Arctic shrinkage

Arctic shrinkage

in 2007 from 2005 and also from 1979-2000 average]

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. Scientific analysis currently has no evidence of seasonally ice-free Arctic over more than 700,000 years, although there were warmer periods.cite journal |last=Overpeck |first=Jonathan T. |url= |format=pdf |title=Arctic System on Trajectory to New, Seasonally Ice-Free State |journal=Eos, Transactions, American Geophysical Union |volume=86 |issue=34 |pages=309–316 |date=2005-08-23 |accessdate=2007-12-24] cite journal |last=Butt |first=F. A. |coauthors=H. Drange, A. Elverhoi, O. H. Ottera & A. Solheim |url= |title=The Sensitivity of the North Atlantic Arctic Climate System to Isostatic Elevation Changes, Freshwater and Solar Forcings |publisher=Quaternary Science Reviews |volume=21 |number=14-15 |pages=1643–1660 |date=2002 |oclc=108566094 |accessdate=] Scientists are studying possible cause and effect factors such as unusual wind patterns, rising Arctic temperatures, cite news |last=Black |first=Richard |title='Drastic' shrinkage in Arctic ice |url= |publisher=BBC News |work=Science/Nature |date=2006-09-14 |accessdate=2007-09-16] or shifting water circulation. [cite news |url=,2933,311753,00.html |title=Study: Circulation Shift May Be Melting Arctic Sea Ice |date=2007-11-24 |publisher=Fox News |accessdate=2007-11-27]

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."cite book |first=James J. |last=McCarthy |coauthors=Intergovernmental Panel on Climate Change Working Group II.
title=Climate Change 2001: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change |url= |publisher=Cambridge University Press |location=New York |isbn=0521807689 |date=2001 |accessdate=2007-12-24
] Reduction of the area of Arctic sea ice means less solar energy is reflected back into space, thus accelerating the reduction.cite news |last=Black |first=Richard |url= |title=Earth - melting in the heat? |publisher=BBC News |date=2007-05-18 |accessdate=2008-01-03]

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.

The sea ice extent for 2008 was greater than that for 2007.

Recent expert statements


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. cite news |title=The Warming of Greenland |url= |publisher=New York Times |date=2007-01-16 |accessdate=2008-04-07] 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...."cite news |first=Ann |last=Baker |title=Arctic Sea Ice Melting Rapidly, ESA Satellite Images Show |url= |format=online |publisher=ScienceMode |page=Earth, Headlines |date=2007-09-15 |accessdate=2007-09-16] 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." [cite news |url= |format=pdf |title=News Release: 2007 Arctic Ice Retreat Concerns National Ice Services |publisher=International Ice Charting Working Group |date=2007-10-23 |accessdate=]

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.cite news |first=Jonathan |last=Amos |url= |title=Arctic summers ice-free 'by 2013' |publisher=BBC News |date=2007-12-12 |accessdate=2007-12-16: "Scientists in the US have presented....modelling studies indicat [ing] northern polar waters could be ice-free in summers within just 5-6 years.... [O] ther teams have variously produced dates for an open summer ocean that, broadly speaking, go out from about 2040 to 2100."]

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.

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." [cite news |url= |title=Melting Arctic ice cap top Canadian weather story of 2007: Environment Canada |first=Alan |last=Black |date=2007-12-30 | |accessdate=2008-01-07]


In February 2008, Josefino Comiso, a senior research scientist with the Cryospheric Sciences Branch of NASA's Goddard Space Flight Center in Maryland, commented about low temperatures this winter in the Arctic: "It's nice to know that the ice is recovering....That means that maybe the perennial ice would not go down as low as last year."cite news |url= |title=Recent cold snap helping Arctic sea ice, scientists find |publisher=CBC News |date=2008-02-15 |accessdate=2008-02-15]

In March 2008, Walt Meier of the National Snow and Ice Data Center (NSIDC) stated:

Thickness is an indicator of long-term health of sea ice, and that's not looking good at the moment. It's like looking at a Hollywood set....It may look OK but if you could see behind you'd see ... it's just empty. And what we're seeing with the ice cover is it's becoming more and more empty underneath the ice cover.Zabarenko, Deborah. [ "Thickest, oldest Arctic ice is melting: NASA data"] , Reuters (2008-03-18).]

