Collapse of the Thwaites glacier and its accompanying ice sheet could lead to more than three metres of sea level rise. The British Antarctic Survey is hoping to find out how fast it might collapse
Antarctica is changing at “a pace that we’ve never seen before” with the potential collapse of key ice sheets threatening three metres of sea level rise in a century, the British Antarctic Survey (BAS) has warned.
Scientists at the BAS, which is launching a new 10-year strategy, are part of a multinational effort to monitor the Thwaites glacier, which has been dubbed the “doomsday glacier”.
The river of ice has retreated more than eight miles since the 90s and is already responsible for 4 per cent of global sea level rises. Were it to melt entirely, this would cause a rise in the sea level of 65 centimetres.
More worryingly, it is thought to be both the keystone and the “weak underbelly” of the West Antarctic Ice Sheet.
If Thwaites were to pass a tipping point and be lost completely, said the BAS, it could potentially lead other glaciers around it to rapidly disintegrate and eventually to the collapse of the entire ice sheet.
Were that to happen, global sea levels would rise by more than three metres, with Cambridge, the headquarters of the BAS, suddenly finding itself on the edge of saltwater marshes.
“There’s this common perception of sea level changes a few millimetres a year, and therefore we all relaxed thinking what are a few millimetres?” said Dr Dominic Hodgson, head of the Ice Sheets and Climate Change team at the British Antarctic Survey. “But when we look back at the historical record, we can see that in the past when ice sheets melted, they do in very non-linear jumps.”
“There are periods of meltwater pulses, where essentially an ice sheet collapses and the sea level rises by several metres in the 100 years or so. It’s really rapid.”
BAS scientists are now racing to understand the composition of the bedrock beneath the glacier. Depending on how hard or soft it is could affect whether the glacier takes just five years to disappear or 500, although Dr Alex Brisbourne, who is part of the bedrock team, said the worst-case scenarios already appeared unlikely.
Even without such a collapse, the picture from the Polar regions is a troubling one. “We’ve seen extreme temperatures in Antarctica in the last couple of years, over 20°C, which is completely unsustainable for keeping ice,” said Dr Hodgson.
“We’ve got serious problems happening, starting in the polar regions and spreading out to the rest of the planet that we have to address now,” he said.
Oceans are the planet’s major heat sinks, acting as a buffer against the warming caused by carbon emissions, but this relationship could be breaking down, said Dr Hodgson.
Sea temperatures off Britain and Ireland reached all-time records this spring, which Dr Hodgson said showed “we can’t rely on” oceans as heat buffers.
Such are the changes going on due to man-made climate change that they are unprecedented even in the BAS’s 800,000-year ice core record.
“[We’ve got] a record spanning 800,000 years. We’re now so far outside of that record in terms of CO2 concentrations and methane concentrations in the atmosphere that we’re entering a completely new phase of planetary climate,” said Dr Hodgson. The race now, he said, was to understand how that would affect the planet.
The BAS hopes in the near future to extend its record back further to 1.5 million years, but beyond that period the Earth was too warm to have any ice.
The sheer rate of change is making the BAS change its approach, said Dr Hodgson. “We realised that changes are happening at a pace that we’ve never seen before and on so many fronts that we’ve had to realign how we think about our science.”
That will mean scientists stepping out of their silos and integrating their work to build a complete picture of the Antarctic and how it is impacting the planet.
Such work will be essential to understanding the future of the earth, he said, because the Antarctic plays such a vital role in moderating the world’s climate and those processes were already breaking down.
- By Daniel Capurro
- Published: June 20, 2023
- inews.co.uk – https://inews.co.uk