The ice sheets in Greenland and Antarctica are melting at a ‘worst-case scenario’ rate, according to a new study published in the Journal Nature Climate Change.
Since the ice sheets were first monitored by satellites in the 1990s, ice melt from Antarctica has increased global sea levels by 7.2mm and Greenland has contributed 10.6mm.
However, the latest measurements taken by researchers at the University of Leeds and the Danish Meteorological Institute has shown that the rate of sea-level rise is accelerating to a worst-case scenario rate of 4mm a year.
So far, the majority of global sea-level rise is because of a process called thermal expansion, when the volume of seawater expands as it gets warmer.
However, according to the study, in the last five years, ice melt has overtaken global warming as the main cause of rising sea levels.
If these rates continue, the ice sheets will raise sea levels by a further 17cm and expose an additional 16 million people to annual coastal flooding by the end of the century.
Dr Tom Slater from the University of Leeds said: ‘Although we anticipated the ice sheets would lose increasing amounts of ice in response to the warming of the oceans and atmosphere, the rate at which they are melting has accelerated faster than we could have imagined.
‘The melting is overtaking the climate models we use to guide us, and we are in danger of being unprepared for the risks posed by sea-level rise.’
Dr Ruth Mottram, a researcher at the Danish Meteorological Institute and co-author of the study, added: ‘It is not only Antarctica and Greenland that are causing the water to rise.
‘In recent years, thousands of smaller glaciers have begun to melt or disappear altogether, as we saw with the glacier Ok in Iceland, which was declared “dead” in 2014. This means that the melting of ice has now taken over as the main contributor of sea-level rise.’
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