Sea ice is melting at an extraordinary pace in the Arctic Fr. Seán McDonagh, SSC

 

This summer Arctic sea ice has melted at a rate not recorded since  satellite observations began in 1972. Floating sea ice melts in summer and early autumn and refreezes again each winter.  The problem for scientists and all of us is that the melting is happening twice as fast as it did when data collection began in 1972 and the consequences will be dire. Furthermore, scientists who have been studying this phenomenon for the past three decades claim that such an extensive melting has not happened for at least 8,000 years[1] The last time that the Arctic Ocean was free of summer ice was 120,000 years ago.

Physicists at Bremen university in Germany released data on  September 8th 2011 showing that floating ice in the Arctic covered only 4.24 million square kilometres. The previous record low happened on September 17th 200 when the sea ice covered 4.27 kilometres. The German researchers were adamant that the reason for this enormous change is global warming caused by climate change. Georg Heygster who is head of the Institute of Environmental Physics at Bremen said that the record melt was undoubtedly caused by human-induced global warming. The sea ice retreat cannot be explained by saying it is caused by  the natural variability we find in weather patterns. [2]

Reducing the area covered in ice and snow on the planet speeds-up global warming and climate change. The reason for this is simple. Ice and snow reflect solar radiation, whereas dark sea-water absorbs and retains the sun’s heat. This is called the albedo effect   As a result temperature changes in both the Arctic and Antarctic are about twice as high as they are in other parts of the world.

It is no wonder that Scientists at the Polar Science Centre of the University of Washington, Seattle are finding that, not only has the extent of the melt-ice increased dramatically, the ice is also thinning. One of the researchers, Axel Schweiger says that the “the ice volume is now plunging faster than it did at the same time last year when the record was set.”[3]  In 2010 the volume of sea ice was 2,135 cubic miles. This is only half the average and it is 62 percent below the maximum coverage in the Arctic recorded in 1972.

Arctic scientists predict that, if the current warming continues, the Arctic ocean will be ice-free during the summer within 30 years.  This new projection of summer-free ice in the Arctic ocean is 40 years ahead of the time-scale predicted in the 2007 Report from the Intergovernmental Panel on Climate Change (IPCC). In response to this new data Shaye Worf, the Director of the Centre for Biological Diversity in San Francisco, told journalists that “This stunning loss of Arctic sea ice is yet another wake-up call that, climate change is here now and is having devastating effects.”[4] The reason for this is that the Arctic ocean plays a crucial role in regulating and moderating the global climate.

Glaciers on land are also shrinking at an extraordinary pace. In May 2011,the Pontifical Academy of Scientists published a report entitled, Fate of Mountain Glaciers in the Anthropocene.  The scientists involved in researching this report came from a variety of scientific disciplines – glaciologists, meteorologists, hydrologists, physicists, and climate scientists. The report states that carbon dioxide which is released by human activity, especially the burning of fossil fuel, was the main driver of climate change.

The Welsh glaciologist, Alan Hubbard, who works at Aberystwyth University, has come to a similar conclusion. He has been studying the Petermann glaciers in northern Greenland.  This glacier, which covers 6 percent of the icecap, is 300 kilometre long and up to 3.1 kilometre in height.  In August 2010, a 260 square kilometre block of ice calved from the Petermann glacier. Satellite data has shown that by July 2011 all the ice had melted and disappeared.  He said that “I was gobsmacked. It [was] like looking into the Grand Canyon full of ice and coming back two years later to find it full of water.”[5]

According to the report of the Pontifical Academy of Sciences, “failure to mitigate climate change will violate our duty to the vulnerable [people] of the earth, including those dependent on the water supply from mountain glaciers, and those facing rising sea levels and stronger storm surges.” The document goes on to call for a worldwide reduction of carbon dioxide emission without delay.

 

 

 


[1]  John Vidal, “Arctic sea ice melts at fastest pace for 40 years,” The Guardian, September 12th 2011, page 13

[2] ibid

[3] ibid

[4] ibid

[5]  John Vidal, op.cit

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