Overview
- The Leipzig-led study estimates embedded contrails contribute about +5 milliwatts per square meter globally, adding roughly ten percent to previously assessed contrail forcing.
- Researchers matched commercial flight tracks with CALIPSO lidar snapshots to detect changes in cirrus before and after aircraft passages and then scaled the signal with a climate model.
- Local radiative effects show a pronounced diurnal asymmetry, with daytime cooling of about −150 to −260 mW/m² and stronger nighttime warming of about +400 to +670 mW/m².
- The authors conclude that routing aircraft through high-altitude ice clouds does not offer a reliable mitigation pathway and that this effect should be included in aviation climate metrics.
- A companion study finds that many persistent contrails likely form within thin or invisible cirrus rather than clear air, revising assumptions used in earlier models.