climáticas extremas” para cerca de 21h.

Em vez de avançar sobre a capital como previsto, porém, a tempestade mudou de direção, restringindo-se ao leste da Hungria. Budapeste continuou seca.

O Serviço Nacional de Meteorologia publicou um pedido de desculpas nas redes sociais no domingo (21), afirmando que certo nível de incerteza faz parte da meteorologia, mas na segunda (22) o ministro de Inovação de Orbán, Laszlo Palkovics, demitiu a chefe e a vice da agência. Kornelia Radics dirigia o serviço desde 2013, e tinha Gyula Horvath como braço direito desde 2016.

Embora Palkovics não tenha dado uma razão oficial para as demissões, a agência meteorológica foi duramente criticada por meios de comunicação alinhados a Orbán. Eles afirmam que o “grave erro” do serviço causou um adiamento desnecessário.

Agências de notícias destacaram, porém, que parcela considerável de húngaros se opunha à escala e ao custo da explosão dos fogos, em especial num momento delicado como o atual, de crise econômica e Guerra da Ucrânia. Uma petição pedindo o cancelamento do espetáculo e um uso mais pragmático de sua verba reuniu quase 200 mil assinaturas.

Ainda segundo a Associated Press, o espetáculo buscaria mostrar de forma resumida os mil anos desde o nascimento da Hungria cristã até os dias de hoje, focando valores nacionais caros à plataforma de Orbán. O lançamento dos fogos foi remarcado para o próximo sábado (27).

Nesta terça (23), a agência de meteorologia publicou uma nota exigindo a readmissão das chefes demitidas. O órgão afirma que está sob “pressão política” no que se refere aos modelos usados para a previsão do tempo no feriado e que os responsáveis por pressioná-los “ignoram incertezas cientificamente aceitas inerentes à previsão do tempo”.

Orbán, que em abril conquistou seu quinto mandato como premiê —o quarto consecutivo—, lidera o que chama de projeto de “democracia iliberal”, com medidas anti-imigração, anti-LGBTQIA+ e contra a liberdade de imprensa. A postura rende uma série de atritos com a União Europeia, bloco do qual a Hungria faz parte.

Seca histórica atinge metade do México e leva a espiral de violência e desespero (Folha de S.Paulo)

Crise climática impacta chuvas, e dois terços do país enfrentam problemas no fornecimento de água

Maria Abi-Habib e Bryan Avelar

7 de agosto de 2022

O homem vestindo um boné de beisebol azul enche baldes com água de um caminhão do governo. Fonte: New York Times

O México —ou grande parte do país— está ficando sem água. Uma seca extrema tem deixado as torneiras secas, e quase dois terços dos municípios enfrentam escassez que vem obrigando as pessoas a encarar horas em filas para entregas de água feitas pelo governo em alguns locais.

A falta d’água está tão grave que moradores já fizeram barreiras em rodovias e sequestraram funcionários para exigir mais carregamentos. Os números são mesmo assustadores: em julho, 8 dos 32 estados enfrentaram estiagem de extrema a moderada, levando 1.546 dos 2.463 municípios a enfrentar cortes no fornecimento, segundo a Comissão Nacional de Água.

Em meados de julho, a seca atingia 48% do território do México —no ano passado, a situação afetou 28% do país.

Vincular uma seca isolada à crise climática requer análise, mas cientistas não têm dúvida de que o aquecimento global pode alterar os padrões de chuva no mundo e está elevando a probabilidade de ocorrência de secas.

Do outro lado da fronteira norte, nos últimos anos a maior parte da metade ocidental dos EUA sofre com estiagem de moderada a severa. São as duas décadas mais secas na região em 1.200 anos.

A crise está especialmente aguda em Monterrey, um dos centros econômicos mais importantes do México, com uma região metropolitana de 5 milhões de habitantes. Alguns bairros estão sem água há 75 dias, levando escolas a fechar as portas antes das férias de verão. Um jornalista percorreu várias lojas à procura de água potável, incluindo um supermercado Walmart, em vão.

Baldes estão em falta no comércio ou são vendidos a preços astronômicos, enquanto os habitantes juntam recipientes para coletar a água distribuída por caminhões enviados aos bairros mais afetados. Alguns usam latas de lixo limpas, e crianças lutam para ajudar a carregar a água.

A crise afeta inclusive as regiões de alta renda. “Aqui a gente tem que sair à caça de água”, diz Claudia Muñiz, 38, cuja família frequentemente tem passado uma semana sem água corrente. “Num momento de desespero, as pessoas explodem.”

Monterrey fica no norte do México e viu sua população crescer nos últimos anos, acompanhando o boom econômico. O clima tipicamente árido da região não ajuda a suprir as necessidades da população, e a crise climática reduz as chuvas já escassas.

Hoje os moradores podem caminhar sobre o leito da represa da barragem de Cerro Prieto, que no passado era uma das maiores fontes de água da cidade e uma importante atração turística, com animados restaurantes à beira da água, pesca, passeios de barco e esqui aquático.

A chuva que caiu em julho em partes do estado de Nuevo León, que faz divisa com o Texas e cuja capital é Monterrey, representou apenas 10% da média mensal registrada desde 1960, segundo Juan Ignacio Barragán Villareal, diretor-geral da agência local de recursos hídricos. “Nem uma gota caiu no estado inteiro em março”, diz. Foi o primeiro março sem chuvas desde que se começou a registrar esses dados, em 1960.

Hoje o governo distribui 9 milhões de litros de água por dia para 400 bairros. O motorista de caminhão-pipa Alejandro Casas conta que, quando começou na função há cinco anos, ajudava os bombeiros e era chamado uma ou duas vezes por mês para levar água a um local incendiado. Ele passava muitos dias de trabalho apenas olhando para o telefone.

Mas desde janeiro ele trabalha sem parar, fazendo até dez viagens por dia, para suprir cerca de 200 famílias a cada vez. Quando ele chega a um local, uma longa fila já serpenteia pelas ruas. Pessoas levam recipientes que comportam até 200 litros e passam a tarde sob o sol para receber água só à meia-noite —e ela pode ser a única entregue por até uma semana.

Ninguém policia as filas, por isso é comum ocorrerem brigas, com moradores de outras comunidades tentando se infiltrar. Em maio o caminhão de Casas foi assaltado por jovens que subiram no assento do passageiro e o ameaçaram, exigindo que ele levasse o veículo ao bairro deles. “Se a gente não fosse para onde eles queriam, iam nos sequestrar.”

Casas seguiu a ordem, encheu os baldes dos moradores e foi libertado.

Maria de los Angeles, 45, nasceu e cresceu em Ciénega de Flores, cidade próxima a Monterrey. Ela diz que a crise está afetando sua família e seu negócio. “Nunca antes vi isso. Só temos água nas torneiras a cada quatro ou cinco dias”, diz.

O viveiro de plantas de jardim é a única fonte de renda de sua família e requer mais água do que a que chega apenas ocasionalmente às torneiras. “Toda semana sou obrigada a comprar um tanque que me custa 1.200 pesos [R$ 300] de um fornecedor particular”, diz. É metade de sua receita semanal. “Não aguento mais.”

Pequenos e microempresários como ela estão frustrados por serem abandonados à própria sorte, enquanto as grandes indústrias podem operar quase normalmente: as fábricas conseguem receber 50 milhões de metros cúbicos de água por ano, devido a concessões federais que lhes garantem acesso especial aos aquíferos da cidade.

O governo está tendo dificuldade em responder à crise. Para tentar mitigar estiagens futuras, o estado está investindo US$ 97 milhões na construção de uma estação de tratamento de águas servidas e pretende comprar água de uma estação de dessalinização em construção num estado vizinho. Também gastou US$ 82 milhões para alugar mais caminhões, pagar motoristas adicionais e cavar mais poços.

O governador de Nuevo León, Samuel García, recentemente exortou o mundo a agir em conjunto para combater a crise climática. “Ela nos alcançou”, escreveu no Twitter. “Hoje precisamos cuidar do ambiente, é uma questão de vida ou morte.”

You’ve heard of water droughts. Could ‘energy’ droughts be next? (Science Daily)

Date: April 12, 2022

Source: Columbia University

Summary: Drawing on 70 years of historic wind and solar-power data, researchers built an AI model to predict the probability of a network-scale ‘drought,’ when daily production of renewables fell below a target threshold. Under a threshold set at the 30th percentile, when roughly a third of all days are low-production days, the researchers found that Texas could face a daily energy drought for up to four months straight. Batteries would be unable to compensate for a drought of this length, and if the system relied on solar energy alone, the drought could be expected to last twice as long — for eight months.

Renewable energy prices have fallen by more than 70 percent in the last decade, driving more Americans to abandon fossil fuels for greener, less-polluting energy sources. But as wind and solar power continue to make inroads, grid operators may have to plan for large swings in availability.

The warning comes from Upmanu Lall, a professor at Columbia Engineering and the Columbia Climate School who has recently turned his sights from sustainable water use to sustainable renewables in the push toward net-zero carbon emissions.

“Designers of renewable energy systems will need to pay attention to changing wind and solar patterns over weeks, months, and years, the way water managers do,” he said. “You won’t be able to manage variability like this with batteries. You’ll need more capacity.”

In a new modeling study in the journal Patterns, Lall and Columbia PhD student Yash Amonkar, show that solar and wind potential vary widely over days and weeks, not to mention months to years. They focused on Texas, which leads the country in generating electricity from wind power and is the fifth-largest solar producer. Texas also boasts a self-contained grid that’s as big as many countries’, said Lall, making it an ideal laboratory for charting the promise and peril of renewable energy systems.

Drawing on 70 years of historic wind and solar-power data, the researchers built an AI model to predict the probability of a network-scale “drought,” when daily production of renewables fell below a target threshold. Under a threshold set at the 30th percentile, when roughly a third of all days are low-production days, the researchers found that Texas could face a daily energy drought for up to four months straight.

