The temperature hasn't been static, it has risen- 1998 got a weird year because of El Nino, but I think 2005 is the hottest on record. There are other influences like a decline in the solar cycle, but we might get 0.2 C on top of CO2 warming over the next 5 years when we head toward maxima (Camp and Tung 2007) You get polar amplification up in the Arctic (much faster than the southern hemisphere) because of feedbacks like ice-albedo, and the nature of ocean heat uptake.
http://data.giss.nasa.gov/gistemp/You get more precipitation at both poles (which can lead to accumulation of ice at the interiors of either ice sheet) while sea-ice is lost at a higher rate in Greenland. If you go over the IPCC AR4 (pp 902-908 @
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch11.pdf) they go into detail about what is going on in the polar regions.
The arctic warming much faster is well understood and expected, but if you keep adding CO2 you keep getting more warming globally. The rapid rise of carbon dioxide is more than the slow response time of the oceans can keep up with and you get more solar radiation coming in than infrared going out, and you heat up. A couple of papers:
http://www.acia.uaf.edu/ (this is a big report, but recommended for anything relating to the arctic from geological to climatic to biological patterns)
http://www.atmos.washington.edu/~bitz/HollandBitz.pdf
http://www.springerlink.com/content/6lt5m95y36vd08yd/Going back to the gulf stream transport, if there is a change in the system, it is very weak. Kanzow et al (2007) and Cunningham et al (2007), both in Science, show there isn't much weakening of the system which is in line with what models show- we aren't going to shut down the gulf stream for at least centuries, and if there is a cycle over the Holocene we are still uncertain in what direction the change is in. When water in the "conveyor belt" reaches northern latitudes it sinks before it freezes, if it shuts down it freezes before it sinks. It would cool the NH if this happened and we'd have widespread consequences but you don't get anything like the "day after tomorrow" movie- the Alley paper goes over this. There are other regional influences in the Arctic in addition to feedbacks and the human influence, which the AR4 goes over.
Chris
