In the News: Is the East Antarctic Ice Sheet less stable than we previously thought?

Image: National Geographic 

In a previous post I examined the stability of the East Antarctic Ice Sheet (EAIS). This week I will touch again on the topic as some interesting new research has just been published. 

The new study, published in Nature, suggests that the EAIS is less stable than previously thought. The subsequent headline in The Independent reads: "Global sea levels could rise by 'up to 15 feet' if East Antarctic ice sheet melts". Today we will delve deeper into the study behind this news. 

Looking back 

As I have discussed previously, the Antarctic has grown and decayed over the last 50 million years as the climate has varied. During this time it was thought that the East remained relatively stable compared to the West. However, Gulick et al., 2017 present new geological evidence that EAIS was more sensitive to changes in temperature in the past than previously thought. 

Paleo-records from EAIS margins indicate how the ice sheet has evolved over millions of years: the EAIS stabilised around 6 million years ago, after a period of instability. These records reveal that the ice sheet was dynamic and sensitive to atmospheric temperature changes, growing and shrinking accordingly. 

This new research focuses on the Aurora subglacial basin (ASB), located in the south-east of the EAIS, and presents records of glacial evolution which document changes in ice extent.  It provides evidence that past changes in the EAIS are likely to have contributed to significant sea level rise. 

Image: The Jackson School of Geoscience 

Looking forward

Understanding how ice sheets respond to a changing climate is key when making projections about future sea level rise. This new evidence suggests that as temperatures continue to rise the ASB glaciers may shift from the relative stability of the last 7 million years to an unstable period, driven by melt. 

If present warming persists, the ice sheet may become unstable and contribute to global sea level rise. According to the research, if the ice sheet in the ASB melted it would result in 3 to 5m of rise. However, the authors note that although the melting of the EAIS is 'not inevitable', it should be considered a possibility in the context of global climatic changes.