Antarctica and sea level riseWhy is it important?
Understanding Antarctica’s (future) climate is important to all of us, because if Antarctica would melt completely, sea level would be about 58 meters higher than today.
Antarctic ice shelves
Ice shelves, which are the floating parts surrounding Antarctica, play an important role in the ice sheet's contribution to sea level rise. Ice shelves act as Antarctica’s border control: by providing resistance to the ice, they prevent the land ice to enter the ocean and as such slow down sea level rise.
Melting ice shelves
These ice shelves can melt at the top due to atmospheric warming or at the bottom due to warm ocean water. When this happens, they become potentially unstable and can collapse. Such a collapse has occurred several times over the past decades in West Antarctica.
Ice shelves in East Antarctica
In this project, we wondered if these processes could also occur in East Antarctica, where the climate is colder and where the ice shelves are believed to be stable.
Camping on an ice shelf
To find out, we went to the Roi Baudouin ice shelf.
T-shirt weather
We find the presence of a micro-climate in a ~20 km wide band in a region where the ice shelf connects to the land ice. Temperatures are 3ºC higher than anywhere else in the region.
Subsurface lakes
This warm micro-climate results in extensive melt.
Water flowing and draining
The water is not only stored in lakes.
Warm micro-climate ...
By combining our field measurements with climate models and satellite data we can explain why this micro-climate occurs. It’s the result of strong downslope (katabatic) winds that originate in the ice sheet’s interior. These winds mix the warmer air in the upper atmosphere with the cold air at the surface, creating these warm conditions and enhancing melt in summer.
... and darker ice ...
These same winds blow away the snow, exposing darker ice at the surface, which further amplifies melt.
... result in melt
This meltwater subsequently collects in the subsurface lakes or streams.
Is East Antarctica in danger?Conclusions
The implications of our study are twofold. Firstly, these features are exceptional for East Antarctica, as they are usually only found in Greenland or West Antarctica. This suggests that surface meltwater processes are important on East Antarctica as well, which is usually considered too cold for these processes to occur.
Is East Antarctica in danger?Conclusions
Secondly, although East Antarctic ice shelves do not show signs of instability right now and climate is still relatively stable, we have pinpointed a potential ‘weak spot’ of these ice shelves. In the future, warmer climates undoubtedly intensify melt, increasing the risk of East Antarctic ice shelves becoming unstable, collapsing, and invoking ice loss from East Antarctica
