A recent article from Smithsonian Magazine (SM) titled “Climate Change Might Increase Satellite Collisions, Limiting How Many Can Safely Orbit Earth, Study Finds” claims that human-induced climate change is causing the upper atmosphere to contract, reducing drag on satellites and space debris, which could lead to more collisions. This is misleading if not outright false. Multiple studies show the dominant factor influencing the density and temperature of the upper atmosphere—where some satellites orbit—is solar activity, not carbon dioxide emissions. Data from decades of space research confirm that variations in solar radiation, particularly changes in ultraviolet (UV) output and solar wind, have far greater impacts on atmospheric density than any CO₂-driven effects.
The study, referenced by the SM article, is summarized as: “The thermosphere, which begins around 50 miles (80 kilometers) above Earth’s surface, is contracting. This is because as greenhouse gases like carbon dioxide and methane accumulate in the lower atmosphere, they radiate heat into space and cause the upper atmosphere to cool and shrink.” This claim exaggerates the role of human greenhouse gas emissions while ignoring the well-documented influence of solar variability.
The thermosphere, seen in the graphic from The Canadian Space Agency below, is primarily heated by the Sun’s intense ultraviolet radiation, and its temperature and density fluctuate significantly in response to the 11-year solar cycle. When solar activity is high, the thermosphere expands, increasing drag on satellites and space debris. Conversely, during solar minima, the thermosphere contracts. These natural solar-driven variations completely overshadow any potential effect from anthropogenic CO₂.
A study in the Journal of Space Research confirms that thermospheric temperature fluctuations are overwhelmingly linked to solar output, not greenhouse gases. Similarly, research in Space Weather Science demonstrates that solar activity is the primary driver of upper atmospheric density changes, affecting satellite drag far more than any CO₂-related cooling. In addition, a report in EOS shows that during a weaker-than-normal solar cycle, the thermosphere cooled and contracted more than expected. This aligns with long-term observations that solar variability dictates thermospheric behavior. NASA also credits the sun as driving the changes in the thermosphere.
While many satellites orbit Earth in the thermosphere, most Earth-orbiting satellites reside in the exosphere, such as geostationary satellites with orbits at 22,500 miles even higher than the exosphere, the outermost layer of the Earth’s atmosphere, where the atmosphere thins out and merges with outer space. So, the concerns about the thermosphere in the SM article are mostly moot, especially since many satellites that orbit in the thermosphere can boost with thrusters to a higher orbit if needed. Engineers plan for this.
The SM article also fails to consider historical data. If CO₂ were truly the primary driver of thermospheric contraction, we would expect to see a steady, predictable decline in atmospheric density as CO2 emissions have increased. Instead, we observe clear cyclical patterns that correspond with the 11 year solar cycle, not industrial CO₂ emissions. During past solar minima, such as the Dalton Minimum (1790–1830) and the Maunder Minimum (1645–1715), similar thermospheric contractions occurred—long before human activity significantly increased CO₂ levels.
By pushing a climate change-driven explanation while ignoring the Sun’s dominant role, and ignoring where most satellites orbit Earth, Smithsonian Magazine is misrepresenting what science tells us about the atmosphere and what drives change in it. Space debris is a real issue that requires attention, but CO2 neither creates space debris nor is making collision with such debris more likely. Blaming CO₂ emissions for upper-atmospheric changes is a false narrative and distracts attention from the real problem of how to handle space debris
Anthony Watts is a senior fellow for environment and climate at The Heartland Institute. Watts has been in the weather business both in front of, and behind the camera as an on-air television meteorologist since 1978, and currently does daily radio forecasts. He has created weather graphics presentation systems for television, specialized weather instrumentation, as well as co-authored peer-reviewed papers on climate issues. He operates the most viewed website in the world on climate, the award-winning website wattsupwiththat.com.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022SW003330
These sat’s were parked in lower staging orbits for testing before being raised to operational orbits.
“This claim exaggerates the role of human greenhouse gas emissions while ignoring the well-documented influence of solar variability.”
The study doesn’t ignore solar. But as it says, solar is a cycle, but GHGs accumulate. Here is their plot of how that works out:
The solar cycle varies density by about 10%, but GHG accumulation reduces it to about 60% on SSP2-4.5.
Here is how they put it:
“The thermosphere regularly experiences expansion and contraction in response to solar activity6. Solar electromagnetic radiation cycles in intensity roughly every 11 years. The globally averaged thermospheric mass density in LEO can vary by an order of magnitude between solar minimum and maximum7. Density fluctuates more rapidly but by similar magnitudes in response to geomagnetic activity enhancements from Joule heating and energetic particle precipitation8. This space-weather-driven variation in thermospheric mass density is generally transient in nature but can severely degrade short-term satellite collision avoidance capabilities9,10. GHG-induced thermosphere contraction is of particular interest in this work because it causes secular changes in density likely to last centuries.”
Ah, CO2! Is there nothing that the Magic Molecule can’t do?
Smithsonian Magazine Uff da!
This is the sort of carp I would expect to see in Scientific American. I quit that subscription and will, likewise, drop Smithsonian if they get too silly.
Does nobody at Smithsonian have any responsibility for truth? Is anybody at Smithsonian accountable for putting out lies? Can any pressure be put on Smithsonian’s funding sources to force compliance with basic scientific truth? Why does the leadership at Smithsonian feel so free to put out such obvious lies? Maybe X can shine some light on these liars?
What is conspicuously absent from the Smithsonian Magazine is an analysis of the number and type of satellites and their orbit altitudes. Many satellites will benefit from longer time in orbit and increase the amortization time for the substantial launch and replacement costs. Generally, it is the larger and more expensive satellites that will benefit from longer on-orbit time. What is important is the net effect, not arm waving about what might, could, possibly, potentially happen.
AAAAAha ha ha ha ha.
If I spent an hour with Nick, I would consider one of those suicide capsules. Not that he would depress me. It would be a means to escape him.
Of course, the “study” uses socio-economic pathway SSP5-8.5, or sociopath 8.5 as I like to call it, to grab the “we’re all gonna die!!!” headline. As we all know, except maybe climate “scientists”, sociopath 8.5 is considered highly unlikely by everyone including the high priests at the IPCC.
Not to mention the “data” is all from flawed computer games.
“claims that human-induced climate change is causing the upper atmosphere to contract, reducing drag on satellites and space debris, which could lead to more collisions”
Is it possible that there could be positive aspects of the change?
SSP5–8.5
Groan. The first thing to do when reading any such study is ctrl-f “8.5”.
The author, Margherita Bassi, uses her creative writing training and skills to produce a fine science fiction article.
Just how much ‘Climate Change’ money are these alarmist journalists like Margherita Bassi paid, in order to perjure their souls and spread fear amongst the public with false propaganda?