A study by Dartmouth researchers lays out a scientific framework for holding individual fossil fuel companies liable for the costs of climate change by tracing specific damages back to their emissions. The researchers use the tool to provide the first causal estimate of economic losses due to extreme heat driven by emissions. They report that carbon dioxide and methane output from just 111 companies cost the world economy $28 trillion from 1991 to 2020, with the five top-emitting firms linked to $9 trillion of those losses.