Evrim Yazgin
Cosmos science journalist
Recent reports that a massive Antarctic glacier is melting reignites the debate about what to do, with experts saying the conversation can’t be about how to stop sea levels rising.
Dr Ben Galton-Fenzi, a glaciologist and senior scientist at the Australian Antarctic Division says mitigation isn’t an option. “Really, what we’re trying to understand now is, how much and how fast are sea levels going to go up?”
Thwaites Glacier, also known as the “Doomsday Glacier”, in the West Antarctic Ice Sheet could, if it collapses, raise sea levels by 65 centimetres according to models.
Human-induced climate change is causing average global temperatures to rise. As the Earth warms, water that is currently trapped in the polar regions of the Arctic and Antarctica melts, raising sea levels and turning the salty ocean waters fresher.
Cosmos reported last week on new research which has used up-to-date technology and modelling techniques to gauge the impact that Thwaites Glacier will have on global sea levels.
Read more: The massive trees you grew up with are under threat
Galton-Fenzi told Cosmos the “Doomsday Glacier” is already making waves.
Thwaites Glacier has “been shown to be rapidly retreating, which is alarming” and “a large part of it broke off last year.”
“It’s contributing to sea level now. It sits on a region of bedrock below sea level that we call marine basin. The bedrock slope backwards towards the interior. It becomes progressively deeper, and we get this runaway retreat called the marine ice sheet instability mechanism.
“This is why a huge international community got together to try to study and understand it better.”
“The ice flow is picking up,” says glaciologist Professor Poul Christoffersen who has recently left the University of Cambridge for the University of Tasmania. “It’s actually flowing relatively slower than many other glaciers in Antarctica, but it’s width of it and size that makes it a bit of a sleeping giant.”
“The biggest reason we think it started to retreat is due to changes in the ocean. Relatively warmer water has been driven onto the Amundsen Sea embayment, which is the ocean environment that sits adjacent to the Thwaites Glacier,” says Galton-Fenzi.
“A lot of that isn’t going to come from the West Antarctic Ice Sheet where Thwaites Glacier is located, it’s going to come out of the East Antarctic Ice Sheet, in our backyard. They’re what’s called the Wilkes and the Aurora subglacial basins.”
Christoffersen agrees. “Thwaites Glacier has been pulled out as being a potential sensitive site or catchment for West Antarctica. One of the first things that comes to mind is there are equally or close to equally sensitive drainage basins in East Antarctica.”
“To give you some comparison, the area of ice that drains out through the Amundsen Sea embayment is about 1.3 metres of sea level if we melted it all and spread it out over the oceans,” adds Galton-Fenzi. “For the Aurora and Wilkes subglacial basins in East Antarctica, that ice is about 12 metres. Greenland is about seven metres.”
Research, like that published in Nature (here and here) that is “technologically innovative” and based on “hard won data” are vital according to Christoffersen.
“These are important pieces of scientific research and new observations that will help models become better. Now we know the rates from observations of Thwaites – that’s crucial for validating and verifying models that we are going to use to predict what kind of sea level rise we’ll get from Thwaites over the coming decades and this century. That’s really valuable in my view.”
Read more: On thin ice: Melting of the doomsday glacier in Antarctica could raise sea levels by 65 centimetres
Hundreds of millions of people around the world live in low-lying areas which will be inundated if even only a fraction of polar ice melts. Many live in and around Australia.
“We’re an island nation, we’re a coastal nation,” says University of New South Wales social sciences PhD candidate Anne Maree Kreller. Kreller specialises in social movements and community-based decision-making around sea level rise.
“Between 30 and 50 percent of the Australian population live within two kilometres of the coastal zone, and six percent are within low elevation coastal zone under five meters.”
Kreller highlights the many places around the world already facing the effects of sea level rise and are at risk of being completely submerged.
“One of the challenges is people think of it as something that’s going to happen down the track. Maybe the take home message is that there are already communities in Australia and overseas grappling with these difficult questions. It’s people in our Pacific community. It’s people in Southeast Asia. It’s people in Australia.”
Kreller also points to the “difficult questions” that will have to be faced.
“Do we protect properties or the beach? Do we relocate? If so, do we relocate as a community, or do we just leave it up to individuals?”
Over the coming days, Cosmos will publish further comments from experts about the impact of melting ice on global sea levels.
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