Abstract:

Climate change and air pollution are two major societal problems. Previous assessments have looked at the co-benefits of climate policies for air pollution, but few have optimised air pollution benefits. In the study presented, the authors lay out a modelling framework that internalises air pollution’s economic impacts on human mortality, while considering climate constraints and aerosol feedback.
The researchers developed a modelling framework based on an integrated assessment model (World Induced Technical Change Hybrid) designed to assess optimal climate change mitigation policies. They included structural and end-of-pipe measures in a detailed process integrated assessment model, that is hard-linked to air pollution and climate models. They analysed a large set of baseline scenarios, including five shared socioeconomic pathways. The shared socioeconomic pathways scenarios were also tested with three different levels of value per statistical life and were combined with the Paris Agreement temperature targets (2°C and 1.5°C).
Results showed that welfare-maximising policies accounting for air pollution benefits reduces premature mortality by 1.62 million deaths annually which is three times greater than the co-benefits of climate policies. Authors also find that global and regional welfare increases when air pollution impacts are internalised, with no negative repercussions on global inequality.
Air pollution control strategies are found to be an important complement to structural emission reductions. Accounting for air pollution impacts reduces climate mitigation costs and inequality and increases global and regional welfare. Results are robust to a broad set of scenarios and assumptions, including debated normative choices on how to value improved health.