For more than a decade, the social cost of carbon has been used to quantify the economic consequences of carbon emissions.
The health impacts of wildfire smoke should be integrated into the models used to calculate the social cost of carbon.
Calculated using models that draw on climate science, agriculture, demographics, public health, and other fields, the figure approximates the societal cost associated with emitting one additional ton of carbon dioxide. It is commonly used by federal agencies when debating the potential impact of rules or legislation on carbon emissions.
However, the underlying models used to calculate the social cost of carbon do not account for the global health impacts of air pollution. A newly published Nature Climate Change review seeks to remedy that. Led by Energy and Resources Group (ERG) researchers Cora Kingdon and David Anthoff, the analysis found sufficient evidence to justify including select pathways through which climate change will affect the quality of the air we breathe—which has knock-on effects on human health—when calculating the social cost of carbon.
“This publication lays the groundwork for future work that will incorporate air quality impacts into future estimates,” said Anthoff, an associate professor and the study’s senior author. “Current estimates of the social cost of carbon are too low and thus underestimate the benefits of stringent climate policy.”
Decades of public health, economic, and climate research demonstrate how climate change, health, and air pollution intersect. Climate-fueled megafires are now larger and more destructive, and their smoke often drifts across countries and continents into the lungs of people nowhere near the burn areas. Longer, hotter summers also supercharge the chemical processes that produce surface-level ozone (an airborne irritant linked to asthma attacks, reduced lung function, and premature death) in the cities least equipped to absorb them.
Co-author Kevin Cromar, who directs the Health, Environment, and Policy program at New York University’s Marron Institute of Urban Management, has long argued that disciplinary silos are part of the problem. “Health researchers and economists have worked in isolation for far too long, and this is the root cause of the incomplete estimates of the health impacts of climate change in [existing] models,” he said in 2022. “The solution is for economists and health researchers to better work together so we can improve the health portion of the social cost of greenhouse gases.”
In 2023, Cromar received a $2.3 million grant from Wellcome, a London-based global charity, to support further research on incorporating air-quality impacts into climate models. For this review, the authors—who include researchers from NYU, George Washington University and Resources for the Future—evaluated nine pathways using two criteria: whether existing studies capture the relationship between climate change and the health impact of specific air-quality pathways, and whether these changes are driven by the increases in the global concentration of carbon dioxide.
“Climate change is expected to worsen human exposure to air pollution in several ways, for example, through exposure to wildfire smoke, dust storms, or aeroallergens, and via the formation of ground-level ozone,” explained Kingdon, a PhD student in ERG and lead author of the study. “These pathways will have adverse impacts on human health around the world.”
Kingdon noted that sufficient evidence exists to reasonably integrate exposure to wildfire smoke and surface-level ozone concentrations into the underlying models used to calculate the social cost of carbon. Further research may support the inclusion of climate-linked changes in dust storm frequency and intensity, as well as increases in allergen concentrations, such as pollen and mold. For now, the authors determined that those studies are too narrow (or localized) in scope.
Read the full study in Nature Climate Change.