“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 UN report which says that the world’s governments haven’t committed to cut enough carbon 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 implied by countries’ new commitments was slightly 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. To avert the most catastrophic consequences of climate change, scientists say, humanity must limit warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels.
“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,” said Simon Stiell, executive secretary of the UN Climate Change Secretariat. “We are still nowhere near the scale and pace of emission reductions required.”
Instead, the UN report found, the world is barreling towards a future of unbearable heat, escalating weather disasters, collapsing ecosystems and widespread hunger and disease.
“It’s a dismal, horrendous, incomprehensible picture,” Inger Andersen, executive director of the UN Environment Program, said of the world’s current warming path. “That picture is just not a picture we cannot accept.”
The fastest way to affect the pace of global warming would be to cut 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 beginning 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, the WMO study said. “The increase in carbon dioxide levels from 2020 to 2021 was greater than the average annual growth rate over the last decade,” he 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 represent 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 necessary changes are economically affordable and technically possible. Time is running out,” he said.
The WMO also pointed to the warming of the 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 the 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.
Yet the United States is also among the vast majority of nations that have not updated their NDCs this year, something that all countries promised to do when the Glasgow summit ended one year ago.
Just 24 countries have submitted new pledges in the past 12 months — and few of the updated commitments represent a meaningful improvement over their past promises, the United Nations report found. Australia made the most significant changes in its national climate goal, which previously had not been updated since the Paris agreement was signed in 2015.
Postcards from our future climate
Altogether, the combined 193 climate pledges made since Paris would increase emissions by 10.6 percent by 2030, compared with 2010 levels. This reflects a slight 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 nations must reduce their carbon output to about 45 percent of their 2010 levels to avoid warming beyond 1.5 degrees Celsius (2.7 degrees Fahrenheit) — a threshold at which scientists say humanity can avoid the most catastrophic effects of climate change.
Just under half of countries have also submitted long-term plans for bringing their emissions down to zero. If these countries make good on their promises, the UN report found, global emissions in the middle of the century could be 64 percent lower than they are now. Scientists say these cuts could keep the temperature rise below 2 degrees Celsius (3.6 degrees Fahrenheit), bringing humanity somewhat closer to tolerable warming levels.
“But it is really not clear if countries will actually pull this off,” warned Joeri Rogelj, a climate scientist at Imperial College London who specializes in global warming pathways.
There are huge discrepancies between nations’ near-term climate pledges and their long-term plans, he noted. For most countries, the emissions trajectories implied by their NDCs would make it almost impossible to achieve a net zero target by the middle of the century.
The UN findings underscore a simple, sobering fact, Andersen said: In waiting so long to act on climate change, humanity has denied itself a chance to make a slow and orderly transition to a safer and more sustainable future. Countries must constantly bolster their ambitions, rather than making modest carbon-cutting pledges that get updated every five years. No nation can rest easy until every country has eliminated planet-warming emissions and restored natural systems that can pull carbon out of the atmosphere, she said.
“We need to see more and faster,” she said. “Today you stretch and tomorrow you stretch and the day after you stretch.”
Chris Mooney contributed reporting
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