Climate warming methane emissions rising faster than ever, study says

By Steven Mufson Published October 26, 2022 washingtonpost.com

The amount of methane in the atmosphere is racing ahead at an accelerating pace, according to a study by the World Meteorological Organization, threatening to undermine efforts to slow climate change.

The WMO’s Greenhouse Gas Bulletin said that “global emissions have rebounded since the COVID-related lockdowns” and that the increases in methane levels in 2020 and 2021 were the largest since systematic record keeping began in 1983.

“Methane concentrations are not just rising, they’re rising faster than ever,” said Rob Jackson, a professor of Earth system science at Stanford University.

The study comes on the same day as a new U.N. report which says that the world’s governments haven’t committed to cut enough climate emissions, putting the world on track for a 2.5 degree Celsius (4.5 degree Fahrenheit) increase in global temperatures by the end of the century.

The analysis said that the level of emissions set out in countries’ commitments was lower than a year ago, but would still lead to a full degree of temperature increase beyond the target level set at the most recent climate summits. Simon Stiell, executive secretary of the U.N. Climate Change Secretariat, said that “we are still nowhere near the scale and pace of emission reductions required to put us on track toward a 1.5 degrees Celsius world.”

The quickest way to affect the pace of global warming would be cutting emissions of methane, the second largest contributor to climate change. It has a warming impact 80 times greater than carbon dioxide over a 20-year period. The WMO said the amount of methane in the atmosphere jumped by 15 parts per billion in 2020 and 18 parts per billion in 2021.

Scientists are studying whether the unusually large increases in atmospheric methane levels in 2020 and 2021 are the result of a “climate feedback” from nature-based sources such as tropical wetlands and rice paddies or whether they are the result of human-made natural gas and industrial leakage. Or both.

Methane emitted by fossil sources has more of the carbon-13 isotope than that produced from wetlands or cattle.

“The isotope data suggest it’s biological rather than fossil methane from gas leaks. It could be from agriculture,” Jackson said. He warned that “it could even be the start of a dangerous warming-induced acceleration in methane emissions from wetlands and other natural systems we’ve been worrying about for decades.”

The WMO said that as the planet gets warmer, organic material decomposes faster. If the organic material decomposes in water — without oxygen — this leads to methane emissions. This process could feed on itself; if tropical wetlands become wetter and warmer, more emissions are possible.

“Will warming feed warming in tropical wetlands?” Jackson asked. “We don’t know yet.”

Antoine Halff, chief analyst and co-founder of the firm Kayross, which does extensive analysis of satellite data, said “we’re not seeing any increase” in methane generated by fossil sources. He said some countries, such as Australia, had cut emissions while others, such as Algeria, had worsened.

Atmospheric levels of the other two main greenhouse gases — carbon dioxide and nitrous oxide — also reached record highs in 2021, WMO study said. “The increase in carbon dioxide levels from 2020 to 2021 was larger than the average annual growth rate over the last decade,” it said.

Carbon dioxide concentrations in 2021 were 415.7 parts per million (or ppm), methane at 1908 parts per billion (ppb) and nitrous oxide at 334.5 ppb. These values represented 149 percent, 262 percent and 124 percent of preindustrial levels.

The report “underlined, once again, the enormous challenge — and the vital necessity — of urgent action to cut greenhouse gas emissions and prevent global temperatures rising even further in the future,” said WMO Secretary General Petteri Taalas.

Like others, Taalas has urged the pursuit of inexpensive techniques for capturing the short-lived methane, especially when it comes to capturing natural gas. Because of its relatively short life span, methane’s “impact on climate is reversible,” he said.

“The needed changes are economically affordable and technically possible. Time is running out,” he said.

The WMO also pointed to the warming of oceans and land, as well as the atmosphere. “Of the total emissions from human activities during the 2011—2020 period, about 48 percent accumulated in the atmosphere, 26 percent in the ocean and 29 percent on land,” the report said.

The WMO report comes shortly before the COP27 climate conference in Egypt next month. Last year, in the run-up to the climate conference in Glasgow, Scotland, the United States and European Union took the lead in promoting the Global Methane Pledge, which set a goal of reaching a 30 percent reduction in the atmosphere by 2030. They estimated that could shave 0.2 degrees Celsius off the rise in temperatures that would otherwise take place. So far, 122 countries have signed up for the pledge.

White House climate negotiator John F. Kerry said that in the US-China joint declaration issued in Glasgow, China vowed to release “an ambitious plan” for this year’s climate summit that would move to cut its methane pollution. So far, however, that has not happened and China still has not issued an up-to-date “nationally determined contribution” or NDC in the lingo of the United Nations.

“We look forward to an updated 2030 NDC from China that accelerates CO2 reductions and addresses all greenhouse gases,” Kerry said.

“To keep this goal alive, national governments need to strengthen their climate action plans now and implement them in the next eight years,” he said.

The U.N. report said that the combined 193 climate pledges made in the international Paris agreement in 2015 would increase emissions by 10.6 percent by 2030, compared with 2010 levels. This reflects an improvement over last year’s assessment, which found that countries were on a path to increase emissions by 13.7 percent by 2030, compared with 2010 levels, the United Nations said.

But only 24 countries have revised their nationally determined contributions, or NDCs, since the climate summit a year ago in Glasgow, Scotland, making it difficult to avoid the worst of climate disasters, the United Nations said. Australia has made the most significant changes in its national climate goal.

The U.N. Intergovernmental Panel on Climate Change’s 2018 report indicated that carbon dioxide emissions needed to be cut 45 percent by 2030, compared with 2010 levels. Earlier this year and using 2019 as a baseline, the IPCC said that greenhouse gas emissions needed to be cut 43 percent by 2030.

“Government decisions and actions must reflect the level of urgency, the gravity of the threats we are facing, and the shortness of the time we have remaining to avoid the devastating consequences of runaway climate change,” Stiell said.