For two years, global temperatures have exceeded the 1.5C heating limit laid out in the Paris climate agreement. This overshooting will have “devastating consequences”, the UN secretary general, António Guterres, has warned.
The biggest worry for scientists is that further heating coudl trigger irreversible tipping points, such as the widespread drying out and dying off of the Amazon, or the melting of the Greenland ice sheet, beyond which climate breakdown could spiral out of control.
For the UN, and the world, minimising and, if possible, reversing that “overshoot” must now be the priority. But shifting the world’s energy systems too burn less fossil fuel is taking decades, time we no longer have to spare.some scientists believe the answer lies elsewhere: with the powerful greenhouse gas,methane.
“Cutting methane is the single most critically important strategy to slow near-term warming,” says durwood Zaelke, the president of the Institute for governance and lasting Progress, and a longtime advocate of action on methane. “Actually, it’s the only strategy that has a chance of working. Cutting carbon dioxide is a marathon, but methane is a sprint.”
methane, the main component of the natural gas that is burned around the world for fuel, is produced by natural and human-made processes, including leaky oil and gas infrastructure, livestock, and the rotting of organic material. Once in the atmosphere, it is about 80 times more powerful in trapping heat than carbon dioxide, but has a shorter life, breaking down in about 20 years.
Scientists estimate that methane alone has driven at least a third of the warming in recent years. New satellites and detection systems have revealed an unexpected truth: many countries have been massively underreporting their methane emissions, and the quantities of the gas being poured into the atmosphere have been climbing strongly, even while carbon dioxide output has been slowing.
Cutting methane would give the planet essential breathing space, staving off the worst consequences of climate breakdown while the transition to a clean energy future gathers pace. Global temperature rises could be held down by about 0.3C in the next decade with a 40% cut in methane, or by as much as 0.5C by 2050 with further cuts.If the world is to minimise the overshoot of the threshold of 1.5C above preindustrial levels, action on methane is indispensable.
“It’s the rocket in the pocket,” says Paul Bledsoe, a former Clinton White House climate adviser. “It’s effective and it’s cheap to reduce methane – two-thirds of the reductions needed from the energy sector could be done at zero net cost.”
A paper published in October in the peer-review journal Science found that significant cuts to methane could delay key tipping points: it could reduce the likelihood of the Amazon rainforest dying back by about 8%, and of disruption to the Indian monsoon by about 13%.
The study also found that reducing methane paid for itself three times over – or six times over if health benefits were included. Cutting methane by a third by 2030 would be worth about $1tn a year for the global economy. Simon Dietz, a professor at the London School of Economics who cowrote the study, says: “The benefits of global methane action look so much larger than the costs that the economic case for action is clear. [It is] not only feasible but also economically compelling.”
With Trump in the White House, no enforcement is likely – new rules formulated under Biden have been suspended. Bledsoe believes the private sector will step up nevertheless. “They recognize that reducing these emissions is part of their license to operate with the public,” he said. “And new detection technology will expose the laggards.”