Written by: Tim Radford

UN experts have found a new way to limit climate change, save lives, save the economy and reduce crop losses. It’s simple: start reducing emissions of the natural gas methane and bring them down by 45 percent in one generation. Drastic methane cuts can work wonders for the global climate.

Methane − also known as marsh gas − is a potent greenhouse gas and a dangerous air pollutant. According to a new UN Environment Programme (UNEP) assessment, a cut of approaching half of emissions by 2045 would prevent an estimated 260,000 premature deaths, save 775,000 asthma-related visits to hospital, and prevent 73 billion hours of labour lost because of extreme temperatures and annual crop losses of 25 million tonnes.

“Cutting methane is the strongest lever we have to slow climate change over the next 25 years and complements necessary efforts to reduce carbon dioxide,” said Inger Andersen, UNEP’s executive director.

“The benefits to society, economies and the environment are numerous and far outweigh the cost. We need international cooperation to urgently reduce methane emissions as much as possible this decade.”

The proposal is unlikely to meet with any argument from the world’s climate scientists, who have welcomed the report and its conclusions. “Seldom in the world of climate change action is there a solution so stuffed with win-wins,” said Dave Reay of the University of Edinburgh’s climate change institute.

“This blunt report makes clear that slashing emissions of methane − a powerful but short-lived greenhouse gas − will deliver large and rapid benefits for the climate, air quality, human health, agriculture, and the economy too.”

And Joeri Rogelj, who directs research at the Grantham Institute of Imperial College London, said: “Methane occupies a special place in the land of climate pollutants.

“It’s the second most important greenhouse gas, after carbon dioxide; its emissions can be reduced rapidly with readily available measures and this can impact temperature over the next decades; and finally, it not only causes climate damage, but also air pollution that leads to hundreds of thousands of premature deaths and crop harvest losses. Together, this costs the economy billions.”

Methane accounts for almost one-fifth of global greenhouse gas emissions: about 30 percent of the warming in the last 200 years can be attributed to methane, escaping from oil fields and refineries; from the stomachs of cattle and other ruminants; from burning peatlands and thawing permafrost.

And prompt and determined action to reduce methane would, UNEP argues, deliver swift results. Molecule for molecule, it is many times more potent as a warming agent than carbon dioxide, but much shorter-lived. Carbon dioxide lingers in the atmosphere for 100 years or more; methane has a lifetime of about 10 years.

Atmospheric methane is a key component in the formation of low-level ozone in polluted cities: ozone pollution or smog is blamed for around half a million premature deaths per year. It also diminishes growth and reduces crop productivity. And best of all, the researchers agree, is that industries, researchers and conservationists all know ways of effectively stopping its release into the atmosphere: it could be reduced by a third just in the next 10 years.

Top-priority pollutant

That is because the oil and gas sector releases, through leaks and escapes, almost 23 percent. Around 12 percent escapes from decomposing waste in landfill sites; 32 percent escapes from livestock and 8 percent from rice cultivation.

Almost two thirds of the action the report recommends could be undertaken at low cost but − as the researchers keep saying − high rewards in health, agriculture and global temperature control. The pay-off could be measurable: with global action on a sufficient and determined scale, the world could reduce potential global average warming by 0.3C by 2025.

In the last century, the world has already warmed in response to greenhouse gas emissions by more than 1°C, and is on course to rise by 2100 by more than 3°C above the long-term average for almost all human history.

But global agreement in Paris in 2015 set a target by 2100 of “well below” 2°C − shorthand for an ideal limit of 1.5°C. Right now, this target looks increasingly optimistic. Drastic methane cuts could help. The US, the European Union, Russia and many of the world’s oil-producing nations have already announced plans to act.

“It is by far the top-priority short-lived climate pollutant that we need to tackle to keep 1.5°C within reach,” said Rick Duke, once a climate adviser to US President Obama and now part of President Joe Biden’s climate team. “The United States is committed to driving down methane emissions both at home and globally.”

This article is published courtesy of the Climate News Network.