Methane cuts urged as cheaper climate path

PARIS (AN) — A new U.N. report on Thursday recommended global reductions of methane emissions by up to 45% this decade as the most efficient and least costly way of preventing another 0.3 degrees Celsius of global warming.

The would require cutting 180 million metric tons of methane releases into the atmosphere — long cited as the second most important global warming culprit behind carbon dioxide — primarily from agriculture, coal mines, landfills and oil and gas systems.

But doing so by 2030 would be a particularly "cost-effective" approach to fulfill the 2015 Paris Agreement’s goal of limiting global average temperatures to no more than 1.5 degrees C. above pre-industrial levels, according to the U.N. Environment Program and the Climate and Clean Air Coalition, which is based in UNEP's Paris office.

Their assessment looked at relatively inexpensive ways of doing that such as by capturing emissions from belching cattle, repairing pipeline leaks and preventing gas vented in energy drilling.

It found the biggest potential for cuts in China were from coal and livestock, while in India and Europe it was from waste. In Africa and Latin America, it was from livestock, while in the Middle East, North America and Russia it was from oil and gas.

“To achieve global climate goals, we must reduce methane emissions while also urgently reducing carbon dioxide emissions,” said Drew Shindell, a physicist and Duke University professor of earth science who oversaw the 173-page assessment co-produced by UNEP and CCAC. “The good news is that most of the required actions bring not only climate benefits but also health and financial benefits, and all the technology needed is already available.”

Methane, a heat-trapping atmospheric gas that largely goes to waste, has the biggest effect on climate after carbon dioxide. Although methane traps heat far more effectively than CO2, it has a shorter life span. Methane lasts for a dozen years; CO2 persists for centuries.

About 40% of all methane is due to natural sources such as termites and wetlands. The other 60% comes from human activities like cattle breeding, fossil fuel burning, incineration, landfills and rice paddies.

It also contributes to ground-level ozone concentrations that create smog, which is why the report found that cutting methane also could prevent 255,000 premature deaths and more than half a million emergency room visits from asthma every year due to air pollution-related causes.

"Fast and ambitious methane mitigation is one of the best strategies available today to deliver immediate and long-lasting multiple benefits for climate, agriculture, human and ecosystem health," UNEP Executive Director Inger Andersen said in a foreward to the report.

Kadri Simson, European commissioner for energy, said the report amounts to a call for "concerted action" internationally. Rick Duke, a senior advisor to John Kerry, the U.S. presidential climate envoy, said methane is "by far the top priority short-lived climate pollutant that we need to tackle to keep 1.5 degrees C. within reach."