Discovering a new turning point under the Antarctic ice sheet! What are the consequences?

Researchers have analyzed How can relatively warm seawater lick the underside of land ice, Which can accelerate the movement of ice towards the ocean.

currently, This process is not taken into account in sea level rise prediction models. So the new findings could give a clearer picture of how the world is changing with global warming and how many coastal areas will need to adapt.

The results, conducted by scientists from the British Antarctic Survey (BAS), were published in the journal Nature Geoscience.

Disturbing study results

“We have identified a potential new tipping point in Antarctic ice sheet melting,” says Alex Bradley, a researcher in ice dynamics at BAS and lead author of the new study. “This means that our projections of sea level rise may be significantly underestimated.”

The research focuses on a region beneath the ice sheet, called the avalanche zone, where land ice meets the sea. Over time, this land ice moves into the surrounding ocean and eventually melts. It is a process that occurs around the coasts of Antarctica and Greenland and contributes significantly to sea level rise.

Seawater seeps between the land and the ice sheet

New study models how sea water It can sneak between the ground and the ice sheet above it, How does this affect localized thawing? By lubricating the bed and affecting the speed at which it can slide into the sea. It is also studying how to speed up this process by heating the water.

“Ice sheets are very sensitive to the melting of their buried areas. We found that burial zone melting exhibits a behavior similar to a “tipping point,” where a small change in ocean temperature can lead to a very large increase in burial zone melting. Which would cause a very significant change in the flow of ice over this area. “, Mr. Bradley explains.

This happens because the melting of warm water in the ice sheet area opens new cavities that allow more warm water to enter. Which leads to further dissolution, expansion of cavities, and so on. The tipping point occurs because a small increase in water temperature can have a very large effect on the extent of dissolution.

The melting of ice has not yet been taken into account

This ice melt, which is not currently taken into account in models used by the Intergovernmental Panel on Climate Change (IPCC) and other bodies, This could explain why the ice sheets in Antarctica and Greenland are shrinking faster than expected, Bradley says. Incorporating the results of this new work into these models may make it possible to obtain more reliable estimates.

“This is missing physics, which is not present in our ice sheet models. They don't have the ability to simulate subglacial melting, which is what we think is happening.” Production. “We are currently working to incorporate this phenomenon into our models,” he adds.

Article reference:

Bradley, A.T., Hewitt, I.G. The tipping point in the melting of the ice sheet grounding zone due to the intrusion of ocean water. Nat. Geosci. (2024). https://doi.org/10.1038/s41561-024-01465-7.