The above maps represent, for three different scenarios (B1, A1B et A2 ; that is in rough terms emissions that remain stable, that double, or that quadruple), the average temperature increase compared to the 1980-1999 mean. On the left the increase is for the 2020-2029 decade, and on the right for the 2090-2099 decade. 6 to 8 models have been used and the results are averaged. Major observations include :

For the 2020-2029 decade the case is settled : the regional temperature changes are scenario-independant, which means that the emissions that will take place between today and 2020 will have very little influence on the situation taking place in 2020-2029. What we will do during the next 20 years will mostly benefit to what will happen after 2030,

temperatures rise faster over the continents than over the oceans (because of the thermal intertia of water and because of the thermohaline circulation, that "burries" part of the heat in the deeper ocean),

the temperature rise is particularly pronounced near the North Pole, because of various factors or feedbacks (sea-ice melting, increased proportion of continents in the Northern Hemisphere, and increased efficiency of the greenhouse effect near the Poles in general terms),

The Northern Atlantic heats less than the rest of the Arctic region, as a result of a weakening overturning,

even with emissions that remain constant throughout the 21st century (B1 scenario), mid-latitude occidental countries undergo a 3 °C temperature increase, which is major already.

Source : IPCC, Summary for Policymakers of the 4th assessment report (working group 1), 2007