infrastructure to reduce their vulnerabilities to potential abrupt climate changes.
This report emphasizes that social and ecological systems have long dealt with climate variability. Societies have taken many steps over the years, decades, and millennia to reduce their vulnerability to the effects of climate change, and ecosystems have weathered ice ages and extreme climatic events, such as the Younger Dryas. To some extent, it might be possible to reduce vulnerability and increase adaptation at little or no cost, by nudging research and policy in directions that will increase the adaptability of systems (NRC, 1992). Put differently, some current policies and practices may be ill advised and may prove inadequate in a world of rapid and unforeseen climatic changes. Improving such inadequate policies would be beneficial even if abrupt climate change turns out to fit a best-case, rather than a worst-case, scenario. Societies would have “no regrets” about the new policies, because they will be good policies in fair as well as in foul weather.
This report cannot provide a complete catalog of potential no-regrets options, but a few areas of interest are highlighted below. Research in these areas may lead to useful policy recommendations.
Energy policies. Earlier National Research Council reports have identified policies that would slow climate change with low or even negative costs. For example, the phaseout of chlorofluorocarbons over the last 2 decades and replacement with gases with typically shorter atmospheric lifetimes has reduced the US contribution to global warming while also reducing future health risks posed by ozone depletion (NRC, 1992). Furthermore, moving away from coal-burning toward other fuels, particularly natural gas, would reduce greenhouse-gas emissions and some effects on health and the environment, and might prove beneficial in the long term.
Ecological policies. In land-use and coastal planning, managers may be helped by information on the effects on ecosystem services of nonlinear future changes in climate. Scientists and government organizations at various levels could collaborate to develop and implement regulations and policies that reduce environmental degradation of water, air, and biota. Conservation measures related to land and watersheds may reduce the rate of biotic invasions, and management strategies may limit the spread of invasions. The economic and ecological costs of disease emerging from abrupt climate change may help guide response.
Forecasting of weather and weather-related events. Hurricanes and other storms can have large impacts. Climate scientists are uncertain how