Why methane emissions are still a mystery

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If you follow papers in climate and energy for long enough, you’re bound to recognize some patterns.

There are a few things I’ll basically always see when I’m sifting through the latest climate and energy research: one study finding that perovskite solar cells are getting even more efficient; another showing that climate change is damaging an ecosystem in some strange and unexpected way. And there’s always some new paper finding that we’re still underestimating methane emissions.

That last one is what I’ve been thinking about this week, as I’ve been reporting on a new survey of methane leaks from oil and gas operations in the US. (Yes, there are more emissions than we thought there were—get the details in my story here.) But what I find even more interesting than the consistent underestimation of methane is why this gas is so tricky to track down.

Methane is the second most abundant greenhouse gas in the atmosphere, and it’s responsible for around 30% of global warming so far. The good news is that methane breaks down quickly in the atmosphere. The bad news is that while it’s floating around, it’s a super-powerful greenhouse gas, way more potent than carbon dioxide. (Just how much more potent is a complicated question that depends on what time scale you’re talking about—read more in this Q&A.)

The problem is, it’s difficult to figure out where all this methane is coming from. We can measure the total concentration in the atmosphere, but there are methane emissions from human activities, there are natural methane sources, and there are ecosystems that soak up a portion of all those emissions (these are called methane sinks).

Narrowing down specific sources can be a challenge, especially in the oil and gas industry, which is responsible for a huge range of methane leaks. Some are small and come from old equipment in remote areas. Other sources are larger, spewing huge amounts of the greenhouse gas into the atmosphere but only for short times.

A lot of stories about tracking methane have been in the news recently, mostly because of a methane-hunting satellite launched earlier this month. It’s designed to track down methane using tools called spectrometers, which measure how light is reflected and absorbed.

This is just one of a growing number of satellites that are keeping an eye on the planet for methane emissions. Some take a wide view, spotting which regions have high emissions. Other satellites are hunting for specific sources and can see within a few dozen meters where a leak is coming from. (If you want to read more about why there are so many methane satellites, I recommend this story from Emily Pontecorvo at Heatmap.)

But methane tracking isn’t just a space game. In a new study published in Nature, researchers used nearly a million measurements taken from airplanes flown over oil- and gas-producing regions to estimate total emissions.

The results are pretty staggering: researchers found that, on average, roughly 3% of oil and gas production at the sites they examined winds up as methane emissions. That’s about three times the official government estimates used by the US Environmental Protection Agency.

I spoke with one of the authors of the study, Evan Sherwin, who completed the research as a postdoc at Stanford. He compared the challenge of understanding methane leaks to the parable of the blind men and the elephant: there are many pieces of the puzzle (satellites, planes, ground-based detection), and getting the complete story requires fitting them all together.

“I think we’re really starting to see an elephant,” Sherwin told me.

That picture will continue to get clearer as MethaneSAT and other surveillance satellites come online and researchers get to sift through the data. And that understanding will be crucial as governments around the world race to keep promises about slashing methane emissions.

Another thing

Making minor changes to airplane routes could put a significant dent in emissions, and a new study found that these changes could be cheap to implement.

The key is contrails, thin clouds that planes produce when they fly. Minimizing contrails means less warming, and changing flight paths can reduce the amount of contrail formation. Read more about how in the latest from my colleague James Temple.

Keeping up with climate

New rules from the US Securities and Exchange Commission were watered down, cutting off the best chance we’ve had at forcing companies to reckon with the dangers of climate change, as Dara O’Rourke writes in a new opinion piece. (MIT Technology Review)

Yes, heat pumps slash emissions, even if they’re hooked up to a pretty dirty grid. Switching to a heat pump is better than heating with fossil fuels basically everywhere in the US. (Canary Media)

Rivian announced its new R2, a small SUV set to go on sale in 2026. The reveal signals a shift to focusing on mass-market vehicles for the brand. (Heatmap)

Toyota has focused on selling hybrid vehicles instead of fully electric ones, and it’s paying off financially. (New York Times)

→ Here’s why I wrote in December 2022 that EVs wouldn’t be fully replacing hybrids anytime soon. (MIT Technology Review)

Some scientists think we should all pay more attention to tiny aquatic plants called azolla. They can fix their own nitrogen and capture a lot of carbon, making them a good candidate for crops and even biofuels. (Wired)

New York is suing the world’s largest meat company. The company has said it’ll produce meat with no emissions by 2040, a claim that is false and misleading, according to the New York attorney general’s office. (Vox)

A massive fire in Texas has destroyed hundreds of homes. Climate change has fueled dry conditions, and power equipment sparked an intense fire that firefighters struggled to contain. (Grist)

→ Many of the homes destroyed in the blaze are uninsured, creating a tough path ahead for recovery. (Texas Tribune)

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