A disturbing study shows that 24% of West Antarctic ice is unstable

According to a new study, in just 25 years, melting oceans has caused the spread of ice thinning in West Antarctica, so quickly that 24% of the ice of the latter is now affected.

By combining 25 years of satellite altimetry measurements from the European Space Agency and a regional climate model, the British Center for Polar Observations and Modeling (CPOM) has tracked the evolution of the coverage of snow and ice on the mainland.

A team of researchers, led by Professor Andy Shepherd of the School of Earth and Environment at the University of Leeds, discovered that the Antarctic ice floe was thinned up to 122 meters in some places. The fastest changes were occurring in western Antarctica, where melting oceans caused glacial imbalance.

This means that affected glaciers are unstable because they lose more mass during melting and calving than they do win under the snow.

The team found that the pattern of thinning glaciers was not static.

Since 1992, the thinning has spread to 24% of western Antarctica and to most of its larger ice currents – the Pine Island and Thwaites glaciers – which now lose ice five times faster than at the beginning of the survey.

Use of satellites to track Antarctic ice

The study, published today in Geophysical Research Letters, used more than 800 million measurements of the height of the Antarctic ice sheet recorded by satellite altimetry missions ERS-1, ERS-2, Envisat and CryoSat -2 between 1992 and 2017, as well as snowfall simulations same period produced by the regional climate model RACMO.

Together, these measures separate changes in ice cap height as a function of weather conditions, such as reduced snowfall, and those due to long-term climate change, such as rising temperatures of the ice sheet. ocean that destroy the ice.

Professor Andy Shepherd, lead author and director of CPOM, explained: "In parts of Antarctica, the ice sheet has become considerably thinned. We wanted to show how climate change and weather changes were at the origin of the change.

To do this, the team compared the measured height change from the measured surface to the simulated snowfall changes and, where the gap was larger, they attributed its origin to glacial imbalance.

They found that fluctuations in snowfall tend to result in small changes in height over large areas for several years, but the most pronounced changes in the thickness of the ice are signs of imbalance of glaciers that have persisted for decades.

Professor Shepherd added, "Knowing how much snow has fallen has really helped us to detect the underlying change of glacier ice in the satellite record.

"We can clearly see now that a wave of thinning has quickly spread on some of the most vulnerable glaciers of the Antarctic, and that their losses are driving up the sea level around of the planet.

"In total, ice losses from the east and west of the Antarctic have contributed 4.6 mm to the rise in sea level around the world since 1992. . "

Dr. Marcus Engdahl of the European Space Agency, co-author of the study, added: "This is an important demonstration of how satellite missions can help us understand the evolution of our planet.

"The polar regions are hostile environments and are extremely difficult to access from the ground.For this reason, the view from space is an essential tool for monitoring the effects of climate change."

This article has been republished from documents provided by the University of Leeds. Note: Content may have changed for length and content. For more information, please contact the cited source.

Reference
Trends in the altitude and mass of the Antarctic Ice Sheet. Geophysical Research Letters, https://doi.org/10.1029/2019GL082182.