Batteries would be unable to compensate for a drought of this length, said Lall, and if the system relied on solar energy alone, the drought could be expected to last twice as long — for eight months. “These findings suggest that energy planners will have to consider alternate ways of storing or generating electricity, or dramatically increasing the capacity of their renewable systems,” he said.

Anticipating Future ‘Energy’ Droughts — in Texas, and Across the Continental United States

The research began six years ago, when Lall and a former graduate student, David Farnham, examined wind and solar variability at eight U.S. airports, where weather records tend to be longer and more detailed. They wanted to see how much variation could be expected under a hypothetical 100% renewable-energy grid.

The results, which Farnham published in his PhD thesis, weren’t a surprise. Farnham and Lall found that solar and wind potential, like rainfall, is highly variable based on the time of year and the place where wind turbines and solar panels have been sited. Across eight cities, they found that renewable energy potential rose and fell from the long-term average by as much as a third in some seasons.

“We coined the term ‘energy’ droughts since a 10-year cycle with this much variation from the long-term average would be seen as a major drought,” said Lall. “That was the beginning of the energy drought work.”

In the current study, Lall chose to zoom in on Texas, a state well-endowed with both sun and wind. Lall and Amonkar found that persistent renewable energy droughts could last as long as a year even if solar and wind generators were spread across the entire state. The conclusion, Lall said, is that renewables face a storage problem that can only realistically be solved by adding additional capacity or sources of energy.

“In a fully renewable world, we would need to develop nuclear fuel or hydrogen fuel, or carbon recycling, or add much more capacity for generating renewables, if we want to avoid burning fossil fuels,” he said.

In times of low rainfall, water managers keep fresh water flowing through the spigot by tapping municipal reservoirs or underground aquifers. Solar and wind energy systems have no equivalent backup. The batteries used to store excess solar and wind power on exceptionally bright and gusty days hold a charge for only a few hours, and at most, a few days. Hydropower plants provide a potential buffer, said Lall, but not for long enough to carry the system through an extended dry spell of intermittent sun and wind.

“We won’t solve the problem by building a larger network,” he said. “Electric grid operators have a target of 99.99% reliability while water managers strive for 90 percent reliability. You can see what a challenging game this will be for the energy industry, and just how valuable seasonal and longer forecasts could be.”

In the next phase of research, Lall will work with Columbia Engineering professors Vijay Modi and Bolun Xu to see if they can predict both energy droughts and “floods,” when the system generates a surplus of renewables. Armed with these projections, they hope to predict the rise and fall of energy prices.

Journal Reference:

  1. Yash Amonkar, David J. Farnham, Upmanu Lall. A k-nearest neighbor space-time simulator with applications to large-scale wind and solar power modeling. Patterns, 2022; 3 (3): 100454 DOI: 10.1016/j.patter.2022.100454

How a little-discussed revision of climate science could help avert doom (Washington Post)

Mark Hertsgaard, Saleemul Huq, Michael E. Mann

Feb. 23, 2022

We can reduce global temperatures faster than we once thought — if we act now

One of the biggest obstacles to avoiding global climate breakdown is that so many people think there’s nothing we can do about it.

They point out that record-breaking heat waves, fires and storms are already devastating communities and economies throughout the world. And they’ve long been told that temperatures will keep rising for decades to come, no matter how many solar panels replace oil derricks or how many meat-eaters go vegetarian. No wonder they think we’re doomed.

But climate science actually doesn’t say this. To the contrary, the best climate science you’ve probably never heard of suggests that humanity can still limit the damage to a fraction of the worst projections if — and, we admit, this is a big if — governments, businesses and all of us take strong action starting now.

For many years, the scientific rule of thumb was that a sizable amount of temperature rise was locked into the Earth’s climate system. Scientists believed — and told policymakers and journalists, who in turn told the public — that even if humanity hypothetically halted all heat-trapping emissions overnight, carbon dioxide’s long lifetime in the atmosphere, combined with the sluggish thermal properties of the oceans, would nevertheless keep global temperatures rising for 30 to 40 more years. Since shifting to a zero-carbon global economy would take at least a decade or two, temperatures were bound to keep rising for at least another half-century.

But guided by subsequent research, scientists dramatically revised that lag time estimate down to as little as three to five years. That is an enormous difference that carries paradigm-shifting and broadly hopeful implications for how people, especially young people, think and feel about the climate emergency and how societies can respond to it.

This revised science means that if humanity slashes emissions to zero, global temperatures will stop rising almost immediately. To be clear, this is not a get-out-of-jail-free card. Global temperatures will not fall if emissions go to zero, so the planet’s ice will keep melting and sea levels will keep rising. But global temperatures will stop their relentless climb, buying humanity time to devise ways to deal with such unavoidable impacts. In short, we are not irrevocably doomed — or at least we don’t have to be, if we take bold, rapid action.

The science we’re referencing was included — but buried — in the United Nations Intergovernmental Panel on Climate Change’s most recent report, issued in August. Indeed, it was first featured in the IPCC’s landmark 2018 report, “Global warming of 1.5 C.”That report’s key finding — that global emissions must fall by 45 percent by 2030 to avoid catastrophic climate disruption — generated headlines declaring that we had “12 years to save the planet.” That 12-year timeline, and the related concept of a “carbon budget” — the amount of carbon that can be burned while still limiting temperature rise to 1.5 degrees Celsius above preindustrial levels — were both rooted in this revised science. Meanwhile, the public and policy worlds have largely neglected the revised science that enabled these very estimates.

Nonscientists can reasonably ask: What made scientists change their minds? Why should we believe their new estimate of a three-to-five-year lag time if their previous estimate of 30 to 40 years is now known to be incorrect? And does this mean the world still must cut emissions in half by 2030 to avoid climate catastrophe?

The short answer to the last question is yes. Remember, temperatures only stop rising once global emissions fall to zero. Currently, emissions are not falling. Instead, humanity continues to pump approximately 36 billion tons of carbon dioxide a year into the atmosphere. The longer it takes to cut those 36 billion tons to zero, the more temperature rise humanity eventually will face. And as the IPCC’s 2018 report made hauntingly clear, pushing temperatures above 1.5 degrees C would cause unspeakable amounts of human suffering, economic loss and social breakdown — and perhaps trigger genuinely irreversible impacts.

Scientists changed their minds about how much warming is locked in because additional research gave them a much better understanding of how the climate system works. Their initial 30-to-40-year estimates were based on relatively simple computer models that treated the concentration of carbon dioxide in the atmosphere as a “control knob” that determines temperature levels. The long lag in the warming impact is due to the oceans, which continue to warm long after the control knob is turned up. More recent climate models account for the more dynamic nature of carbon emissions. Yes, CO2 pushes temperatures higher, but carbon “sinks,” including forests and in particular the oceans, absorb almost half of the CO2 that is emitted, causing atmospheric CO2 levels to drop, offsetting the delayed warming effect.

Knowing that 30 more years of rising temperatures are not necessarily locked in can be a game-changer for how people, governments and businesses respond to the climate crisis. Understanding that we can still save our civilization if we take strong, fast action can banish the psychological despair that paralyzes people and instead motivate them to get involved. Lifestyle changes can help, but that involvement must also include political engagement. Slashing emissions in half by 2030 demands the fastest possible transition away from today’s fossil-fueled economies in favor of wind, solar and other non-carbon alternatives. That can happen only if governments enact dramatically different policies. If citizens understand that things aren’t hopeless, they can better push elected officials to make such changes.

As important as minimizing temperature rise is to the United States, where last year’s record wildfires in California and the Pacific Northwest illustrated just how deadly climate change can be, it matters most in the highly climate-vulnerable communities throughout the global South. Countless people in Bangladesh, the Philippines, Madagascar, Africa’s Sahel nations, Brazil, Honduras and other low-income countries have already been suffering from climate disasters for decades because their communities tend to be more exposed to climate impacts and have less financial capacity to protect themselves. For millions of people in such countries, limiting temperature rise to 1.5 degrees C is not a scientific abstraction.

The IPCC’s next report, due for release Feb. 28, will address how societies can adapt to the temperature rise now underway and the fires, storms and rising seas it unleashes. If we want a livable future for today’s young people, temperature rise must be kept as close as possible to 1.5 C. The best climate science most people have never heard of says that goal remains within reach. The question is whether enough of us will act on that knowledge in time.

Dia da Marmota: Phil prevê que frio vai continuar nos Estados Unidos (Folha de S.Paulo)


Tradição acontece desde 1887 em pequena cidade da Pensilvânia

A marmota Phil prevê que frio vai continuar nos Estados Unidos – Alan Freed/Reuters

Na manhã desta quarta (2), a marmota Phil viu a sua própria sombra e voltou para a sua toca. Segundo a tradição americana do Dia da Marmota, o movimento do animal significa que o frio continuará por mais seis semanas nos Estados Unidos.

Se Phil não tivesse visto a própria sombra, significaria que o calor da primavera estaria a caminho.

A previsão feita pela marmota é uma tradição que acontece desde 1887, sempre no dia 2 de fevereiro, na pequena cidade de Punxsutawney, na Pensilvânia. Após uma edição virtual em 2021 por causa da pandemia, neste ano o evento reuniu milhares de pessoas.

O roedor —que é substituído e rebatizado a cada vez que um animal titular morre— acertou 50% das vezes nos últimos dez anos —ou seja, índice de acerto igual ao de uma previsão aleatória, segundo o Noaa (Centros Nacionais de Informação Ambiental, na sigla em inglês),

O evento do Dia da Marmota foi retratado na comédia “Feitiço do Tempo“, de 1993, no qual um repórter de TV, vivido por Bill Murray, fica “preso” neste dia e é obrigado a reviver a mesma data inúmeras vezes, em sequência. Com isso, Dia da Marmota passou a ser uma forma de se referir à sensação de que os dias se repetem, situação comum na pandemia.

