Incorporating Air Pollution-related Health Damages from Wildland Fires into the Social Cost of Carbon

Wildland fires pose a pernicious threat to infrastructure, the economy, and human health and livelihood that is expected to grow under anthropogenic climate change. Epidemiological evidence points to links between wildland fire smoke and premature mortality and morbidity, and these impacts can extend far beyond the burned area. Currently, the social cost of carbon—an estimate of the economic costs or damages that result from an additional ton of carbon dioxide emissions—does not account for wildland fire impacts on human health via air pollution, thereby likely underestimating the cost of continued emissions and the benefits of reducing emissions.

Here, we present preliminary results expanding the social cost of carbon to include health impacts from fine particulate matter (PM_2.5) due to wildland fires globally through 2100. We first simulate future fire-related carbonaceous emissions under different Representative Concentration Pathways (RCPs) using a fire-land surface model driven by atmospheric conditions from several earth system models. We then estimate PM_2.5 concentrations from these emissions using emission-to-concentration sensitivities simulated with the adjoint of the GEOS-Chem chemical transport model. We apply these estimated PM_2.5 concentrations in a health impact assessment using epidemiologically-derived concentration-response functions to estimate the number and monetized value of premature deaths attributable to wildland fire PM_2.5 at global and national levels. Finally, we transform the RCP-specific damages to a scenario-agnostic metric (i.e., per degree warming) for consistency with other damage pathways in social cost of carbon estimates from the Greenhouse Gas Impact Value Estimator model.

Our results illuminate the future impacts of fire-sourced air pollution on premature mortality and update the social cost of carbon to incorporate the monetary value of these damages. The updated social cost of carbon estimates can be incorporated into policymaking tools used to evaluate potential climate policies.