The Methane Hunter: Behind the Pledge to Cut Emissions

Ilse Aben in the lab. (Courtesy SRON Netherlands Institute for Space Research)

President Biden announced in September that the United States and the European Union would be launching a “Global Methane Pledge” at the November climate summit in Scotland. It’s a sweeping commitment to cut global methane emissions by roughly a third over the next nine years. Such promises are benchmarks upon which the world can hold governments to account, but those goals can only be met after researchers get down into the weeds of the math, physics, and chemistry needed to detect sources of airborne methane.

The efforts of people not in the political spotlight will be the critical element upon which global deciders can adopt measures that may save the future of our planet.

Enter the work of a mathematician named Ilse Aben, who is a principal investigator at the SRON Netherlands Institute for Space Research. Aben has spent years in the weeds of methane emissions, swamped by data from the satellite-borne Tropospheric Monitoring Instrument (TROPOMI).

As it circles the Earth, TROPOMI delivers Aben a continuous stream of spectrographic snapshots of the gases below. “I get that for the whole globe, every day, 14 million observations,” she said in a phone interview.

TROPOMI’s imaging instrument, which captures the fingerprints of gases, was not particularly conceived to look for methane emissions coming from oil and gas industry facilities. But the acceleration of climate change has notched up the urgency to find greenhouse gas emissions that can yield big reductions fast. While reducing carbon emissions has long been a global target because of the gas’s persistence in the atmosphere — 100 years or more — there’s no quick fix for our CO2 challenges.

Methane, however, in its briefer 10- to 20-year lifetime, can wreak 80 times more warming than CO2. In the short term, reducing methane can go a long way toward preventing catastrophic warming, and buy us more time.

Aben and her colleagues are on the hunt for fixable methane emissions among the swirling array of trace gases TROPOMI studies. They have trained artificial intelligence to comb through volumes of data, and have built algorithms, fine-tuning them using known data, to tease out methane leaks from background noise.

“With the satellite,” Aben explained, “You measure what we call the ‘total column’ of methane, which is all the methane from the top of the atmosphere down to the Earth’s surface. And in that total column, most of it is background [noise] coming from somewhere other than the location you are looking at.”

Gases live long and travel. Odorless and invisible, Methane has historically been difficult to detect, for both industry and regulators. So Aben’s “weedy” calculations, duplicated by other researchers, are a game changer. Scientists can now document runaway methane emissions above oil and gas infrastructure.

“You see a lot of [industry] flare installations that are not flaring,” Aben said. In the oil and gas industry, methane is sometimes vented into the air to release pressure. Flares burn off the methane — unless they aren’t working. In that case, the methane "is just pouring out,” she said. “That’s stupid. Really stupid.”

Aben’s frustration comes from having a window seat to watch emissions she can’t control. But frustration has increased her determination: “As a researcher, I could say, ‘My work stops, I’ve done my research, I’ve written the publication … I’m going to start the next project.’ But as a human being, it would be a shame to not make the next step.”

That step takes her beyond pure science into the rocky realm of human behavior. She and her team reach out to the owners of methane leaks, such as oil and gas companies, in the hopes of making change. When Aben’s team discovered large methane emissions over a facility in Turkmenistan, they reported it to the owner.

“We could see a couple of months later, from the satellite, that the emissions stopped,” she said.

However, the victory was short-lived. Six months after that, her team watched as the same emissions started up again.

“So this is where we are now,” Aben said. “There’s no regulation in place to say, well, but if you emit more than this or that, you’re going to get a fine.”

The European Commission has been closing in on regulating methane since it announced its methane strategy in October 2020. And Aben expects that it will issue fines. But this remains to be seen —legislative proposals are due out at the end of 2021.

Aben, however, is not just waiting until then. She continues to press for reporting protocols. She wants to funnel her findings into a centralized repository regulators can use for enforcement. The UN initiated a clearinghouse, the International Methane Emissions Observatory, for exactly this purpose.

Meant to monitor methane emissions worldwide, the observatory plans to provide data access to the public. The hope is that this will foster engagement and increase public pressure. Access to data is part of most next-generation, methane-targeted satellite projects, like California’s Carbon Mapper (scheduled to have a satellite in orbit by 2023). Aben is on a Carbon Mapper advisory committee. The California Air Resources Board will use the mapper — with its public dashboard — to improve industry compliance with the state’s robust methane standards.

To monitor the state’s facilities, Carbon Mapper will have to zoom in closer than TROPOMI does — but first it has to know where to focus its precision eye. It will find these targets, according to its website, through “a combination of prior knowledge of infrastructure locations and follow-up based on ‘tips’ from other satellites designed for wider area monitoring.”

TROPOMI was designed for this kind of monitoring, which is why Aben is going the extra mile to perfect a global map of methane hot spots — a tip sheet.

Despite her groundbreaking work, Aben is unlikely to appear on the Sunday morning talk shows discussing methane emissions. But if the methane pledges of world leaders meet even a little success, Aben’s remote, persistent work will be there in the fabric of that victory.