This counterintuitive technology fights climate change by making more carbon dioxide
Scientists are trying to pull methane from dairy barns and coal mines to make CO2. It’s a surprisingly good idea.
By Peter Fairley
The half-century old brick-clad Parsons Laboratory that houses chemical and environmental engineering labs at MIT is easy to overlook amidst the shiny corporate and billionaire-financed science centers adjoining the campus. Bút big bucks and flash clearly aren’t a prerequisite for ambition and impact in the eyes of oceanographer-turned-chemical engineer Desirée Plata.
Plata is working up materials that could one day rip apart megatons of heat-trapping methane, stalling global climate change. Yet she starts visits to her 4th-floor lab at Parsons at a desktop plywood-and-steel contraption, continuously tumbling low-key concoctions in what could easily be glass mayonnaise jars secured with garden-variety hose clamps.
The MIT professor led me to the device, nicknamed the rotisserie, to talk up the clay solutions sloshing inside the jars.
Plata’s work on the ‘zeolite’ clays—commonly found in cat litter—began with a recognition that some have tiny pores similar in size to bacterial enzymes that break down methane. Plata sloshed the zeolites in a copper-nitrate solution (the crucial step that’s now handled by the rotisserie). And when she fed methane through the copper-doped zeolites, out came carbon dioxide plus heat and water vapor. In essence, the methane had burned without a flame.
Funding to advance methane-destroying strategies like Plata’s is a rounding error in the global climate solutions space. But it could have an outsized impact: Methane is currently projected to cause as much climate change over the next decade as CO2. Converting half of the atmosphere’s methane to CO2 would avoid over one-half of a degree C of warming this century.
Zeolite’ clays, commonly found in cat litter, could one day rip apart megatons of heat trapping methane.
What makes burning methane to put yet more CO2 into the atmosphere a counterintuitive climate solution is methane’s potency. A molecule of methane released from a leaky gas pipe or a belching cow can trap almost 90 times more heat over the next two decades than each molecule of CO2. And as humanity seeks to deal with its methane emissions, ‘natural’ emissions appear to be growing. Higher temperatures dry out wetlands and melt permafrost, causing bacteria in soil to convert more of their massive carbon stores to methane.
Unless, that is, we make some radical moves. Rapid change is possible because methane happens to be short-lived. Whereas CO2 lasts for over a century, much of the airborne methane breaks down within a decade. “Methane is the only greenhouse gas for which we could reduce atmospheric concentrations in a decade or two,” says Rob Jackson, an expert on methane emissions at Stanford University.
Destroying concentrated methane, such as unwanted methane from oil and gas wells, is as easy as burning it off in one of those flares that light up the night sky above refineries. Alas, many methane sources—and definitely methane already in the atmosphere—are too dilute to feasibly attack using any of today’s technologies. “It’s only present in two parts out of a million [in the air]. So it’s a classic needle in a haystack problem,” says Jackson.
Alarmed by the risk of runaway methane emissions from permafrost, Jackson and an international group of collaborators set about drawing up a research agenda to solve the methane removal problem. Their report two years ago has spurred considerable interest.
Jackson sees progress from multiple groups working to make better methane-breaking catalysts—both heat-enhanced catalysts such as Plata’s copper-enhanced zeolites, and catalysts that turn solar energy into chemical action that his own lab is collaborating on.
His photocatalysts could be built into a methane-munching device with artificial lights, says Jackson, or potentially blended into paints so that rooftops, walls and even airplanes could use the sun’s energy to moonlight as methane-busters. “Most of the work, including our own, is being done with highly energetic ultraviolet light. We need to ideally nudge that down toward the visible wavelengths that dominate the solar spectrum,” says Jackson.
Erika Reinhardt, Executive Director of Spark Climate Solutions, a nonprofit that advocates for methane destruction R&D, cites recent work on biofilters by Mary Lidstrom, a professor emeritus of both microbiology and chemical engineering who has studied methanotrophic (methane-munching) bacteria for over 40 years. In August, Lidstrom reported a bacterium that can grow on just 200 parts per million of methane—25 to 50 times lower than most methanotrophs.
Most of the emerging approaches will work better on higher concentrations of methane, and are likely to be first put to work attacking emissions sources rather than pulling the gas out of thin air. “Research on methane removal is about working our way down a concentration curve towards atmospheric levels,” says Jackson.
A prime early target is methane-rich air ventilated from coal mines and dairy barns. Reminders of their significant methane levels arrive regularly as catastrophic accidents when ventilation falls short, such as the methane explosion at a Texas dairy farm that killed 18,000 cows last April, and a Siberian coal mine explosion that killed 52 people in 2021.
Most approaches will work better on higher concentrations of methane. . .a prime early target is methane-rich air ventilated from coal mines and dairy barns.
Plata’s game plan is to start with coal mines. In January 2022, her lab and others at MIT picked up an 18-month $2-million investment from the Department of Energy to fast-track development of a mine methane mitigation system. She says they’re moving fast by tweaking the copper-doped zeolites’ fabrication to work at lower temperatures and higher air flows. Last year, the team demonstrated the catalysts’ capabilities in the field at a large dairy producer in the Midwest.
By early 2025, Plata expects to start fabricating a commercial-scale unit for a demonstration at a coal mine in Australia, where the $120-billion per year coal sector faces growing pressure to cut its climate impact. “The Australian government has committed to reducing methane emissions 30 percent by 2030, and they can’t do it without reducing emissions from coal,” she says.
Achieving practical destruction of atmospheric methane will require a more fundamental understanding of the zeolite catalysts. “They can completely destroy atmospheric levels of methane, which is already an achievement. The problem is they need to be way too hot,” says Plata.
To continuously burn atmospheric methane, Plata’s team must heat today’s zeolites to about 300 degrees C. That energy and the strain it would put on a device would render the process infeasible, and erode the net climate benefit of destroying methane. To get a material that does the job closer to 100 degrees C, she needs to learn how heat restructures zeolite, restoring its methane-burning potential. “We need to figure out how it’s regenerating itself and how we might motivate it to do so at lower temperatures,” says Plata.
Of course, the easiest and most economical route to reducing atmospheric methane levels is to squelch its sources wherever possible, and as fast as possible. That means doing a far better job of plugging up natural gas leaks, and probably dropping natural gas altogether from our energy mix.
Some climate-concerned experts and activists go further, adding dairy consumption and coal mining to the list of must-drops. They argue that researching how to treat methane from coal mines and dairy barn exhaust, and ultimately even from the atmosphere, sends the wrong signal—that it cuts against ‘mitigating’ sources of methane by telling us we can eat our cake and have it too, if today’s methane releases can be recovered tomorrow.
Plata says she hears such complaints about her work. But she argues they are based on an unrealistic premise that society can or will change overnight: “People are going to keep eating ice cream because it’s delicious. And much of that coal coming out of the ground in Australia is metallurgical coal we need to make steel, since we’re building cities at the rate of one per week.”
In other words, as Plata puts it, dairy and coal will happen, and “it’s much better for the climate if we reduce the methane emissions.”
Peter Fairley is an independent journalist who has covered energy, technology, and the climate crisis for two decades. His work appears in Scientific American, Technology Review, Discover, Nature, the Los Angeles Times, and other outlets.
Top image: ©Anthropocene Magazine
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