After twenty-five years of failure, climate negotiations continue to use a "pledge and review" approach: countries pledge (almost anything), subject to (unenforced) review. This approach ignores everything we know about human cooperation. In this book, leading economists describe an alternate model for climate agreements, drawing on the work of the late Nobel laureate Elinor Ostrom and others. They show that a "common commitment" scheme is more effective than an "individual commitment" scheme; the latter depends on altruism while the former involves reciprocity ("we will if you will").