Global emissions of heat-trapping methane hit record high

While a lot of our efforts to combat global warming center on limiting the buildup of carbon dioxide in the atmosphere, methane also has a significant role to play. New analysis has revealed that emissions of this particularly potent greenhouse gas have now hit record highs, with the surge being driven in large part by the burning of fossil fuels and increased agricultural activity.

Although methane isn’t as abundant in our atmosphere as carbon dioxide, it is more than a bit-part player in the overall trend of global warming. This is because of the potency of its greenhouse effect, with the gas around 28 times more powerful than carbon dioxide when it comes to trapping heat over a 100-year span.

Methane can come from all kinds of sources, including burping cows, the fertilizer industry, leaky gas facilities and the world’s reservoirs. All up, however, more than half of all methane emissions now come from human activities, and the new study has revealed that we are only generating more and more.

The analysis was carried out by researchers working on the Global Carbon Project, an initiative to trace the impacts of human-generated greenhouse gases on the planet. In May, the group published a report detailing an “extreme” dip in global carbon emissions driven by the widespread stay-at-home measures in response to the pandemic, but they say it's inconceivable methane emissions would follow the same trend.

"There’s no chance that methane emissions dropped as much as carbon dioxide emissions because of the virus," says Rob Jackson, a professor of Earth system science at Stanford University and leader of the Global Carbon Project. “We’re still heating our homes and buildings, and agriculture keeps growing.”

The team tracked global methane emissions between 2000 and 2017, the last year from which complete data is available, and found that emissions are up nine percent from the early 2000s, equal to an extra 50 million tons per year. The researchers say this is like putting 350 million more cars on the road, or doubling the emissions of Germany or France.

Across the period studied, the team says that agriculture contributed roughly two-thirds of human-generated methane emissions, with an increase of nearly 11 percent in 2017 compared to the 2000-2006 average. Those emissions generated by the fossil fuel industry, meanwhile, made up most of the rest and were up nearly 15 percent across the same timeframe.

While methane emissions have actually decreased in Europe over the last two decades, sharp surges were seen in Africa and the Middle East, China and South Asia, and Oceania, with these three regions increasing their methane emissions by 10 to 15 million tons per year. The US, meanwhile, increased by 4.5 million tons per year, driven largely by increases in natural gas drilling operations.

“Natural gas use is rising quickly here in the US and globally,” Jackson says. “It’s offsetting coal in the electricity sector and reducing carbon dioxide emissions, but increasing methane emissions in that sector.”

When it comes to driving these emissions down and avoiding dangerous levels of global warming, the researchers see a few possibilities. Better monitoring of leaks from pipelines and wells using drones and satellites could form part of the solution, as could reductions in fossil fuel use. Feed supplements could also be used to cut down on methane from burping cows.

Two papers detailing the research were published in the journals Earth System Science Data and Environmental Research Letters, respectively.

Source: Stanford University