A marmota Punxsutawney Phil é mostrada ao público após sair da sua toca. Alan Freed/Reuters

Do You Know the Story Behind Naming Storms? (Word Genius)

Friday, October 29, 2020

Can you imagine turning on the Weather Channel to get an update on Storm 34B-SQ59? While major storms aren’t sentient beings, it’s become standard to give them human names to make it easier to communicate about them, especially during critical news updates. From Hurricane Elsa to Tropical Storm Cristobal, there’s an intriguing legacy behind naming storms.

The History of Naming Storms

A few hundred years ago, storms were named after the Catholic saint’s day that lined up with the storm. For example, Hurricane Santa Ana landed in Puerto Rico on July 26, 1825. But if storms hit on the same day in different years, names doubled up. Hurricane San Felipe I struck Puerto Rico on September 13, 1876 and then San Felipe II hit in 1928.

In the late 19th century, Australian meteorologist Clement Wragge began using women’s names for tropical storms. The practice was adopted by the U.S. Navy and Air Force during World War II when latitude and longitude identifications proved to be too cumbersome.

Outside of the military, early 20th century storms were named and tracked by the year and order, with names such as “1940 Hurricane Two” and “1932 Tropical Storm Six.” This created some confusion when multiple storms were happening during the same time, especially during news broadcasts. To reduce confusion, United States weather services also began using female names for storms in 1953, and later added male names to the list in 1978. This began the modern version of how we name storms.

Who Is in Charge of Storm Names?

Although NOAA’s (National Oceanic and Atmospheric Administration) National Hurricane Center is the premier source for news about storms, this organization does not name them. Instead, the World Meteorological Organization does. The WMO is a specialized agency of the United Nations, headquartered in Switzerland, that focuses on weather, climate, and water resources. Each year, the WMO creates a list of potential names for the upcoming storm season.

Where Do the Names Come From?

There is a bit of an art to naming modern-day storms. The WMO compiles six lists of names for each of the three basins under its jurisdiction: Atlantic, Eastern North Pacific, and Central North Pacific. Countries outside of this jurisdiction have their own naming conventions. For areas within the WMO, such as the United States, storm names are cycled through every six years. That means that the list of names for the 2021 season will be used again in 2027.

Each list contains 21 names that begin with a different letter of the alphabet (minus Q, U, X, Y, Z because of the limited number of names). For the Atlantic basin, names are typically chosen from English, French, and Spanish, because the countries impacted primarily speak one of those three languages. While the names are supposedly random, there are some pop culture-related coincidences, such as 2021’s Hurricane Elsa.

When Is a Storm Named?

A tropical storm can be named once it meets two criteria: a circular rotation and wind speeds more than 39 MPH. Once a storm reaches 74 MPH, it becomes a hurricane but keeps the same name it was first given as a tropical storm, such as when Tropical Storm Larry turned into Hurricane Larry in September 2021.

Hurricane names can also be retired, and this is often done when a hurricane is especially destructive. As of the 2020 season, there are 93 names on the retired Atlantic hurricane list, including 2004’s Katrina, 2012’s Sandy, and 2016’s Matthew. When a name is retired, it is replaced with a new name.

New Rules in 2021

Before the 2021 season, if the full list of storm names was used before the end of the season, any additional storms that reached the necessary criteria for naming would use the Greek alphabet — Alpha, Beta, Gamma, etc. There were 30 named storms in 2020, only the second time the full list of names had been used.

As of 2021, the WMO will use a supplementary list of names, similar to the original list (starting with Adria and ending with Will). The WMO felt that the Greek names were too distracting. From a technical perspective, the Greek names could also not be replaced in a way that made sense if they were retired (such as Eta and Iota in 2020).

Featured image credit: Julia_Sudnitskaya/ iStock

Trust in meteorology has saved lives. The same is possible for climate science. (Washington Post)

Placing our faith in forecasting and science could save lives and money

Oliver Uberti

October 14, 2021

2021 is shaping up to be a historically busy hurricane season. And while damage and destruction have been serious, there has been one saving grace — that the National Weather Service has been mostly correct in its predictions.

Thanks to remote sensing, Gulf Coast residents knew to prepare for the “life-threatening inundation,” “urban flooding” and “potentially catastrophic wind damage” that the Weather Service predicted for Hurricane Ida. Meteorologists nailed Ida’s strength, surge and location of landfall while anticipating that a warm eddy would make her intensify too quickly to evacuate New Orleans safely. Then, as her remnants swirled northeast, reports warned of tornadoes and torrential rain. Millions took heed, and lives were saved. While many people died, their deaths resulted from failures of infrastructure and policy, not forecasting.

The long history of weather forecasting and weather mapping shows that having access to good data can help us make better choices in our own lives. Trust in meteorology has made our communities, commutes and commerce safer — and the same is possible for climate science.

Two hundred years ago, the few who studied weather deemed any atmospheric phenomenon a “meteor.” The term, referencing Aristotle’s “Meteorologica,” essentially meant “strange thing in the sky.” There were wet things (hail), windy things (tornadoes), luminous things (auroras) and fiery things (comets). In fact, the naturalist Elias Loomis, who was among the first to spot Halley’s comet upon its return in 1835, thought storms behaved as cyclically as comets. So to understand “the laws of storms,” Loomis and the era’s other leading weatherheads began gathering observations. Master the elements, they reasoned, and you could safely sail the seas, settle the American West, plant crops with confidence and ward off disease.

In 1856, Joseph Henry, the Smithsonian Institution’s first director, hung a map of the United States in the lobby of its Washington headquarters. Every morning, he would affix small colored discs to show the nation’s weather: white for places with clear skies, blue for snow, black for rain and brown for cloud cover. An arrow on each disc allowed him to note wind direction, too. For the first time, visitors could see weather across the expanding country.

Although simple by today’s standards, the map belied the effort and expense needed to select the correct colors each day. Henry persuaded telegraph companies to transmit weather reports every morning at 10. Then he equipped each station with thermometers, barometers, weathervanes and rain gauges — no small task by horse and rail, as instruments often broke in transit.

For longer-term studies of the North American climate, Henry enlisted academics, farmers and volunteers from Maine to the Caribbean. Eager to contribute, “Smithsonian observers” took readings three times a day and posted them to Washington each month. At its peak in 1860, the Smithsonian Meteorological Project had more than 500 observers. Then the Civil War broke out.

Henry’s ranks thinned by 40 percent as men traded barometers for bayonets. Severed telegraph lines and the priority of war messages crippled his network. Then in January 1865, a fire in Henry’s office landed the fatal blow to the project. All of his efforts turned to salvaging what survived. With a vacuum of leadership in Washington, citizen scientists picked up the slack.

Although the Chicago Tribune lampooned Lapham, wondering “what practical value” a warning service would provide “if it takes 10 years to calculate the progress of a storm,” Rep. Halbert E. Paine (Wis.), who had studied storms under Loomis, rushed a bill into Congress before the winter recess. In early 1870, a joint resolution establishing a storm-warning service under the U.S. Army Signal Office passed without debate. President Ulysses S. Grant signed it into law the following week.

Despite the mandate for an early-warning system, an aversion to predictions remained. Fiscal hawks could not justify an investment in erroneous forecasts, religious zealots could not stomach the hubris, and politicians wary of a skeptical public could not bear the fallout. In 1893, Agriculture Secretary J. Sterling Morton cut the salary of one of the country’s top weather scientists, Cleveland Abbe, by 25 percent, making an example out of him.

While Moore didn’t face consequences for his dereliction of duty, the Weather Bureau’s hurricane-forecasting methods gradually improved as the network expanded and technologies like radio emerged. The advent of aviation increased insight into the upper atmosphere; military research led to civilian weather radar, first deployed at Washington National Airport in 1947. By the 1950s, computers were ushering in the future of numerical forecasting. Meanwhile, public skepticism thawed as more people and businesses saw it in their best interests to trust experts.

In September 1961, a local news team decided to broadcast live from the Weather Bureau office in Galveston, Tex., as Hurricane Carla angled across the Gulf of Mexico. Leading the coverage was a young reporter named Dan Rather. “There is the eye of the hurricane right there,” he told his audience as the radar sweep brought the invisible into view. At the time, no one had seen a radar weather map televised before.

Rather realized that for viewers to comprehend the storm’s size, location and imminent danger, people needed a sense of scale. So he had a meteorologist draw the Texas coast on a transparent sheet of plastic, which Rather laid over the radarscope. Years later, he recalled that when he said “one inch equals 50 miles,” you could hear people in the studio gasp. The sight of the approaching buzz saw persuaded 350,000 Texans to evacuate their homes in what was then the largest weather-related evacuation in U.S. history. Ultimately, Carla inflicted twice as much damage as the Galveston hurricane 60 years earlier. But with the aid of Rather’s impromptu visualization, fewer than 50 lives were lost.

In other words, weather forecasting wasn’t only about good science, but about good communication and visuals.

Data visualization helped the public better understand the weather shaping their lives, and this enabled them to take action. It also gives us the power to see deadly storms not as freak occurrences, but as part of something else: a pattern.

A modified version of a chart that appears in “Atlas of the Invisible: Maps and Graphics That Will Change How You See the World.” Copyright © 2021 by James Cheshire and Oliver Uberti. With permission of the publisher, W.W. Norton & Co. All rights reserved.

Two hundred years ago, a 10-day forecast would have seemed preposterous. Now we can predict if we’ll need an umbrella tomorrow or a snowplow next week. Imagine if we planned careers, bought homes, built infrastructure and passed policy based on 50-year forecasts as routinely as we plan our weeks by five-day ones.

Unlike our predecessors of the 19th or even 20th centuries, we have access to ample climate data and data visualization that give us the knowledge to take bold actions. What we do with that knowledge is a matter of political will. It may be too late to stop the coming storm, but we still have time to board our windows.

Clima nos apavora justamente quando conseguimos sobreviver a ele (Folha de S.Paulo)

Luta contra o aquecimento global precisa de inovadores, e não de ativistas obcecados com o apocalipse

Leandro Narloch – artigo original aqui.

