As the climate changes, the frequency and intensity of hot and cold days will shift across the globe, with considerable implications for human health. In this review, I survey the available literature on the projected effects of climate change on heat- and cold-related mortality, with the goal of identifying studies that can be most useful in updating the social cost of carbon (SCC). I identify and discuss in detail several studies that are strong candidates for use in updating the SCC. However, major challenges continue to exist in the literature, including estimating damages for parts of the world where data are limited or nonexistent and quantifying the effects of future adaptation. In general terms, most studies estimate that climate change scenarios with high levels of warming will, on average, result in increased global mortality, with the most acute effects in warmer and low-income regions. At the same time, numerous studies estimate that under lower levels of warming, higher income regions in cooler climatic zones will experience modest reductions in mortality. However, all studies report large uncertainty ranges for future effects.
As the Earth’s climate changes, shifts in temperature, precipitation, sea level, and other physical drivers have the potential to affect human health in a variety of ways, both positive and negative. Some of these effects occur indirectly, mediated through pathways such as disease vectors, changes in agricultural productivity, or the potential for human conflict.
Along with these indirect effects, heat and cold contribute directly to human mortality. Such effects occur when an individual’s physiological response to heat or cold (e.g., increased heart rate) endangers their well-being, particularly through cardiovascular, cerebrovascular, and respiratory pathways (a recent review of reviews is presented in Song et al. 2017).
A large body of public health literature has examined the potential effects of a changing climate on human health and is reviewed in the 11th chapter from Working Group II of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (Smith et al. 2014).  A smaller but growing body of economics-based work has also examined the topic.
The purpose of this review is to examine the most recent economics and public health literature, with the goal of identifying which studies may be most appropriate to improve estimates of the social cost of carbon (SCC), as recommended by the National Academies of Science, Engineering, and Medicine (2017). The SCC is an estimate, presented in dollar terms, of the economic damages caused by each additional ton of carbon dioxide (CO2) emissions. The SCC is used widely across the public and private sectors to inform decisions regarding public policies and other measures to reduce CO2 emissions, and a robust literature has emerged to update and improve it (e.g., Greenstone, Kopits, and Wolverton 2013; Moore et al. 2017; Tol 2019; Daniel, Litterman, and Wagner 2019).
This article provides a comprehensive review of the economics-based research and an updated review of the public health literature focused on studies carried out within roughly the last five years, along with major studies from earlier years. Table 1 presents a concise summary of the 67 studies reviewed here.
This review does not focus on the mortality effects of other climate-related impacts, such as crime and civil conflicts (e.g., Ranson 2014; Buhaug 2015; Burke, Hsiang, and Miguel 2015; Carleton, Campbell, and Collard 2017; Abel et al. 2019), suicide (Carleton 2017; Burke et al. 2018), vector-borne diseases (e.g., Martens et al. 1995; Campbell-Lendrum et al. 2015; Gaythorpe et al. 2020), or other risks such as malaria, undernutrition, and diarrhoeal disease (Honda et al. 2014).
 The chapter also reviews other impact pathways that could be affected by climate change, including vector-, food-, and water-borne diseases and impacts on nutrition and occupational health.