The public health community has long recognized the relationship between climate and disease. Almost a century ago, AJPH published an article noting the influence of climate on smallpox epidemics.1 Today, however, the stakes have changed, with anthropogenic climate change as one of the most pressing public health threats of our time. Yet historically, climate change was often discussed in ecological terms, such as sea-level rise and temperature increases. The early 1990s literature on climate change and human health generally assessed risk in qualitative terms.