Methane: Its big impact on climate change, how humans create it and can reduce it

Written by Amy Ta, produced by Brian Hardzinski and Caleigh Wells

About 35% of global human-induced methane comes from oil and gas production, 57% comes from agriculture (mostly livestock) and landfills, and 8% comes from biomass and biofuel burning (wildfires). That’s according to the Global Carbon Project. Photo by Shutterstock.

President Biden was at the United Nations climate summit (COP26) in Glasgow today, announcing that more than 90 countries will try to cut methane emissions by at least 30% by the end of the decade. 

“They've got many big polluters, like Brazil for the first time signing on to a methane pledge. Nigeria, European Union, Indonesia, and even Iraq. But absent so far are Russia and China — two major emitters — as well as India,” says Paasha Mahdavi, UC Santa Barbara professor who studies energy and environmental politics. 

He adds, “This is low-hanging fruit in the emissions battle. … It's a very clear way to reduce future warming, just looking at methane, by .2 degrees Celsius by 2040. So that is a big, big chunk. And this pledge is going to get us a third of the way there, assuming nobody else signs on.”

Methane v. CO2

Compared to carbon dioxide, what is methane’s potency, meaning how much heat can it trap and how much does it affect surface temperature? Estimates vary because methane dissipates into the atmosphere more quickly than carbon dioxide does, and it depends on what time period you’re looking at, Mahdavi says. 

“So methane emitted now, and you track the next 20 years, methane is just over 80 times more potent than carbon dioxide. And within a 100 year period … it dissipates faster, so it's 30 times more potent. And then beyond that, it dissipates even faster. So carbon dioxide is a longer term problem, stays in the atmosphere for much longer. But in the short term, methane is just brutal.”

New regulations on industrial activities  

President Biden wants the U.S. Environmental Protection Agency to impose monetary fines on oil and gas companies who don’t cap their emissions, and offer them incentives to meet those caps. 

“A lot of what is being planned involves regulatory changes that don't need congressional approval, so that's key. So that's … better monitoring and enforcement by agencies — like EPA, the Bureau of Land Management, the Bureau of Ocean Energy Management — to reduce methane emissions from industrial activities. So not just oil and gas, but other industrial activities that are on public lands and federal offshore waters. And that by itself is a huge slice of the pie,” Mahdavi says.

Where does human-induced methane come from? 

About 35% of it comes from oil and gas production, 57% comes from agriculture (mostly livestock) and landfills, and 8% comes from biomass and biofuel burning (wildfires). That’s all according to the Global Carbon Project, Mahdavi says. 

Adding to that complexity is the “carbon cycle feedback problem.” He explains, “As the planet warms because of climate change, it's melting more permafrost. That's a big problem because permafrost stores a lot of methane. So that's releasing even more methane into the atmosphere as a direct result of global warming. So it's quite a mix.”

Why does food waste in landfills produce so much methane?

Ferris Kawar, sustainability manager at Santa Monica College, explains that when things go into a landfill, they get mashed down by machines, then covered with soil, and mashed down again. All the air is squeezed out, creating methane gas, which is also why landfills smell so bad. 

Thus, consumers should be more mindful of how much food they’re trashing. 

“They have it in the fridge for a couple of weeks, they look at the date of freshness, and they think, ‘Oh I got to get rid of that.’ But it really doesn't need to be tossed out. We can shop better. We can use the sniff test more than just the freshness date. … Manufacturers want you to toss it out faster than it really needs to be,” says Kawar. 

Composing and using green (compost) bins

To turn food scraps into compost, that involves breaking down the waste by using air, water, microorganisms, and heat.

“If you go to a composting facility, it actually is a very different smell because it's a whole different process. It does create a little bit of carbon release in the composting process. But that's a lot less potent … than the methane release,” says Kawar.

He notes that Los Angeles has a new program called RecycLA, which requires haulers to provide bins that can be used for both compost and green waste (like leaves from the backyard). “Now it can also accept food scraps, bones, meat, dairy … anything that comes out of your kitchen.”

Raising and consuming cattle

Kawar says cows make up 58% of California emissions, so people can make a big difference by simply eating less meat. 

One innovative idea is to add red seaweed to cows’ diets, he points out. “They have multiple chambers in their stomach. And it's not designed to be fed soy and corn, which cows in typical feedlot are given. And so when they digest that kind of material, it creates extra methane. And if you add seaweed to that type of feed, it will help reduce it by 70 to 80%, is what studies are showing.” 

This story is part of Covering Climate Now, a global journalism collaboration strengthening coverage of the climate story during the U.N. Climate Change Conference (COP26) in Glasgow. 

Credits

Guests:

  • Paasha Mahdavi - UC Santa Barbara professor who studies energy and environmental politics
  • Ferris Kawar - sustainability manager at Santa Monica College