A quarter of the glacier ice sheet in West Antarctic is unstable

A team of researchers from the UK Centre for Polar Observation and Modelling (CPOM), based at the University of Leeds and led by Professor Andy Shepherd has found that Antarctica’s ice sheet has thinned by up to 122 meters (400 feet) in places, with the most rapid changes occurring in West Antarctica where ocean melting has triggered glacier instability.

The scientist’s findings were published in the journal, Geophysical Research Letters on May 16, 2019. The research team used over 800 million measurements of Antarctic ice sheet height recorded by radar altimeter instruments on ESA’s ERS-1, ERS-2, Envisat and CryoSat satellite missions between 1992 and 2017, according to the ESA in a news release.

RACMO regional model output example of Antarctica identifying Ice sheet height [,. asl.] RACMO Regional Model

RACMO 2.4 Model

Additional observations were made using the RACMO regional climate model to create snowfall simulations over the same time period. Using the RACMO modeling along with the satellite data, scientists were able to separate changes in ice-sheet height from those caused by meteorological events, which affect snow, and those caused by longer-term changes in climate, which affect the ice.

The research team found that glacier instability caused by the melting and calving due to warming oceans waters has caused the glaciers to lose mass quicker than it can be replaced by snowfall, with the thinning having spread across 24 percent of West Antarctica’s ice sheet.

This loss of mass and instability was most evident on the Pine Island and Thwaites Glaciers – which are now losing ice five times faster than they were at the start of the survey. “In parts of Antarctica the ice sheet has thinned by extraordinary amounts, and so we set out to show how much was due to changes in climate and how much was due to weather,” Shepherd said, reports CNN.

ESA’s CryoSat mission provides data to determine the precise rate of change in the thickness of the polar ice sheets and floating sea ice. It is capable of detecting changes as little as 1 cm per year. The information from CryoSat is leading to a better understanding of how the volume of ice on Earth is changing and, in turn, a better appreciation of how ice and climate are linked.

ESA

Altogether, ice losses from East and West Antarctica have added 4.6 mm (0.18 inches) of water to global sea level since 1992, Shepherd added, according to Science Daily.

Dr. Marcus Engdahl of the European Space Agency, a co-author of the study, added: “This is an important demonstration of how satellite missions can help us to understand how our planet is changing. The polar regions are hostile environments and are extremely difficult to access from the ground. Because of this, the view from space is an essential tool for tracking the effects of climate change.”