Arquivo da tag: Pegada de carbono

Rich nations could see ‘double climate dividend’ by switching to plant-based foods (Carbon Brief)

Ayesha Tandon

10.01.2022 | 4:00pm

Adopting a more plant-based diet could give rich countries a “double climate dividend” of lower emissions and more land for capturing carbon, a new study says.

Animal-based foods have higher carbon and land footprints than their plant-based alternatives, and are most commonly consumed in high-income countries. The study, published in Nature Food, investigates how the global food system would change if 54 high-income countries were to shift to a more plant-based diet.

High-income countries could cut their agricultural emissions by almost two-thirds through dietary change, the authors find. They add that moving away from animal-based foods could free up an area of land larger than the entire European Union.

If this land were all allowed to revert to its natural state, it would capture almost 100bn tonnes of carbon – equal to 14 years of global agricultural emissions – the authors note. They add that this level of carbon capture “could potentially fulfil high-income countries’ CO2 removal obligations needed to limit warming to 1.5C under equality sharing principles”.

The US, France, Australia and Germany would collectively see roughly half of the total carbon benefits, the study notes, because meat and dairy production and consumption are high in these countries.

‘Double climate dividend’

Feeding the world’s population of almost eight billion people is no small task. The global food system is responsible for around one-third of all human-caused greenhouse gas emissions, and half of the planet’s habitable land is used to produce food.

However, not all calories have an equal impact on the planet. On average, animal-based foods produce 10-50 times more emissions than plant-based foods. Meanwhile, livestock takes up nearly 80% of global agricultural land, despite producing less than 20% of the world’s supply of calories.

Individuals in high-income nations currently have the greatest potential to reduce greenhouse gas emissions through their dietary choices, because their diets are usually the most meat-orientated. Animal-derived products drive 70% of food-system emissions in high-income countries but only 22% in low–middle-income countries.

(In 2019, Carbon Brief produced a week-long series of articles on food systems, including a discussion of the climate impacts of meat and dairy, and expert views on how changing diets are expected to affect the climate.)

The study explores how the carbon footprint of food production could change if 54 high-income countries were to adopt the EAT-Lancet planetary health diet. This is a mainly plant-based diet that is “flexible by providing guidelines to ranges of different food groups that together constitute an optimal diet for human health and environmental sustainability”. 

Dr Paul Behrens from Leiden University, an author on the paper, tells Carbon Brief that the diet varies between countries to account for their “local production and food cultures”.

The study investigates the immediate reduction in emissions from adopting the EAT-Lancet diet using a dataset from the 2010 Food and Agriculture Organization’s statistical Database, linked at the national level to the Food and Agriculture Biomass Input–Output dataset (FABIO).

The authors also determine how much land could be spared by a shift in diet. They use global crop and pasture maps – combined with soil carbon and vegetation maps – to quantify how much extra carbon could be drawn down by soil and vegetation if this surplus land were allowed to revert to its natural state of mixed native grassland and forest. 

As well as investigating changes in the 54 high-income countries, the study follows the trade of food between nations to see how dietary shifts in one country can affect the food-related land and carbon footprints around the world.

The analysis is performed for the 54 high-income countries available in FABIO. For example, Chile is considered a high-income country, while India is not.

The map below shows the drop in greenhouse gas emissions from global agriculture if the 54 high-income countries were to shift to the EAT-Lancet planetary health diet. Dark red shading indicates the largest reductions. Changes in lower-income countries are due to knock-on impacts for food trade.

According to the study, high-income nations could reduce their agricultural emissions by 62% by shifting to a more plant-based diet. Dr Sonja Vermeulen is the lead global food scientist at WWF, and is not involved in the study. She helped to put this figure into perspective:

“To put this in perspective, it’s about the same positive impact as all countries signing up to and implementing the COP26 declaration on the transition to 100% zero emission cars and vans globally by 2040.” 

