3.5 Interaction between mitigation and adaptation, in the light of climate change impacts and decision-making under long-term uncertainty

3.5.1 The interaction between mitigation and adaptation, an iterative climate policy process

Responses to climate change include a portfolio of measures:

a. Mitigation – actions that reduce net carbon emissions and limit long-term climate change.

b. Adaptation – actions that help human and natural systems to adjust to climate change.

c. Research on new technologies, on institutional designs and on climate and impacts science, which should reduce uncertainties and facilitate future decisions (Richels et al., 2004; Caldeira et al., 2003; Yohe et al., 2004).

A key question for policy is what combination of short-term and long-term actions will minimize the total costs of climate change, in whatever form these costs are expressed, across mitigation, adaptation and the residual climate impacts that society is either prepared or forced to tolerate. Although there are different views on the form and dynamics of such trade-offs in climate policies, there is a consensus that they should be aligned with (sustainable) development policies, since the latter determine the capacity to mitigate and to adapt in the future (TAR, Hourcade and Shukla, 2001). In all cases, policy decisions will have to be made with incomplete understanding of the magnitude and timing of climate change, of its likely consequences, and of the cost and effectiveness of response measures.