11.ago.2021 às 8h56

Na sua opinião, o que aconteceu nos últimos cem anos com o número total de mortes causadas por furacões, inundações, secas, ondas de calor e outros desastres climáticos? Peço que escolha uma destas alternativas:

  • a) Aumentou mais de 800%
  • b) Aumentou cerca de 50%
  • c) Manteve-se constante
  • d) Diminuiu cerca de 50%
  • e) Diminuiu mais de 80%

Como a população mundial cresceu de 1,8 bilhão em 1921 para 8 bilhões em 2021, é razoável cravar as respostas B ou C, pois o fato de haver mais pessoas resultaria em mais vítimas. Muitos leitores devem ter escolhido a primeira opção, tendo em vista as notícias assustadoras do relatório do IPCC desta semana.

A alternativa correta, porém, é a última. As mortes por desastres naturais diminuíram 87% desde a década de 1920 até os anos 2010, segundo dados coletados pelo Our World in Data.

Passaram de 540 mil por ano para 68 mil. A taxa em relação à população teve picos de 63 mortes por 100 mil habitantes em 1921, e 176 em 1931. Hoje está em 0,15.

Esses números levam a dois paradoxos interessantes sobre a relação entre o homem e o clima. O primeiro lembra o Paradoxo de Spencer –referência a Herbert Spencer, para quem “o grau de preocupação pública sobre um problema ou fenômeno social varia inversamente a sua incidência”.

Assim como os ingleses se deram conta da pobreza quando ela começava a diminuir, durante a Revolução Industrial, a humanidade está apavorada com os infortúnios do clima justamente depois de conseguir sobreviver a eles.

O segundo paradoxo: ao mesmo tempo em que emitimos muito (mas muito mesmo) carbono na atmosfera e causamos um grave problema de efeito estufa, também nos tornamos menos vulneráveis à natureza. Na verdade, proteger-se do clima foi um dos principais motivos para termos poluído tanto.

Veja o caso da construção. Produzir cimento consiste grosseiramente em queimar calcário e liberar dióxido de carbono.

Se a indústria de cimento fosse um país, seria o terceiro maior emissor de gases do efeito estufa. Mas essa indústria poluidora permitiu que as pessoas deixassem casas de pau-a-pique ou madeira para dormirem abrigadas em estruturas mais seguras.

Já a fome originada pela seca, principal causa de morte por desastres naturais nos anos 1920, foi resolvida com a criação dos fertilizantes químicos, sistemas de irrigação e a construção de represas e redes de saneamento.

Todas essas atividades causaram aquecimento global –mas não deixam de ser grandes conquistas humanas, que merecem ser celebradas e difundidas entre os pobres que ainda vivem sob risco de morrer durante furacões, secas ou inundações.

Será que a queda histórica das mortes por desastres naturais vai se reverter nos próximos anos, tornando realidade os vaticínios apocalípticos de Greta Thunberg, para quem “bilhões de pessoas morrerão se não tomarmos medidas urgentes”?

O ativista climático Michael Shellenberger, autor do brilhante “Apocalipse Nunca”, que será lançado este mês no Brasil pela editora LVM, acha que não.

Pretendo falar mais sobre o livro de Shellenberger em outras colunas, mas já adianto um dos argumentos: o alarmismo ambiental despreza a capacidade humana de se adaptar e resolver problemas.

“Os Países Baixos, por exemplo, tornaram-se uma nação rica mesmo tendo um terço de suas terras abaixo do nível do mar, incluindo áreas que estão nada menos do que sete metros abaixo do mar”, diz ele.

A luta contra o aquecimento global não precisa de ativistas obcecados com o apocalipse (que geralmente desprezam soluções óbvias, como a energia nuclear). Precisa de tecnologia, de inovadores, de gente que dê mais conforto e segurança à humanidade interferindo na natureza cada vez menos.

Previsão atualizada confirma temperatura de -0ºC em SP e neve no Sul (Cajamar Notícias)

[Previsão do tempo e previsão de mortes. Observar reação do poder público municipal.]

Se confirmada, a onda de frio será a maior do século, com geada generalizada e temperaturas negativas, o que pode provocar até morte. 25 de julho de 2021

Mapa mostra a intensidade da nova onda de frio e sua abrangência.

A última atualização dos modelos meteorológicos continuam mantendo a previsão de temperaturas negativas nos três Estados do Sul do Brasil e em áreas do Estado de São Paulo e Sul de Minas Gerais. A fortíssima massa de ar polar poderá ser a mais forte do século e causar prejuízos na agricultura e até mesmo morte de pessoas em situação de vulnerabilidade.


A frente fria que antecede a massa polar vai entrar no Brasil pelo Estado do Rio Grande do Sul na segunda-feira, dia 26, provocando chuva e acentuada queda de temperatura. No dia 27, terça-feira, a chuva já chega em Santa Cataria e no Paraná, fazendo a temperatura despencar rapidamente. Nas serras e áreas de planalto dos três Estados, a temperatura mínima já pode chegar a zero grau.

Na quarta, quinta, sexta e sábado, dias 28,29,30 e 31, praticamente todas as regiões do Sul do Brasil, exceto litoral, terão temperaturas negativas com possibilidade de geada negra, que pode matar a vegetação, provocando sérios prejuízos à agricultura.


Os modelos meteorológicos mantém a chance alta de neve nas serras do Rio Grande do Sul, Santa Catarina e até mesmo no planalto sul do Paraná, entre a noite de quarta-feira (28) e madrugada de quinta-feira (29), atingindo cidades, tais como: Canela/RS, Caxias do Sul/RS, São Joaquim/SC, Urupema/SC, Caçador/SC e Cruz Machado/PR. Confira o mapa abaixo:

Mapa mostra a região com chance de neve na madrugada de quinta-feira (29).


Na quarta-feira, dia 28, é a vez do Estado de São Paulo experimentar a volta da chuva, que não cairá em todas as regiões, mas manterá o céu nublado com ventos gélidos e temperatura máxima entre 17ºC e 18ºC enquanto as mínimas ficarão entre 5ºC a 10ºC na Grande São Paulo.

Na quinta-feira, dia 29, o Estado de São Paulo já vai amanhecer com muito frio. Temperaturas entre 1ºC e 7ºC serão registradas em toda a Grande São Paulo, Vale do Paraíba, Vale do Ribeira, regiões de Sorocaba, Bauru, Presidente Prudente e Campinas, conforme mapa abaixo:

Temperaturas previstas para o amanhecer de quinta-feira, dia 29 de julho, na Grande São Paulo, Vale do Paraíba e Ribeira, regiões de Campinas, Sorocaba, Bauru e Bragança Paulista.


A sexta-feira, dia 30 de julho de 2021, deverá ficar marcada na história da meteorologia. Se confirmada, será o dia mais frio do século, com geada generalizada no Estado de São Paulo e temperaturas negativas em várias regiões, o que pode provocar a morte de moradores de rua e/ou pessoas em vulnerabilidade.

Em praticamente todas as regiões do Estado de São Paulo, os modelos atuais indicam temperaturas negativas, conforme mapa baixo: (ATENÇÃO: As previsões podem mudar com o passar dos dias, essa é a indicação atual publicada no domingo, dia 25).

Mapa mostra o tamanho da massa de ar frio e temperatura prevista para o dia 30 a 1500 metros de altitude, com inacreditáveis -10ºC em áreas do Sul e faixa leste de São Paulo e até -5ºC nas demais regiões de São Paulo, Rio de Janeiro, sul e leste de Minas, Mato Grosso do Sul, Mato Grosso e Rondônia.

It’s so hot in Dubai the government is paying scientists to make it rain (Wasington Post)

Jonathan Edwards – July 21, 2021

Sunlight reflects off the Burj Khalifa, the world’s tallest building, during a rain shower in Dubai in 2018. (Jon Gambrell/AP)

Facing a hotter future, dwindling water sources and an exploding population, scientists in one Middle East country are making it rain.

United Arab Emirates meteorological officials released a video this week of cars driving through a downpour in Ras al Khaimah in the northern part of the country. The storm was the result of one of the UAE’s newest efforts to increase rainfall in a desert nation that gets about four inches a year on average.

Washington, D.C., in contrast, has averaged nearly 45 inches of rain annually for the past decade.

Scientists created rainstorms by launching drones, which then zapped clouds with electricity, the Independent reports. Jolting droplets in the clouds can cause them to clump together, researchers found. The larger raindrops that result then fall to the ground, instead of evaporating midair — which is often the fate of smaller droplets in the UAE, where temperatures are hot and the clouds are high.

“What we are trying to do is to make the droplets inside the clouds big enough so that when they fall out of the cloud, they survive down to the surface,” meteorologist and researcher Keri Nicoll told CNN in May as her team prepared to start testing the drones near Dubai.

Nicoll is part of a team of scientists with the University of Reading in England whose research led to this week’s man-made rainstorms. In 2017, the university’s scientists received $1.5 million for use over three years from the UAE Research Program for Rain Enhancement Science, which has invested in at least nine different research projects over the past five years.

To test their research, Nicoll and her team built four drones with wingspans of about 6½ feet. The drones, which are launched from a catapult, can fly for about 40 minutes, CNN reported. During flight, the drone’s sensors measure temperature, humidity and electrical charge within a cloud, which lets the researchers know when and where they need to zap.

Water is a big issue in the UAE. The country uses about 4 billion cubic meters of it each year but has access to about 4 percent of that in renewable water resources, according to the CIA. The number of people living in the UAE has skyrocketed in recent years, doubling to 8.3 million between 2005 and 2010, which helps explain why demand for water spiked by a third around that time, according to the government’s 2015 “State of Environment” report. The population kept surging over the next decade and is now 9.9 million.

“The water table is sinking drastically in [the] UAE,” University of Reading professor and meteorologist Maarten Ambaum told BBC News, “and the purpose of this [project] is to try to help with rainfall.”

It usually rains just a few days out of the year in the UAE. During the summer, there’s almost no rainfall. Temperatures there recently topped 125 degrees.

