Thousands of meltwater lakes mapped on the Antarctic ice sheet is

According to new research, the number of meltwater lakes on the surface of the East Antarctic Ice Sheet is larger than previously thought.

A study led by Durham University in the United Kingdom discovered more than 65,000 supraglacial lakes using high-resolution satellite imagery covering five million square kilometers of the ice cap, including in areas where surface smelting was considered less intense.

This is the first time that researchers have been able to map the vast distribution of lakes over a vast area of ​​the eastern Antarctic ice cap – the largest mass of ice in the world – during the summer. a single year of melting.

Although most of the icecap is incredibly cold, with temperatures falling below -40 degrees Celsius in winter, summer temperatures can often be above zero and cause surfaces to melt. The study shows that meltwater lakes are forming in most coastal areas of the icecap, suggesting that East Antarctica might be more sensitive to the effects of global warming than in other parts of the world. we did not think so before.

The results are published in the journal Scientific reports.

The researchers examined the satellite images acquired in January 2017 during the summer melting season of the East Antarctic Ice Sheet.

The images showed that the meltwater lakes often cluster only a few kilometers from where the pack ice begins to float on the sea, but that some may exist hundreds of kilometers away. 39, inland and at quite high altitudes, up to 1000 m.

About 60% of lakes develop on floating ice floes, some of which may collapse if the meltwater lakes become large enough to cause fracturing and drain through the ice.

This new study has allowed researchers to see where lakes are forming at the highest densities because of surface melt and what parts of the ice cap may be most vulnerable to climate change.

Most lakes were the size of a standard pool, while the largest measured over 70 square kilometers.

Principal Professor Chris Stokes of the Department of Geography, University of Durham, said: "We had known for some time that lakes were forming in East Antarctica, but we were surprised at the number of are formed around the pack ice.

"The density of lakes in some areas is similar to that observed on the Greenland Ice Cap and the Antarctic Peninsula, which are generally considered to be much warmer.

"This is disturbing because we know that in other areas, the drying up of many lakes can fracture the floating ice floes, causing an acceleration of continental ice."

The researchers said the number of lakes mapped was minimal, as some small lakes may have been lost, while others may have been larger in December or February.

Professor Stokes added, "This dataset should help us better understand why lakes are formed where they are, and it will help us to predict the evolution of lake distributions in the future, especially if the air temperature is high, our study has shown what areas we should be watching closely over the next few years and beyond. "

Dr. Amber Leeson, co-author of the Lancaster Environmental Center, Lancaster University, said: "At the opposite end of the Earth, we have seen the population of supraglacial lakes of Greenland s & # 39; 39, expand inland as the air temperature has increased, and we're worried about the potential consequences of increased melting and melting Until recently, we had assumed that East Antarctica was too cold to be vulnerable in the same way, but this work shows that there may be a narrower parallel than what we had thought before. "

Dr. Stewart Jamieson, co-author of the Department of Geography at the University of Durham, said: "At a time when the pressure to act on climate change is increasing, it is more important than ever before." establish benchmarks with which to compare future changes. " "This study will allow it precisely for the melting of surfaces on the periphery of the largest ice cap in the world."