Letter* published in Nature Geoscience concluded at last: Overall, despite the paucity of observations, we find that human-induced warming is detectable in both these regions of high vulnerability to climate change.

The regions in focus are the Antarctica and the Arctic region. Eight scientists from seven organizations are the researchers of this study. They used CRUTEMP3 near-surface, gridded temperature data set for January 1900- July 2008. They compared those observations with simulations from four CMIP3-coupled climate models, which are UKMO-HadCM3, PCM, CCSM3, and MIROC3.2(medres). They found that the changes in Arctic and Antarctic temperatures are attributable to global human influence. The internal climate variability or the natural climate forces were found distinguishable from the man-made influences.

This study contradicts the 2007 report of the Intergovernmental Panel on Climate Change with the new conclusion that Antarctic climate has also changed -- as have the other continents' climates  -- due to human impact. 

*"Attribution of polar warming to human influence" by Nathan P. Gillett, Daithi A. Stone, Peter A. Stott, Toru Nozawa, Alexey Yu. Karpechko, Gabriele C. Heger, Michael F. Wehner, and Philip D. Jones, Geoscience, doi:10.1038/ngeo,338, published 30 October 2008.