Noah’s Ark in a Warming World: Climate Change, Biodiversity Loss, and Public Adaptation Costs in the United States

Climate change poses a growing threat to biodiversity, but the welfare consequences of these changes are not well understood. Here we analyze data on the US Endangered Species Act and project increases in species listing and spending due to climate change. We show that higher endangerment is strongly associated with the probability of listing but also find a large bias toward vertebrate species for both listing and spending. Unmitigated warming would cause the listing of an additional 690 species and committed spending of $21 billion by 2100. Several thousand more species would be critically imperiled by climate change but remain unlisted. Finally, we compare ESA spending with estimates of willingness to pay for conservation of 36 listed species. Aggregate WTP is larger than ESA spending for the vast majority of species even using conservative assumptions and typically one to two orders of magnitude larger than direct ESA spending using less restrictive assumptions.