I'd like to add that Paul has become both a good friend and a close collaborator in the time since I first reported on his essay the Worth of an Ice Sheet, here. I'm pleased and honored to be associated with him.
I had the good fortune to be invited to co-chair a session at the “Climate Change Congress” held in Copenhagen, Denmark last week. It was an impressive meeting, frankly overwhelming in its density, with far too many sessions to choose from and people to speak with. There were many interesting presentations of all kinds, and I could write about the meeting for far longer than I actually spent there.
What fascinates me – and frustrates me – is the complexity of the process by which a very diverse community of scientists is trying to find how to wield a collective voice in the political process. I focus here on only one very important question: the question of “targets.”
In the closing plenary, five prominent academics and the Danish Prime Minister, Anders Fogh Rasmussen, all spoke to the conference’s “key messages.” One of the academics who is actually a climate scientist, Stefan Rahmstorf of the Potsdam Institute for Climate Impacts Research, said in his response to the prime minister that “2ºC is not safe.” Rasmussen in turn asked pointedly whether he and his fellow policymakers should abandon the 2ºC target, and the “at least 50% below 1990 levels in 2050” long term goal that has also been embraced by the EU and elsewhere.
If you read the exchange, you’ll find that Rahmstorf tries to say that the 2ºC target should be considered an upper limit, not as “we’ll take fifty fifty odds of staying below it,” while Dan Kammen of UC Berkeley explicitly argues for an 80% below 1990 level in 2050 to achieve a lower risk – on the order of 15-30% - of staying below 2ºC. Will Steffen of ANU, somewhat in contrast says that 2ºC is a “reasonable” goal for the Copenhagen meeting, but stresses the need to take an “adaptive management” approach which allows for subsequent revision.
But when Rasmussen has his final comments, all that he seems to take away, is yes, the 2ºC target and the 50% below 1990 in 2050 is still good enough. Worse, he stresses that he needs fixed numbers, not the kind of nuance and hedging that proper science always produces. In this realm, there was no possible argument that could have prevailed that would have justified a lower target. Or so it feels…
If you don’t wish to read the whole transcript, start from where Katherine Richardson of the University of Copenhagen, the Chair of the session and the whole conference, introduces Rasmussen with “Mr. Prime Minister”.
Update: There's some interesting discussion over at Stoat's.