Weather patterns are altered.

Average surface temperature anomaly (oC)

The degradation of arctic sub-sea permafrost is already releasing methane from the massive, frozen, undersea carbon pool and more is expected with further warming.

Simulated a) permafrost area and active layer thickness (a) 1980- 1999 and (b) 2080-2099. (c) Observational estimates of permafrost (continuous, discontinuous, sporadic, and isolated). (d) Time series of simulated global permafrost area (excluding glacial Greenland and Antarctica).

The global ocean circulation system will change under the strong influence of arctic warming.

Images of Antarctica (left) and Greenland (right) to scale. Antarctica is 50 per cent larger than the United States or Europe. Greenland is 7 times smaller than Antarctica. There is enough ice in Antarctica to raise global sea level by 60 metres and 7 metres in Greenland.

The Arctic Ocean connections are changing

Left panel: Schematic of the Arctic Ocean, central basin (Canada and Eurasian basins) and arctic continental shelves (with approximate boundaries for each Arctic Ocean coastal sea), and major rivers draining into the region. Right panel: The three generic types of continental shelves (i.e., inflow, interior and outflow) are shown

The Arctic Ocean experiences much less exchange with the atmosphere than other oceans; momentum exchange (wind drag), heat exchange and freshwater exchange are limited due to the sea ice cover.

The loss of ice from the Greenland Ice Sheet has increased and will contribute substantially to global sea level rise.

Summary of arctic amplification depicted from one of the climate models participating in the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC 2007).

The temperature regime of sub-sea permafrost is determined by the annual temperature of the surrounding seawater, just like the thermal regime of terrestrial permafrost is determined by the arctic surface temperature.

Arctic terrestrial ecosystems will continue to take up carbon, but warming and changes in surface hydrology will cause a far greater release of carbon.

Increase in mass loss by the West Antarctic ice sheet. The mass loss has been steadily increasing since the 1970s as a result of accelerations in glacier flow; snowfall has not changed significantly in Antarctica over the past 50 years.

Initially, meltwater was assumed to be the prime cause of glacier acceleration, making its way to the ground beneath ice sheets, lubricating it and causing the glaciers to flow more quickly to the sea.

Regional variability in sea level change relative to the global average by the end of this century.

Arctic sea ice and atmospheric circulation.

Mixing ratio of methane in the air above the water surface measured along a ship’s route in September 2005. The dotted line shows the Latitude-specific monthly average of 1.85 parts per million by volume established for the Barrow, Alaska, USA, monitoring station at 71° 19’ N, 156° 35’ W (http://www. cmdl.noaa.gov/ccgg/insitu.html); this is the normal level of methane in the atmosphere at this latitude.

Changes in mass of the Greenland Ice Sheet from 1958-2007.

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