Precipitation threatens Svalbard

The archipelago’s wet winters may presage a future of flooding

Svalbard precipitation at Vårfluesjøen

Photo: Jostein Bakke
Bjerknes Center scientists conduct research in the field at Vårfluesjøen on Svalbard in September 2017.

Torgeir O. Røthe & Jostein Bakke
Bjerknes Center for Climate Research

Trans. M. Michael Brady
Asker, Norway

In recent winters Svalbard has been wetter than anyone can remember; its climate is beginning to be like that of west Norway. Our research has shown that those who live in Svalbard must prepare for future floods and avalanches.

We’ve long been aware that the Arctic is warming in step with global warming and climate prognoses increasingly forecast new weather records and less sea ice. That said, one thing surprises: precipitation. Changes in precipitation, summer and winter, have led to serious avalanche accidents and floods, not just on Svalbard but throughout the Arctic.

The landscape of Svalbard has been shaped by water in various forms, including glaciers, floods, and avalanches. Long ago, there were similar wet periods. Through several field trips in Svalbard we have searched for traces of previous wet periods, with the aim of finding if the traces of bygone climate might tell us something about the future of a warmer Arctic.

Ice Age climate revealed
We recently returned from field work in Svalbard. We took samples from the beds of lakes. In them we could see the characteristic fingerprints of glaciers, floods, and avalanche incidents. It’s a unique archive that we can page back in, for Svalbard all the way back to the end of the Ice Age 11,000 years ago.

The polar desert is disappearing
Our research has been motivated by a need for new knowledge of the long-term nature of Svalbard’s climate. That will enable us to say something meaningful on the future of the Arctic. We know that the ambient temperatures have risen by 3°C since they were first recorded in Svalbard in the early 20th century. There have been both colder and warmer periods, but over the past 50 years, the temperature has gone only up.

Today the climate of Svalbard is dry. The annual precipitation at Longyearbyen is usually 7.5 inches. That’s small compared to Bergen’s 88.5 inches a year. Hence it’s sensational that in recent winters in Svalbard, precipitation has been twice what is normal.

Longyearbyen Norway’s warmest
It’s also sensational that winter temperatures have increased the most, now 2 to 3 degrees Celsius warmer each decade. Recently, there have been wintertime periods in which the temperature in Longyearbyen has been Norway’s highest.

Increased sea and atmospheric temperatures have lowered sea-ice coverage in winter. It’s a big change for Svalbard, from being iced in to being exposed to the open sea, such as along the west coast of the mainland.

Svalbard without ice
It’s easy to think of the glaciers of Svalbard as eternal, existing all the way back to the Ice Age. But our climate record reveals another history, as many of the glaciers are not remnants from the Ice Age. Many of them have disappeared and then appeared again during the last 11 centuries.

In the period of 9,000 to 6,000 years ago, the climate was 3 to 6 degrees Celsius warmer than today. In the fingerprint from the bottom of Vårfluesjøen we find traces of frequent precipitation flood periods. In other words, it’s been both warmer and wetter. But then, about 4,000 years ago, the climate was colder. That change brought glaciers back to Svalbard. Where there once were precipitation floods, we see traces of snow-melt floods.

A future with floods and avalanches
Since the peak warm period 9,000 years ago, Svalbard has gradually cooled down. The cooling has been steady, though now broken by the recent warming that began 50 years ago. Now the warming is rapid and overrides the natural climatic variations.

Based on new knowledge of the past, the future of the polar desert of Svalbard isn’t bright. All indications are that the inhabitants of Svalbard must prepare for a climate that more and more resembles that of west Norway, with more floods and avalanches. In particular, the combination of larger spring snow-melt and precipitation floods can have serious consequences. The future horizon for the Arctic must include planning settlements and infrastructures that take geologic hazards more seriously.

Original article (Nynorsk): “Nedbør vil truge Svalbard,” Science chronicle, Aftenposten Viten, Dec. 14, 2017, downloadable file available from Bjerknes Center for Climate Research at bjerknes.uib.no/artikler/nyheter/nedbor-vil-truge-svalbard.

This article originally appeared in the Feb. 9, 2018, issue of The Norwegian American. To subscribe, visit SUBSCRIBE or call us at (206) 784-4617.

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