Global Warming and Arctic Polar Amplification

Why is the Arctic warming at twice the global average?

Change of annual air temperature (⁰C) 1963 to 2012. Image — NASA Goddard Institute for Space Studies, http://data.giss.nasa.gov/gistemp/maps/

The Arctic has warmed at about twice the global average of temperature increase and this is termed polar amplification. Several factors cause this: the resulting decrease in sea ice and snow has contributed to the warming through the ice-albedo feedback; with warming an increase in water vapour…