A NY Times editorial sums it up:
The coming week could set a record for the number of high-profile hours spent discussing global warming and what to do about it. It begins with a special one-day session at the United Nations, at which Al Gore will press the case for strong collective action to stop the rise of greenhouse gases. It ends with a two-day White House “summit” involving all of the major emitters, including India and China. Both of those nations have been conspicuously absent from climate negotiations, but their help in arresting global emissions is essential.
The problem needs all the attention it can get. But if talk is good, it is also cheap. And it will change nothing unless it leads to a real treaty with real, and enforceable, limits on the production of greenhouse gases. That means a broader and more inclusive version of the Kyoto Protocol, a noble but flawed treaty that expires in 2012.