Temps de lecture :4 minutes
The Arctic as a region is defined in two ways, either as being north of the Arctic Circle ( at 66°30’ north latitude), or north of the 10°C summer isotherm (a line connecting all the points where there is an average annual temperature of 0°C in winter and an average temperature of 10°C in the hottest month of summer). The area is divided between a partially frozen ocean and diverse types of land including ice, arid land with sparse vegetation, tundra, a vast, open plain covered with short, continuous vegetation, wetlands and forests. Nearly 80% of this land is in the Russian Federation and Canada, 16% in Scandinavian countries and 4% in Alaska. An immense glacier several kilometers thick, covers Greenland (2,175,600 km²) and forms an ice cap or ice sheet . Ice covers a surface of between 7.5 and 15 million km2 and is on average three metres thick. The Arctic is inhabited by a limited number of well-known species, some of which are a key resource for indigenous peoples, their crops and economy. The survival of these animals is largely dependent on the stability of the local ecosystems, which is extremely sensitive to environmental imbalance and pollution.
An overall decline
The surface area of arctic ice cover is at its lowest since 1978. The previous record of 5.3 million km² in 2005 was surpassed by a new decline to 4.1 million km² in 2007, which left half of the world’s oceans uncovered. Most climatic models predict a further 75% reduction by 2100. A recent study conducted by the National Snow and Ice Data Center shows that the surface area of ice over the Arctic Sea has already been reduced by 20% since 1979 and could be reduced to winter levels of under 6 million km2 within the next 100 years. It appears that these models underestimate trends already observed in the last 30 years: some forecasts now predict that the ice cover may disappear completely during summer from 2040 onwards, or even earlier. The National Center of Atmospheric Research in Colorado found that 50% of permafrost GLOSSARY zones could melt before 2050, while 90% could melt by 2100. The melting process may be associated with an increase in runoff water into the Arctic Ocean, as well as a rise in greenhouse gas emissions due to the release of methane previously trapped in frozen ground.
The polar bear is likely to be one of global warming’s most prolific victims, with 30% of its population disappearing by mid-century because of the migration of seals, its staple diet. The ivory gull is another arctic species threatened with total extinction in the medium-term. This bird requires permanent ice cover in order to reproduce. In Canada, up to 80% of the total population has disappeared in 20 years and only 10,000 to 25,000 remain worldwide. The future is equally uncertain for reindeer, muskox, arctic foxes and lemmings. Since1998, populations of these species and their predators no longer peak at certain points and since 2000, news types of insects and birds have colonised the eastern shores of Greenland.
Coveted natural resources
There are vested economic interests in the melting of the polar ice cap, particularly where the opening of new shipping routes are concerned. The Northeast Passagewould link Asia to Europe by just 13,000 km in comparison to the current 21, 000 km-long route via the Suez Canal. American ships could get to Alaska 3 to 4 weeks earlier by way of the Northwest Passage. Besides their commercial importance, shipping routes would also offer exploration possibilities in this resource-rich area, particularly in terms of fishing. Because of global warming, certain fish species migrate to the north. According to the United Nations Convention of the Law of the Sea (UNCLOS), a country may exploit these fish stocks if these are located within 22 to370 kilometres of that country’s shores.
The Arctic is said to hold 10% of the world’s hydrocarbon and natural gas reserves which would be rendered exploitable with easier access. Denmark has granted a prospection and exploitation license to the Canadian company Encana, and the United States would like to open up its maritime zone in Alaska for development, even though it has been a protected area since 1960. Norway has invested US$8.8 billion in a natural gas exploration project in the Barents Sea near Hammerfest, one of the northernmost cities in the world.
United Nations Environment Programme (UNEP) Global environment outlook