In recent years, the UAE’s massive push into desalination technology — which transforms seawater into freshwater by removing the salt — has helped close the gap between the demand for water and supply. Most of the UAE’s drinkable water, and 42 percent of all water used in the country, comes from its roughly 70 desalination plants, according to the UAE government.

Still, part of the government’s “water security strategy” is to lower demand by 21 percent in the next 15 years.

Ideas to get more water for the UAE have not lacked imagination. In 2016, The Washington Post reported government officials were considering building a mountain to create rainfall. As moist air reaches a mountain, it is forced upward, cooling as it rises. The air can then condense and turn into liquid, which falls as rain.

Estimates for another mountain-building project in the Netherlands came in as high as $230 billion.

Other ideas for getting more water to the UAE have included building a pipeline from Pakistan and floating icebergs down from the Arctic.

Study finds humans are directly influencing wind and weather over North Atlantic (EurekaAlert!)

News Release 17-Apr-2021

The findings suggest that winters in Europe and in eastern US may get warmer and wetter

University of Miami Rosenstiel School of Marine & Atmospheric Science

Research News

IMAGE: The Positive NAO index phase shows a stronger than usual subtropical high pressure center and a deeper than normal Icelandic low. The increased pressure difference results in more and stronger… view more  Credit: Columbia University Lamont-Doherty Earth Observatory.

MIAMI–A new study led by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science provides evidence that humans are influencing wind and weather patterns across the eastern United States and western Europe by releasing CO2 and other pollutants into Earth’s atmosphere.

In the new paper, published in the journal npj Climate and Atmospheric Science, the research team found that changes in the last 50 years to an important weather phenomenon in the North Atlantic–known as the North Atlantic Oscillation–can be traced back to human activities that impact the climate system.

“Scientists have long understood that human actions are warming the planet,” said the study’s lead author Jeremy Klavans, a UM Rosenstiel School alumnus. “However, this human-induced signal on weather patterns is much harder to identify.”

“In this study, we show that humans are influencing patterns of weather and climate over the Atlantic and that we may be able to use this information predict changes in weather and climate up to a decade in advance,” said Klavans.

The North Atlantic Oscillation, the result of fluctuations in air pressure across the Atlantic, affects weather by influencing the intensity and location of the jet stream. This oscillation has a strong effect on winter weather in Europe, Greenland, the northeastern U.S. and North Africa and the quality of crop yields and productivity of fisheries in the North Atlantic.

The researchers used multiple large climate model ensembles, compiled by researchers at the National Center for Atmospheric Research, to predict the North Atlantic Oscillation. The analysis consisted of 269 model runs, which is over 14,000 simulated model years.

The study, titled “NAO Predictability from External Forcing in the Late Twentieth Century,” was published on March 25 in the journal npj Climate and Atmospheric Science. The study’s authors include: Klavans, Amy Clement and Lisa Murphy from the UM Rosenstiel School, and Mark Cane from Columbia University’s Lamont-Doherty Earth Observatory.

The study was supported by the National Science Foundation (NSF) Climate and Large-Scale Dynamics program (grant # AGS 1735245 and AGS 1650209), NSF Paleo Perspectives on Climate Change program (grant # AGS 1703076) and NOAA’s Climate Variability and Predictability Program.

New study ties solar variability to the onset of decadal La Nina events (Science Daily)

[Linking solar activity to the onset of droughts in places like Northeast Brazil has historically been treated as something that did not deserve attention by mainstream meteorology. The El Niño Southern Oscillation – of which La Niña is part – was always presented as the main causal factor for droughts. This new study connects solar activity with the La Niña. The interesting thing here is that many local farmers seen as knowledgeable about rains and drought in NE Brazil mention a 10 years period for the repetition of climate events. -RT]

Date: April 5, 2021

Source: National Center for Atmospheric Research/University Corporation for Atmospheric Research

Summary: A new study shows a correlation between the end of solar cycles and a switch from El Nino to La Nina conditions in the Pacific Ocean, suggesting that solar variability can drive seasonal weather variability on Earth.

A new study shows a correlation between the end of solar cycles and a switch from El Nino to La Nina conditions in the Pacific Ocean, suggesting that solar variability can drive seasonal weather variability on Earth.

If the connection outlined in the journal Earth and Space Science holds up, it could significantly improve the predictability of the largest El Nino and La Nina events, which have a number of seasonal climate effects over land. For example, the southern United States tends to be warmer and drier during a La Nina, while the northern U.S. tends to be colder and wetter.

“Energy from the Sun is the major driver of our entire Earth system and makes life on Earth possible,” said Scott McIntosh, a scientist at the National Center for Atmospheric Research (NCAR) and co-author of the paper. “Even so, the scientific community has been unclear on the role that solar variability plays in influencing weather and climate events here on Earth. This study shows there’s reason to believe it absolutely does and why the connection may have been missed in the past.”

The study was led by Robert Leamon at the University of Maryland-Baltimore County, and it is also co-authored by Daniel Marsh at NCAR. The research was funded by the National Science Foundation, which is NCAR’s sponsor, and the NASA Living With a Star program.

Applying a new solar clock

The appearance (and disappearance) of spots on the Sun — the outwardly visible signs of solar variability — have been observed by humans for hundreds of years. The waxing and waning of the number of sunspots takes place over approximately 11-year cycles, but these cycles do not have distinct beginnings and endings. This fuzziness in the length of any particular cycle has made it challenging for scientists to match up the 11-year cycle with changes happening on Earth.

In the new study, the researchers rely on a more precise 22-year “clock” for solar activity derived from the Sun’s magnetic polarity cycle, which they outlined as a more regular alternative to the 11-year solar cycle in several companion studies published recently in peer-reviewed journals.

The 22-year cycle begins when oppositely charged magnetic bands that wrap the Sun appear near the star’s polar latitudes, according to their recent studies. Over the cycle, these bands migrate toward the equator — causing sunspots to appear as they travel across the mid-latitudes. The cycle ends when the bands meet in the middle, mutually annihilating one another in what the research team calls a terminator event. These terminators provide precise guideposts for the end of one cycle and the beginning of the next.

The researchers imposed these terminator events over sea surface temperatures in the tropical Pacific stretching back to 1960. They found that the five terminator events that occurred between that time and 2010-11 all coincided with a flip from an El Nino (when sea surface temperatures are warmer than average) to a La Nina (when the sea surface temperatures are cooler than average). The end of the most recent solar cycle — which is unfolding now — is also coinciding with the beginning of a La Nina event.

“We are not the first scientists to study how solar variability may drive changes to the Earth system,” Leamon said. “But we are the first to apply the 22-year solar clock. The result — five consecutive terminators lining up with a switch in the El Nino oscillation — is not likely to be a coincidence.”

In fact, the researchers did a number of statistical analyses to determine the likelihood that the correlation was just a fluke. They found there was only a 1 in 5,000 chance or less (depending on the statistical test) that all five terminator events included in the study would randomly coincide with the flip in ocean temperatures. Now that a sixth terminator event — and the corresponding start of a new solar cycle in 2020 — has also coincided with an La Nina event, the chance of a random occurrence is even more remote, the authors said.

The paper does not delve into what physical connection between the Sun and Earth could be responsible for the correlation, but the authors note that there are several possibilities that warrant further study, including the influence of the Sun’s magnetic field on the amount of cosmic rays that escape into the solar system and ultimately bombard Earth. However, a robust physical link between cosmic rays variations and climate has yet to be determined.

“If further research can establish that there is a physical connection and that changes on the Sun are truly causing variability in the oceans, then we may be able to improve our ability to predict El Nino and La Nina events,” McIntosh said.

Story Source:

Materials provided by National Center for Atmospheric Research/University Corporation for Atmospheric Research. Original written by Laura Snider. Note: Content may be edited for style and length.

Journal Reference:

  1. Robert J. Leamon, Scott W. McIntosh, Daniel R. Marsh. Termination of Solar Cycles and Correlated Tropospheric Variability. Earth and Space Science, 2021; 8 (4) DOI: 10.1029/2020EA001223

NOAA Acknowledges the New Reality of Hurricane Season (Gizmodo)

Molly Taft, March 2, 2021

This combination of satellite images provided by the National Hurricane Center shows 30 hurricanes that occurred during the 2020 Atlantic hurricane season.
This combination of satellite images provided by the National Hurricane Center shows 30 hurricanes that occurred during the 2020 Atlantic hurricane season.

We’re one step closer to officially moving up hurricane season. The National Hurricane Center announced Tuesday that it would formally start issuing its hurricane season tropical weather outlooks on May 15 this year, bumping it up from the traditional start of hurricane season on June 1. The move comes after a recent spate of early season storms have raked the Atlantic.

Atlantic hurricane season runs from June 1 to November 30. That’s when conditions are most conducive to storm formation owing to warm air and water temperatures. (The Pacific ocean has its own hurricane season, which covers the same timeframe, but since waters are colder fewer hurricanes tend to form there than in the Atlantic.)

Storms have begun forming on the Atlantic earlier as ocean and air temperatures have increased due to climate change. Last year, Hurricane Arthur roared to life off the East Coast on May 16. That storm made 2020 the sixth hurricane season in a row to have a storm that formed earlier than the June 1 official start date. While the National Oceanic and Atmospheric Administration won’t be moving up the start of the season just yet, the earlier outlooks addresses the recent history.

“In the last decade, there have been 10 storms formed in the weeks before the traditional start of the season, which is a big jump,” said Sean Sublette, a meteorologist at Climate Central, who pointed out that the 1960s through 2010s saw between one and three storms each decade before the June 1 start date on average.

It might be tempting to ascribe this earlier season entirely to climate change warming the Atlantic. But technology also has a role to play, with more observations along the coast as well as satellites that can spot storms far out to sea.

“I would caution that we can’t just go, ‘hah, the planet’s warming, we’ve had to move the entire season!’” Sublette said. “I don’t think there’s solid ground for attribution of how much of one there is over the other. Weather folks can sit around and debate that for awhile.”

