Current estimates of the cost of the impacts of climate change in developing countries and of the needed adaptation measures are in very short supply, and the available ones are rather crude. To a large extent this is because this is a very new research area and no agreed methodology exists to assess the economics of adaptation to climate change, particularly in the context of more limited data. An understanding of the full array of adaptation options and their costs and benefits including institutional and policy changes, and fostering of private sector and community-level engagement on adaptation, is crucial to facilitate prioritization of the most effective strategies at international, national, sectoral and local levels.