Due to reductions and changes in sea ice, animals will encounter difficulties. Small benthic organisms along the ice edge utilize the ice for survival and reproduction, and the polar bear depends on ice for hunting and rising cubs. The Sea ice extent in the Arctic has shrunk by almost 40 per cent since 1979, causing the polar bear to lose a significant area of its habitat.

The global climate changes, and the changes are especially powerful in the Arctic. The consequences of climate changes in the Arctic will have an impact on the climate in the rest of the world, as changes in the arctic physical processes influences the global climate. 

One degree matters — Full movie from European Environment Agency on Vimeo.

Rising temperatures in the Arctic

Annual average temperature in the Arctic has increased about twice as much as the global average the last decades, except for some local variations within the region. The majority of the increase is during winter time, and in Alaska and western Canada winter temperature have risen by 3-4°C the last 50 years.

Model estimates indicate a continuing rise in temperature in the entire Arctic in the years to come. It is estimated an annual average increase of 3-5°C over land and as much as 7°C over ocean areas by the end of this century. Winter temperature is expected to increase more, 4-7°C over land and 7-10°C over ocean areas.

We expect more precipitation

Observations indicate an increase in precipitation of approximately 8 per cent for the Arctic the last 100 years. However, these observations are somewhat uncertain, as measurements of precipitation in the cold arctic environment constitutes certain challenges, and as data from parts of the region is lacking.

Total precipitation in the Arctic is expected to increase by approximately 20 per cent by the end of this century. The increase will mostly be rain in the coastal areas during winter and autumn.

Rising temperatures, changes in ocean currents and radiation are of great importance for the changes in the sea ice extent. 

Glaciers and sea ice are reduced

Most glaciers and ice caps have shrunk since the beginning of the 1960s. This trend became more evident in the 1990s. Satellite data show an increase in melting since 1979. 

For three monitored glaciers in Svalbard a negative mass balance were measured between 2002 and 2007. As the glaciers melt, more water is being added to the ocean, contributing to global sea level rise. Estimates from global climate models indicate that the contribution from Arctic glaciers will increase the next 100 years. By 2100 the melting of arctic glaciers might contribute to a global sea level increase of 4-6 cm.

From 1982 to 2005 the arctic sea ice extent decreased by 25 per cent, more than 1 million square kilometers. This is an area bigger than the total area of Norway, Sweden and Denmark. In September 2007 the lowest record of sea ice extent ever was measured in the Arctic. Sea ice extent in the summer has decreased more dramatically than the annual average, with a reduction of 8.9 per cent per decade.

Year-to-year variations

Natural variations in the sea ice extent in the Arctic is large. The reduction rate in the sea ice is expected to accelerate, and climate model simulations indicate a practically ice free summer within decades. Sea ice has also become thinner the last decades. Measurements over a longer time period is however important to make reliable conclusions.

While a snow covered surface only absorbs 10-20 per cent of the incoming solar radiation, an open ocean absorbs more than 90 per cent of this energy.  Hence, changes in the sea ice cover influates the ocean surface temperature. This is an example of the arctic feedback mechanisms: Increasing absorption of solar radiation due to melting of sea ice accelerates further melting.

Ocean circulation is affected

Ocean circulation in the Arctic is controlled by the relatively warm Atlantic water coming in to the area by the Gulf Stream and the relatively cold and less saline water coming out of the Polar basin by the East Greenland current.

Some climate theories indicate that global warming can cause a cooling effect in our part of the world. The driving force behind this is disturbances in the regulation of the Gulf Stream. The Gulf Stream causes an average temperature which is  5-8°C higher than in other areas at the same latitude. The last years climate studies indicate that it is not likely that this will happen during the next 200 years.

Animals and plants in the Arctica are affected

Both animals and plants experience the impacts of the climate change in the Arctic. The ACIA-report from 2004 highlighted some findings:

• The forest covered areas are expected to expand northwards and higher up in the mountains, and forests will grow over large tundra areas. Tundra vegetation will spread into polar desert areas. Vegetation with a higher productivity will most likely increase the uptake of carbon, but reduced reflection of incoming solar radiation will at the same time still cause a warming effect.
   
• Agriculture has the potential to expand northwards as a result of a longer and a warmer growth season.
   
• Reduced area of sea ice means a dramatic decline in the habitat of polar bears, seals and some sea birds. Some species are threatened by extinction.
   
• Reindeer and other terrestric animals will experience more stress as climate change alter the access to food resources and preferred areas. Both terrestric and marine species are expected to move northwards, bringing new species into the Arctic.  This might have impact on arctic species. Some fisheries in arctic regions are important in a global context, and it is expected that some of the fisheries will become more productive.
   
• Limnic fisheries are of importance to local food supply. This fishery will most likely decrease as a result of climate change.

Heat radiation from the earth is trapped by greenhouse gases in the atmosphere, and the amount of these gases is increasing due to human emissions. This causes an increased average temperature and changes in the climatic situation.

Changes vary from region to region, and most of the global climate models describe a stronger heating of the Polar Regions. Intensive research and monitoring is now done to describe the effects on climate.

It is important to monitor the climate on a long time basis, and register the changes of sea ice extension, ocean circulation, radiation balance and the mass balance of the glaciers. It is also important to improve our understanding of the energy exchange between atmosphere, sea ice and ocean.

Follow-up on the Arctic Council climate assessment (ACIA)

Arctic Climate Impact Assessment (ACIA) from 2004 was the first extensive assessment of the climate change in the Arctic, and gave an analysis of the impacts for the region and the rest of the world.

Norwegian authorities initiated a process to focus more detailed on the Norwegian Arctic (NorACIA – Norwegian Arctic Climate Impact Assessment). NorACIA’s goal is to contribute to the development, consolidation and dissemination of the climate changes and impacts in the Norwegian Arctic.

• Read more about NorACIA
• Read more in the main report from from 2010 (PDF) 
  

The third International Polar Year

The third International Polar year started 1st of March 2007, with a main focus on climate. Extensive international and multidisciplinary research and monitoring have been carried out to provide better data for the climate models and prognoses. The Norwegian Research Council contributed with 288 million NOK to polar research in the period 2007-2010.