My latest Bridges column is out. Here is an excerpt:

An effective carbon policy will also require humility. No developed country has decarbonized its economy at a rate of more than about 1-2 percent per year for any length of time, including those who have signed on to Kyoto and those who have implemented even more aggressive climate policies. Thus, no one really knows how fast a major economy can decarbonize, or what measures will actually work. Given that policy makers are moving into the policy unknown, every policy put into place will be an experiment. Some will work while others will not. Setting grandiose long-term goals with fantasies about specific targets and timetables is a distraction and will likely set back the task of reducing emissions.

The Obama Administration is currently learning many of these lessons as its climate policy aspirations are engaged in the emerging Congressional debate. Whether these lessons will result in a healthy evolution of policy proposals remains unclear. What is clear is that Obama’s climate policies are a work in progress.

Read it in full here.