To view climate change adaptation from an economic perspective requires a definition of adaptation, an economic framework in which to view adaptation, and a review of the literature on specific adaptations (especially in agriculture). A focus on tools for applying adaptation to developing countries highlights the difference between mitigation and the adaptation decision-making process. Mitigation decisions take a long-term perspective because carbon dioxide lasts for a very long time in the atmosphere. Adaptation decisions typically last the lifespan of the investments, so the time frame depends on the specific adaptation investment, but it is invariably short compared to mitigation choices, which have implications for centuries. The short time frame means that adaptation decisions are not plagued by the same uncertainty that plagues mitigation choices. Finally, most adaptation decisions are local and private, whereas mitigation is a global public decision. Private adaptation will occur even without large government programs. Public adaptations that require government assistance can mainly be made by existing government agencies. Adaptation does not require a global agreement.