Earlier storms don’t necessarily mean more harmful ones, either. In fact, hurricanes earlier in the season tend to be weaker than the monsters that form in August and September when hurricane season is at its peak. But regardless of their strength, these earlier storms have generated discussion inside the NHC on whether to move up the official start date for the season, when the agency usually puts out two reports per day on hurricane activity. Tuesday’s step is not an official announcement of this decision, but an acknowledgement of the increased attention on early hurricanes.

“I would say that [Tuesday’s announcement] is the National Hurricane Center being proactive,” Sublette said. “Like hey, we know that the last few years it’s been a little busier in May than we’ve seen in the past five decades, and we know there is an awareness now, so we’re going to start issuing these reports early.”

While the jury is still out on whether climate change is pushing the season earlier, research has shown that the strongest hurricanes are becoming more common, and that climate change is likely playing a role. A study published last year found the odds of a storm becoming a major hurricanes—those Category 3 or stronger—have increase 49% in the basin since satellite monitoring began in earnest four decades ago. And when storms make landfall, sea level rise allows them to do more damage. So regardless of if climate change is pushing Atlantic hurricane season is getting earlier or not, the risks are increasing. Now, at least, we’ll have better warnings before early storms do hit.

New study detects ringing of the global atmosphere (Science Daily)

Date: July 7, 2020

Source: University of Hawaii at Manoa

Summary: A ringing bell vibrates simultaneously at a low-pitched fundamental tone and at many higher-pitched overtones, producing a pleasant musical sound. A recent study shows that the Earth’s entire atmosphere vibrates in an analogous manner, in a striking confirmation of theories developed by physicists over the last two centuries.  

A ringing bell vibrates simultaneously at a low-pitched fundamental tone and at many higher-pitched overtones, producing a pleasant musical sound. A recent study, just published in the Journal of the Atmospheric Sciences by scientists at Kyoto University and the University of Hawaii at Manoa, shows that the Earth’s entire atmosphere vibrates in an analogous manner, in a striking confirmation of theories developed by physicists over the last two centuries.

In the case of the atmosphere, the “music” comes not as a sound we could hear, but in the form of large-scale waves of atmospheric pressure spanning the globe and traveling around the equator, some moving east-to-west and others west-to-east. Each of these waves is a resonant vibration of the global atmosphere, analogous to one of the resonant pitches of a bell. The basic understanding of these atmospheric resonances began with seminal insights at the beginning of the 19th century by one of history’s greatest scientists, the French physicist and mathematician Pierre-Simon Laplace. Research by physicists over the subsequent two centuries refined the theory and led to detailed predictions of the wave frequencies that should be present in the atmosphere. However, the actual detection of such waves in the real world has lagged behind the theory.

Now in a new study by Takatoshi Sakazaki, an assistant professor at the Kyoto University Graduate School of Science, and Kevin Hamilton, an Emeritus Professor in the Department of Atmospheric Sciences and the International Pacific Research Center at the University of Hawaii at Manoa, the authors present a detailed analysis of observed atmospheric pressure over the globe every hour for 38 years. The results clearly revealed the presence of dozens of the predicted wave modes.

The study focused particularly on waves with periods between 2 hours and 33 hours which travel horizontally through the atmosphere, moving around the globe at great speeds (exceeding 700 miles per hour). This sets up a characteristic “chequerboard” pattern of high and low pressure associated with these waves as they propagate.

“For these rapidly moving wave modes, our observed frequencies and global patterns match those theoretically predicted very well,” stated lead author Sakazaki. “It is exciting to see the vision of Laplace and other pioneering physicists so completely validated after two centuries.”

But this discovery does not mean their work is done.

“Our identification of so many modes in real data shows that the atmosphere is indeed ringing like a bell,” commented co-author Hamilton. “This finally resolves a longstanding and classic issue in atmospheric science, but it also opens a new avenue of research to understand both the processes that excite the waves and the processes that act to damp the waves.”

So let the atmospheric music play on!

Story Source:

Materials provided by University of Hawaii at Manoa. Note: Content may be edited for style and length.

Journal Reference:

  1. Takatoshi Sakazaki, Kevin Hamilton. An Array of Ringing Global Free Modes Discovered in Tropical Surface Pressure Data. Journal of the Atmospheric Sciences, 2020; 77 (7): 2519 DOI: 10.1175/JAS-D-20-0053.1

Cold War nuke tests changed rainfall (Science Daily)

Radioactive period following nuclear bomb tests changed rainfall patterns thousands of miles from the detonation sites

Date: May 13, 2020

Source: University of Reading

Summary: Historic records from weather stations show that rainfall patterns in Scotland were affected by charge in the atmosphere released by radiation from nuclear bomb tests carried out in the 1950s and ’60s.

Nuclear bomb tests during the Cold War may have changed rainfall patterns thousands of miles from the detonation sites, new research has revealed.

Scientists at the University of Reading have researched how the electric charge released by radiation from the test detonations, carried out predominantly by the US and Soviet Union in the 1950s and 1960s, affected rainclouds at the time.

The study, published in Physical Review Letters, used historic records between 1962-64 from a research station in Scotland. Scientists compared days with high and low radioactively-generated charge, finding that clouds were visibly thicker, and there was 24% more rain on average on the days with more radioactivity.

Professor Giles Harrison, lead author and Professor of Atmospheric Physics at the University of Reading, said: “By studying the radioactivity released from Cold War weapons tests, scientists at the time learnt about atmospheric circulation patterns. We have now reused this data to examine the effect on rainfall.

“The politically charged atmosphere of the Cold War led to a nuclear arms race and worldwide anxiety. Decades later, that global cloud has yielded a silver lining, in giving us a unique way to study how electric charge affects rain.”

It has long been thought that electric charge modifies how water droplets in clouds collide and combine, potentially affecting the size of droplets and influencing rainfall, but this is difficult to observe in the atmosphere. By combining the bomb test data with weather records, the scientists were able to retrospectively investigate this.

Through learning more about how charge affects non-thunderstorm clouds, it is thought that scientists will now have a better understanding of important weather processes.

The race to develop nuclear weapons was a key feature of the Cold War, as the world’s superpowers sought to demonstrate their military capabilities during heightened tensions following the Second World War.

Although detonations were carried out in remote parts of the world, such as the Nevada Desert in the US, and on Pacific and Arctic islands, radioactive pollution spread widely throughout the atmosphere. Radioactivity ionises the air, releasing electric charge.

The researchers, from the Universities of Reading, Bath and Bristol, studied records from well-equipped Met Office research weather stations at Kew near London and Lerwick in the Shetland Isles.

Located 300 miles north west of Scotland, the Shetland site was relatively unaffected by other sources of anthropogenic pollution. This made it well suited as a test site to observe rainfall effects which, although likely to have occurred elsewhere too, would be much more difficult to detect.

Atmospheric electricity is most easily measured on fine days, so the Kew measurements were used to identify nearly 150 days where there was high or low charge generation over the UK while it was cloudy in Lerwick. The Shetland rainfall on these days showed differences which vanished after the major radioactivity episode was over.

The findings may be helpful for cloud-related geoengineering research, which is exploring how electric charge could influence rain, relieve droughts or prevent floods, without the use of chemicals.

Professor Harrison is leading a project investigating electrical effects on dusts and clouds in the United Arab Emirates, as part of their national programme in Rain Enhancement Science. These new findings will help to show the typical charges possible in natural non-thunderstorm clouds.

WMO is concerned about impact of COVID-19 on observing system (WMO)

WMO concerned about impact of COVID19 on global observing system

1 April 2020 Press Release Number: 01042020

Geneva, 1 April 2020 – The World Meteorological Organization (WMO) is concerned about the impact of the COVID-19 pandemic on the quantity and quality of weather observations and forecasts, as well as atmospheric and climate monitoring.

WMO’s Global Observing System serves as a backbone for all weather and climate services and products provided by the 193 WMO Member states and territories to their citizens. It provides observations on the state of the atmosphere and ocean surface from land-, marine- and space-based instruments. This data is used for the preparation of weather analyses, forecasts, advisories and warnings.

“National Meteorological and Hydrological Services continue to perform their essential 24/7 functions despite the severe challenges posed by the Coronavirus pandemic,” said WMO Secretary-General Petteri Taalas. “We salute their dedication to protecting lives and property but we are mindful of the increasing constraints on capacity and resources,” he said.

“The impacts of climate change and growing amount of weather-related disasters continue. The COVID-19 pandemic poses an additional challenge, and may exacerbate multi-hazard risks at a single country level. Therefore it is essential that governments pay attention to their national early warning and weather observing capacities despite the COVID-19 crisis,” said Mr Taalas.

Large parts of the observing system, for instance its satellite components and many ground-based observing networks, are either partly or fully automated. They are therefore expected to continue functioning without significant degradation for several weeks, in some cases even longer. But if the pandemic lasts more than a few weeks, then missing repair, maintenance and supply work, and missing redeployments will become of increasing concern.

Some parts of the observing system are already affected. Most notably the significant decrease in air traffic has had a clear impact. In-flight measurements of ambient temperature and wind speed and direction are a very important source of information for both weather prediction and climate monitoring.

AMDAR observation - March 2020

Meteorological data from aircraft

Commercial airliners contribute to the Aircraft Meteorological Data Relay programme (AMDAR), which uses onboard sensors, computers and communications systems to collect, process, format and transmit meteorological observations to ground stations via satellite or radio links.

In some parts of the world, in particular over Europe, the decrease in the number of measurements over the last couple of weeks has been dramatic (see chart below provided by EUMETNET).  The countries affiliated with EUMETNET, a collaboration between the 31 national weather services in Europe, are currently discussing ways to boost the short-term capabilities of other parts of their observing networks in order to partly mitigate this loss of aircraft observations.

The AMDAR observing system has traditionally produced over 700 000 high-quality observations per day of air temperature and wind speed and direction, together with the required positional and temporal information, and with an increasing number of humidity and turbulence measurements being made.

Surface-based observations

In most developed countries, surface-based weather observations are now almost fully automated.

