Climate change is bringing more bad news to Antarctica — according to not one, but two recent studies published this week.
In one study, scientists found the first active leak of methane gas from the Antarctic seafloor. In the second, they learned that the ice sheet is less stable than previously thought.
This is not good news
Antarctica is witnessing some of the most rapid warming on Earth. In the last 50 years, it has warmed almost 3ºC (5.4 Fahrenheit), much higher than the global average of 0.9ºC (1.6 Fahrenheit). This has led to visible effects, including snow turning red, reduced penguin populations, and ice retreat. But the changes aren’t always obvious, and sometimes it takes a while to see all of them.
A group of researchers has discovered for the first time an active leak of methane gas from the seafloor, a process likely to accelerate climate change. Methane is a powerful greenhouse gas, more potent than CO2; the risk of it leaking from under ice has long worried scientists.
The study said the leak was first discovered in 2011, and for several years, it’s been leaking right beneath the surface. According to researchers, methane-consuming microorganisms are now present at the seep and limit some of its emissions, but it took five years for the microorganisms to develop at the site. Andrew Thurber, an oceanographer who led the research, told The Guardian that this “is not good news” and that the microbes were of an unexpected strain.
To make things even worse, a second seep was discovered in 2016. A large amount of methane is stored under ice, with Antarctica estimated to have as much as a quarter of Earth’s marine methane. Researchers have longed warned the climate effect a methane leak would bring to an already warming planet. In 2018, NASA said ice melting in the Arctic could release methane to the atmosphere.
The release of methane from ice is also considered one of the tipping points in climate change, where the effects of rising temperatures cannot be stopped or reversed. But until now no active leak of methane had been registered in Antarctica. The findings will now help to understand how methane is consumed and released in Antarctica, but researchers fear we may be already losing control of the Earth’s climate.
Antarctica’s ice sheet is shaking
A group of researchers at the University of California, Santa Cruz, University of Washington, and the University of Kansas, report that the East Antarctic ice sheet isn’t as stable as previously thought, adding to the many pieces of evidence of historic ice loss in the area.
The study found evidence that East Antarctica experienced melting 400,000 years ago when the world was 1ºC to 2ºC (1.8 to 3.6 Fahrenheit) warmer. Enough ice melted could have happened there to raise the sea by about 10 to 13 feet (3 to 4 meters), the researchers argued.
Back in 2017, a previous study discovered evidence based on sediment data, suggesting the glaciers in the region experience cycles of advance and retreat. This challenged the previous idea that this part of Antarctica had remained frozen for millions of years. Then, in 2019, researchers found the regions were already experiencing some ice loss, which raised concerns.
This paper elevates those concerns even more. The researchers looked at three samples of subglacial sediment to see what minerals have accumulated beneath the ice historically. The team focused on the Wilkes Basin, a huge swath of ice that covers an area roughly the size of France.
They were able to date the opal and calcite found in their samples, taken near the Pensacola Mountains and Elephant Moraine in East Antarctica. The samples showed that East Antarctica hasn’t been stable for as long as previously thought. About 400,00 years ago the ice receded in the basin, contributing to sea-level rise. While researchers have grown worried over parts of the West Antarctic ice sheet facing a likely collapse, the new findings show some of the eastern portions of the continent could be in trouble.
“This supports the idea that future sea levels in response to warming will be much higher than present,” Terry Blackburn, one of the authors, said in a statement.
We’ve read a lot of bad news from Antarctica lately, and this one-two punch is nothing to scoff at. We may be reaching a climate tipping point — after which there could be no turning back.
The studies were published in the journals Proceedings of the Royal Society B and Nature.
