Their research indicates that the area of summer sea ice in the Arctic Ocean could thin by as much as 60 per cent if carbon dioxide levels reach double their pre-industrial levels in the atmosphere. Experts anticipate that CO2 concentrations will reach this level in 2050 unless countries back swift and deep cuts in emissions from cars, factories, power stations and homes.
The scientists say they cannot rule out the possibility that the Arctic Ocean may become totally ice-free as a result of climate change. Klaus Toepfer, Executive Director of the United Nations Environment Programme (UNEP), said: "We have, during the last half of the 20th century, seen sea ice in the region disappearing at a rate of nearly three per cent a decade". In the Arctic the extent of sea ice has declined by nearly a third over the past 130 years.
"These new findings on the future impacts of climate change in the Arctic should be sending alarm bells across the globe. What happens in the Arctic and the Antarctic have implications for everyone on the planet. The polar regions play a crucial role in driving the circulation of the world's oceans which in turn affect weather systems and the climate on every continent," he said.
Mr Toepfer said the findings made it even more urgent that the Climate Change negotiations, which stalled in The Hague at the end of last year, were resumed without delay. Svein Tveitdal, Managing Director of GRID-Arendal which is UNEP's key polar centre, said: "The report confirms that global warming in the Arctic is accelerating. This is expected to have major ecological, sociological and economic impacts". "Significant climate change here now seems unavoidable. Arctic countries need to act now to help people living in Arctic areas adapt to the damaging impacts that are likely to occur during this new century," he said.
Mr Toepfer and Mr Tveitdal were reacting to today's release of the Intergovernmental Panel on Climate Change's (IPPC) third assessment report of its Working Group II. The IPCC was launched in 1988 by UNEP and the World Meteorlogical Organization. It has a chapter on the polar regions.
The researchers involved are claiming increased confidence in their forecasts as more data on the Arctic is acquired and global climate circulation models are refined. Impacts on Ice "Changes in the polar climate will have a direct impact on the great ice sheets, ice caps and glaciers of the polar regions," says the report. During the 20th century, winter air temperatures climbed by up to five degrees C.
The new assessment claims that temperatures in the Arctic might rise by as much as 14 degrees C during the 21st century. The vast, Greenland, ice sheet is expected suffer extensive melting. "The Greenland ice sheet suffers melting in summer at its margins. There is a trend towards an increase in area and duration of this melt.. If warming continues, the Greenland ice sheet will shrink considerably, as occurred in previous interglacial periods, and if sustained will completely melt," says the IPCC report.
It also says that global warming will reduce the amount of sea ice in the Arctic. At least three computer models are cited. One predicts a 60 per cent loss of summer sea ice if CO2 levels reach double pre-industrial levels. The summer season, during which the ice retreats far offshore, increases from 60 days to 150 days, this models predicts.
At the moment sea ice retreats from the coastline of countries in the Arctic by between 150km and 200km. By 2050 the sea ice might retreat up to 800km as a result of global warming. Another model forecasts that 80 per cent of sea ice will be lost by 2050. The report warns that "with prolonged warming, a transition to an Arctic Ocean that is ice-free in summer and perhaps even in winter could take place".
Mr Tveitdal said the loss of ice in the Arctic could lead a sudden, acceleration, of global warming. Ice reflects radiation or heat from the sun back into space. "Absorbed radiation over snow and ice is three times lower than over land. Reduced ice and snow cover might trigger an accelerated climate change," he said.
Wildlife, Fisheries and Indigenous People
The retreat and loss of ice in the Arctic will have harmful impacts for many of the species living in the region. Polar bears need sea ice so they can hunt for seals. A retreat and loss of sea ice could make it harder for these animals to get enough food. Pregnant females and those with cubs may be particularly at risk Those species of seal that need ice for resting, pup rearing and molting, will also be at risk.
Climate change in the Arctic is expected to alter the speed and patterns of ocean currents which in turn will impact fish stocks. "Arctic fisheries are among the most productive in the world. Changes in the velocity and direction of ocean currents affect the availability of nutrients and the disposition of larval and juvenile organisms, thereby influencing recruitment, growth and mortality," says the IPCC report.
