The usefulness of adaptation strategies to changing climate depends on the characteristics of the system that must adapt. Divergent views on whether climate change will seriously affect society and what society can do about it can be traced, in part, to divergent views on these characteristics of systems. Issues of scale and how impacts are measured are also important. We identify a set of fundamental characteristics of natural systems and social systems that help to make underlying assumptions in climate change adaptation studies explicit. These are: Short-run autonomous flexibility; short-run non-autonomous flexibility; knowledge and capacity to undertake short-run actions; long-run autonomous flexibility; long-run non-autonomous flexibility; and knowledge and capacity to plan for and undertake adaptations that require changes in long- lived assets. Applications to crop agriculture and ecosystems illustrate how these portraits can be used. We find that if empirical research is to resolve questions of adaptability, more careful specification of the exact measure of impact and far richer models of the process of adaptation, able to test implicit assumptions in much of the existing empirical research, are needed.

© 2000 Kluwer Academic Publishers