Freeing up land

The study finds that moving away from animal-based foods could free an area of land larger than the entire European Union. If this area were allowed to revert to its natural state, it would capture around 100bn tonnes of carbon – equal to 14 years of global agricultural emissions from 2010 – by the end of the century, the authors find.  

The map below shows the potential carbon sequestration from surplus land if the 54 high-income countries were to shift to the EAT-Lancet planetary health diet, with dark green shading indicating the largest potential. Changes in lower-income countries are due to knock-on impacts for food trade. 

Approximately half of the carbon benefit from cutting emissions and increasing carbon sequestration could be seen collectively in the US, France, Australia and Germany, the study says.

The authors also highlight that, according to past research, limiting warming to 1.5C above pre-industrial levels requires the 54 high-income countries in this analysis to achieve cumulative CO2 removals of 85-531bn tonnes of CO2 by the end of the century. This range comes from uncertainty in the amount of CO2 removal required, and in the amount that should be allocated to each country.

Based on these numbers, the study concludes that the 100bn carbon sequestration “could potentially fulfil high-income countries’ CO2 removal obligations needed to limit warming to 1.5C under equality sharing principles”.

The study finds that many low and mid-income countries – such as Brazil, India and Botswana – would export less food to high-income nations if they consumed less meat. This would reduce their own agricultural emissions and free up land for drawing down carbon, despite no dietary changes in their own countries, the researchers say. (The study does not assess the economic impact of this reduced trade.)

Around two-thirds of the carbon sequestration potential from dietary changes in high-income countries is domestic, the study finds. Meanwhile, almost a quarter is located in other high-income countries and around an eighth is from low and middle income countries.

Dr Nynke Schulp is an associate professor of land use, lifestyle and ecosystem change at the Vrije Universiteit Amsterdam, and was not involved in the study. She tells Carbon Brief that existing studies “tend to work from the assumption that the whole world adopts a specific dietary change”, and so “this study’s focus on dietary change in high-income nations is an important nuance, both from a mitigation potential perspective and from a climate justice perspective”.

Capturing carbon

The study assumes that any land freed up by a change in diet would be allowed to revert to its natural state through a “natural climate solution” called passive restoration, in which land is allowed to revert to its past state. Behrens explains in a press release that this technique has a range of co-benefits, including “water quality, biodiversity, air pollution and access to nature, to name just a few”.

The study breaks down the carbon sequestration potential of passive restoration into three categories: aboveground biomass carbon (AGBC), belowground biomass carbon (BGBC) and soil organic carbon (SOC) stocks. These refer to carbon held in plant matter above the soil, plant matter below the soil, and the soil itself, respectively.

The plot below shows the total carbon sequestration (left) and emissions reductions (right) potentials from a range of different food types. The red lines on the left and right mark fixed values to make comparisons between the charts easier. Note that carbon sequestration is shown as a total over the 21st century, while the reduction in emissions is shown per year.

The plot shows that animal-based products – most notably beef – have high carbon and land footprints. The authors highlight that the US and Australia in particular would see benefits from reducing their beef intake, due to their high domestic production and consumption. 

Vermeulen tells Carbon Brief that changing diets in these countries could “transform” them:

“The term ‘food system transformation’ is perhaps often used too lightly – but there can be no doubt that the changes in these places would constitute total transformation of local economies, landscapes and cultures. Imagine the vast cattle ranches of the US and Australia replaced with equally vast rewilded or repurposed lands – would these be used for biomass and bioenergy, or conservation and biodiversity, and how would rural communities create new livelihoods for themselves?”

Dietary choices

High-income countries could see the largest per-capita carbon reductions by shifting to a planet-friendly diet, the study concludes. However, asking individuals to take charge of their personal carbon footprints can be a controversial area of discussion.

For example, the authors note that alcoholic beverages and “stimulants” including coffee, cocoa products and tea comprise 5.8% of dietary greenhouse gas emissions. These “luxury, low-nutrition crops” are predominantly consumed in high-income countries and present a “non-negligible” opportunity for cutting emissions and capturing carbon, according to the study. However, “sociological and policy complications” would make it difficult to reduce consumption of these products in practice, the authors say.

