At the COP26 climate meeting in Glasgow on Tuesday, global leaders announced that more than 100 countries had signed a pledge to reduce their methane emissions 30 percent by 2030.
If the whole world were to achieve that goal, temperatures in the next few decades would rise 0.2 degree Celsius (0.4 degree Fahrenheit) less than they would otherwise—a potentially huge savings that could, theoretically, keep global warming levels below 1.5°C (2.7°F).
Cutting methane emissions will “not just address future climate change but … curb the climate change that’s happening right now,” says Ilissa Ocko, a methane expert at the Environmental Defense Fund.
The United States and the European Union, the world’s third and sixth largest methane emitters, respectively, announced the pledge in September. They have since gathered support from many other major emitters, such as Brazil, Indonesia, and Nigeria, enough to account for more than 40 percent percent of global emissions of the ultra-potent greenhouse gas, according to EPA emissions estimates.
Methane is highly potent but lasts only a short time in the atmosphere. So any action that quickly reduces its concentration could have enormous climate benefits within the next few decades, scientists stress. What’s more, methane emissions can often be cut at little or no cost.
On Tuesday the Biden administration announced plans to regulate methane leaks at more than a million oil and gas rigs in the U.S.
“It’s something that is really a win-win to focus on,” says Lena Höglund Isaksson, a methane expert at the International Institute for Applied Systems Analysis in Austria.
Why quick action on methane can have such big impacts
The potential stems from physics.
Freshly released into the atmosphere, methane is an extraordinarily powerful heat absorber: Pound for pound, it traps roughly 100 times as much heat as carbon dioxide. But whereas carbon dioxide persists for centuries, most methane converts to carbon dioxide or gets cycled out of the atmosphere within about a decade. When the effects of methane emissions today are averaged over the next 20 years—a common framework used to analyze the power of different greenhouse gases—methane causes about 80 times as much warming as the same amount of carbon dioxide. Over 100 years, it heats the planet about 30 times more.
That is a daunting reality, but one that also offers great opportunity, says Kathleen Mar, an atmospheric chemist at the Institute for Advanced Sustainability Studies in Germany. Because methane is so powerful, trimming its atmospheric load even slightly can dramatically curtail temperature rise. And because it lasts such a short time, its concentration in the atmosphere falls relatively quickly when emissions are reduced. In contrast, the atmospheric concentration of carbon dioxide won’t start falling until the world cuts emissions to near zero.
If fulfilled, the Global Methane Pledge would “be enough to bend the curve from having increasing emissions…to actually starting to decrease, which is a really important shift,” Mar says.
Earlier this year, the United Nations Environment Programme (UNEP) released the Global Methane Assessment, a report that found that, with relatively little effort and currently available technologies, methane emissions could be lowered by up to 45 percent by 2030.
Scientists found that such a large reduction would keep temperatures from rising about 0.3°C. Even a 30 percent cut, the fraction suggested in the pledge, could trim future temperatures by about 0.2°C.
“Methane can help us in the short run to stay below the [Paris temperature] goals while we fix the CO2 problem,” says Höglund Isaksson.
How could it happen?
How to enact methane reductions is still an open question. The details will be up to each country that joins the pledge.
But there are plenty of emissions to be stopped, since humans are responsible for about two-thirds of all the methane in the atmosphere, pushing concentrations up faster than ever before seen and to levels not equaled in the past 800,000 years.
Cutting all of those emissions would be difficult, but there are some obvious places to start, says Höglund Isaksson. The oil and gas industry accounts for about 35 to 40 percent of annual emissions, primarily from leaks at wells, along pipelines, and at transfer stations. (Coal mines are another source.)
Those problems are more common at all points along the fossil fuel chain than previously thought. In the U.S., oil-and-gas exploration in the Permian Basin of Texas and New Mexico is a major and increasing source; in Russia, methane leaks from pipelines shot up 40 percent in 2020 and have continued to rise this year. And a recent study of natural gas leaks in Boston suggested that emissions from urban distribution networks might be much higher than has been estimated.
The UNEP report estimated that the oil and gas industry could reduce as much as 75 percent of its methane leaks at little, no, or negative cost—meaning the industry could in some places make money while doing something that would help the planet.
Technology to find leaks is leapfrogging forward. New high-resolution satellites can pinpoint leaks to within a few hundred meters, and many more are set to launch in the next few years. Their data could help interested companies stop their leaks—and let watchdogs keep track of who does, or doesn’t, fix their problems. A new collaboration, the International Methane Emissions Observatory, aims to provide independent monitoring data.
“The key is, industry already knows how to reduce their emissions—by a factor of 10 in some cases,” says Steven Hamburg, a methane expert at the Environmental Defense Fund. “It’s really nice when you have problems you know how to clean up.”
In 2016, the U.S. Environmental Protection Agency put rules in place that required new oil and gas infrastructure to be carefully controlled for methane leaks. Those rules, weakened during the Trump administration, were reinstated in June of 2021, but covered only a fraction of the potential sources. Now, the Biden administration aims to expand the regulations to include existing infrastructure, thus covering a much wider swath of methane sources. A “fee” on excess methane leakage, which would charge producers for emissions beyond a threshold, is also under consideration in the ongoing budget reconciliation negotiations in Congress.
There are also relatively straightforward ways to lower methane emissions from one of its other major sources: waste. Methane is produced when bacteria break down organic material in waste—food, sewage, or anything else that was once living—and it can be captured at treatment plants and landfills. Europe has already made significant progress, reducing its waste emissions by about 20 percent since 2010. Other countries would likely have to invest heavily to make big cuts.
Agriculture, the other major source, will be a harder challenge. Cattle, dairy, and rice production all produce vast amounts of methane, but scalable solutions to their emissions are still being developed.
While the success of the Global Methane Pledge would be invaluable, “we can never, ever use methane reduction as an excuse for delaying action on CO2,” Höglund Isaksson stresses. But because global heating has already progressed to such a dire state, says Ocko, “we need both of these strategies: reducing CO2 and methane…. They go hand in hand.”
A powerful option
The leader of the COP26 meeting, the U.K.'s Alok Sharma, has made the goal of the conference to “keep 1.5 alive,” pushing countries to accelerate emissions reductions enough to keep the planet from heating beyond 1.5°C, a goal first articulated in the 2015 Paris Agreement.
The importance of that goal has grown since 2015 as scientists have honed their understanding of the physical, social, and economic costs climate change is already forcing. In 2018, a report from the Intergovernmental Panel on Climate Change (IPCC) showed that risks to many human and ecological systems balloon when warming exceeds 1.5°C. At 2°C (3.6°F), some 400 million more people would be at risk of extreme heat waves. Coral reefs would “mostly disappear.” At 1.5°C, some reefs might survive.
Another IPCC report, released in August, reinforced the message that for every 0.1°C of extra heating, the consequences intensify. A brutal heat wave that in the past would have occurred, on average, once every 50 years will likely occur 8.6 times more frequently in a 1.5°C world, and nearly 14 times as often in a 2°C world, making the possibility of deadly heat waves like the one this summer in the Pacific Northwest much more common.
But so far, countries have not even come up with plans—let alone actions—that get them close to keeping warming below 2°C, let alone 1.5°C. When added up, the “Nationally Determined Contributions,” or NDCs, that countries submitted ahead of the COP26 meeting still put Earth on track to warm about 2.7°C.
So any actions that can quickly rein in temperature rise while the tough work of winding down all fossil fuel emissions gets underway are invaluable. Methane, says Ocko, “is an amazing place to start.”