Changes are already taking place, boosting some stocks and damaging others. "Many groundfish stocks have shown a positive response to recent climate change. But Greenland turbot, a species more adapted to colder climes, and King crab stocks in the eastern Bering Sea and Kodiak, have declined," says the report. It says that projected climate change might halve or double harvests depending on the stocks concerned. Meanwhile some fisheries might die out altogether while new ones develop. "This could increase or decrease local economies by hundreds of millions of dollars annually," says the report.
Changes in the abundance and distribution of fish stocks and wildlife are just one of the issues facing fishermen, Arctic communities and the traditional,indigenous, peoples. The disappearance of sea ice will affect their ability to hunt and the conditions for reindeer herding may be aversely affected by increased global warming.
The Arctic accumulates pollution, including Persistent Organic Pollutants (POPs) like the pesticide DDT and polychlorinated biphenols (PCBs), which have been discharged from industry and agriculture around the globe. Loss of sea ice could trigger the release of these "ghosts of the past" which are currently trapped in the ice causing them to enter the food chain. This which would pose a health threat to top predators such as polar bears and human beings in the region.
The coastline along which many communities live might suffer accelerated rate of erosion, more frequent flooding and damage to buildings and infrastructure, the report argues. "Without sea ice, wave heights will increase, and the Arctic coast will be more exposed to such severe weather events as storm surges causing increased coastal erosion, inundation and threat to structures," it says.
Mr Tveitdal said:"One economic benefit, however, could be in the area of shipping. A retreat of the sea ice northwards is likely to open up the so called Northern Sea Route allowing vessels to sail from Europe to the Far East and Japan by going north of Russia rather than using the existing routes which involve, for example, the Suez Canal". "Experts estimate this should reduce sailing times, cutting the costs of goods and cutting air pollution from shipping. The only risk is one of accidents. More ships sailing in the area will increase the chance of a vessel sinking or running aground with the danger that oil and other pollutants could enter the Arctic environment," he said.
The extent of permafrost, the solid layer of ice and soil, in the Arctic could be reduced by up to 22 per cent as a result of global warming, the report says. In Canada up to half of the present-day cover of permafrost could be lost if CO2 levels double. "This thawing of the permafrost will destroy buildings, roads, pipelines and transmission lines.
In Siberia, a large number of five-storey builldings have already been weakened or damaged. It is predicted that by 2030 most buildings in cities like Yakutsk and Tikisi could be lost," said Mr Tveitdal. Permafrost also stores large amounts of ancient carbon and methane, another global warming gas. Thawing is likely release some of this stored carbon and methane back into the atmosphere, increasing the risk of further climate change, he said.
Ocean Circulation and Weather
Increased snow and rainfall and widespread melting of ice and permafrost may lead to higher levels of freshwater entering the Arctic Ocean. This freshening of the Arctic Ocean could have important impacts on ocean circulation. The formation of sea ice, which leads to salty, heavy water, sinking down deep into the ocean, also plays a key role in driving deepwater currents which in turn affect weather patterns and climate across the globe.
"The IPCC report raises concern that this so called global thermohaline circulation may weaken as a result of global warming. This could have significant effects on economies, lifestyles and ecosystems. Past climate change has led to circulation patterns switching from one condition to another. These have caused large and sometimes abrupt regional impacts. For example the ports of western European countries like Britain are kept ice free in winter because of the Gulf Stream.
Changes in the thermohaline circulation, even though they are unlikely, might cause a shift in the Gulf Stream, deflecting it away from western Europe with far reaching effects," said Mr Tveitdal.
UNEP News Release
For more information, please contact:
Svein Tveitdal, Managing Director of GRID-Arendal on Tel: 47 370 35730, mobile: 47 90 589032, e-mail: email@example.com
Nick Nuttall, Media Officer, UNEP, P.O. Box 30552, Nairobi, Kenya: Tel: 254 2 623381, mobile, 254 (0)733 632755, e-mail: firstname.lastname@example.org or
Tore Brevik, UNEP spokesman/Director, Communications and Public Information, in Nairobi on Tel: 254 2 623292, fax: 254 2 623927, e-mail: email@example.com
See also http://www.grida.no for a series of useful and downloadable graphs, http://www.ipcc.ch/ to download reports, http://www.unfccc.int for official documents about the climate talks, and http://www.wmo.ch and http://www.unep.ch/conventions/info/infoindex.htm for additional background information.