How will the Arctic sea ice cover develop this summer?

Jul 09, 2008
Simulated minimum sea-ice extent in 2008 when forced with atmospheric data from each year between 1988 and 2007 from the initial state of June 27, 2008. Model derived ice extents have been adjusted with a constant offset to account for discrepancies with satellite-derived ice extents. The thick black horizontal line displays the yearly minimum ice extent from 2007. Credit: Alfred Wegener Insitute

The ice cover in the Arctic Ocean at the end of summer 2008 will lie, with almost 100 per cent probability, below that of the year 2005 – the year with the second lowest sea ice extent ever measured. Chances of an equally low value as in the extreme conditions of the year 2007 lie around eight per cent. Climate scientists from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association come to this conclusion in a recent model calculation.

They participate with their prognosis in an international scientific contest, in which some of the most renowned institutes on climate research want to fathom out possibilities for seasonal predictions on Arctic sea ice cover by means of different methods and climate models.

"After the strong decrease of the Arctic ice during the last summer, climate scientists all around the world are constantly asked: how will the ice develop in the next years?" describes Prof. Dr. Rüdiger Gerdes from the Alfred Wegener Institute his motivation. "To answer this question, we did not want to guess, but to rely on sound calculations."

The scientists' problem: scenarios of the long-term development of sea ice clearly indicate a de-creased ice cover - exact prognoses for the following summer, however, are not yet possible. This is mainly due to the fact that the short-term development of sea ice depends strongly on the actual atmospheric conditions, namely the weather and in particular wind, cloud cover and air temperatures.

Because the exact atmospheric conditions which determine the weather patterns in the Arctic Ocean during the coming months are not predictable, Rüdiger Gerdes and his team have entered atmospheric data of the last twenty years into an ocean sea ice model developed at the Alfred Wegener Institute.

"Through this, we are still not able", says Gerdes, "to make a definitive statement on sea ice cover in September. However, this 'trick' enables us to compute the bandwidth of possible ice covers, and to quantify the probability of extreme events." Apart from the variability of atmospheric quantities during the melting season, ice thickness at the beginning of the season determines the new ice minimum. Accordingly, computations of ice thickness enter the models of the researchers from Bremerhaven. Start conditions from June 27th 2008 were used for their current prognosis.

Different from long-term prognoses, the researchers' forecasts can quickly be checked by reality. This is all right by Rüdiger Gerdes and his team. "It is a first test, and all participating researchers are eager to know how their prognosis has fared at the end of the summer. In the end, this small competition serves the optimisation of our models, so that we are able to improve our predictions concerning short-term seasonal fluctuations. It has to be added, however, that even perfect models would not be able to rule out a component of chance regarding the atmosphere. These forecasts will always be about probability, and not exact prognoses."

Source: Helmholtz Association of German Research Centres

Explore further: New discovery helps solve mystery source of African lava

add to favorites email to friend print save as pdf

Related Stories

There's something ancient in the icebox

Apr 17, 2014

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

River ice reveals new twist on Arctic melt

Apr 02, 2014

A new study led by Lance Lesack, a Simon Fraser University geographer and Faculty of Environment professor, has discovered unexpected climate-driven changes in the mighty Mackenzie River's ice breakup. This ...

Canada's subarctic lakes could face widespread desiccation

Feb 04, 2014

In Canada's subarctic—the boreal ecosystem that spans most of mainland Canada—the temperature is climbing and the snowpack is thinning. Previous research has shown that snow is disappearing even faster than sea ice.

Recommended for you

NASA sees last vestiges of Tropical Depression Jack

14 hours ago

Tropical Cyclone Jack had weakened to a tropical depression when NASA and JAXA's Tropical Rainfall Measuring Mission (TRMM) satellite passed above on April 22, 2014 at 1120 UTC/7:20 a.m. EDT.

New discovery helps solve mystery source of African lava

18 hours ago

Floods of molten lava may sound like the stuff of apocalyptic theorists, but history is littered with evidence of such past events where vast lava outpourings originating deep in the Earth accompany the breakup ...

Climate change likely to make Everest even riskier

18 hours ago

Climbing to the roof of the world is becoming less predictable and possibly more dangerous, scientists say, as climate change brings warmer temperatures that may eat through the ice and snow on Mount Everest.

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

mikiwud
2.8 / 5 (4) Jul 10, 2008
Don't these people read any other "research" than their own? There have been large volcanoes erupting under the Arctic sea ice in recent years,at least pay lipservice to factoring it into your deliberations.
GrayMouser
4.3 / 5 (3) Jul 10, 2008
It makes a nice graph but I don't understand why it isn't in chronological order instead of jumping around.
Glis
2.3 / 5 (3) Jul 12, 2008
It makes a nice graph but I don't understand why it isn't in chronological order instead of jumping around.


Good call. 01-04,06 were all pretty thick. What a sleazy way to manipulate data!
Excalibur
2.3 / 5 (3) Jul 16, 2008
The data are not manipulated, but ranked by magnitude for ease of comparing by that value, not by time. Thus, those years which show the greatest deviation are most easily identified.
Glis
1 / 5 (2) Jul 17, 2008
No, it's just plain misleading.

The title is about how will it develop THIS SUMMER. You expect a graph that will allow you to forecast the next year, but a graph that doesn't have a chronological time axis is near useless.

More news stories

On global warming, settled science and George Brandis

The Australian Attorney General, Senator George Brandis is no stranger to controversy. His statement in parliament that "people do have a right to be bigots" rapidly gained him notoriety, and it isn't hard to understand why ...