logical and economic systems to the effects of abrupt climate change is that these systems are peculiar to particular locations and adapted to particular climates. Effects are likely to increase when abrupt climate change causes ecological systems to cross thresholds. For example, climatic conditions change greatly over short distances in some areas, and cause similarly steep gradients in vegetation types, allowing even a small climate change to cause dramatic change in vegetation type in a given locale. Rapid climate change will probably result in the redistribution—and possibly in the extinction—of terrestrial and marine species and have major effects on ecosystems worldwide.
Water resources might be greatly affected by abrupt changes in climate. Changes in water supplies could result in increased demands for water, affect agricultural production, and potentially trigger adverse health effects. Those consequences and the economic effects resulting from them provide a strong motivation for enhancing the understanding of physical processes that cause abrupt climate change.
There is increased effort to understand the probability, rate, and magnitude of abrupt climate change. But there is virtually no research on the economic and ecological impacts of abrupt climate change; most research has concentrated on gradual change. It is important to improve knowledge of climate processes that lead to abrupt climate change, and knowledge of the impacts of such changes.
Because there was no comprehensive review of the science and potential impacts of abrupt climate change and no overall plan for improving the understanding of abrupt climate change, the US Global Change Research Program asked the National Research Council for assistance. In response, the NRC formed the Committee on Abrupt Climate Change, which was charged to:
describe what is currently known from paleoclimate proxies, historical observations, and numerical modeling about abrupt climate change, including patterns and magnitudes of possible changes, mechanisms, forcing thresholds, and probability of occurrence (at least qualitatively);
identify the critical knowledge gaps concerning the potential for future abrupt climate changes, including those aspects of change that are of potential importance to society and economies; and