Researchers have found that the melting of ice across the planet is accelerating at a record rate. Leading this speed-up are the Greenland and Antarctic ice sheets.
In a paper published in the journal The Cryosphere, the researchers describe the rate of loss now being in line with the worst-case scenarios of the Intergovernmental Panel on Climate Change, the world’s leading authority on the climate.
“Sea level rise on this scale will have very serious impacts on coastal communities this century,” said Thomas Slater, lead author and research fellow at the centre for polar observation and modelling at the University of Leeds. He warned that the consequences would have a global impact.
The study used satellite observations over a 23-year period between 1994 and 2017 to assess ice all over the globe. In that time, about 28tn tonnes of ice was lost. The rate of ice loss accelerated by 57%, from 0.8tn tonnes a year in the 1990s to 1.2tn tonnes a year by 2017, raising sea levels by an estimated 35 millimetres.
About half of all the ice lost was from land, contributing directly to global sea level rise. Approximately two thirds of the ice loss was caused by the warming of the atmosphere, whereas about a third was caused by warming oceans.
Polar regions constituted the greatest ice were loss from floating ice, raising the risk of a feedback mechanism known as albedo loss. Solar radiation is reflected back into space by white ice. However, when floating sea ice melts, what is left is dark water which absorbs more heat, speeding up the warming further in a feedback loop.
Glaciers showed the next biggest loss of ice volume, with about a quarter of global ice loss over the period. According to Inès Otosaka, report co-author and a PhD researcher at the University of Leeds centre for polar observation and modelling: “As well as contributing to global mean sea level rise, mountain glaciers are also critical as a freshwater resource for local communities. The retreat of glaciers around the world is therefore of crucial importance, at both local and global scales.”
Image credit: Christian Hoiberg via Flickr