ern Greenhouse Gas Reduction Accord). The California Global Warming Solutions Act (AB32) enacted a sweeping set of GHG emission control programs for the state (and it survived a ballot proposition to repeal the Act in 2010).
Many states and communities have also developed policies to expand mass transit systems, discourage urban sprawl, increase efficiency, and tighten the energy provisions of building codes,14 and there are important developments being led by sub-national governments and nongovernment organizations in the development of protocols and registries for reporting and verifying GHG missions (e.g., the Climate Registry, the California Climate Action Registry, the Carbon Disclosure Project of ICLEI—Local Governments for Sustainability).15
Climate change adaptation planning efforts are also under way in a number of states, counties, and local communities.16 Adaptation strategies are being explored in climate-sensitive sectors such as agriculture and water resources management, which have historically adapted to natural climate variability in ways that may reduce vulnerabilities to climate change. Several non-governmental organizations have also become active in promoting adaptation planning. In 2009, the White House Council on Environmental Quality, the Office of Science and Technology Policy, and the National Oceanic and Atmospheric Administration initiated an Interagency Climate Change Adaptation Task Force to recommend adaptation initiatives both domestically and internationally. The U.S. intelligence community is assessing how climate change may affect national security (for instance, through geopolitical destabilization from water scarcity or sea level rise), and the U.S. military has begun to consider how climate change will affect their facilities, capabilities, and theatres of operation.17
The collective effect of these local, state, federal, and private sector efforts to limit and adapt to climate change is potentially quite significant but, as suggested by recent analyses, it is not likely to yield emission reductions comparable to what could be achieved with strong federal policies.18 Moreover, it is not clear if the current patchwork of initiatives will prove durable in the absence of an overarching federal policy. For example, evidence suggests that many early actors have been motivated at least in part by a belief that federal legislation on climate change is inevitable and that getting out in front of that legislation will offer a competitive advantage.19 Without a federal policy, emission cuts made in states with climate programs may be undermined by “leakage” to states without such programs, and varying policies across state lines may also lead to inefficiencies and market imbalances. It also possible, of course, that some commitments made during periods when the economy was growing will be reconsidered as the economy struggles to recover from a recession.