Climate change poses significant risks to future crop productivity as temperatures rise, rainfall patterns become more variable, and pest and disease pressures increase. The use of crop genetic resources to develop varieties more tolerant to rapidly changing environmental conditions will be an important part of agricultural adaptation to climate change. Finding new genetic traits that can facilitate adaptation—and incorporating them into commercially successful varieties—is time-consuming, expensive, and technically difficult. The public-goods characteristics of genetic resources can create obstacles to rewards for private research and development. Because of insufficient private incentives, public-sector investment in the use of genetic resources will help determine the agricultural sector’s ability to maintain crop productivity, and for society as a whole, the potential benefits of public investment are large. The study authors find, however, that factors such as intellectual property rules for genetic resources and for research tools, or international agreements governing genetic resource exchange, have the potential both to promote and to hamper greater use of genetic resources for climate change adaptation.