According to Meier, NASA satellite data shows that there has been a 50% decrease of perennial Arctic ice between February 2007 and February 2008.

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. [ [ NASA Earth Observatory "Arctic Sea Ice Younger than Normal"] ]

In March 2008, NSIDC senior scientist Mark Serreze stated: "We're in for a world of hurt this summer. Depending on the weather, there could be as much melting this year as last, maybe more." [ [ San Francisco Chronicle, March 18, 2008] ] From the May 5, 2008 NSIDC report: [ [ "Arctic Sea Ice News and Analysis"] , National Snow and Ice Data Center (2008-05-05).]

Although there is more ice than this time last year, the average decline rate through the month of April was 6,000 square kilometers per day (2,300 thousand square miles per day) faster than last April....An assessment of the available evidence points to another extreme September sea ice minimum. Could the North Pole be ice free this melt season? Given that this region is currently covered with first-year ice, that seems quite possible.

According to Dr. Martin Sommerkorn, an ecosystem ecologist at The Macaulay Institute, and Senior Climate Change Adviser at World Wildlife Federation International's Arctic Programme, "The area of ice that is at least five years old has dramatically fallen by more than half since 1985." [cite news |first=Louise |last=Gray |title=Polar bears 'could become extinct' because of melting ice, scientists claim |url= |work= | |date=2008-09-15 |accessdate=2008-09-23]



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 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. [cite web |url= |title=Less Arctic ice means higher risks, experts warn |date=2007-10-26 |publisher=European Space Agency |accessdate=2007-11-27]
* 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. [cite web |first=Annakarin |last=Svenningsson |title=Global Environmental Change - The Role of the Arctic Region |url= |work= | |date=2007-10-14 |accessdate=2007-10-16] [cite web |first=Corinne |last=Wininger |url= |title=E SF, VR, FORMAS sign MOU to promote Global Environmental Change Research | |date=2007-10-26 |accessdate=2007-11-26]
* 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 convert|7|m|ft|0. [cite web |url= |title=Climate Change 2001: The Scientific Basis |publisher=Intergovernmental Panel on Climate Change |format=Table 11.3 |date=2001-02-16 |accessdate=2007-12-24] Models predict a sea-level contribution of about convert|5|cm|in|0 from melting in Greenland during the 21st century. [IPCC AR4 chapter 10 [] Table 10.7] 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. [Gregory, Jonathan; Huybrechts, Philippe; Raper, Sarah. [ “Threatened loss of the Greenland ice sheet”] "Nature", 428, 616 (2004): “The Greenland ice-sheet would melt faster in a warmer climate and is likely to be eliminated — except for residual glaciers in the mountains — if the annual average temperature in Greenland increases by more than about 3 degrees centigrade. This would raise the global average sea-level by 7 metres over a period of 1000 years or more. We show here that concentrations of greenhouse gasses will probably have reached levels before the year 2100 that are sufficient to raise the temperature past this warming threshold.”] [cite web |publisher=Intergovernmental Panel on Climate Change | url = | title = Regional Sea Level Change | format = Figure 11.16]

Sea ice loss could cause more rapid warming of Northern latitudes, with effects on permafrost, methane release, and wildlife. [{cite web |url= |title=Permafrost Threatened by Rapid Retreat of Arctic Sea Ice, NCAR Study Finds |publisher=University Corporation for Atmospheric Research |date=2008-6-10 |accessdate=2008-06-11}]

