London: Current rates of climate change may trigger instability in a major Antarctic glacier, ultimately leading to a sea-level rise of almost three metres, a new study has warned.
Researchers studied the Totten Glacier, a significant glacier in Antarctica. It drains one of the world's largest areas of ice on the East Antarctic Ice Sheet (EAIS). They discovered that if climate change continues unabated, the glacier may cross a critical threshold within the next century, entering an irreversible period of rapid retreat.
This would cause it to withdraw up to 300 kilometres inland in the following centuries and release vast quantities of water, contributing up to 2.9 metres to global sea-level rise. The EAIS is currently thought to be relatively stable in
the face of global warming compared with the much smaller ice sheet in West Antarctica, but Totten Glacier is bucking the trend by losing substantial amounts of ice.
The research from Imperial College London and institutions in Australia, the US, and New Zealand shows that Totten Glacier may be even more vulnerable than previously thought. Earlier, the team had found that there is currently warm
water circulating underneath a floating portion of the glacier that is causing more melting than might have been expected. The new research looks at the underlying geology of the glacier and shows that if it retreats another 100-150 km, its front will be sitting on an unstable bed and this could trigger a period of rapid retreat for the glacier.
This would cause it to withdraw nearly 300 km inland from its current front at the coast. Retreating the full 300 km inland may take several hundred years, said Martin Siegert, from the Imperial College London. However, once the glacier crosses the threshold into the unstable region, the melting will be unstoppable - at least until it has retreated to the point where the geology becomes more stable again.
"The evidence coming together is painting a picture of East Antarctica being much more vulnerable to a warming environment than we thought," Siegert said.
"Totten Glacier is only one outlet for the ice of the East Antarctic Ice Sheet, but it could have a huge impact. The EAIS is by far the largest mass of ice on Earth, so any small changes have a big influence globally," he said. The study was published in the journal Nature.