Arctic shrinkage.html



Very substantial decrease in Arctic Sea ice in 2007 from 2005 and also from 1979-2000 average

Greenland Ice Sheet Mass Trend

Arctic Temperature Trend 1987-2007

Arctic shrinkage is the marked decrease in Arctic sea ice and the observed melting of the Greenland Ice Sheet in recent years. Computer models predict that the sea ice area will continue to shrink in the future, though there is no consensus on when the Arctic Ocean might become ice-free in summer; a common theory estimates between 2040 and 2100.¹ Scientific analysis currently has no evidence of seasonally ice-free Arctic over more than 700,000 years, although there were warmer periods.²³ Scientists are studying possible cause and effect factors such as unusual wind patterns, rising Arctic temperatures,⁴ or shifting water circulation.⁵

According to the Intergovernmental Panel on Climate Change, "warming in the Arctic, as indicated by daily maximum and minimum temperatures, has been as great as in any other part of the world."⁶ Reduction of the area of Arctic sea ice means less solar energy is reflected back into space, thus accelerating the reduction.⁷

2007 saw a record low in summer sea ice. Most of the newly melted area refroze, and the iced area was near normal during the winter of 2007-2008. However the amount of thick perennial ice was below levels measured in the previous winter.⁸

The sea ice extent for 2008 was the second lowest observed, and slightly greater than that for 2007.

Recent expert statements

2007

Associate professor Carl Egede Bøggild, University Centre in Svalbard was quoted by the New York Times as saying the melting rate of Greenland's ice sheet could be as high as 80 cubic miles per year.⁹

Leif Toudal Pedersen of the Danish National Space Center commented about Arctic sea ice: "The strong reduction in just one year certainly raises flags that the ice (in summer) may disappear much sooner than expected...."¹⁰ The International Ice Charting Working Group issued a statement that the Arctic sea ice in September 2007 had reached the lowest extent "in the history of ice charting."¹¹

Arctic Sea Ice September Trend 1979-2007, showing the historic September 2007 minimum (from NSIDC)

A 2007 study by Professor Wieslaw Maslowski at the U. S. Naval Postgraduate School, Monterey, California predicted that the Arctic Ocean may be free of ice during summer by as soon as 2013. The study used data sets from 1979 to 2004 and did not include the more recent record low ice minima set in 2005 and 2007. Maslowski suggested that other researchers seriously underestimated some key melting processes, producing models that predict an ice free Arctic Ocean to first occur from 2040 to 2100.¹

Professor Peter Wadhams from University of Cambridge, UK, agreed that some models have not been taking proper account of the physical processes occurring in nature. He said that Maslowski's model is more efficient because it takes account of processes that happen internally in the ice. Wadhams predicted that, in the end, the Arctic ice will just melt away quite suddenly, perhaps not as early as 2013 but much earlier than 2040.¹

In December 2007, the Canadian Press selected Arctic shrinkage as Canada's biggest environmental story of the year. Environment Canada senior climatologist David Phillips summed it up: "This huge chunk of ice the size of Ontario vanished within one year."¹²

2008

Arctic Sea ice age in February 2008, (right), compared to the average for 1985-2000, (left) (NASA)

Arctic Sea ice composition by age 1985-2008 (NASA)

These maps show the date of first melting of the sea ice in the Arctic Ocean for the years 2005, 2006, 2007, and 2008 up to June 18. They show that in 2008 the sea ice started melting sooner than previous years, including 2005 and 2007 which saw the sea ice melt back to record minimum extents. The earlier start of melting, coupled with the 2008 sea ice pack being composed of much more relatively thin first-year ice, suggest that another record low minimum may be reached when the Arctic sea ice reaches its minimum low level, which usually occurs in September.¹³ From NSIDC

According to Walt Meier of the National Snow and Ice Data Center (NSIDC), NASA satellite data shows that there has been a 50% decrease of perennial Arctic ice between February 2007 and February 2008.⁸

While the cold winter did allow ice to re-cover much of the Arctic Sea surface area during the Winter of 2007/2008, conditions were far from normal as the pair of NASA images to the right reveals. The February 2008 ice pack contained much more young ice than the long-term average. In the past, more ice survived the summer melt season and had the chance to thicken over the following winter. In the mid- to late 1980s, over 20 percent of Arctic sea ice was at least six years old; in February 2008, just 6 percent of the ice was six years old or older.¹⁴

NSIDC says

Arctic sea ice extent during the 2008 melt season dropped to the second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on September 14, 2008. Average sea ice extent over the month of September... was 4.67 million square kilometers... The record monthly low, set in 2007, was 4.28 million square kilometers... the now-third-lowest monthly value, set in 2005, was 5.57 million square kilometers... The 2008 season strongly reinforces the thirty-year downward trend in Arctic ice extent. The 2008 September low was 34% below the long-term average from 1979 to 2000 and only 9% greater than the 2007 record... Because the 2008 low was so far below the September average, the negative trend in September extent has been pulled downward, from –10.7 % per decade to –11.7 % per decade. [2]

Research

National

Individual countries within the Arctic zone, Canada, Denmark (Greenland), Finland, Iceland, Norway, Russia, Sweden, and the United States (Alaska) conduct independent research through a variety of organizations and agencies, public and private, such as Russia's Arctic and Antarctic Research Institute. Countries who do not have Arctic claims, but are close neighbors, conduct Arctic research as well, such as the Chinese Arctic and Antarctic Agency.

