There is overwhelming scientific agreement that human activities are changing the global climate system and that these changes are already affecting human and natural systems. Significant advances in climate change detection and attribution science—the branch of science that seeks to isolate the effect of human influence on the climate and related earth systems—have continued to clarify the extent to which anthropogenic climate change causes both slow onset changes and extreme events. Attribution science is central to recent climate litigation, as it informs discussions of responsibility for climate change. Climate science also plays a central role in policymaking and planning, particularly where decisions need to be made about how to allocate the costs of mitigating and adapting to climate change. This Article describes the role that attribution science has played in recent litigation as well as policymaking and planning activities, and discusses future directions in the law and science of climate change attribution, addressing questions such as how attribution science can better support policymaking and help resolve questions of liability and responsibility for climate change.