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How Long Can the Arctic Survive from Melting Down?

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How Long Can the Arctic Survive from Melting Down?

Researchers from America’s National Centre for Atmospheric Research in Boulder, Colorado suggest that the Arctic ice cap could disappear in a few decades. They analyze the impact of greenhouse gas emissions on the Arctic – and predict that its summertime ice cap could vanish by 2040. The result was that in the longer term it could vanish in winter too.

Every year scientists use satellites to calculate the area of the Arctic ice cap as it grows and shrinks with the seasons. In winter it normally reaches about 5.8m square miles before receding to about 2.7m square miles in summer. In the summer of 2007, things suddenly changed. The water temperature increases by 4.3C above the average. By September the Arctic ice cap had lost extra 1.1m square miles, equivalent to more than 12 times the area of Britain.

The melting reduced the summer ice cover to just 1.6m square miles, 43% less than in 1979 when accurate satellite observations began. It left so much open sea that the Northwest Passage, the fabled link between Asia and Europe, became navigable.

When they looked at their models again, they found the events of 2007 had indeed been predicted. The models showed that there could be periods of very rapid ice melt much earlier. Some even showed that the summertime ice cap could start to vanish by 2013.

How will it affect the world? Ice is white, so most of the sunlight hitting it is reflected back into space. When it melts, it leaves behind open ocean which absorbs light and so gets warmer. This can melt more ice. It means that the ice cannot recover. The process keeps accelerating until there is no more ice to melt.

Some scientist have searched the thickness of the ice and found that the average thickness has fallen by 40%. This shows that it reaches a point where it becomes very vulnerable. It gets so thin that it can get broken up or just melts away very easily. Once that happens it could be very hard for it to recover, especially if we get more hot summers.

There is some faintly good news. The melting of the Arctic ice cap will not, for example, cause a rise in sea levels – because it is already floating. The major sea level rise associated with global warming would come if the massive ice sheets covering Greenland and Antarctica melt and flow into the oceans. According to scientists, the place that gets the impact first is in the extreme places, such as the Arctic and the world’s highest and coldest places.

When the ice melts, sea level remains unchanged, though salinity can be altered. There are 150,000-200,000 ice masses around the world and most of them are decreasing.  They estimate that between 1961 and 2005 melting glaciers raised global sea levels by 20mm. It’s less than an inch but it represents the melt water from only 4% of the world’s glaciers. Even those amounts are tiny compared with the Greenland ice sheet. It contains enough water to raise global sea levels by 23ft and it is showing signs of instability too.

Some researchers believe the loss of the Arctic ice cap could have profound effects on Greenland and the surrounding Arctic lands.

Further south, Europe’s mountain ranges such as the Alps are already feeling the heat. About 9% of the 666 Alpine ski areas are categorized as marginal and the 2C global temperature rise predicted by 2050 will put another 200 ski areas out of business.

At the other end of the earth, the Antarctic is relatively stable in comparison with its northern equivalent. Most of its ice is protected by the cold Antarctic circumpolar current that keeps warm water away from its ice sheet. While some melting is occurring, the Eastern ice sheet – which accounts for about 85% of Antarctica’s ice – may even be growing, according to scientists.