The IPCC's assessments are pretty scary. The front page of their web site links to the PDFs. The Summaries for Policymakers are probably the most readable unless you want to tackle the underlying science.
Arctic sea ice is melting at a significantly faster rate than projected by the most advanced computer models, a new study concludes.
Scientists at the National Snow and Ice Data Center (NSIDC) and the
for Atmospheric Research (NCAR) found that satellite and other observations show the Arctic ice cover is retreating more rapidly than estimated by any of the eighteen computer models used by the Intergovernmental Panel on Climate Change (IPCC) in preparing its 2007 assessments. National Center
The article goes on to say that "experts" (it doesn't specify which ones) currently speculation that the models underestimate the effect of atmospheric greenhouse gases on the Arctic, leading to the rather large discrepancy. It does not discuss what effect revising this estimate would have on the models' overall predictions.