Effects on Wildlife

In September 2007, the United States Geological Survey completed a year-long study, [cite web |first=Eric |last=DeWeaver |coauthor=U.S. Geological Survey |url= |format=pdf |title=Uncertainty in Climate Model Projections of Arctic Sea Ice Decline: An Evaluation Relevant to Polar Bears |publisher=United States Dept. of the Interior |oclc=183412441 |date=2007 |accessdate=] 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. [ cite news |first=John |last=Broder |coauthors= Revkin, Andrew C. |title=Warming Is Seen as Wiping Out Most Polar Bears |url= |work= |publisher=New York Times |date=2007-07-08 |accessdate=2007-09-23] April 3 2007, the National Wildlife Federation urged the U.S. Congress to place polar bears under the Endangered Species Act. [cite news |url= |title=Protection For Polar Bears Urged By National Wildlife Federation |date=2008-04-03 |publisher="ScienceDaily" |accessdate=2008-04-03]

Halting Arctic shrinkage


According to the most ambitious of IEA emissions scenarios [ International Energy Agency, World Energy Outlook 2008] , 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 2008 [ [ Diomede Crossroads – Saving the North Pole? Thoughts on plausibility - Clever Climate] ] building the St. Lawrence Dam was proposed, a plan to influence temperature and salinity in the Artic Ocean, favouring sea ice conditions. Up to date this seems to be the only publicly proposed geoengineering approach focussing specifically on halting Arctic shrinkage.


Halting Arctic shrinkage may also have a benificial, 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

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.cite news |first=Mike |last=Eckel |title=Russia: Tests Show Arctic Ridge Is Ours |url= |work=The Associated Press |publisher=Washington Post |date=2007-09-20 |accessdate=2007-09-21]

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.cite news |title=Denmark aims for meeting of Arctic nations to discuss borders |url= |format=online |work=Denmark-Diplomacy |publisher=EUX.TV the Europe channel |date=2007-09-13 |accessdate=2007-09-16] At the Arctic Ocean Conference, Foreign Ministers and other officials representing the five countries announced the Ilulissat Declaration on May 28, 2008. [cite news |first= |last= |title=Conference in Ilulissat, Greenland: Landmark political declaration on the future of the Arctic |url= |publisher=Ministry of Foreign Affairs of Denmark |date=2008-05-28 |accessdate=2008-06-06] [cite web |url= |title=The Ilulissat Declaration |date=2008-05-28 | |accessdate=2008-06-06]


ee also

* 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]

Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Arctic Ocean — Arctic Sea redirects here. For the cargo ship, see MV Arctic Sea. The Arctic Ocean Earth s oceans (World Ocean) …   Wikipedia

  • Arctic Refuge drilling controversy — Arctic National Wildlife Refuge Map The question of whether to drill for oil in the Arctic National Wildlife Refuge (ANWR) has been an ongoing political controversy in the United States since 1977.[1] The issue has been used by both Democrats and …   Wikipedia

  • Arctic haze — is the phenomenon of a visible reddish brown haze in the atmosphere at high latitudes in the Arctic due to air pollution. A major distinguishing factor of Arctic haze is the ability of its chemical ingredients to persist in the atmosphere for an… …   Wikipedia

  • Arctic Alaska — or Far North Alaska is a region of the U.S. state of Alaska generally referring to the northern areas on or close to the Arctic Ocean. It commonly includes North Slope Borough, Northwest Arctic Borough, Nome Census Area, Wade Hampton Census Area …   Wikipedia

  • Arctic — For the ships, see MV Arctic, SS Arctic, USS Arctic. For other uses, see Arctic (disambiguation) Location of the Arctic …   Wikipedia

  • Arctic Council — The Arctic Council   members …   Wikipedia

  • Arctic Circle — This article is about one of the five major circles of latitude. For other uses, see Arctic Circle (disambiguation). World map showing the Arctic Circle in red …   Wikipedia

  • Arctic methane release — The release of methane from the Arctic seabed is a potential contribution to global warming induced by Arctic shrinkage and the thawing of seabed permafrost. Recent observations [ [ change/exclusive …   Wikipedia

  • Climate change in the Arctic — Very substantial decrease in Arctic Sea ice in 2007 from 2005 and also from 1979–2000 average …   Wikipedia

  • Climate of the Arctic — The climate of the Arctic is characterized by long, cold winters and short, cool summers. There is a large amount of variability in climate across the Arctic, but all regions experience extremes of solar radiation in both summer and winter. Some… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”