Antarctica is shedding 160 billion tonnes a year of ice into the ocean, twice the amount of a few years ago, according to new satellite observations. The ice loss is adding to the rising sea levels driven by climate change and even east Antarctica is now losing ice.
The new revelations follows the announcement last week that the collapse of the western Antarctica ice sheet has already begun and is unstoppable, although it may take many centuries to complete.
Global warming is pushing up sea level by melting the world’s major ice caps and by warming and expanding oceans waters. The loss of the entire western Antarctica ice sheet would eventually cause up to 4 metres (13ft) of sea-level rise, devastating low-lying and coastal areas around the world.
The new data, published in journal Geophysical Research Letters, comes from the European Space Agency’s CryoSat-2 satellite, which was launched in 2010.
It shows that the western Antarctica ice sheet is where 87% of the lost ice is being shed, with the east Antarctic and the Antarctic peninsula shedding the rest. The data collected from 2010-2013 was compared to that from 2005-2010.
The satellite measures changes in the height of the ice and covers virtually the whole of the frozen continent, far more of than previous altimeter missions.
CryoSat-2 collected five times more data than before in the crucial coastal regions where ice losses are concentrated and found key glaciers were losing many metres in height every year. The Pine Island, Thwaites and Smith Glaciers in west Antarctica were losing between 4m and 8m annually.
“The increased thinning we have detected in west Antarctica is a worrying development,” said Professor Andrew Shepherd, at the University of Leeds and who led the study. “It adds concrete evidence that dramatic changes are underway in this part of our planet.”
Professor David Vaughan, at the British Antarctic Survey and not involved in this research, said: “The increasing contribution of Antarctica to sea-level rise is a global issue, and we need to use every technique available to understand where and how much ice is being lost. Through some very clever technical improvements, [Shepherd’s team] have produced the best maps of Antarctic ice-loss we have ever had. Prediction of the rate of future global sea-level rise must be begin with a thorough understanding of current changes in the ice sheets – this study puts us exactly where we need to be.”
