In the fight against climate change, CO2 gets more attention than any other greenhouse gas. That’s not surprising: It’s the biggest driver of global warming, and every pound of CO2 emitted now will be around for centuries. But the recent report from the U.N.’s Intergovernmental Panel on Climate Change also spelled out the importance of reducing the emissions of methane, an even more potent gas. And because methane doesn’t last as long in the atmosphere, any steep cuts in methane emissions now can help buy the world a little more time as we simultaneously work to cut CO2.
“Methane is the next crucial, fast, climate-stabilization prize,” Rick Duke, White House liaison for the Special Presidential Envoy for Climate Change, said at a press conference after the IPCC report was released. “There’s simply nothing that comes close for securing our near-term climate future, buying us crucial time to decarbonize energy and to develop advanced options like negative-emissions technologies.”
Methane, which comes from leaks in oil and gas production, rotting food in landfills, cow burps, and other sources, traps around 80 times as much heat as CO2 when it’s first emitted. But unlike CO2, it’s also gone from the air in roughly 12 years (once it rises high enough, it reacts with other chemicals in the atmosphere and breaks down).
“Half of today’s warming that we’re experiencing from CO2 is from 100-plus years of burning fossil fuels and burning down forests,” says Ilissa Ocko, a senior climate scientist at the Environmental Defense Fund. “So it’s this buildup over time. Methane only lasts in the atmosphere for around a decade.” Right now, methane is responsible for more than a quarter of the global warming that we’re experiencing, and the impacts from reducing it can show up faster than cuts in CO2.
In a study published earlier this year, Ocko and other scientists looked at existing solutions for reducing methane emissions and found that it would be possible to cut emissions in half this decade. As the total concentration of methane drops, it would have a cooling effect that could help counteract the overall trend. It can’t reverse global warming, since CO2 emissions are still rising. But the researchers calculated that it could slow down global warming by 30%.
Some of the changes needed are easy to make and have little or no cost, and the majority need to happen in the oil and gas sector. “Once you know where the emissions are coming from in the gas sector, it can be very simple and straightforward to reduce the emissions,” Ocko says. “It can be as simple as just closing a vent or tightening a valve. There are really simple measures that can be done that are basically plumbing. But the reason why they haven’t been done is because it has been a challenge to identify where the emissions are coming from.” Now, she says, it’s getting easier to track methane emissions through remote sensing tools. The Environmental Defense Fund, for example, is working with partners to launch a methane-tracking satellite in 2022 that will share data about emitters publicly.
At landfills, where rotting garbage releases methane, it’s possible to employ pipes to capture the gas and use it to make electricity or fuel. Composting food waste also significantly reduces methane. On farms, changing the diet for livestock—such as cattle feed supplements made from seaweed that can reduce cow burps—also reduces methane emissions. Manure can be converted into energy. Rice farmers can use techniques like adding compost to reduce methane emissions from rice paddies. In the future, direct air capture machines could also potentially be used to pull methane from the air in the same way that early machines are already capturing CO2.
Some other methane emissions are being driven directly by global warming, as hotter temperatures release more methane from wetlands and melting permafrost—even more reason to do everything possible to slow down warming now.
Methane didn’t initially get as much attention as CO2 because of the way that scientists chose to calculate “global warming potential”: If you look at a longtime horizon, methane doesn’t appear to be quite as bad as it actually is. It was only as the popularity of natural gas grew—ironically, because it was supposed to be a more climate-friendly option than coal—that scientists began focusing on methane. Partly because of the growth of natural gas, methane emissions have grown quickly in the last decade.
In the U.S., President Joe Biden has asked the Environmental Protection Agency to propose new regulations to cut methane leaks and flaring from oil and gas. He also wants to cap thousands of leaking, abandoned oil and gas wells, an initiative that’s part of the current budget reconciliation bill.
Ocko argues that governments also need to set clear goals to cut total methane emissions so that all the solutions that are feasible now are implemented. “I think if we set methane targets by country, or as part of the Paris Agreement,” she says, “it would really speed up the implementation of these options. Because these options exist.”