Unit 1: Impacts of global warming. The Arctic.

• The Arctic reigon lies within the Arctic Circle (the 66.5'c line of latitude).
• It consists of an ice sheet surrounding the North Pole, as well as the northern parts of eight coutnries- Canada, Greenland, Russia, USA (Alaska), Iceland, Norway, Sweeden and Finland. 
• The area has an incredibly cold climate: January tempretures average at -35'c, and July tempretures -1.5'c. 
• The majority of the Arctic is ice. 
• However, increasing average tempretures are melting the Arctic ice. In 2006, NASA reported that the amount of permentant sea ice decrease, by 14% between 2004 and 2005, which is equivelant to an area 3x the size of the UK.
• The rate at which the ice is melting has risen massively. Until recently, 80% of solar radiation was reflected from the polar ice caps. Now the amount of ice has decreased and the area of open ocean has increased. Oceans are darker than ice and snow, and absorb more energy which converts it into heat.
• This speeds up the warming effect, which melts more ice and creates a vicious cycle (the positive ice albedo feedback.
• At current rates, 50-60% of Arctic ice will be lost by 2100. One theory suggests it could disapear by 2070.

Increasing tempretures have led to..

• The tree line (the edge of the habitat within which the trees will grow) moving north, and also to higher altitudes. 
• Tundra ecosystems in Artic areas (which can withstand intense cold) being lost as the climate warms and other plants take over.
• Permentantly frozen ground thawing out. 
• The spread of spices such as the spruce bark beetle in Alaska, changing the food chain.
• Increases in the number and extent of northern coniferous fires in Artic Russia. 10 million hectars burn each year , loosing 0.8% of the worlds corniferous forest. Boreal ecosystems account of 37% of the worlds carbon pool on land and are effective carbon sinks.

• The marine ecosystems has altered considerably as a result of Arctic warming. It is difficult to assess the true impact of warming because so much commercial fishing of spices such as cod has taken place. But shrinking ice sheets have affected more marien spices in the Arctic.
• Warmer water has reduced the quantity of mariene plants on which many smaller fish feed. In turn the reduction of smaller fish spieces affects those higher up on the food chain, such as cod and halilbut, which in turn affects higher mariene spices such as seals. This has a negitive multiplier effect. Smaller seal stocks reduce the available food supply for polar bears. 
  
• The melting Artic ice has had a devestating impact on polar bears. They hunt seals on the ice, and the faster annual ice melt had reduced their spring hunting season. Hudson Bay is now ice-free for three weeks longer than it was in 1985, giving polar bears less time in which to hunt the reduced number of seals. 
• Female polar bears rely on the spring to build up their body fat to ensure their survival during the summer when the ice they hunt on recedes naturally. Currently each animal looses 80kg of fat during the longer summer, making them susceptible to disease, and reducing their ability to reproduce or feed their cubs. 
• Now they face the risk of extinction.

• Global warming poses social and economic threats to the 155,000 inuit living in the Arctic reighon. Global warming is disrupting their lifestyle, which are adapted to the cold but predictable climate in the Arctic.

Impacts include:

• Each winter Inuit men take their fishing shacks and equipment on to the ice for three months. Now weaker and thinner sea ice collapses easily, making it more dangerous. 
• The ice used to protect Inuit villages along the coast. However, coasts are now exposed to more ocean waves and storms, causing the distruction of entire villages , and forcing people to move futher inland. 
• 24 inuit villages in Alaska are now threatened by flooding. 
• 80% still hunt caribou, fish and marine mammals- all of which are declining in numbers. As marine stocks decline, the Inuit rely more on hunting caribou for income, which in turn places greater pressure on caribou stocks. 70% of Inuit income is from paid employment of hunting. This means decline in stocks hit the income of Inuits hard.
  

• Enviromental change creates futher problem. 
• Caribou and marine animals provide vital nutrition for the Inuit.
• Together Caribou, seal, narwhal, fish and walrus provide over 90% of their food, and reductions in their numbers are dangerous for Inuit lifestyle. Expecially as high protien intake is needed to cope with the cold and imported food is expensive.
• Clyde River Settlement on Baffin Island has 450 residents, who eat 100 tonnes of seal meat annually. To import replacement food would cost US$1 million, and provide less iron, magnesium and calcium than the natural diet.

• The melting ice creates some concerical advantages for the Artic reigon. 
• The Northern Sea Route, north of Canada, is the quickest way of traveling from Europe to the Pacific and Asia, but, until now the ice has only allowed ships to use it for about 6 weeks between August and October.
• Now tourist ships are able to visit northern Canada, and 30% of Inuit now earn income from sculpture or print-making for tourists. 
• In 2007, the North-West Passage between canada and the Arctic melted sufficiently to allow shipping through for the first time.

However this brings problems too:

• Oil tankers have negociated Arctic waters for nearly 40 years, bringing oul from the shores of norther Alaska.
• Greater frequencies and use of the passage north of Canada increases the risk of pollution and of oil spills in the Arctic.
• Now Russia has started to allow nuclear waste disposal in its Arctic waters off the coast of its North Western territories, posing a futher threat to marine ecosystem.