Abstract: Future changes in climate pose significant challenges for society, not the least of which is how best to adapt to observed and potential future impacts of these changes to which the world is already committed. Adaptation is a dynamic social process: the ability of societies to adapt is determined, in part, by the ability to act collectively. This article reviews emerging perspectives on collective action and social capital and argues that insights from these areas inform the nature of adaptive capacity and normative prescriptions of policies of adaptation. Specifically, social capital is increasingly understood within economics to have public and private elements, both of which are based on trust, reputation, and reciprocal action. The publicβgood aspects of particular forms of social capital are pertinent elements of adaptive capacity in interacting with natural capital and in relation to the performance of institutions that cope with the risks of changes in climate. Case studies are presented of presentβday collective action for coping with extremes in weather in coastal areas in Southeast Asia and of communityβbased coastal management in the Caribbean. These cases demonstrate the importance of social capital framing both the public and private institutions of resource management that build resilience in the face of the risks of changes in climate. These cases illustrate, by analogy, the nature of adaptation processes and collective action in adapting to future changes in climate.