International

International cooperative research between nations has become a priority.

• DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies): European integrated project "specifically concerned with the potential for a significantly reduced sea ice cover, and the impacts this might have on the environment and on human activities, both regionally and globally".
• European Space Agency (ESA) is scheduled in 2009 to launch CryoSat-2 which will provide satellite data on Arctic ice cover change rates.¹⁵
• International Arctic Buoy Program: deploys and maintains buoys that provide real-time position, pressure, temperature, and interpolated ice velocity data
• International Arctic Research Center: Main participants are the United States and Japan.
• International Arctic Science Committee: non-governmental organization (NGO) with diverse membership, including 18 countries from 3 continents.
• 'Role of the Arctic Region', in conjunction with the International Polar Year, was the focus of the second international conference on Global Change Research, held in Nynäshamn, Sweden, October, 2007.¹⁶¹⁷
• SEARCH (Study of Environmental Arctic Change): Supported by the Arctic Research Office, a division of the United States' National Oceanic and Atmospheric Administration (NOAA), and the Russian Academy of Sciences.

Effects and possible effects

Greenland's ice sheet contains enough fresh water as ice to raise sea level worldwide by 7 metres (23 ft).⁷¹⁸ Models predict a sea-level contribution of about 5 centimetres (2 in) from melting in Greenland during the 21st century.¹⁹ It is also predicted that Greenland will become warm enough by 2100 to begin an almost complete melt during the next 1,000 years or more.²⁰²¹

Sea ice loss could cause more rapid warming of Northern latitudes, with effects on permafrost, methane release, and wildlife.²²

Effects on Wildlife

Projected change in polar bear habitat from 2001–2010 to 2041–2050

In September 2007, the United States Geological Survey completed a year-long study,²³ which concluded in part that the floating Arctic sea ice will continue its rapid shrinkage over the next 50 years, consequently wiping out much of the polar bears’ habitat. The bears would disappear from Alaska, but would continue to exist in the Arctic archipelago of Canada and areas off the northern Greenland coast.²⁴ April 3, 2007, the National Wildlife Federation urged the U.S. Congress to place polar bears under the Endangered Species Act.²⁵

Halting Arctic shrinkage

Mitigation

According to the most ambitious of IEA emissions scenarios²⁶, cutting global CO2 emissions by 50 percent to 2050 is possible. However ambitious, this will only lead to a further rise in CO2 concentrations and temperatures, compared to 2008 values. Concluding from that present mitigation efforts will not be able to prevent continued Arctic melting.

Alternative methods

Perhaps other means are at hand to halt Arctic melting, for instance geoengineering approaches influencing local sea-ice albedo or ice dynamics. In September 2008²⁷ building the St. Lawrence Dam was proposed, a plan to influence temperature and salinity in the Arctic Ocean, favouring sea ice conditions. Up to date this seems to be the only publicly proposed geoengineering approach focusing specifically on halting Arctic shrinkage.

Benefits

Halting Arctic shrinkage may also have a beneficial, stabilizing influence on the global climate system as it will slow down two important positive feedbacks, one being the albedo effect (that increases temperature rise), the other Arctic methane release from thawing permafrost (that increases greenhouse gas emissions).

Territorial claims

Main article: Territorial claims in the Arctic

Growing evidence that global warming is shrinking polar ice has added to the urgency of several nations' Arctic territorial claims in hopes of establishing resource development and new shipping lanes, in addition to protecting sovereign rights.²⁸

Danish Foreign Minister Per Stig Møller and Greenland's Premier Hans Enoksen invited foreign ministers from Canada, Norway, Russia and the United States to Ilulissat, Greenland for a summit in May 2008 to discuss how to divide borders in the changing Arctic region, and a discussion on more cooperation against climate change affecting the Arctic.²⁹ At the Arctic Ocean Conference, Foreign Ministers and other officials representing the five countries announced the Ilulissat Declaration on May 28, 2008.³⁰³¹

References

See also

Wikinews has related news: The North Pole may possibly be ice free by summer

• Arctic Climate Impact Assessment
• Climate of the Arctic

Further reading

External links

• Arctic Change website, in near-realtime
• International Arctic Buoy Programme
• International Arctic Research Center
• International Arctic Science Committee
• World Wildlife Foundation's International Arctic Programme
• 38th Annual International Arctic Workshop 2008
• Radical past climatic changes in the Arctic Ocean and a geophysical signature of the Lomonosov Ridge north of Greenland