They also highlight that eating more offal – a co-product of meat production – could be a good way for individuals to reduce their meat-related carbon footprints. However, the authors say that offal is “not typically consumed in high-income nations due to convention and consumer preference”.

Dr Matthew Hayek is an assistant professor in the Department of Environmental Studies at NYU arts and science, who was not involved in the study. He tells Carbon Brief how governments could incentivise individuals to eat more sustainably: 

“Folks in developed countries eat far more meat and dairy than the global average… Reducing emissions from food consumption in rich countries is critical. For consumers who have ample food choices, these choices play a sizable role in contributing to our climate goals. Our policies must reflect this by making healthy and sustainable food choices more prevalent, convenient, and inexpensive.”

And Behrens tells Carbon Brief that “the onus is on high-income nations to transform food systems”. In the press release, he adds:

“It will be vital that we redirect agricultural subsidies to farmers for biodiversity protection and carbon sequestration. We must look after farming communities to enable this in a just food transition. We don’t have to be purist about this, even just cutting animal intake would be helpful. Imagine if half of the public in richer regions cut half the animal products in their diets, you’re still talking about a massive opportunity in environmental outcomes and public health.”

Sun, Z. et al. (2022) Dietary change in high-income nations alone can lead to substantial double climate dividend, Nature Food, doi: 10.1038/s43016-021-00431-5

The Internet Cloud Has a Dirty Secret (Fortune)

By Naomi Xu Elegant, September 18, 2019 6:23 AM GMT-3

The music video for “Despacito” set an Internet record in April 2018 when it became the first video to hit five billion views on YouTube. In the process, “Despacito” reached a less celebrated milestone: it burned as much energy as 40,000 U.S. homes use in a year.

Computer servers, which store website data and share it with other computers and mobile devices, create the magic of the virtual world. But every search, click, or streamed video sets several servers to work — a Google search for “Despacito” activates servers in six to eight data centers around the world — consuming very real energy resources.

A lot of them.

Today, data centers consume about 2% of electricity worldwide; that could rise to 8% of the global total by 2030, according to a study by Anders Andrae, who researches sustainable information and communications technology for Huawei Technologies Ltd.

U.S. data centers consumed 70 billion kilowatt-hours of electricity in 2014, the same amount that 6.4 million American homes used that year. Data centers need electricity to power their servers, storage equipment, backups, and power cooling infrastructure; most servers require temperatures below 80 degrees Fahrenheit to operate, and cooling can comprise up to 40% of electricity usage in conventional data centers.

“People don’t think about the backend consequences of Netflix streaming,” says Debra Tan, the director of Hong Kong-based nonprofit China Water Risk. “The information and communications technology (ICT) sector is probably one of the most power-hungry sectors going forward.”

The global shift toward what Tan calls “cloud-based societies”—and the rise of nascent tech like 5G networks, robotics, artificial intelligence, and cryptocurrencies—means electricity consumption in data centers will keep surging.

Data’s massive carbon footprint

Because servers are housed in nondescript data centers rather than factories with billowing smokestacks, the size of their carbon footprint is easily overlooked.

But the constant and increasing demand for connectivity means ever more energy funneled into these data centers, and much of that energy is non-renewable and contributes to carbon emissions. Data centers contribute 0.3% to global carbon emissions, according to Nature; the ICT sector as a whole contributes over 2%, and those numbers could increase.

The U.S. is home to 3 million data centers, or roughly one for every 100 Americans. A large number are clustered in Loudoun County in northern Virginia. Tech giants like Amazon, Microsoft, and Google operate data centers there, and county officials claim that 70% of the world’s Internet traffic flows through the area’s data centers.

Only 12% of Amazon’s Loudoun County data centers and 4% of Google’s are powered by renewable energy, despite their pledges to shift to 100% clean energy, according to Greenpeace. The region’s low commercial electricity rates make it an attractive site for power-guzzling data centers.

