Expectations are running high for the United Nations climate change conference in Copenhagen this December. But will we get the global commitment for radical cuts in carbon dioxide emissions that the world so urgently needs? The scientific evidence that global temperatures are rising and that man is responsible has been widely accepted since the Intergovernmental Panel on Climate Change’s report in 2007.1 There is now equally wide consensus that we need to reduce carbon dioxide emissions to at most 50% of 1990 levels by 2050 if we are to have even a 50% chance of preventing temperatures from exceeding preindustrial levels by more than 2 degrees, considered by many to be the tipping point for catastrophic and irreversible climate change.2 The economic argument that taking action now rather than later will be cheaper has also been widely accepted since the Stern report in 2006.3 The election of President Obama has shifted policy in the United States from seeking to block an agreement to seeking to find one.

So the chances of success should be good but …