Climate change isn’t just warming the planet—it’s reshaping space.
As greenhouse gases trap heat in the lower atmosphere, the upper atmosphere cools and contracts, reducing the drag that naturally pulls old satellites back to Earth. With satellites lingering longer in orbit, the risk of collisions and space debris skyrockets, threatening the future of satellite communications, weather forecasting, and navigation.
Rising Satellite Numbers and a Changing Atmosphere
More than 8,000 satellites currently orbit Earth at altitudes between 300 and 1,000 km, within the thermosphere — our planet’s upper atmosphere. While space weather events like solar flares and coronal mass ejections can briefly alter the density of this region, researchers at the University of Birmingham suggest that climate change is driving a much longer-term shift.
Greenhouse gases (GHGs) play a key role in this change. In the lower atmosphere, these gases trap heat, warming the planet. However, they also transfer heat away from the upper atmosphere, causing it to cool and contract. As a result, satellites are left in areas where the atmosphere is thinner.
Less Atmospheric Drag, More Space Junk
This reduced atmospheric density means less drag on satellites, which significantly affects their lifespan. Normally, atmospheric friction gradually slows satellites, causing them to fall back to Earth over time. Without enough drag, they remain in orbit longer than intended.
This extended stay increases the risk of satellite collisions, leading to more space debris and making it harder to launch new satellites safely.
A New Threat to Space Sustainability
The findings, published today (March 10) in Nature Sustainability, provide a clear link between ground-level sustainability and space sustainability.
Lead researcher Matthew Brown, from the SERENE research group, said: “Often we think only about the ground-, or sea-level impacts of climate change, but this research demonstrates that the impacts will reach as high as space.
“The number of satellites in low Earth orbit is rapidly expanding and we rely heavily on them for communications, Earth observation, weather forecasting, and navigation. For this reason, we need to take the long-term sustainability of space very seriously.”
The Growing Risk of Kessler Syndrome
Dr. Brown added: “Discussions are already underway about how many satellites can be put into space at any one time, as more and more instruments are being launched into low Earth orbit. Without checking this proliferation, we are in danger of entering a ‘Kessler syndrome’, where a chain reaction of collisions causes space to become unusable.
“While technology can help these objects avoid collision, recognizing the influence that the Earth’s natural environment has on our ability to operate in space is becoming increasingly important. A coordinated approach to reducing greenhouse gas emissions would ensure we can prevent the exploitation of the thermosphere and protect it for future generations.”
Reference: “Greenhouse gases reduce the satellite carrying capacity of low Earth orbit” by William E. Parker, Matthew K. Brown and Richard Linares, 10 March 2025, Nature Sustainability.
DOI: 10.1038/s41893-025-01512-0
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5 Comments
“The numbers of satellites in low Earth orbit is rapidly expanding and we rely heavily on them for communications, Earth observation, weather forecasting and navigation. For this reason, we need to take the long-term sustainability of space very seriously.”
Satellites are abandoned if their batteries die, they run out of maneuvering fuel, or there is damage from micrometeors or cosmic rays. With solar power, battery depletion is less of a concern. Similarly, with less drag, there is less need for orbit adjustments, prolonging fuel. Therefore, if a satellite continues to operate as intended, it obviates a need for launching a replacement.
I think that this concern is misplaced and a stretch for justifying reducing anthropogenic CO2. During the COVID shutdowns, there was no change in the shape or peak of the seasonal CO2 ramp-up phase compared to 2019 or 2021. That is, a 10-20% reduction in anthropogenic emissions seems to have no immediate impact on the atmospheric concentration of CO2. That is probably because the CO2 emissions are driven primarily by biological activity, and changes in the 4% of total CO2 flux provided by humans is not measurable.
They now want to make us care for the gazillion of satellites that clog the skies, too?
Let them collide away. For communication, GPS and science we only needed like fifty of them. The remaining fifty thousand is just commercial and military junk.
For communication, we only need copper telephone cables, analog telephones, fax machines and a decent postal service withe twice a day deliveries. The rest is over-sophisticated space junk.
….and shrapnel.
Unfortunately there is a consortium to publish anything – and ‘stretch’ of half-logic to promote climate hysteria. Spencer Publishing – has purchased every ‘company’ with a title to saturate discourse –
We now live in a world where non-truths permeate and there is no science. Not the science we all expect of it.