Contrails, the white streaks planes leave behind, are not just a visual curiosity. According to a new report from Klima Consulting, commissioned by T&E and authored by a former IPCC scientist, these thin clouds contribute to global warming on a scale similar to aviation's carbon dioxide emissions. That is striking because only a small fraction of flights produce the contrails that matter most.
The report's central finding is that tackling contrails could avoid roughly ten years of aviation-related climate warming. Because the warming effect is concentrated in a limited set of flights, relatively small operational changes—such as adjusting flight altitudes—could have an outsized impact. The research adds to a growing body of evidence that non-CO₂ effects of aviation deserve more attention in climate policy.
Unlike fuel emissions, contrails are not yet regulated in most climate frameworks. The new analysis suggests that closing that gap could be one of the fastest ways to reduce aviation's near-term climate footprint, even as the industry works on cleaner fuels and more efficient engines. The report does not claim contrails can be eliminated entirely, but it argues that the potential savings are large enough to warrant immediate action.