Methane emissions cuts as an Arctic ice shield
Making significant, near-term methane emissions cuts in tandem with slashing carbon emissions would dramatically improve the odds that Arctic sea ice could survive during the summertime through 2100, a new study finds.
Why it matters: Sea ice loss is already having ramifications throughout the Arctic and beyond, affecting extreme weather events in the U.S. and Europe, altering the way of life for indigenous populations of the Far North and posing threats to iconic species.
- A seasonally ice-free Arctic, which at present emissions rates is expected to emerge as soon as the 2030s, would also present geopolitical risks as a contested region between the U.S. and Russia, among other countries.
- The findings are surprising given the different timescales on which these greenhouse gases operate, and the current downward trajectory of sea ice.
Driving the news: The study, from a trio of researchers at the Environmental Defense Fund, adds to a growing body of work showing the potential benefits of slashing methane emissions. The new work was published Tuesday in Environmental Research Letters.
How it works: The researchers used computer modeling to determine the likelihood that certain policies to cut methane and carbon dioxide simultaneously might prevent the complete loss of Arctic sea ice in the summer.
- If steep methane emissions cuts were to start now and be combined with aggressive reductions in CO2, then Arctic sea ice would have a fighting chance to survive the century and beyond.
The big picture: Methane is a potent greenhouse gas but only remains in the air for a decade, compared to centuries to millennia for carbon dioxide.
- The study finds that if all technically feasible methane emissions reduction measures were to be put in place by 2030, and carbon dioxide emissions reductions were to drop to net zero by 2050, there would be less than a 30% chance of routinely seeing sea ice-free Arctic summers through at least 2100.
- The study also looked at methane cuts and CO2 emissions reductions alone and found that neither would be sufficient.
By the numbers: The seasonal minimum in Arctic sea ice extent has been decreasing at a rate of about 13% per decade. This is largely due to the effects of Arctic amplification, which refers to quirks in the polar climate that are causing this region to warm about three times faster than the rest of the globe.
Between the lines: Methane is already on the global policy agenda. At the COP26 climate summit late last year, leaders from more than 100 countries agreed to make methane emissions cuts on the order of 30% below 2020 levels by 2030.
Yes, but: It is unclear if countries will hit the 30% cuts they've committed to, and if they would undertake even more aggressive emissions reductions. Also, the study's modeling may miss some sea ice variability and trends.
What they’re saying: “Reducing current methane emissions represents a huge opportunity to help pump the brakes on global warming,” said lead author Tianyi Sun in a statement.
"This paper is just focusing on the response of a single aspect of the climate system (sea ice) to a mitigation strategy that (if implemented) would be reflected in all parts of the climate system," Mark Serreze, the director of the National Snow and Ice Data Center in Boulder, Colo., told Axios in an email. Serreze was not affiliated with the new research.