Even if the environment cools, research study discovers, glaciers will continue to diminish.
Nearly 40 years of satellite information from Greenland reveals that glaciers on the island have actually diminished a lot that even if worldwide warming were to stop today, the ice sheet would continue diminishing.
The finding, released today, Aug. 13, in the journal Communications Earth and Environment, implies that Greenland’s glaciers have actually passed a tipping point of sorts, where the snowfall that renews the ice sheet each year cannot stay up to date with the ice that is streaming into the ocean from glaciers.
“We’ve been looking at these remote sensing observations to study how ice discharge and accumulation have varied,” stated Michalea King, lead author of the research study and a scientist at The Ohio State University’s Byrd Polar and Climate Research Center. “And what we’ve found is that the ice that’s discharging into the ocean is far surpassing the snow that’s accumulating on the surface of the ice sheet.”
King and other scientists evaluated regular monthly satellite information from more than 200 big glaciers draining pipes into the ocean around Greenland. Their observations demonstrate how much ice breaks off into icebergs or melts from the glaciers into the ocean. They likewise reveal the quantity of snowfall each year—the method these glaciers get renewed.
The scientists discovered that, throughout the 1980s and 90s, snow acquired through build-up and ice melted or calved from glaciers were primarily in balance, keeping the ice sheet undamaged. Through those years, the scientists discovered, the ice sheets usually lost about 450 gigatons (about 450 billion lots) of ice each year from streaming outlet glaciers, which was changed with snowfall.
“We are measuring the pulse of the ice sheet—how much ice glaciers drain at the edges of the ice sheet—which increases in the summer. And what we see is that it was relatively steady until a big increase in ice discharging to the ocean during a short five- to six-year period,” King stated.
The scientists’ analysis discovered that the standard of that pulse—the quantity of ice being lost each year—began increasing progressively around 2000, so that the glaciers were losing about 500 gigatons each year. Snowfall did not increase at the exact same time, and over the last years, the rate of ice loss from glaciers has actually remained about the exact same—indicating the ice sheet has actually been losing ice more quickly than it’s being renewed.
“Glaciers have been sensitive to seasonal melt for as long as we’ve been able to observe it, with spikes in ice discharge in the summer,” she stated. “But starting in 2000, you start superimposing that seasonal melt on a higher baseline—so you’re going to get even more losses.”
Before 2000, the ice sheet would have about the exact same possibility to get or lose mass each year. In the present environment, the ice sheet will get mass in just one out of every 100 years.
King stated that big glaciers throughout Greenland have actually pulled back about 3 kilometers usually because 1985—“that’s a lot of distance,” she stated. The glaciers have actually shrunk enough that much of them are being in much deeper water, indicating more ice touches with water. Warm ocean water melts glacier ice, and likewise makes it challenging for the glaciers to grow back to their previous positions.
That implies that even if people were in some way astonishingly able to stop environment modification in its tracks, ice lost from glaciers draining pipes ice to the ocean would likely still surpass ice gotten from snow build-up, and the ice sheet would continue to diminish for a long time.
“Glacier retreat has knocked the dynamics of the whole ice sheet into a constant state of loss,” stated Ian Howat, a co-author on the paper, teacher of earth sciences and identified university scholar at Ohio State. “Even if the climate were to stay the same or even get a little colder, the ice sheet would still be losing mass.”
Shrinking glaciers in Greenland are an issue for the whole world. The ice that melts or breaks off from Greenland’s ice sheets winds up in the Atlantic Ocean—and, ultimately, all of the world’s oceans. Ice from Greenland is a leading factor to water level increase—in 2015, sufficient ice melted or broke off from the Greenland ice sheet to trigger the oceans to increase by 2.2 millimeters in simply 2 months.
The brand-new findings are bleak, however King stated there are silver linings.
“It’s always a positive thing to learn more about glacier environments, because we can only improve our predictions for how rapidly things will change in the future,” she stated. “And that can only help us with adaptation and mitigation strategies. The more we know, the better we can prepare.”
Reference: “Dynamic ice loss from the Greenland Ice Sheet driven by sustained glacier retreat” by Michalea D. King, Ian M. Howat, Salvatore G. Candela, Myoung J. Noh, Seonsgu Jeong, Brice P. Y. Noël, Michiel R. van den Broeke, Bert Wouters and Adelaide Negrete, 13 August 2020, Communications Earth and Environment.
This work was supported by grants from NASA. Other Ohio State scientists who dealt with this research study are Salvatore Candela, Myoung Noh and Adelaide Negrete.