Previously unknown processes Researchers solve a years-old Antarctic melting mystery thanks to elephant seals
From 2015, the area of Antarctic sea ice shrank surprisingly sharply. A study by the University of Gothenburg now shows that this collapse was years in the making - based on data from elephant seals, among others.
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- Antarctic sea ice increased until 2015, but then collapsed drastically from a record high to a record low within two years.
- According to a new study, the cause is a layer of cold water that has been weakened for years, allowing stored heat from strong winds to reach the surface in 2015, causing the ice to melt rapidly.
- With the help of sensors on elephant seals, the researchers were able to collect data in places that were previously difficult to reach.
Sea ice in the Antarctic was the exception for a long time: unlike in many other regions of the world, its area initially increased. At least until 2015, when it suddenly fell from a record high to a record low within two years. In a recently published study in the journal "Nature Climate Change", researchers from the University of Gothenburg investigated why this happened.
According to the study, the sharp decline did not come out of nowhere, but was prepared over years. Between 2005 and 2015, a cold layer of water in the ocean became thinner and thinner, while warmer deep water rose closer to the surface. This layer acted as a barrier, preventing heat from reaching the surface and melting the ice.
Elephant seals provided valuable data
When unusually strong winds then occurred in 2015, the water was mixed and the stored heat reached the surface. This caused the sea ice to melt rapidly. Since then, it has remained at a low level because the stabilizing stratification in the ocean has weakened and more heat can continue to rise to the surface.
The researchers also used data from marine mammals, including elephant seals, for their study. These were equipped with sensors that measure temperature and salinity when diving. This allowed the animals to provide data from hard-to-reach, ice-covered regions where measuring devices would otherwise hardly be able to reach.
The findings are valuable because they reveal processes that are missing or insufficiently taken into account in previous climate models - and therefore help to predict future developments in Antarctic sea ice more accurately.
