Arctic: Sea ice continues to shrink

The summery area of ​​Arctic sea ice is the second smallest since the beginning of the measurement

Research icebreaker Polarstern in thin ice: The Arctic sea ice has in September 2019 the second smallest extent since the beginning of the measurements. © Stefanie Arndt
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Scarcely past the negative record: the Arctic sea ice once again reaches a summer low. With only about 3.9 million square kilometers, the ice has the second smallest area since the beginning of the satellite measurements, as glaciologists report. This puts the annual minimum below four million square kilometers for the second time since 1979. From February to August 2019, the ice surface was even at a record low for that time.

The Arctic heats up more than any other region of the world as a result of climate change - with visible consequences: the Arctic sea ice has been shrinking for years, its supplies are dwindling and seasonal differences have also intensified. Even near the North Pole there are now many open water areas in summer. Researchers even predict that the central Arctic could become navigable as early as 2040 in the summer.

September mean values ​​of the Arctic sea ice extent since 1979. In red the estimated value for 2019. © meereisportal.de

Only 3.9 million square kilometers

This year, too, no signs of recovery of Arctic sea ice are apparent - rather the opposite. For at present, only about 3.9 million square kilometers of the Arctic Ocean are covered by sea ice, as ice researchers from the Alfred Wegener Institute (AWI) and the University of Bremen report. Typically, the sea ice area in the northern polar region reaches its annual minimum in September.

If the current values ​​remain the same, the annual minimum could remain below four million square kilometers for the second time since satellite measurements began. It was the second-smallest stretch of sea ice since 1979. Only in 2012 did sea ice shrink even more in summer than this year. At that time, only 3.4 million square kilometers of ice remained in September a negative record,

Until August on low-record course

By mid-August 2019, it even looked as if this year's ice sheet would reach a new minimum record: it was smaller than ever seen by satellites during that period. "Our satellite data showed an unusually strong decrease in ice extent between March and April 2019, from which the Arctic sea ice did not recover by summer, " explains Christian Haas of the AWI. Since the second half of August, however, the seasonal decline has slowed. display

Map of the sea ice extent on 12 September 2019. meereisportal.de

The ice may, however, continue to decline somewhat in the next few weeks: even if the Arctic air temperature is again below freezing for seasonal reasons, the heat in the water can keep the sea ice from the bottom for a few weeks continue to melt for a long time. But if it gets very cold in the Arctic in the next few days, the ice cover can also increase again. The scientists will analyze the data for the entire month of September in October and then draw the final balance of the sea ice minimum in 2019.

"Drastic changes"

"Record or not, this year confirms the further long-term climate-related decline in Arctic ice, which makes it increasingly likely that there will be ice-free summers in the Arctic in a few decades, " says Haas. "This means drastic changes for the Arctic, with consequences for the climate and ecosystem and for us humans, including in Europe."

The AWI team around Haas and colleagues at the Institute of Environmental Physics at the University of Bremen have been analyzing satellite data for ice concentration, its extent, thickness and the parameters of the atmosphere over the Arctic sea ice for many years. From this they create daily updated ice maps and protect the sea ice development with the aid of evaluation algorithms.

Source: Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research

- Nadja Podbregar