For the 28th year in a row, Greenland's ice sheet is shrinking

Greenland's ice sheet has lost around 80 gigatonnes of ice during this year's melt season ending in September. The calculation is done yearly by the National Geological Surveys for Denmark and Greenland (GEUS) with Chief consultant Andreas Ahlstrøm as one of the project managers. He explains that the ice has behaved a little differently this year, but that the result is the same – less ice and rising sea levels.  

"This year we have actually seen less melting than usual from the surface of the ice, due to large snowfalls over the ice in July and August. On the other hand, more icebergs than usual have calved from the glaciers that flow into the fjords. Therefore, the ice has diminished overall for the 28th year in a row. This continuous shrinking is worrying," says Andreas Ahlstrøm. 

According to the estimates, the total amount of ice lost from the ice sheet this year adds about 0.2 mm to global sea levels. This means a total increase of 15.9 mm since 1986.

When snow turns to rain

The size of the Greenland Ice Sheet is dynamic and affected by snowfall, melt and glacier calving, which varies greatly from year to year. With the climate changing quickly in the Arctic these years, it is therefore of utmost importance to keep monitoring how these changes cascade through the ice dynamics and ultimately affect how fast the ice melts. More Arctic rain looming on the horizon is especially concerning, Andreas P. Ahlstrøm explains:  

"In a warmer climate, we can expect more variability from year to year, and this also applies to snowfall. A warmer atmosphere will be able to transport more moisture and thus increase precipitation. The concern is that the warming could mean that the precipitation in the Arctic increasingly falls as rain instead of snow. This will accelerate melting at the surface rather than slowing it down as it did this year.” 

GEUS's ice sheet monitoring projects PROMICE and GC-Net continuously monitor the state of the ice sheet by measuring the processes removing and contributing mass, respectively. Although measurements from individual years may vary considerably, the last 28 years have all shown an overall decline in the total mass of the ice sheet.

Read more about the researchers' work on the project's website promise.org