Evidence of Antarctic glacier tipping point confirmed – sciencedaily

Researchers confirmed for the first time that the Pine Island Glacier in West Antarctica could cross tipping points, leading to a rapid and irreversible retreat that would have significant consequences for global sea level.

The Pine Island Glacier is a region of fast-flowing ice draining an area of ​​West Antarctica about two-thirds the size of the United Kingdom. The glacier is of particular concern because it is losing more ice than any other glacier in Antarctica.

Currently, the Pine Island Glacier and its neighboring Thwaites Glacier are responsible for about 10% of the continued rise in global sea level.

Scientists have argued for some time that this region of Antarctica could reach a tipping point and suffer an irreversible retreat from which it could not recover. Such a retreat, once begun, could lead to the collapse of the entire West Antarctic Ice Sheet, which contains enough ice to raise global sea level by more than three meters.

While the general possibility of such a tipping point in the ice caps has already been raised, showing that the Pine Island Glacier has the potential to enter an unstable retreat is a very different question.

Now, researchers at the University of Northumbria have shown, for the first time, that this is indeed the case.

Their findings are published in the leading journal, The Cryosphere.

Using an advanced ice flow model developed by the Northumbria Glaciology Research Group, the team developed methods that identify tipping points in ice caps.

For Pine Island Glacier, their study shows that the glacier has at least three distinct tipping points. The third and final event, triggered by the increase in ocean temperatures of 1.2 ° C, leads to an irreversible retreat of the entire glacier.

The researchers say that long-term warming trends and shoals in deep circumpolar waters, in combination with variations in wind pattern in the Amundsen Sea, could expose the sea ice of the Pine Island Glacier to more water. hot for longer periods of time, resulting in more and more temperature changes of this likely magnitude.

The lead author of the study, Dr Sebastian Rosier, is an Assistant Researcher to the Vice-Chancellor in the Department of Geography and Environmental Sciences in Northumbria. He specializes in modeling processes controlling ice flow in Antarctica with the aim of understanding how the continent will contribute to future sea level rise.

Dr Rosier is a member of the University’s Glaciology Research Group, led by Professor Hilmar Gudmundsson, who is currently working on a major £ 4million study to determine whether climate change will drive the Antarctic ice cap towards a tipping point.

Dr Rosier explained, “The potential for this region to cross a tipping point has been raised in the past, but our study is the first to confirm that Pine Island Glacier does indeed cross these critical thresholds.

“Many different computer simulations around the world attempt to quantify how climate change might affect the West Antarctic ice sheet, but it is difficult to determine if a period of decline in these models is a tipping point.

“However, this is a critical question and the methodology we use in this new study greatly facilitates the identification of potential future tipping points.”

Hilmar Gudmundsson, professor of glaciology and extreme environments worked with Dr. Rosier on the study. He added, “The possibility of Pine Island Glacier entering an unstable retreat has been raised before, but this is the first time that this possibility has been rigorously established and quantified.

“This is a major step forward in our understanding of the dynamics of this field and I am delighted that we were finally able to provide firm answers to this important question.

“But the results of this study also worry me. If the glacier were to enter an unstable and irreversible retreat, the impact on sea level could be measured in meters, and as this study shows, once the retreat begins. , it might be impossible to stop it. “

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