Debra Tan of China Water Risk says that American tech firms with a global presence like Google and Facebook must step up their existing commitments to clean energy, as must Chinese tech companies like Baidu, Alibaba, and Tencent, which sourced 67% of their energy from coal in 2017. China’s data center industry is the world’s second-largest, comprising 8% of the global market.

“The ICT sector can definitely lead the world in aggressive decarbonization because they’re the sector that will add on the most power going forward,” says Tan. “They have the capability [and] they have the scale.”

The data never ends

The Internet’s “never-ending creation of data” explains why electricity demand in data centers will likely surge in the future, says Huawei researcher Anders Andrae, who cites more advanced video, 5G networks, A.I. training, holography, and cryptocurrency mining as some of the drivers.

The energy consumption of Bitcoin mining has been a concern for many watching the rise of cryptocurrencies, and analysts have said Bitcoin mining consumes around 0.3% of global electricity (some skeptics argue that such estimates are exaggerated, however).

In China, the government is starting to crack down on the practice. Authorities in China’s Inner Mongolia province said earlier this month that they will no longer support the crypto mining industry, though they did not issue an official ban.

Inner Mongolia’s cheap electricity, thanks to a wealth of coal, is what first drew crypto miners to the far-flung province. In China, data centers get 73% of their power from coal and 23% from renewable sources. The country’s clean energy industry is still developing, so there is a lack of infrastructure compared to coal-powered sources, which are relatively cheap and abundant—China accounts for half of global coal consumption.

China’s data centers emitted 99 million tons of carbon dioxide in 2018 and will emit two-thirds more by 2023 unless industry addresses its energy consumption, per a 2019 study by Greenpeace and North China Electric Power University.

Ye Ruiqi, a climate and energy campaigner for Greenpeace East Asia, says that the initiative to move the industry towards renewable energy “must come from internet data center companies themselves.”

“We need to start addressing the carbon emissions and air pollutants associated with the source[s] of power that feed into our data centers.” Ye says, noting that a handful of Chinese companies have started shifting to renewables and “the results are promising.”

While consumers can make some daily changes to their consumption—streaming Netflix on medium quality rather than high-definition could save over 75% of carbon and water used—companies and governments must take the lead in the greening of the supply chain and development of renewable energy infrastructure, says Tan.

“We can get more efficient […] but our demand is also going to go up,” Tan says. “Your best bet is to go 100% renewables for the backend, cloud, all the transmission towers, et cetera. If you can get that infrastructure to green then there’s less pressure to curbing demand.”

It will be difficult, but if the sector takes action to shift from coal to renewable energy, electricity consumption can decouple from carbon emissions, Ye says: “Technology innovation doesn’t have to contradict [sustainable] development.”

Países desenvolvidos exportam emissões de carbono (Folha de São Paulo)

JC e-mail 4882, de 28 de janeiro de 2014

Matéria do “The New York Times” sobre efeitos climáticos publicada na Folha de São Paulo

Durante sua vida útil, o iPhone 5S emite o equivalente a 70 kg de dióxido de carbono. A boa notícia: isso é 4 kg a menos do que o iPhone 5.

Seja como for, cerca de três quartos desse dióxido de carbono são considerados de responsabilidade não dos Estados Unidos, mas de lugares como China, Taiwan, Coreia do Sul e Mongólia Interior (região autônoma da China), onde o telefone e seus componentes são fabricados.

A globalização -a qual, no processo de “exportar” produção e emprego dos países ricos para os pobres, “exportou” também o dióxido de carbono emitido para a fabricação dos produtos- adiciona um novo aspecto à alocação das responsabilidades pela emissão de carbono na atmosfera: será que essas emissões devem ser de responsabilidade dos países fabricantes ou dos países para os quais os produtos se destinam?

Dois anos atrás, algumas das localidades mais ambientalmente corretas dos EUA solicitaram à seção americana do Instituto Ambiental de Estocolmo que calculasse suas emissões de carbono. Em vez de contabilizar o carbono que produziam, elas queriam um inventário das emissões geradas na fabricação, no transporte, na utilização e na eliminação do que é consumido nesses lugares.

