Policymakers need to use the knowledge from the scientists to develop programs that benefit the environment and economy. Droughts, floods, hot spells, and cold waves will continue to occur irregularly. Over longer time periods, global warm and cold cycles have naturally occurred and undoubtedly will again. The current state of knowledge of atmospheric science leaves us with uncertainty about the future. But this does not mean that effective policies to meet the challenges of global change cannot be formulated.
Decentralization allows for different responses in various contexts.
Policies that are small-scale limit the costs of being wrong about what's going to happen or what to do about it. Short-term policies also allow for rapid feedback into the policy process. In this manner, society can avoid placing all its eggs in one basket based on a scenario that may or may not occur. Similarly, effective policies on greenhouse gas emissions should emphasize using fossil-fuel energy more efficiently and cleanly. We also need to make effective use of solar and wind energy.