Despite global commitments, methane emissions are rising

A new scientific paper published Tuesday finds that methane concentrations in our atmosphere have increased over the past five years, despite a global pledge in 2021 to reduce emissions. In addition, the study’s authors note that at least two-thirds of methane emissions come from human-caused sources, including fossil fuel burning and agriculture, and that methane concentrations are rising faster than in the past.

“This is pretty much all bad news,” said Stanford climate scientist Rob Jackson, lead author of the paper, published in the journal Environmental Research Letters.

Although methane receives less attention than carbon dioxide, according to Jackson and his co-authors, it is a far more potent contributor to global warming than carbon dioxide — 84 times more potent when measured on a 20-year timescale — and its proportion is rising faster, relatively speaking, than that of any other major greenhouse gas.

The new article comes shortly after the release of the latest Global Methane Budget – a four-yearly inventory of atmospheric methane and its sources, to which Jackson contributed.

There is no single cause for the increased emissions, but rather a combination of factors, including increased fossil fuel use, higher beef consumption and more waste (which leads to methane emissions from landfills), Jackson said.

When methane is burned as fuel, as in Massachusetts, carbon dioxide is released into the atmosphere. Extreme greenhouse gas pollution occurs when unburned methane leaks from pipes.

In addition to these leaks, there is a new concern: the increase in methane emissions from certain natural sources, particularly tropical wetlands in the Congo, the Amazon and Southeast Asia. This is likely due to warmer, wetter temperatures that are ideal for methane-emitting microbes to thrive.

That’s a concern because tropical wetlands are the largest natural source of methane, Jackson said, and as the planet continues to warm, emissions from wetlands are expected to rise. “But if they do start to rise, we have no tools to curb them or slow emissions,” he said.

That means “we need to try even harder” to offset human-caused emissions, says Gabrielle Dreyfus, chief scientist at the Institute for Governance and Sustainable Development, who was not involved in the recent methane reports.

The situation is also worrying because forecasts of expected global warming do not take into account the increase in natural emissions, said Dreyfus.

The projections that form the basis for most global policy action come from the IPCC, a huge body of leading scientists that produces comprehensive reports on the causes and impacts of climate change. When it came to methane, however, the IPCC predicted methane emissions from human activity alone.

This is largely because the science on methane and its role in warming the planet is still relatively new. In the early 2000s, when the IPCC was developing some of its models, methane was relatively stable. That started to change in 2007, says Drefus, before it really took off in the 2010s.

Methane is now responsible for about a third of the warming of our planet to date.

As the concentration of methane in the atmosphere has increased, scientific knowledge on the subject of methane has also improved and expanded significantly – and with it global attention to the problem.

In 2021, the United States was among more than 100 countries that joined a so-called Global Methane Pledge to reduce global methane emissions by at least 30 percent below 2020 levels by 2030.

Since then, the United States has passed new methane emissions regulations that require oil and gas operators to take steps such as detecting, monitoring and repairing leaks, phase out routine flaring of excess gas at new oil wells, and impose fines on operators who have excessive methane emissions.

It’s a start, says Drew Shindell, a climate scientist at Duke University who studies methane but was not involved in the recent article. But globally, “our words outstrip our actions.”

The challenge is that, similar to As with most climate-related commitments, including the Paris Climate Agreement, the methane commitment is voluntary. Each country puts forward its own plan to work toward a target, and there is no remedy (other than continued climate catastrophe) if those targets are not met.

As significant as the promise is – considering that only a few Although methane has received a lot of attention in advance, it is far from enough, says Shindell.

“Urgent action is needed here,” he said.

You can reach Sabrina Shankman at [email protected]. Follow her @shankman.