Overview
- The policy analysis published Thursday, June 11, 2026, in Science estimates that indirect gases and black carbon together have driven roughly 15% of human‑caused warming, about 0.3°C.
- These indirect pollutants — chiefly carbon monoxide, non‑methane volatile organic compounds and nitrogen oxides — do not trap heat directly but fuel atmospheric chemistry that forms tropospheric ozone and extends methane’s lifetime.
- The authors say indirect gases now rank as the third‑largest human source of warming after CO2 and methane and report that CO and VOC chemistry accounts for about 0.25°C of warming compared with roughly 0.1°C from nitrous oxide.
- Researchers call for expanded, geographically broad atmospheric monitoring and better emission attribution because current networks focus on city pollution peaks and cannot reliably measure sources that drive global forcing.
- Because many of these pollutants are already regulated for health, the paper says tighter air‑quality controls and new accounting could yield near‑term climate benefits, though technical measurement challenges and geopolitical hurdles remain.