The Intergovernmental Panel on Climate Change's Fourth Assessment Report is due out on Friday - but the contents are already being widely leaked. And according to the summary in the Independent today, they're scary. The Third Assessment Report, released in 2001, predicted an average global temperature increase over the next century of between 1.4C and 5.8C, with considerable uncertainty about where in that range was most likely; now that has been narrowed to 2C to 4.5C, with increases of 6C or more unable to be ruled out. What this means is that we are almost certain to breach the 1.5C (2C over pre-industrial) threshhold that the EU considers to signify dangerous levels of climate change - unless we do something about it of course.
Meanwhile, it also puts the final nail in the coffin of the Deniers, stating that
Confidence in the assessment of the human contributions to recent climate change has increased considerably since the TAR [Third Assessment Report]
which was already pretty confident, and that the increase has occured when natural climate signals were very much pushing the other way. But overwhelming evidence hasn't silenced those who deny the reality of the Holocaust, and I doubt it will silence the similar cranks in the climate denial movement either.