Melting Ice

As the average global temperatures rise, the Earth’s icy extremes are disappearing. Both polar regions are losing sea ice, and glaciers and permafrosts are melting around the world.

The Intergovernmental Panel on Climate Change (IPCC) states that average air temperatures in the Arctic have warmed at twice the global rate. In addition, the pace of warming in the Arctic is increasing faster than the IPCC climate models predicted.

These temperature rises have caused the Arctic sea ice and glaciers to shrink by around 11.1% each decade – or 72,000 square kilometers per year.

Most recently, the extent of the September 2011 Arctic sea ice was just 4.24 million square kilometers, the lowest level for the past 8,000 years.

At current rates, Arctic sea ice could disappear entirely over the Summer period by 2040.

While the Antarctic is also losing ice, melt occurs at a slower rate than in the Arctic because the Antarctic is buffered by a large ocean that absorbs heat.

The fresh water released from retreating sea ice and glaciers is joined with the rapid melting along the ice edges of Greenland and Western Antarctica. This water runoff contributes to rising sea levels.

Recent science suggests that if the current rate of ice melt continues, sea levels will rise by up to 55cm by the end of the century.

As this cold, fresh water runs into the ocean, it alters the balance of salts and temperature, which changes the structure of ocean ecosystems.

The IPCC predict that melting Arctic sea ice could flow into ocean currents and circulate around the world, with impacts on global temperature.

Melting Arctic sea ice also impacts the productivity of the marine ecosystem, with reduced incomes for economies in the Arctic.

Arctic sea ice plays a crucial role in the global ecosystem. White ice layers reflect the warming rays of the sun, so they help to prevent further global warming from the greenhouse effect.

Ice also provides cold insulation for the Arctic Ocean, preventing it from exposure to higher surface temperatures.

Because Arctic sea ice reflects the sun’s heat, its retreat is predicted to increase the pace of climate change. Hence Arctic sea ice areas are a positive feedback loop, so as they reduce, the rate of global warming will increase, leading to uncontrollable climate change.

Melting permafrosts are another positive feedback loop caused by melting ice. Northern Hemisphere permafrosts (permanently frozen soils that can be several metres thick) have been melting and releasing the carbon dioxide and methane stored in tiny pockets of air frozen into the ice. These greenhouse gases contribute to more warming and further ice melt.

References

Anisimov, O.A., D.G. Vaughan, T.V. Callaghan, C. Furgal, H. Marchant, T.D. Prowse, H. Vilhjálmsson and J.E. Walsh, 2007: Polar regions (Arctic and Antarctic). Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, 653-685, http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_wg2_report_impacts_adaptation_and_vulnerability.htm

John Vidal, 2011, ‘Arctic Could be Free of Sea Ice in 30 Years’, The Age, http://www.theage.com.au/world/arctic-could-be-free-of-sea-ice-in-30-years-20110912-1k5w1.html; National Snow and Ice Data Centre, ‘Arctic Sea Ice News and Analysis: frequently asked questions about Arctic sea ice’,http://nsidc.org/arcticseaicenews/faq.html

Ian Ammison, et. al., 2011, ‘The Copenhagen Diagnosis: Updating the world on the latest climate science’, Elsevier, p. 41.

Ian Ammison, et. al., 2011, ‘The Copenhagen Diagnosis: Updating the world on the latest climate science’, Elsevier, p. 27-33.

Anisimov, O.A., D.G. Vaughan, T.V. Callaghan, C. Furgal, H. Marchant, T.D. Prowse, H. Vilhjálmsson and J.E. Walsh, 2007: Polar regions (Arctic and Antarctic). Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, 653-685,http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_wg2_report_impacts_adaptation_and_vulnerability.htm

Anisimov, O.A., D.G. Vaughan, T.V. Callaghan, C. Furgal, H. Marchant, T.D. Prowse, H. Vilhjálmsson and J.E. Walsh, 2007: Polar regions (Arctic and Antarctic). Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, 653-685,http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_wg2_report_impacts_adaptation_and_vulnerability.htm

NASAExplorer, ‘A tour of the Cyrosphere’, 1 September 2009,http://www.youtube.com/watch?v=PjAXoETeVIce structure of ocean ecosystems.

Ian Ammison, et. al., 2011, ‘The Copenhagen Diagnosis: Updating the world on the latest climate science’, Elsevier, p. 25.