Melting Antarctica ice sheet could trigger more volcanic eruptions Study warns

Proceeding from a recent article, Live Science describes that a slow but potentially significant process is unfolding beneath Antarctica's ice sheet. 

The continent, split by the Transantarctic Mountains, is home to both prominent volcanoes like Mount Erebus and its famous lava lake, as well as at least 100 lesser-known volcanoes scattered across the region, particularly along its western coast. Some of these volcanoes rise above the surface, while others are hidden several kilometers beneath the ice sheet.

As climate change accelerates the melting of the ice sheet, it contributes to rising sea levels. However, this thawing also alleviates the weight pressing down on the underlying rocks, with significant local effects. Similar processes in other parts of the world have shown that melting ice can trigger increased volcanic activity, especially in subglacial volcanoes. In a study, Coonin et al. used 4,000 computer simulations to examine how the loss of ice affects these buried volcanoes, concluding that gradual ice melt could lead to more frequent and larger eruptions beneath Antarctica.

This occurs because the reduction in pressure from the melting ice sheet allows the magma chambers below to expand. As the magma expands, it increases pressure on the surrounding chamber walls, potentially causing volcanic eruptions.

Magma chambers also contain significant amounts of volatile gases, which are typically dissolved within the magma. When the magma cools and the pressure from the overlying ice decreases, these gases escape from the magma, similar to the way carbonation escapes from a freshly opened soda bottle. This release of gases increases the pressure within the magma chamber, making it more likely that melting ice will accelerate the triggering of an eruption from a subglacial volcano.

While eruptions from subglacial volcanoes may not be directly visible on the surface, they can still impact the ice sheet. The heat generated by these eruptions can accelerate melting beneath the surface, weakening the overlying ice. This process could trigger a feedback loop, where reduced pressure from the surface leads to even more volcanic eruptions and further weakening of the ice sheet.

The authors emphasize that this process occurs gradually over centuries. However, this means the proposed feedback loop could persist even if global efforts to reduce human-driven warming are successful. During the last ice age, Antarctica's ice sheet was significantly thicker, and it’s possible that a similar process of ice unloading and magma expansion played a role in past volcanic eruptions.

By Naila Huseynova