This article compares and synthesizes approaches to estimating future human death tolls from climate change, focusing on the number of human deaths caused by climate change as the most important metric for setting appropriate energy policies. Several studies support the "1000-ton rule," estimating that burning 1000 tons of fossil carbon results in one future death. If warming reaches 2°C, richer nations will be primarily responsible for approximately 1 billion deaths, mainly among poorer populations. This warrants aggressive energy policies to drastically reduce carbon emissions. The article outlines limitations of these calculations and recommends future research to accelerate decarbonization while minimizing human life loss.

Joshua M. Pearce, Richard Parncutt