Greenland and Antarctica’s ice caps are melting six times faster than they were in the 1990s due to global warming conditions, new analysis shows.
The most comprehensive analysis to date of satellite data from both poles leaves no doubt in its assessment of accelerating trends, scientists said.
Greenland and Antarctica collectively lost 6.4 trillion tonnes of ice between 1992 and 2017.
The ice loss from both poles is tracking the worst-case climate warming scenario set out by the Intergovernmental Panel on Climate Change (IPCC), according to scientists. The analysis suggests that 400 million people could be exposed each year to coastal flooding by 2100 owing to a rise in sea levels, unless global carbon emissions rapidly decrease.
Rising sea levels are one of the most damaging long-term effects of climate change. Greenland and Antarctica’s contribution is accelerating. The new analysis predicts that when the latest data is processed, it will show that 2019 – with its summer Arctic heatwave – has been a record-breaking year.
"That's not a good news story," Professor Andrew Shepherd from Leeds University told the BBC.
"Today, the ice sheets contribute about a third of all sea-level rise, whereas in the 1990s, their contribution was actually pretty small at about 5 percent. This has important implications for the future, for coastal flooding and erosion.”
Professor Andrews co-leads a team of experts in a project called the Ice Sheet Mass Balance Intercomparison Exercise (Imbie).
The project has reviewed polar measurements acquired by observational satellites which have tracked the changing volume, flow and gravity of the ice sheets for over three decades.
Imbie published its Greenland summary this week in the journal Nature.
The team’s studies show that ice losses are now meeting the upper end of the IPCC’s expectations. The IPPC’s mid-range predictions suggested global sea levels might rise by 53cm in the next century. But Imbie’s studies show that ice losses are greater than this forecast, and sea levels will likely rise by 70cm by 2100.
“Every centimetre of sea level rise leads to coastal flooding and coastal erosion, disrupting people’s lives around the planet,” Professor Shepherd said. “These are not unlikely events with small impacts. They are already under way and will be devastating for coastal communities.”
On average, Greenland and Antarctica lost 81bn tonnes of ice each year in the 1990s. In the 2010s, they lost on average 475bn tonnes – six times as much. 60 percent of ice losses came from Greenland, and 40 percent came from Antarctica. About a third of the total sea level rise now comes from the two polar ice caps.
Between them, they lost 6.4tn tonnes of ice from 1992 to 2017.
