“Methane concentrations are not only rising, they are rising faster than ever,” said Rob Jackson, professor of Earth system science at Stanford University.
The study comes on the same day as a new UN report which says the world’s governments have not committed to cutting enough carbon emissions, putting the world on track for a rise of 2.5 degrees Celsius (4.5 degrees Fahrenheit) in global temperature by the end. the century.
The analysis said the level of emissions suggested 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 latest climate summits . To avoid 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 seriousness of the threats we face, and the shortness of time we have left to avoid the devastating consequences of runaway climate change,” said Simon Stiell, executive secretary the United Nations. Climate Change Secretariat. “We are nowhere near the scale and speed of emissions reductions that are needed.”
Instead, the UN report found, the world is barreling towards a future of unbearable heat, increasing weather disasters, collapsing ecosystems and widespread hunger and disease.
“It’s a depressing, horrible, incomprehensible picture,” said Inger Andersen, executive director of the United Nations Environment Programme, of the current global warming trajectory. “That picture is not a picture we can accept.”
The fastest way to affect the pace of global warming would be to cut methane emissions, the second largest contributor to climate change. It has a warming effect 80 times greater than carbon dioxide over a period of 20 years. The WMO said the amount of methane in the atmosphere increased 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 “climate feedback” from nature-based sources such as tropical wetlands and rice paddies, or whether they are the result of natural gas human and industrial discharges. Or both.
Methane emitted by fossil sources has more of the isotope carbon-13 than that produced from wetlands or cattle.
“The isotope data suggests it is biological rather than fossil methane from gas leaks. It could come 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 that we’ve been concerned about for decades.”
The WMO said that as the planet warms, organic matter breaks down faster. If the organic matter 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 company Kayrros, which does extensive analysis of satellite data, said “we are not seeing any increase” in methane produced 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 levels in 2021, the WMO study said: “The increase in carbon dioxide levels between 2020 and 2021 was greater than the average annual growth rate over the past year. decade.”
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 pre-industrial levels, respectively.
The report “underlined, once again, the enormous challenge – and the critical need – for urgent action to cut greenhouse gas emissions and prevent global temperatures from rising even further in the future,” said the WMO Secretary-General , Petteri Taalas.
Like others, Taalas has encouraged the pursuit of cheap techniques for capturing the short-lived methane, particularly in the case of natural gas. Because of its relatively short lifetime, “methane’s impact on climate is reversible,” he said.
“The changes required are economically affordable and technically possible. Time is running out,” he said.
The WMO also drew attention to the warming of oceans and land as well as the atmosphere. “Of the total emissions from human activities during the period 2011-2020, approximately 48 percent accumulated in the atmosphere, 26 percent in the ocean and 29 percent on land,” the report said.
The WMO report comes just 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 were at the forefront of promoting the Global Methane Pledge, which set a goal of achieving a 30 percent reduction in the atmosphere by 2030. They estimate that could shave 0.2 degrees Celsius off the increase in temperature that would otherwise occur. So far, 122 countries have signed up for the pledge.
White House climate negotiator John F. Kerry said in the joint US-China statement issued in Glasgow that China had promised to release an “ambitious plan” for this year’s climate summit that would move to reduce its methane pollution. So far, however, that hasn’t happened and China still hasn’t announced a “nationally determined contribution,” or NDC, in UN lingo.
“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 a year ago.
Only 24 countries have submitted new pledges in the last 12 months – and few of the updated commitments represent a meaningful improvement over their past pledges, according to the UN report. Australia made the most significant changes to its national climate goal, which had not previously been updated since the signing of the Paris agreement in 2015.
Postcards from our climate future
Taken together, the combined 193 climate pledges made since Paris would increase emissions by 10.6 per cent by 2030, compared to 2010 levels. This reflects a slight improvement over last year’s assessment, which found countries were on track to increase emissions by 13.7 percent by 2030, compared to 2010 levels, the United Nations said.
But nations must reduce their carbon outputs 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. the climate.
Just under half of the countries have also presented long-term plans for bringing their emissions down to zero. If these countries fulfill 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 rise in temperature below 2 degrees Celsius (3.6 degrees Fahrenheit), bringing humanity a little closer to tolerable warming levels.
“But it’s not really clear whether 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 pointed out. For most countries, the emission pathways suggested by their NDCs would make it almost impossible to reach a net zero target by mid-century.
The UN’s findings underscore a simple sobering fact, Andersen said: By waiting so long to act on climate change, humanity has denied itself an opportunity to make a slow and orderly transition to a safer and more sustainable future. Countries must constantly strengthen their ambitions, rather than making modest carbon reduction pledges that are updated every five years. No nation can rest easy until all countries have eliminated planet-warming emissions and restored natural systems that can pull carbon out of the atmosphere, he said.
“We need to see more and faster,” he said. “Today you stretch and tomorrow you stretch and the day after you stretch.”
Chris Mooney contributed to this report.
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