Research suggests East Antarctic ice sheet advances and retreats with climate change more than scientists had realised
Pic: Flickr / Austronesian Expeditions
By Sophie Yeo
The East Antarctic glaciers are more sensitive to climate change than previously thought, according to a new study, and could retreat dangerously as global temperatures increase.
Compared to the rapidly retreating glaciers in the northern hemisphere, the remote ice sheets in the Antarctic receive relatively little attention.
But using satellite imagery to record how the glaciers along the 5,400km coastline of the East Antarctic have changed since 1963, researchers from Durham University have shown that the glaciers are sensitive to periods of warming and cooling, and have been retreating and advancing as the temperatures rise and fall.
Scientists had previously assumed that glaciers in the cold and remote East Antarctica, which can be more than 4km thick, had so far been fairly immune to the effects of climate change, which last year caused the ice sheets in the Arctic to reach their lowest levels yet.
But the new research, published today in Nature, suggests that these glaciers are more vulnerable to periods of warming and cooling, which could have a serious effect on rising sea levels if the climate warms over the next 100 years in line with scientific forecasts. The entire East Antarctic ice sheet contains enough water to increase global sea levels by 50m.
Chris Stokes, a researcher in geography at Durham University, and one of the authors of the paper, told RTCC, “The issue with the east Antarctic ice sheet is that it’s so big and it’s located in such a cold environment that people have just generally assumed that there are no clear trends in the glaciers there – that even if there was a little bit of warming we wouldn’t expect to see a response.
“What our study showed was that it can actually get quite warm there, and when it gets warm the glaciers shrink and when it cools down the glaciers advance or grow. This is the first study to show the sensitivity of the east Antarctic ice sheet to variations in climate.”
Advance and retreat
The observations showed that, during the 1970s and 80s, when temperatures were rising, most of the glaciers retreated, while during the 1990s, temperatures decreased and the glaciers correspondingly advanced.
During the 2000s, a combination of increase and decrease in temperatures meant that there was an even mix of retreat and advance.
For the moment, Stokes said, the overall volume of the ice sheets remains in equilibrium – the warmer periods which cause the glaciers to melt cause a corresponding increase in rain and snowfall, which compensate for the melting that the team observed around the margins of the ice sheet.
But the importance of the research is that it highlights that this balance should not be taken for granted over the next two centuries, and that the sensitivity of the ice sheets is a factor that must now be given more consideration when looking at the impacts of climate change.
Stokes said, “The difficulty is working out whether the additional snowfall will be enough to compensate for any additional shrinkage of the ice around the margins of the ice sheet.
“What our study shows is we need to start looking at the ice sheet in a lot more detail. We shouldn’t be complacent, we should just assume that it’s always going to be in balance.”