A major international agreement at Copenhagen would be great. But much of the progress against climate change must take place at a local level.
This week, leaders from around the world gather here, in a quest for a global pact to reduce greenhouse-gas emissions and tackle the single greatest challenge of our time.
I am joining them to discuss the urgency of their efforts, the economic opportunities we can seize, and the tremendous role of subnational governments in climate-change mitigation.
Some pundits have described Copenhagen as the most important world summit since the end of the Second World War. And it has been suggested that without a binding international agreement, the fight against climate change is unwinnable.
Now, it certainly would be terrific if the world's governments reached such an agreement. But as much as 80 percent of the necessary greenhouse-gas reductions will happen at the subnational level. So why should we focus all our faith and hope in international action?
Throughout the course of history, all great movements have been born at the grassroots level. The American independence movement, the civil-rights movement, and the women's suffrage movement were all begun by people who did not wait for others. Then they gained momentum and speed, and swept throughout our nation.
There is a lesson in this when discussing climate change. Even in the absence of national and international commitments, we must not ignore the tremendous movement that is already under way to solve our environmental and energy problems.
For example, states, provinces, and cities have been busy passing their own laws and emission targets.
In California, we are implementing a law to cut our greenhouse-gas emissions 25 percent by the year 2020. We approved the world's first Low Carbon Fuel Standard and tailpipe emissions standards, which the Obama administration has now adopted.