However, in many developing countries, the transition to automated observations is still in progress, and the meteorological community still relies on observations taken manually by weather observers and transmitted into the international networks for use in global weather and climate models.

WMO has seen a significant decrease in the availability of this type of manual observations over the last two weeks. Some of this may well be attributable to the current coronavirus situation, but it is not yet clear whether other factors may play a role as well. WMO is currently investigating this.

“At the present time, the adverse impact of the loss of observations on the quality of weather forecast products is still expected to be relatively modest. However, as the decrease in availability of aircraft weather observations continues and expands, we may expect a gradual decrease in reliability of the forecasts,” said Lars Peter Riishojgaard, Director, Earth System Branch in WMO’s Infrastructure Department.

“The same is true if the decrease in surface-based weather observations continues, in particular if the COVID-19 outbreak starts to more widely impact the ability of observers to do their job in large parts of the developing world. WMO will continue to monitor the situation, and the organization is working with its Members to mitigate the impact as much as possible,” he said.

Variability of surface observations - January 2020
(Map provided by WMO; countries shown in darker colors provided fewer observations over the last week than averaged for the month of January 2020 (pre-COVID-19); countries shown in black are currently not sending any data at all).

Currently, there are 16 meteorological and 50 research satellites, over 10 000 manned and automatic surface weather stations, 1 000 upper-air stations, 7 000 ships, 100 moored and 1 000 drifting buoys, hundreds of weather radars and 3 000 specially equipped commercial aircraft measure key parameters of the atmosphere, land and ocean surface every day. 

For further information contact: Clare Nullis, media officer. Email, Cell +41 79 709 13 97

See original article here.

Meteorologia pode sofrer impacto com covid-19, diz WMO (Climatempo)

02/04/2020 – por redação

Organização Meteorológica Mundial (WMO) teme que coronavírus influencie na qualidade das previsões e no monitoramento da atmosfera

A Organização Meteorológica Mundial (Word Meteorological Organization, WMO, na sigla em inglês) está preocupada com o impacto da pandemia do covid-19 na quantidade e qualidade das observações e previsões meteorológicas, bem como no monitoramento da atmosfera e do clima.

O Sistema de Observação Global da WMO serve como espinha dorsal de todos os serviços e produtos climáticos fornecidos a seus cidadãos pelos 193 estados e territórios membros da organização. Ele fornece observações sobre o estado da atmosfera e da superfície do oceano a partir de instrumentos terrestres, marinhos e espaciais. Estes dados são utilizados para a preparação de análises meteorológicas, previsão do tempo e monitoramento do clima.

“Os Serviços Meteorológicos e Hidrológicos Nacionais continuam desempenhando suas funções essenciais 24 horas por dia e sete dias por semana, apesar dos graves desafios impostos pela pandemia de coronavírus”, disse o secretário-geral da WMO, Petteri Taalas. “Saudamos sua dedicação em proteger vidas e propriedades, mas estamos atentos às crescentes restrições de capacidade e recursos”.

Taalas afirmou ainda que os impactos das mudanças climáticas e a crescente quantidade de desastres relacionados ao clima continuam. “A pandemia do Covid-19 representa um desafio que  grava os riscos de vários perigos em um único país. Portanto, é essencial que os governos prestem  atenção em seu alerta nacional e às capacidades de observação do clima, apesar da crise do Covid-19”.

Grande parte do sistema de observação, como os componentes de satélite e redes de observação terrestres, por exemplo, são parcialmente ou totalmente automatizados. Por isso, espera-se que continuem funcionando sem problemas significativos por várias semanas, em alguns casos até mais. Porém, se a pandemia durar mais de algumas semanas, a falta de reparos, manutenção e suprimentos, e as redistribuições se tornarão uma preocupação crescente.

Algumas partes do sistema de observação já estão sendo afetadas, com destaque para a diminuição significativa do tráfego aéreo. As medições de temperatura ambiente e da velocidade e direção do vento em voo são uma fonte muito importante de informações para a previsão do tempo e monitoramento do clima.

Dados meteorológicos de aeronaves 

Aviões comerciais contribuem para o programa “Airbus Meteorological Data Relay” (AMDAR), que usa sensores, computadores e sistemas de comunicação a bordo para coletar, processar, formatar e transmitir observações meteorológicas para estações terrestres via satélite ou rádio.

Em algumas partes do mundo, em particular na Europa, a diminuição do número de medições nas últimas duas semanas tem sido dramática.  Veja o gráfico fornecido pela  EUMETNET.

Total de observações do sistema AMDAR em março de 2020 (Fonte: WMO)

Os países afiliados à EUMETNET, que reúne 31 serviços meteorológicos nacionais na Europa, estão atualmente discutindo maneiras de aumentar as capacidades de curto prazo de outras partes de suas redes de observação, a fim de diminuir parcialmente a perda de observações de aeronaves.

O sistema de observação AMDAR normalmente produzia por dia mais de 700 mil observações de alta qualidade de temperatura do ar, velocidade e direção do vento. Além disso, fornecia informações posicionais e temporais necessárias, com número crescente de medições de umidade e turbulência.

Observações baseadas em superfície

Na maioria dos países desenvolvidos, as observações meteorológicas de superfície são quase totalmente automatizadas. No entanto, em muitos países em desenvolvimento, como é o caso do Brasil, a transição para observações automatizadas ainda está em andamento, e a comunidade meteorológica ainda depende de observações feitas manualmente por observadores, que as transmitem às redes internacionais para uso em modelos globais de tempo e clima.

A WMO registrou diminuição significativa na disponibilidade de observação manual nas últimas duas semanas. Parte disso pode estar relacionada à situação atual de coronavírus, mas ainda não está claro se outros fatores também podem ter contribuído. A WMO está investigando outras possíveis causas.

Atualmente, o impacto adverso da perda de observações na qualidade dos produtos para previsão do tempo ainda é relativamente pequeno. No entanto, à medida que a diminuição na disponibilidade de observações meteorológicas das aeronaves continua e se expande, podemos esperar uma queda gradual na confiabilidade das previsões”, disse Lars Peter Riishojgaard, diretor da filial do sistema terrestre no departamento de infraestrutura da WMO.

Segundo Riishojgaard, o mesmo vale se a diminuição das observações meteorológicas na superfície continuar e, em particular, se o surto de covid-19 começar a impactar de forma mais significativa a capacidade de trabalho de observadores em países subdesenvolvidos. “A WMO continuará monitorando a situação, e a organização está trabalhando com seus membros para mitigar o impacto o máximo possível”, afirmou.

Mapa fornecido pela WMO: os países mostrados em cores mais escuras forneceram menos observações na última semana do que a média do mês de janeiro de 2020 (pré-covid-19); os países mostrados em preto atualmente não estão enviando nenhum dado.

Atualmente, existem 16 satélites meteorológicos e 50 de pesquisa no mundo, além de mais de 10 mil estações meteorológicas de superfície automáticas e tripuladas, mil estações aéreas, 7 mil navios, 100 bóias ancoradas e mil flutuantes, centenas de radares meteorológicos e 3 mil estações comerciais especialmente equipadas em aeronaves, que medem parâmetros-chave da atmosfera, da terra e da superfície do oceano todos os dias.

Tradução e adaptação de Paula Soares e Amanda Sampaio, do conteúdo publicado no site da WMO – World Meteorological Organization.

Link da matéria original no site da WMO:

Link da matéria no site da Climatempo:

Distant tropical storms have ripple effects on weather close to home (Science Daily)

Researchers describe a breakthrough in making accurate predictions of weather weeks ahead

February 20, 2018
Colorado State University
Researchers report a breakthrough in making accurate predictions of weather weeks ahead. They’ve created an empirical model fed by careful analysis of 37 years of historical weather data. Their model centers on the relationship between two well-known global weather patterns: the Madden-Julian Oscillation and the quasi-biennial oscillation.

Storm clouds (stock image). Credit: © mdesigner125 / Fotolia

The famously intense tropical rainstorms along Earth’s equator occur thousands of miles from the United States. But atmospheric scientists know that, like ripples in a pond, tropical weather creates powerful waves in the atmosphere that travel all the way to North America and have major impacts on weather in the U.S.

These far-flung, interconnected weather processes are crucial to making better, longer-term weather predictions than are currently possible. Colorado State University atmospheric scientists, led by professors Libby Barnes and Eric Maloney, are hard at work to address these longer-term forecasting challenges.

In a new paper in npj Climate and Atmospheric Science, the CSU researchers describe a breakthrough in making accurate predictions of weather weeks ahead. They’ve created an empirical model fed by careful analysis of 37 years of historical weather data. Their model centers on the relationship between two well-known global weather patterns: the Madden-Julian Oscillation and the quasi-biennial oscillation.

According to the study, led by former graduate researcher Bryan Mundhenk, the model, using both these phenomena, allows skillful prediction of the behavior of major rain storms, called atmospheric rivers, three and up to five weeks in advance.

“It’s impressive, considering that current state-of-the-art numerical weather models, such as NOA’s Global Forecast System, or the European Centre for Medium-Range Weather Forecasts’ operational model, are only skillful up to one to two weeks in advance,” says paper co-author Cory Baggett, a postdoctoral researcher in the Barnes and Maloney labs.

The researchers’ chief aim is improving forecast capabilities within the tricky no-man’s land of “subseasonal to seasonal” timescales: roughly three weeks to three months out. Predictive capabilities that far in advance could save lives and livelihoods, from sounding alarms for floods and mudslides to preparing farmers for long dry seasons. Barnes also leads a federal NOAA task force for improving subseasonal to seasonal forecasting, with the goal of sharpening predictions for hurricanes, heat waves, the polar vortex and more.

Atmospheric rivers aren’t actual waterways, but”rivers in the sky,” according to researchers. They’re intense plumes of water vapor that cause extreme precipitation, plumes so large they resemble rivers in satellite pictures. These “rivers” are responsible for more than half the rainfall in the western U.S.

