Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security

TLDR

Tropospheric ozone and black carbon worsen air quality and accelerate warming, and the selected controls target diverse sources to affect climate on shorter timescales than CO₂ reductions. The study evaluated roughly 400 existing emission control measures to curb ozone and black carbon using current technology. The selected 14 methane and black carbon measures cut projected warming by ~0.5 °C by 2050, avert 0.7–4.7 million premature deaths, boost crop yields by 30–135 million metric tons, are valued at $700–$5,000 per ton—well above marginal abatement costs—and together lower the risk of exceeding the 2 °C threshold.

Abstract

Tropospheric ozone and black carbon (BC) contribute to both degraded air quality and global warming. We considered ~400 emission control measures to reduce these pollutants by using current technology and experience. We identified 14 measures targeting methane and BC emissions that reduce projected global mean warming ~0.5°C by 2050. This strategy avoids 0.7 to 4.7 million annual premature deaths from outdoor air pollution and increases annual crop yields by 30 to 135 million metric tons due to ozone reductions in 2030 and beyond. Benefits of methane emissions reductions are valued at $700 to $5000 per metric ton, which is well above typical marginal abatement costs (less than $250). The selected controls target different sources and influence climate on shorter time scales than those of carbon dioxide-reduction measures. Implementing both substantially reduces the risks of crossing the 2°C threshold.