The document discusses the evolving legal framework around climate change liability. It summarizes that the IPCC has determined warming is unequivocal and human activity significantly contributes to climate change. Impacts are diverse and difficult to predict. A range of potential legal liabilities exist under existing laws and regulations, and new strategies are being developed or proposed at both federal and state levels in the US and other countries. Litigation is also emerging as a strategy to address climate change, through both public nuisance claims and lawsuits related to extreme weather events.