To mitigate or to adapt; is that the question? Observations on an appropriate response to the climate change challenge to development strategies, The World Bank Research Observer

Climate change is a new and important challenge to development strategies. In light of the current literature a framework for assessing responses to this challenge is provided. The presence of climate change makes it necessary to at least review development strategies—even in apparently nonclimate-sensitive and nonpolluting sectors. There is a need for an integrated portfolio of actions ranging from avoiding emissions (mitigation) to coping with impacts (adaptation) and to consciously accepting residual damages. Proactive (ex ante) adaptation is critical, but subject to risks of regrets when the magni-tude or location of damages is uncertain. Uncertainty on location favors nonsite-specific actions, or reactive (ex post) adaptation. However, some irreversible losses cannot be compensated for. Thus, mitigation might be in many cases the cheapest long-term sol-ution to climate change problems and the most important to avoid thresholds that may trigger truly catastrophic consequences. To limit the risks that budget constraints prevent developing countries from financing reactive adaptation—especially since climate shocks might erode the fiscal base—“rainy-day funds ” may have to be developed within countries and at the global level for transfer purposes. Finally, more research is required on the impacts of climate change, on modeling the interrelations between mitigation and adaptation, and on operationalizing the framework. JEL codes: O10, Q54, Q56 Until recently, policymakers and development experts could at least assume that where there was water today, there would still be water in the future. Or tha