Carbobrief.org - The Antarctic Peninsula is a long, relatively narrow limb extending 800 miles out from West Antarctica, and is home to hundreds of glaciers.
These rivers of ice ooze their way down through the Peninsula’s rocky mountain range and into the ocean, powered by gravity and their own weight.
But of the 674 glaciers on the Peninsula’s western side, almost 90% are retreating. This happens when their ice melts faster than new snowfall can replenish it.
The prevailing theory has been that warming air are melting the glaciers. But a new study, just published in Science, finds that the main cause is actually rising ocean temperatures.
As the Peninsula’s glaciers are among the main contributors to sea level rise, knowing how and why they’re changing will help make predictions more accurate, the lead author tells Carbon Brief.
Glacier retreat
The Antarctic Peninsula is one of the fastest warming regions on Earth. Temperatures have risen by more than 3C over the past 50 years.
The warming atmosphere has caused some remarkable changes to the eastern side of the Peninsula. The Larsen ice shelf, a floating sheet of ice formed from glaciers spilling out onto the cold ocean, has lost two of its four sections in recent decades.
Larsen-A collapsed in 1995, followed by its neighbour, Larsen-B, in 2002. Rising air temperatures are also contributing to the thinning of Larsen-C, which is now at risk of collapse.
Over on the western side of the Peninsula, around 600 small glaciers of various shapes and sizes have also been melting. Scientists had thought that warming air temperatures were the likely cause of these retreating glaciers, says lead author Dr Alison Cook, a research fellow at the Durham University. She explains to Carbon Brief:
“Few of these glaciers had been studied in detail and it was thought that their retreat was in response to the atmospheric warming, which has been the predominant driver on the eastern side.”
However, recent research suggests the glaciers are retreating even more quickly than can be explained by just the warming atmosphere.
Cook’s study finds that the main cause of glacier melt actually lies deep in the ocean – several hundred metres beneath the surface. Read more..
