This article is draft version of a chapter in the forthcoming book, Development in the Balance: How Will the World’s Poor Cope with Climate Change?, to be published by the Brookings Institution Press.

A successful post-2012 climate agreement must engage all the world’s major economies through a “multi-track” framework allowing different types of commitments for developed and developing countries. The 25 major economies accounting for 84 percent of global emissions are extremely diverse, with per capita incomes and per capita emissions ranging by a factor of 18. Strategies for integrating climate action with broader economic and development agendas will vary with national circumstance. Accommodating these differences requires a flexible but binding international framework integrating different types of commitments, such as economy-wide emission targets, policy-based commitments, and sectoral agreements. Incentives for developing countries, including both market-based schemes and direct assistance, also must be provided. A post-2012 agreement might advance adaptation on two fronts: proactively, by facilitating comprehensive national planning; and reactively, by helping countries cope with the risks that remain. Given the time it will take a new U.S. administration and Congress to establish a domestic climate policy, a detailed post-2012 agreement is unlikely when governments meet in late 2009 in Copenhagen. Instead, governments should aim for consensus on a broad framework and continue negotiating toward specific commitments.