Mount Erebus, Ross Sea, in the Southern Ocean, south of New Zealand
More than 100 volcanoes are hidden beneath the surface of Antarctica. However, the imminent melting of the ice sheet could cause them to explode.
A slow climate feedback loop may be bubbling beneath Earth’s vast ice sheet Antarctica.
The continent, divided from east to west by the Transantarctic Mountains, includes volcanic giants like Mount Erebus and its iconic lava lake.
At least 100 volcanoes Less visible ones dot Antarctica, many of them clustered along its western coast. Some of these volcanoes peak above the surface, but others are situated several kilometers below the Antarctic ice sheet.
As climate change are causing the ice sheet meltingincreasing global sea levels.
Melting snow is also lifting weight off the rocks below, with more local consequences. Melting ice sheets have been shown to increase volcanic activity at subglacial volcanoes elsewhere on the globe.
On the sidelines of a study at the end of November in Advancing Earth and Space Sciencethey ran 4,000 simulations to study how ice sheet loss affects Antarctica’s buried volcanoes and found that gradual melting can increase the number and size of subglacial eruptions.
The reason is that this discharge from the ice sheets reduces the pressure on the magma chambers below the surface, causing the compressed magma to expand. This expansion increases pressure on the walls of magma chambers and can lead to eruptions.
As writes, some magma chambers also contain large amounts of volatile gases, which are normally dissolved in magma.
As the magma cools and when the overburden pressure decreases, these gases come out of solution like the carbonation from a freshly opened bottle of soda, increasing the pressure in the magma chamber. This pressure means that melting ice can accelerate the start of an eruption from a subglacial volcano.
Eruptions from subglacial volcanoes may not be visible on the surface, but they can have consequences for the ice sheet.
The heat from these eruptions can increase the melting of ice deep below the surface and weaken the overlying ice sheet – potentially leading to a feedback cycle of reduced surface pressure and new volcanic eruptions.
The study authors stressed that this process is slow, occurring over hundreds of years. This means the theorized feedback could continue even if the world reduces anthropogenic warming.
The Antarctic ice sheet was much thicker during the last ice age, and it is possible that the same process of discharging and expanding magma and gas contributed to past eruptions.
