two degrees
James Hrynyshyn at Island of Doubt yesterday put up a really interesting examination of the Copenhagen Conference's efforts to deal with just what is the "safety limit" for global warming. I won't add much accept to lament the fact that "as much as possible as soon as possible" is too vague for public policy goals.
Because really, that is the only correct answer to the question politicians want scientists to answer: how much do we need to reduce CO2 emissions?
Have a read.