Pine Island Ice Shelf in West Antarctica, which holds back enough ice to raise sea levels by 50cm, could be more vulnerable to complete disintegration than previously thought, according to British Antarctic Survey (BAS) scientists.
A new study has demonstrated that two processes – thinning and calving, the enhancement of which already threatens the stability of the shelf – can interact to increase the likelihood of collapse.
This large ice shelf controls the flow of ice from Pine Island Glacier (roughly the size of England) into the Amundsen Sea. This is a crucial role as the glacier is one of the world’s largest and fastest changing, and accounts for approximately 25% of ice loss from Antarctica.
Scientists have previously observed that Pine Island Ice Shelf is becoming increasingly fragile due to two processes: enhanced thinning, because of an increase in ice shelf melting into the sea, and an increase in calving events in which masses of ice break off into icebergs.
Graphic shows how the ice front of the Pine Island Glacier ice front has retreated
Now, a team of researchers has shown that the combination of calving and melting will likely make an even greater contribution to melting of Pine Island Ice Shelf than had previously been assumed.
Dr Alex Bradley, an ocean modeler at BAS and lead author of the study, said, “This study highlights the extreme sensitivity of ice shelves to climate change. It shows the interplay between calving and melting can promote disintegration of the Pine Island Ice Shelf, which we already thought was vulnerable to collapse.”
The team used advanced ocean modeling techniques to simulate the effects of continued calving events to see how this would affect melt rate. Their simulations show that calving events could result in further thinning of the ice shelf, which will in turn make the ice shelf more vulnerable to calving. This suggests that a feedback loop between the two processes could exist and expedite the complete disintegration of the ice shelf. This would reduce its ability to stem the flow of ice from Pine Island Glacier into the sea and increase its contribution to global sea-level rise.
Bradley added, “Complete disintegration of the Pine Island Ice Shelf will have profound consequences not only for the glacier but all of West Antarctica as it is thought to play an integral role in maintaining the stability of the West Antarctic Ice Sheet.”
To view the full study, The influence of Pine Island Ice Shelf calving on basal melting, published in the Journal of Geophysical Research: Oceans, click here.
