The best quick fix for climate change? Curbing methane
The greenhouse gas warms the planet far more than carbon dioxide but dissipates more quickly. There are many promising ways to cut emissions.
If greenhouse gases were prizefighters, methane would be a heavyweight—a powerful puncher that tires quickly. Pound for pound, it is 90 times stronger than carbon dioxide (CO2) at warming the Earth. But it is also much shorter lived than CO2, leaving the air naturally after only a decade.
If we could eliminate all methane emissions from human activities, including agriculture, waste, and fossil fuels—a big if—the level of methane in Earth’s atmosphere would fall to preindustrial levels in only a decade or two, reducing global warming by 0.5 of a degree Celsius. This drop would help tremendously as we attempt to keep increased global warming from all gases below 1.5 or 2 degrees.
No other major greenhouse gas provides such an immediate opportunity to slow climate change, and policymakers are taking note. More than 150 countries have signed the Global Methane Pledge to cut methane emissions 30% by 2030. Unfortunately, though, methane emissions aren’t falling yet. In fact, methane concentrations in the atmosphere are rising faster than ever.
Methane concentrations are now 2.6-fold higher than in preindustrial times. Almost all sources of methane from human activities appear to be increasing—agriculture, landfills and waste, and oil and gas development.
Much of this recent additional methane appears to be coming from China and southeast Asia, followed by equatorial Africa and the U.S. Europe is the only region where methane emissions appear to be dropping. And, perhaps most troubling of all, tropical wetlands such as those in the Congo River basin of Africa are starting to release more methane as the planet warms. You can turn a wrench to quench methane emissions in an oil field, but there is no wrench to turn for the Congo.
The good news is that new technologies are making it easier to reduce methane emissions and clear the air. New satellites such as MethaneSAT, launched in March 2024 by the Environmental Defense Fund, and Carbon Mapper, due to be launched later this year by a public-private partnership, can detect “super-emitters” from space. A blowout at the Aliso Canyon gas storage field in Los Angeles in 2015, for instance, went unreported for weeks and ultimately emitted 97,000 tons of methane. The new satellites will be able to monitor oil wells, coal mines, landfills and cattle feedlots from space, making it harder for polluters to hide.
But to be effective, surveillance and monitoring need rules and enforcement. Methane emissions in the U.S. are governed by a patchwork of state and federal rules. The EPA’s new Source Performance Standards for oil-and-gas operations should reduce emissions not just of methane but of smog-forming volatile organic compounds and air toxics such as benzene, too.
Washington state recently implemented new rules to reduce methane emissions from landfills, which yield a sixth of U.S. methane emissions from human activities. Collecting methane gas as it leaves a landfill limits harmful warming, and the methane can be burned for electricity or processed into vehicle fuel. A cheaper and lower-tech solution is also available: Composting to keep organic matter out of our landfills. Food waste, lawn trimmings and other organic material make up half of everything we send to U.S. landfills—a waste of landfill space and a major source of greenhouse gases.
A major source of unregulated methane is the world’s 1 billion-plus cattle, which belch more methane than the entire oil-and-gas industry. Reducing those emissions will require changing our diets to eat less meat and dairy: Americans eat four times more beef than the global average.
What cows eat matters, too. A typical cow burps a bathtub’s worth of methane a day. If some of that amount could be cut, cows would grow a little faster. That incentive is driving research on feed additives to cut methane emissions and increase beef and dairy yields. Small amounts of one species of algae, Asparagopsistaxiformis, have been shown to decrease cows’ methane emissions by 82% and sometimes increase their weight gain. Blue Ocean Barns, a Hawaiian startup, is farming it commercially to answer demand. In May, the FDA approved Bovaer, a feed supplement made by the Dutch company DSM-Firmenich, for use in dairy cows in the U.S. The chemical cuts methane emissions from dairy and beef cattle by 30-45%.
The fuel we use for cooking also releases methane. Leaks from gas stoves produce as much pollution as a half million U.S. cars. Cooking with gas also emits carbon dioxide as the gas is burned. The best way to eliminate this indoor pollution is to replace a gas stove with an electric cooktop.
Even if we substantially reduce methane emissions, it’s unlikely that we’ll be able to bring them to zero. And climate change is likely to increase methane emissions from tropical wetlands and Arctic permafrost as warmer temperatures help methane-emitting microbes grow more quickly. We may need technologies to remove methane from the atmosphere or destroy it there.
Methane removal is more of a concept than a reality today, much further from commercial use than carbon removal. But scientists and engineers have begun testing chemicals and microbes that can oxidize methane, turning it into carbon dioxide, which is far less polluting. Other researchers are studying how chlorine-rich mineral dust from the Sahara catalyzes methane destruction in the open air.
Methane removal may be unnecessary if we curtail methane emissions, and fortunately, low-hanging fruit abound. The Global Methane Assessment estimates that approximately one tenth of anthropogenic methane emissions can be mitigated at “negative cost,” meaning mitigation would pay for itself if companies acted. Oil-and-gas companies and landfill operators, for instance, can sell or use any methane they collect.
Still, stemming methane emissions won’t be free. We will eventually need a price on methane emissions to maintain a safe climate, in the same way that Europe prices CO2 pollution. Such incentives are driving technological innovation, like the world’s first green steel being produced using green electricity and hydrogen by the HYBRIT consortium for Volvo and other companies. What’s economically feasible changes when the polluter pays.
With methane as with other greenhouse gases, the costs of climate inaction dwarf the costs of climate action. Insurance giant Swiss Re recently estimated that the global economy could shrink by 18%, at a cost of up to $23 trillion annually by 2050, if no climate mitigation action is taken. With the right policies and focus, we can all live to see the benefits of cleaning methane from our atmosphere, providing us and our children with a less chaotic, more sustainable planet.
Rob Jackson is a professor of earth sciences at Stanford University and chair of the Global Carbon Project. This essay is adapted from his new book, “Into the Clear Blue Sky: The Path to Restoring Our Atmosphere,” which will be published on July 30 by Scribner.
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First Published:26 Jul 2024, 07:00 AM IST
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