Antarctica is heading towards “uncontrolled melting” of its ice caps, study warns

Scientists say a new “tipping point” may be about to be reached.

Antarctica is heading towards “uncontrolled melting” of its ice caps, according to a study published Tuesday June 25 in Nature Geosciencewhich claims that scientists have discovered that a new “tipping point” could be about to be crossed. This amounts to a critical threshold beyond which a system reorganizes, often abruptly and/or irreversibly, leading to a series of cascading consequences.

The melting is caused by now warmer ocean water seeping between the ice and the land it sits on. Indeed, the Antarctic ice sheets sit on rocky substrate and extend beyond the coast to float on the sea. Previous studies had already shown that seawater, whose temperature increases below the The effect of global warming caused by human activities could infiltrate the area where land and sea meet and thus progress under the terrestrial ice.

The study confirms this hypothesis and quantifies it through modeling: as seawater warms, intrusion accelerates over short distances of 100 meters to tens of kilometers, melting the ice in heating it from below, according to the study’s lead author, Alexander Bradley.

That “can lead to the passing of a tipping point, beyond which ocean water enters in an unlimited manner under the ice cap, via a process of uncontrolled melting”, warns the study. With the risk of sea level rise, when accelerated melting outpaces the formation of new ice on the continent, threatening coastal populations around the world.

However, the models used by the United Nations Intergovernmental Panel on Climate Change (IPCC) to project the impact of global warming on Antarctica did not take this phenomenon into account. They also systematically underestimated the ice loss observed so far, according to the study, which says these models need to be updated.