The risk that climate change could cause sharp rises in global sea levels was highlighted in a recent study that revealed the shrinkage of ice sheet in Greenland by a record amount last year.
While high temperatures were critical to the melting seen in Greenland last year, scientists say that clear blue skies also played a key role.
In a study, they found that a record number of cloud free days saw more sunlight hit the surface while snowfall was also reduced.
These conditions were due to wobbles in the fast moving jet stream air current that also trapped heat over Europe, according to BBC.
As a result, Greenland’s ice sheet lost an estimated 600bn tonnes, the media outlet said.
The huge melt was due not only to warm temperatures, but also atmospheric circulation patterns that have become more frequent due to climate change, suggesting scientists may be underestimating the threat to the ice, the authors found.
“We’re destroying ice in decades that was built over thousands of years,” Dr Marco Tedesco, research professor at Columbia University’s Lamont-Doherty Earth Observatory, who led the study, told Reuters. “What we do here has huge implications for everywhere else in the world.”
Greenland’s ice sheet, the world’s second largest, recorded its biggest outright drop in what scientists call “surface mass” since record-keeping began in 1948, according to the study.
Greenland lost around 600bn tonnes of water last year, an amount that would contribute about 1.5mm of sea level rise, according to the study from Columbia and Belgium’s Liege university, published in The Cryosphere.
Greenland’s ice sheet covers 80% of the island and could raise global sea levels by up to 23 feet if it melted entirely.
Greenland contributed 20-25% of global sea level rise over the last few decades, Tedesco said.
If carbon emissions continue to grow, this share could rise to around 40% by 2100, he said, although there is considerable uncertainty about how ice melt will develop in Antarctica — the largest ice sheet on Earth.
Most models used by scientists to project Greenland’s future ice loss do not capture the impact of changing atmospheric circulation patterns — meaning such models may be significantly underestimating future melting, the authors said.
Greenland’s ice sheet is seven times the area of the UK and up to 2-3km thick in places.
It stores so much frozen water that if the whole thing melted, it would raise sea levels worldwide by up to 7m.
Last December, researchers reported that the Greenland ice sheet was melting seven times faster than it had been during the 1990s.
Dr Tedesco explained that Greenland in 2019 experienced the largest drop in surface mass balance since records began in 1948.
The term surface mass balance describes the overall state of the ice sheet after accounting for gains from snowfall and losses from surface melt-water run-off.
The authors believe their study explains why, despite the fact that 2019 was not as warm as 2012, last year produced a record drop in surface mass balance.
“This is really pushing Greenland into the red,” said Dr Tedesco.