The Madden-Julian Oscillation is a cluster of rainstorms that moves east along the Equator over 30 to 60 days. The location of the oscillation determines where atmospheric waves will form, and their eventual impact on say, California. In previous work, the researchers have uncovered key stages of the Madden-Julian Oscillation that affect far-off weather, including atmospheric rivers.

Sitting above the Madden-Julian Oscillation is a very predictable wind pattern called the quasi-biennial oscillation. Over two- to three-year periods, the winds shift east, west and back east again, and almost never deviate. This pattern directly affects the Madden-Julian Oscillation, and thus indirectly affects weather all the way to California and beyond.

The CSU researchers created a model that can accurately predict atmospheric river activity in the western U.S. three weeks from now. Its inputs include the current state of the Madden-Julian Oscillation and the quasi-biennial oscillation. Using information on how atmospheric rivers have previously behaved in response to these oscillations, they found that the quasi-biennial oscillation matters — a lot.

Armed with their model, the researchers want to identify and understand deficiencies in state-of-the-art numerical weather models that prevent them from predicting weather on these subseasonal time scales.

“It would be worthwhile to develop a good understanding of the physical relationship between the Madden-Julian Oscillation and the quasi-biennial oscillation, and see what can be done to improve models’ simulation of this relationship,” Mundhenk said.

Another logical extension of their work would be to test how well their model can forecast actual rainfall and wind or other severe weather, such as tornadoes and hail.

Journal Reference:

  1. Bryan D. Mundhenk, Elizabeth A. Barnes, Eric D. Maloney, Cory F. Baggett. Skillful empirical subseasonal prediction of landfalling atmospheric river activity using the Madden–Julian oscillation and quasi-biennial oscillation. npj Climate and Atmospheric Science, 2018; 1 (1) DOI: 10.1038/s41612-017-0008-2

Nível do mar na costa brasileira tende a aumentar nas próximas décadas (Pesquisa Fapesp)

05 de junho de 2017

Elton Alisson | Agência FAPESP – O nível do mar na costa brasileira tende a aumentar nas próximas décadas. No Brasil, contudo, onde mais de 60% da população vive em cidades costeiras, não há um estudo integrado da vulnerabilidade dos municípios litorâneos a este e a outros impactos decorrentes das mudanças climáticas, como o aumento da frequência e da intensidade de chuvas. Um estudo desse gênero possibilitaria estimar os danos sociais, econômicos e ambientais e elaborar um plano de ação com o intuito de implementar medidas adaptativas.

As conclusões são do relatório especial do Painel Brasileiro de Mudanças Climáticas (PBMC) sobre “Impacto, vulnerabilidade e adaptação das cidades costeiras brasileiras às mudanças climáticas”, lançado nesta segunda-feira (05/06) durante um evento no Museu do Amanhã, no Rio de Janeiro.

A publicação tem apoio da FAPESP e parte dos estudos nos quais se baseia são resultado do Projeto Metrópole e de outros projetos apoiados pela Fundação no âmbito do Programa FAPESP de Pesquisa sobre Mudanças Climáticas Globais (PFPMCG) e do Instituto Nacional de Ciência e Tecnologia (INCT) para Mudanças Climáticas, financiado pela Fundação e pelo Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).

“A ideia do relatório foi mostrar o estado da arte sobre mudanças de clima e cidades costeiras, baseado em uma exaustiva revisão de publicações internacionais e nacionais sobre o tema, e também identificar lacunas no conhecimento para que os formuladores de políticas públicas e tomadores de decisão no Brasil possam propor e implementar medidas de adaptação”, disse José Marengo, coordenador-geral de pesquisa e desenvolvimento do Centro Nacional de Monitoramento e Alertas de Desastres Naturais (Cemaden) e um dos autores e editores do relatório, à Agência FAPESP.

De acordo com dados do documento, entre 1901 e 2010 o nível médio do mar globalmente aumentou 19 centímetros – com variação entre 17 e 21 centímetros.

Entre 1993 e 2010, a taxa de elevação correspondeu a mais de 3,2 milímetros (mm) por ano – com variação entre 2,8 e 3,6 mm por ano.

No Brasil também há uma tendência de aumento do nível do mar nas regiões costeiras com algum grau de incerteza porque não há registros históricos contínuos e confiáveis, ponderam os autores.

“Ainda não conseguimos detectar o aumento do nível do mar no Brasil por conta das poucas observações existentes e de estudos de modelagem para avaliar os impactos. Mas já identificamos por meio de estudos regionais diversas cidades de médio e grande porte que apresentam alta exposição à elevação do nível relativo do mar e já têm sofrido os impactos desse fenômeno, particularmente na forma de ressacas e inundações”, disse Marengo.

Entre essas cidades, onde 60% da população reside na faixa de 60 quilômetros da costa, estão Rio Grande (RS), Laguna e Florianópolis (SC), Paranaguá (PR), Santos (SP), Rio de Janeiro (RJ), Vitória (ES), Salvador (BA), Maceió (AL), Recife (PE), São Luís (MA), Fortaleza (CE) e Belém (PA).

Nos estados de São Paulo e do Rio de Janeiro, por exemplo, têm sido registradas taxas de aumento do nível médio do mar de 1,8 a 4,2 mm por ano desde a década de 1950.

Na cidade de Santos, no litoral sul paulista, onde está situado o maior porto da América Latina, o nível do mar tem aumentado 1,2 mm por ano, em média, desde a década de 1940. Além disso, ocorreu um aumento significativo na altura das ondas – que alcançava 1 metro em 1957 e passou a atingir 1,3 m, em 2002 – e na frequência de ressacas no município.

Já no Rio de Janeiro, a análise dos dados da estação maregráfica da Ilha Fiscal – que tem a série histórica mais antiga do Brasil e fica no meio da Baía da Guanabara – indica uma tendência média de aumento do nível do mar de mais ou menos 1,3 mm por ano, com base nos dados mensais do nível do mar do período de 1963 a 2011 e com um índice de confiança de 95%.

Por sua vez, em Recife o nível do mar aumentou 5,6 mm entre 1946 e 1988 – o que corresponde a uma elevação de 24 centímetros em 42 anos. A erosão costeira e a ocupação do pós-praia provocaram uma redução da linha de praia em mais de 20 metros na Praia de Boa Viagem – a área da orla mais valorizada da cidade –, apontam os autores do relatório.

“Existem poucas observações como essas em outras regiões do país. Quando tentamos levantar dados dos últimos 40 ou 100 anos sobre o aumento do nível do mar em outras cidades do Nordeste, como Fortaleza, por exemplo, é difícil encontrar”, disse Marengo.

Impactos socioeconômicos

De acordo com os autores do relatório, as mudanças climáticas e um acelerado ritmo de elevação do nível do mar podem causar sérios impactos nas áreas costeiras do Brasil.

Os impactos socioeconômicos seriam mais restritos às vizinhanças das 15 maiores cidades litorâneas, que ocupam uma extensão de 1,3 mil quilômetros da linha costeira – correspondente a 17% da linha costeira do Brasil.

Entre as principais consequências da elevação do nível do mar, entre diversas outras, estão o aumento da erosão costeira, da frequência, intensidade e magnitude das inundações, da vulnerabilidade de pessoas e bens e a redução dos espaços habitáveis.

“Os impactos mais evidentes da elevação do nível do mar são o aumento da frequência das inundações costeiras e a redução da linha de praia. Mas há outros não tão perceptíveis, como a intrusão marinha, em que a água salgada do mar começa a penetrar aquíferos e ecossistemas de água doce”, ressaltou Marengo.

As projeções do quinto relatório (AR5) do Painel Intergovernamental sobre Mudanças Climáticas (IPCC) são que a elevação do nível do mar globalmente varie entre 0,26 e 0,98 metro até 2100 – em um cenário mais pessimista. O relatório apresenta estimativas similares para a costa brasileira.

Considerando que a probabilidade de inundações aumenta com a elevação do nível do mar pode ser esperada uma maior probabilidade de inundações em áreas que apresentam mais de 40% de mudanças no nível do mar observadas nos últimos 60 anos – como é o caso de várias metrópoles costeiras brasileiras, ressaltam os autores.

As inundações costeiras serão mais preocupantes no litoral do Nordeste, Sul e Sudeste, e também podem afetar o litoral sul e sudoeste da cidade do Rio de Janeiro. Os seis municípios fluminenses mais vulneráveis à elevação do nível do mar, de acordo com estudos apresentados no relatório, são Parati, Angra dos Reis, Rio de Janeiro, Duque de Caxias, Magé e Campos dos Goytacazes.

“A combinação do aumento do nível do mar com tempestades e ventos mais fortes pode provocar danos bastante altos na infraestrutura dessas cidades”, estimou Marengo.

Exemplo de plano

O documento destaca o Plano Municipal de Adaptação à Mudança de Clima (PMAMC) da cidade de Santos como exemplo de plano de ação para adaptação às mudanças de clima e os seus impactos nas cidades [Leia mais sobre o assunto em].

A elaboração do plano foi baseada nos resultados do Projeto Metrópole, coordenado por Marengo.

O estudo internacional estimou que a inundação de áreas costeiras das zonas sudeste e noroeste de Santos, causada pela combinação da elevação do nível do mar com ressacas, marés meteorológicas e astronômicas e eventos climáticos extremos, pode causar prejuízos acumulados de quase R$ 2 bilhões até 2100 se não forem implementadas medidas de adaptação.

O estudo é realizado por pesquisadores do Cemaden, dos Institutos Nacional de Pesquisas Espaciais (Inpe) e Geológico (IG) e das Universidades de São Paulo (USP) e Estadual de Campinas (Unicamp), em parceria com colegas da University of South Florida, dos Estados Unidos, do King’s College London, da Inglaterra, além de técnicos da Prefeitura Municipal de Santos.

“Nossa intenção é aplicar essa metodologia utilizada em Santos em outras cidades litorâneas brasileiras para termos pelo menos uma estimativa inicial do custo de adaptação à elevação do nível do mar”, disse Marengo.

Every Year, the Sky ‘Rains Fish.’ Explanations Vary. (N.Y.Times)