UCL Warns Megaconstellations Could Drive 42% of Space Climate Impact by 2029
Updated
Updated · The Cool Down · May 24
UCL Warns Megaconstellations Could Drive 42% of Space Climate Impact by 2029
2 articles · Updated · The Cool Down · May 24
UCL researchers said satellite megaconstellations could account for about 42% of the space industry's climate impact by 2029, up from roughly 35% in 2020, as low-Earth-orbit deployments accelerate.
540 times stronger than surface soot, black carbon from rocket launches lingers in the upper atmosphere for years; the study projects annual space-sector soot emissions of about 870 tons by 2029.
329 launches in 2025, up from 114 in 2020, reflect the boom led by networks such as SpaceX's nearly 12,000-satellite Starlink and rival systems under development by Amazon and Chinese operators.
The study said upper-atmosphere particles could reduce sunlight reaching Earth and modestly deplete ozone by about 0.02% worldwide by 2029, with possible knock-on effects on rainfall, agriculture and weather.
Researchers said regulation remains limited and warned the industry's expansion is becoming a small-scale, unregulated geoengineering experiment unless oversight tightens soon.
Is the race for global satellite internet creating an unregulated experiment with Earth's climate?
As private rockets pollute the stratosphere, who has the authority to protect our shared atmosphere?
Space Launch Surge Triples in Five Years: Unregulated Rocket Emissions Pose Imminent Climate and Ozone Threats
Overview
Recent studies in May 2026 warn that the rapidly increasing number of space launches, mainly driven by satellite megaconstellations like Starlink, is creating a new and urgent climate threat. From 2020 to 2025, rocket launches have surged, introducing large amounts of particulate matter and gases into the upper atmosphere. This pollution is now a critical environmental concern, as it could reduce the amount of sunlight reaching Earth's surface by as early as 2029. The findings highlight the need for immediate attention to the upper atmosphere as a new frontier for climate impact.