Greenland's ice sheet lost a record amount of mass in 2019, a finding that could prompt scientists to redefine their worst-case scenario as they assess the effects of climate change.
Key points:
- Greenland lost 532 gigatonnes of ice, 15 per cent more than the previous record in 2012
- Its icy bulk melted more quickly than anticipated amid climate warming
- Another study indicated Greenland is no longer getting enough annual snowfall to replace ice loss
Geoscientist and glaciologist Ingo Sasgen of the Alfred Wegener Institute in Germany said that the rate of ice loss — which had slowed in the previous two-year period — increased again as warm air flowed northward from lower latitudes, leading to the island experiencing a record loss in its ice mass.
That loss of 532 gigatonnes of ice — equivalent to about 66 tonnes of ice for each person on Earth — was 15 per cent more than the previous record in 2012.
Greenland's ice melt is of particular concern, as the ancient ice sheet holds enough water to raise sea levels by at least 6 metres if it were to melt away entirely.
The study added to evidence that Greenland's icy bulk has been melting more quickly than anticipated due to global warming.
Another study last week indicated the island was no longer getting enough annual snowfall to replace ice lost to melting and calving at the edges of glaciers.
"We are likely on the path of accelerated sea level rise," Dr Sasgen said.
The study, published in the journal Communications Earth & Environment, used data collected by satellites to the gravitational force of the ice mass, which scientists can use to calculate how much snow and ice is locked within.
A 'depressing' new record
Other research has shown the melting is being helped by water pooling atop the ice and at meltwater streaming between the ice sheet and the bedrock.
These studies have helped scientists refine their projections of how climate change will impact the Arctic, and how quickly.
Dr Sasgen compared the sobering process to getting difficult news from a doctor.
"It's always depressing to see a new record," he said.
He says the studies offer insight into "where the problem is, and you also know to some extent what the treatment is."
The Arctic already has been warming at least twice as quickly as the rest of the world for the past 30 years, as the amount of greenhouse gases accumulated in the atmosphere continues to rise.
That warming has also affected the Arctic sea ice, which shrank to its lowest level since figures were originally recorded 40 years ago.
In terms of Greenland's fate, "I would argue that we've been in a new normal for the past couple decades of accelerating mass loss," glaciologist at the NASA Goddard Space Flight Centre, Laura Andrews said.
"Greenland is going to continue to lose mass."
If the rate of ice loss experienced in 2019 were to continue, the annual impact on sea levels could cause increasing coastal flooding that affects up to 30 million more people each year by the end of the century, said Andrew Shepherd, a polar scientist at University of Leeds.
The new findings underline that "we need to prepare for an extra 10 centimetres of global sea level rise by 2100 from Greenland alone," Mr Shepherd said.
Reuters
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