Global Environmental Impacts of a Warming Arctic

Severe Global Warming Effects Posed by Arctic Climate Feedbacks

Oct 20, 2009

Arctic climate feedbacks, such as declining sea ice, glacier retreat, warming ocean surface and thawing permafrost, will have severe global environmental impacts.

A new peer reviewed report, titled “Arctic Climate Feedbacks: Global Implications”, edited by Martin Sommerkorn and Susan Joy Hassol and published by the World Wildlife Fund in June 2009, examines the work of several eminent environmental scientists on the global environmental impacts of a warming Arctic. The report concentrates on the danger of climate feedbacks caused by present day global warming and warns that, “Recent observations strongly suggest that climate change may soon push some systems past tipping points, with global implications.” It goes on to point out that, “There is also a concern that arctic feedbacks may increase regional or global warming significantly enough that it would alter other climate feedbacks.”

Arctic Climate Feedbacks

The report lists major climate feedbacks which are either occurring or about to in the Arctic. These are:

The report shows that the environmental changes occurring in the Arctic are ensuring that global warming is increasing significantly beyond what the current projections from the Intergovernmental Panel on Climate Change have predicted.

Thawing Permafrost

The report points out that the Arctic contains the largest deposits of organic carbon on Earth. Most of these deposits are in the form of methane hydrates, formerly trapped in the frozen permafrost. With rapid Arctic warming this permafrost, especially the east Siberian Arctic Shelf, which is the shallowest of the methane sinks, could release huge amounts of methane into the atmosphere. Methane is over sixty times more powerful a greenhouse gas than carbon dioxide and the report postulates that the release of even half of one percent of the methane trapped in the permafrost could cause abrupt global climate change.

Melting Greenland Ice Shelf

According to the report, melting of the Greenland Ice Shelf could increase sea levels by a disastrous 7 meters. It is estimated that the Greenland Ice Shelf lost 280 gigatonnes of water in 2008. More significantly, the Greenland Ice Shelf loss has been increasing over the last twenty years. If the present rate of loss is maintained then global sea level rise from Greenland alone will equal over 30cms by the end of the century.

Ocean Circulation Feedbacks

One of the greatest dangers to Earth’s climate is a change in global ocean circulation. The Arctic Ocean feeds into the north Atlantic and north Pacific oceans. Should the increase in Arctic Ocean freshwater (from declining sea ice and melting glaciers) feed into the global oceans, then the global environmental consequences, such as altering fisheries, changing weather patterns and effects on global air temperatures are enormous.

Atmospheric Circulation Feedbacks

The report notes that the Arctic can be considered the northern hemisphere’s air conditioner. The dramatic sea ice loss over the last number of decades combine with widespread glacier retreat, has amplified warming in the Arctic through the albedo effect, with less heat being reflected back to space. This amplification in atmospheric warming will likely spread over the northern land masses, increasing the likelihood of further release of methane trapped in the frozen permafrost, further fueling global warming.

Arctic Ocean Carbon Sink Feedbacks

The Arctic Ocean is an important global carbon sink. The report estimates that the Arctic Ocean is responsible for the uptake of 5 to 15% of the global ocean’s net uptake of carbon dioxide. The ability of the Arctic Ocean to absorb carbon dioxide is being compromised by the release of large amounts of greenhouse gas into the ocean from the surrounding land mass. The loss of summer sea ice and the thinning of winter sea ice are combining to increase the atmosphere-ocean gas exchange rate, increasing the release of the stored carbon dioxide to the atmosphere.

As the world struggles to curb the growth in carbon dioxide emissions, the climate change feedbacks arising in the Arctic due to the present level of greenhouse gases, threaten to overwhelm such efforts. Large increases in methane release, due to thawing permafrost raise the specter of rapidly approaching carbon tipping points, while declining sea ice, changing ocean currents and the melting Greenland ice shelf threaten irreversible environmental changes.

The copyright of the article Global Environmental Impacts of a Warming Arctic in Climate Change is owned by Laurence O'Sullivan. Permission to republish Global Environmental Impacts of a Warming Arctic in print or online must be granted by the author in writing.