A new study looking into the future of the Totten Glacier has concluded that current rates of climate change look set to trigger instability that could ultimately lead to a global sea-level rise of up to 2.9m.
This rise would see the majority of the Netherlands underwater, with large stretches of the US east coast also affected. In the UK, water would spread in at various points on the eastern coast, affecting areas such as Cambridge and Norwich.
The Totten Glacier drains one of the world’s largest areas of ice, on the East Antarctic Ice Sheet (EAIS). The new study, by scientists from Imperial College London and institutions in Australia, the US and New Zealand, looked to chart the history of Totten’s advances and retreats, so as to predict its future movements.
The research, published today in Nature, looks at the underlying geology of the glacier and reveals that a mere 100-150km retreat will see it on an unstable bed. This new position could trigger a retreat that would end with an almost 300km withdrawal inland from its current coastal front.
Professor Martin Siegert, study co-author and co-director of the Grantham Institute at Imperial College London, has said that the inland retreat may take several hundred years to complete. However, once it has begun, the melting will not stop until the glacier once again reaches a more stable geology.
“The evidence coming together is painting a picture of East Antarctica being much more vulnerable to a warming environment than we thought,” he said.
“This is something we should worry about. Totten Glacier is losing ice now, and the warm ocean water that is causing this loss has the potential to also push the glacier back to an unstable place.
“Totten Glacier is only one outlet for the ice of the East Antarctic Ice Sheet, but it could have a huge impact. The East Antarctic Ice Sheet is by far the largest mass of ice on Earth, so any small changes have a big influence globally.”
The study was conducted by looking at the sedimentary rocks below the glacier, using airborne geophysical surveys. The geological record, influenced by the erosion of ice above, allowed the scientists to understand the glacier’s movements from a history stretching back for millions of years.
Their findings showed that the glacier has retreated more quickly over certain ‘unstable’ regions in the past and is headed to do so again now. The scientists believe that when Totten hits these regions, it will once more trigger the pattern of rapid retreat.
The EAIS has been considered stable as compared to West Antarctic Ice Sheet, but these findings – alongside the team’s discovery last year that there is warm water circulating underneath a floating portion of the glacier, causing increased melting – suggest that we may well have more to be concerned about when it comes to this ice sheet.