Abstract:In the absence of national-level action in the United States during most of the 2000s to plan for climate change, states, regions and local governments have taken the lead. In the US system of federalism, states can adopt a wide range of policies that go well beyond those of the national government. The State of California, for example, has air quality regulation substantially stronger than the U.S. as a whole, and many states have passed environmental quality acts and energy policies tougher than those approved in Washington. Local governments for their part have great authority over land use planning, building codes, transportation systems, recycling, water systems and other areas of activity important to reducing greenhouse gas emissions and adapting to climate change.