North Greenland ice shelves have lost 35% of their volume, with ‘dramatic consequences’ for sea level rise, study says

Scientists have long believed that the glaciers in North Greenland have been stable—a vital condition since they contain enough ice to raise sea levels by nearly 7 feet. But a new study published on Tuesday found that ice shelves in the region have lost more than a third of their volume in the past half century due to rising temperatures – and if that continues, scientists say there could be “dramatic consequences” for glaciers , and the planet.

Using thousands of satellite images and climate modeling, the study was published in Nature communicationfound that North Greenland’s ice shelves “have lost more than 35% of their total volume” since 1978.

Ice shelves are part of ice caps – a form of glacier – flowing over water. Three of those shelves in North Greenland have “completely” collapsed, researchers said, and of the five main shelves that remain, they said they’ve seen a “widespread increase” in how much mass they’ve lost, mostly due to of warming of the ocean.

One of the shelves, called Steenbsy, shrank to just 34% of its former area between 2000 and 2013. Along with the loss of total ice shelf volume, the researchers said the area of ​​liquid ice has decreased by more than a third of its original extent since 1978.

Huge icebergs are breaking off from the front of the Zachariæ Ice Stream, whose floating ice tongue collapsed in 2003. The ice discharge to the sea from this glacier has increased dramatically since then.

Anders Bjørk, August 2016

This observation can pose a major problem, as the Greenland ice sheet is the second largest contributor to sea level rise. From 2006 to 2018, scientists noted that the single sheet was responsible for more than 17% of sea level rise during that period.

“The observed increase in melting coincides with a clear increase in ocean potential temperature, suggesting a strong oceanic control on the ice shelves,” the study authors said. “…We are able to identify a widespread ongoing phase of weakening for the last remaining ice shelves in this sector.”

Basal melting — the melting of ice from below — may also “play a complex and crucial role in thinning the ice shelf from below,” the study’s authors said. And when that ice gets too thin, it makes the structure more “prone to enhanced fracturing.”

“This makes them extremely vulnerable to unstable retreat and ice shelf collapse if ocean thermal forcing continues to increase, as is likely to be the case in the coming century,” they wrote, adding that the resulting discharge “could have dramatic consequences in terms of of sea level rise.”

Glaciers and ice caps are melting faster than they can accumulate new snow and ice as global temperatures rise – especially in the oceans, which absorb 90% of the warming on the planet. To have both warmer air and warmer seawater amplifies the loss of ice.

Earlier this year, the World Meteorological Organization predicted that Earth will have its warmest year ever recorded in at least one of the next five years, pushing the planet past 1.5 degrees of warming compared to pre-industrial times. In September, the EU’s Copernicus Climate Change Service reported that this summer was Earth’s the hottest three months on record.

Leave a Reply

Your email address will not be published. Required fields are marked *