Every few years sees a new UN report warning of anthropogenic climate change and the need for immediate global action. These reports are the product of the Intergovernmental Panel on Climate Change (IPCC), a group of hundreds of climate researchers whose carefully prepared scientific assessments inform what action needs to be taken by the world's governments. O'Reilly is the first researcher to gain observer access to the IPCC's closed-door process. In Science in the Balance, she investigates how international experts transform fast-moving, complex, uncertain, and partial evidence into the reports that shape global climate policy. Through a social science lens, the book explores how people, institutions, and procedures interact to communicate state-of-the-art climate science to policymakers and the global public, revealing the complex collaborative work that is behind scientific consensus in an era of political and environmental urgency.