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Rising methane emissions threaten to take climate change goals out of reach

The climate crisis on Earth looks worse than scientists feared – also because we eat so much meat and move around.

According to two new studies that tracked the growing sources of odorless, colorless gas, global methane emissions, a powerful greenhouse gas, have increased significantly in the past decade. The increased methane combined with carbon dioxide and other greenhouse gases could warm the Earth’s atmosphere by 3 to 4 degrees Celsius before the end of this century – well above the level that scientists have warned could be catastrophic for millions of people around the world.

“This totally exceeds our budget to stay below 1

.5 to 2 degrees warming,” said Benjamin Poulter, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Poulter is the author of both studies, published Tuesday, one in Earth System Science Data and the other in Environmental Research Letters.

Poulter and his colleagues found that the largest increase in methane emissions since 2000 is due to agricultural activities – particularly livestock such as cattle and sheep – and the fossil fuel industry, which includes coal mining and oil and gas exploration .

According to the researchers, human activity accounts for about 60 percent of global methane emissions. Agriculture accounts for about two thirds of this, with the production and use of fossil fuels making up the majority of the rest.

In the new studies, researchers analyzed methane emissions from 2000 to 2017 – the last year for which global methane numbers were available – and found that the Earth’s atmosphere in 2017 absorbed a record 600 million tons of methane. Annual methane emissions have also increased at a rate of 9 percent per year since the early 2000s, a pace that could contribute to global warming of more than 2 degrees Celsius by 2100.

A report published by the Intergovernmental Panel on Climate Change in October 2018 highlighted that the planet has warmed by 1 degree Celsius since the 19th century. 1.5 degrees of warming above pre-industrial levels has been used as a threshold at which the effects of climate change, including extreme heat and sea level rise, are life-threatening for tens of millions of people around the world.

Another author of both studies, Rob Jackson, a professor of Earth Systems Science at Stanford University, said the amount of methane released into the atmosphere since 2000 is roughly equivalent to the addition of 350 million more cars on the road.

In 2017, methane emissions from agriculture increased by almost 11 percent compared to the 2000-2006 average, while fossil fuel methane emissions increased by almost 15 percent compared to the early 2000s.

Methane is released into the atmosphere when coal, oil and natural gas are mined and transported. However, microbes also emit it in low-oxygen environments.

“Any place where there is little to no oxygen – wetlands, paddy fields, landfills, a cow’s gut – are all sources of methane,” said Jackson.

Overall, methane accounts for a much lower percentage of global greenhouse gas emissions than carbon dioxide, but it is particularly important for scientists because its molecular structure makes it easier for methane to absorb heat radiation.

“Methane doesn’t last as long as carbon dioxide in the atmosphere, but it stores heat much more efficiently than carbon dioxide,” said Poulter, making the gas a key factor in global warming.

To curb methane emissions, countries need to reduce their dependency on fossil fuels and reduce the number of harmful leaks from pipelines and wells, Jackson said.

Scientists are also investigating how methane emissions can be minimized in agricultural practices, for example by changing the water level in rice fields and experimenting with changes in the diet of cattle and sheep to reduce the amount of methane that leaks from their digestive systems. Burger King recently announced that it is adding lemongrass to its cows’ diets to help reduce methane emissions through low-carb feeding.

However, the slowdown in greenhouse gas emissions also requires major changes in human behavior, Jackson said.

“Diet is important,” said Jackson. “Here in the United States, we have one of the highest rates of red meat consumption in the world. We don’t have to stop eating red meat, but eating less meat or more fish and chicken instead of beef reduces emissions.” also.”

And while the coronavirus pandemic is expected to lead to a significant drop in carbon dioxide emissions in 2020 – mainly due to economic slowdowns and closures that severely restricted air travel and other modes of transport – similar declines in methane are not expected.

“Our farmers are still producing food, oil and gas. Production has not declined very much yet, and methane plays a tiny role in the transportation sector,” said Jackson. “Although we may see a slight decrease this year due to the corona virus, methane emissions have been increasing over the past decade. At this rate, we will no longer see top methane emissions in the near future.”

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