O resultado surpreendeu. San Francisco, por exemplo, gerou em 2008 apenas 8 milhões de toneladas de CO2 ou equivalente. O consumo da cidade, por outro lado, acrescentou quase 22 milhões de toneladas de carbono à atmosfera. Usando medições baseadas no consumo, as emissões do Oregon saltaram em 2005 de 53 milhões para 78 milhões de toneladas. “As pessoas que nos contrataram se viam como muito ‘verdes’ e inovadoras”, disse Frank Ackerman, que na época chefiava o Grupo de Economia Climática da entidade nos EUA. “Eles achavam que, por terem boas iniciativas em andamento, teriam um resultado menor, apesar de muitos dos produtos industriais por eles consumidos serem fabricados no exterior.”

O foco no consumo faz sentido. Compreender o seu impacto sobre a mudança climática é um primeiro passo necessário para que as pessoas e as cidades, grandes ou pequenas, tomem medidas concretas para reduzir as emissões de carbono. Este novo tipo de cálculo, no entanto, pode ter um efeito imprevisto sobre a política internacional de mudança climática, deslocando a responsabilidade em escala global.

Enquanto a concentração de CO2 disparou no primeiro semestre de 2013 para o seu maior nível desde que os mastodontes vagavam pela Terra, há 3 milhões de anos, as Nações Unidas, contrariando todas as probabilidades, esperam que 2014 finalmente traga os avanços necessários para que as grandes nações cuspidoras de carbono cheguem a um acordo sobre um plano climático até 2015.

“Desafio os senhores a trazer promessas ousadas para a cúpula”, disse o secretário-geral da ONU, Ban Ki-moon, ao convidar líderes mundiais para uma reunião em setembro próximo, em Nova York.

Um estudo publicado há dois anos na revista “PNAS”, da Academia Nacional de Ciências dos EUA, observou que, entre 1990 e 2008, a globalização exportou o equivalente a 1,2 bilhão de toneladas de emissões de carbono por ano do mundo desenvolvido para nações em desenvolvimento.

Cálculos com critérios estritamente geográficos dão a impressão de que os países industriais avançados conseguiram estabilizar suas emissões de carbono.

Mas eles apenas transferiram o aumento para fora das suas fronteiras. As emissões de carbono criadas pelo consumo dos americanos são cerca de 8% superiores às emissões produzidas nos EUA, de acordo com os cientistas do Projeto Global do Carbono. Por outro lado, cerca de um quinto das emissões da China são de produtos consumidos fora de suas fronteiras.

A União Europeia, satisfeita com seus resultados ambientais nos cálculos habituais, com base no lugar onde o carbono é emitido, parece menos virtuosa sob uma lente baseada no consumo. Em 2011, os europeus emitiram apenas 3,6 bilhões de toneladas de CO2, mas 4,8 bilhões de toneladas foram jogados na atmosfera para a produção das coisas que os europeus consumiram.

Aqui está o dilema. A abordagem habitual, a qual está sendo considerada para contabilizar o custo do carbono “comercializado”, consistiria em taxar as emissões registradas nas fronteiras. Não surpreende que países exportadores, como a China, não gostem dessa abordagem.

Um estudo recente corroborou a imposição de um imposto de carbono sobre as importações. Mas “a China tem tudo a perder”, disse GlenPeters, do Centro para o Clima Internacional e a Pesquisa Ambiental, em Oslo. “Se a China trouxesse isso para as negociações, estaria permitindo que os EUA e Europa regulamentassem as exportações chinesas.”

Outra pesquisa concluiu que a imposição de uma penalidade na fronteira incentivaria a China e outros países em desenvolvimento a tributarem suas próprias emissões de carbono -ficando com o dinheiro- em vez de deixar que outros as tributem. Mas, se o mundo quiser evitar uma mudança climática catastrófica, alguém -em algum lugar- deve arcar com o custo de consumir menos carbono. E ninguém está se voluntariando.