Rising CO2 levels could destabilize satellite and radio communications

Rising CO2 won’t just warm the earth’s surface. High above, in the ionosphere, it cools the air, thins it, and stirs stronger winds. 

New modeling work shows those changes make “sporadic-E” layers more frequent, stronger, lower, and longer-lived at night. Such conditions can garble shortwave and VHF signals used by aviation, ships, and broadcasters.

The study, led by researchers ar Kyushu University, links long-term climate change to small-scale plasma structures that steer and scatter radio waves.

The research draws a direct line from rising CO2 emissions to future risks for communications and satellite operations.

The climate signal in space weather

While we know that increasing CO2 levels in our atmosphere causes global warming at Earth’s surface, something different is happening in the ionosphere located 100 km above sea level. Up there, it’s cooling.

“This cooling doesn’t mean it is all good. It decreases the air density in the ionosphere and accelerates wind circulation,” explained study lead author Huixin Liu. 

“These changes affect the orbits and lifespan of satellites and space debris and also disrupt radio communications through localized small-scale plasma irregularities.”

Cooling at those heights has a clear driver: more CO2 means more efficient infrared radiation to space. As the upper atmosphere sheds heat, density drops and winds intensify.

The new work shows how those neutral-air changes cascade into the ionized environment that carries radio signals.

Rising CO2 can block radio signals

One such irregularity is known as “sporadic-E” or “Es,” a phenomenon where a dense layer of metal ions forms at an altitude of 90 to 120 km.

These thin, patchy sheets of ionization act like mirrors. They can bounce high-frequency (HF) and very-high-frequency (VHF) radio in unusual ways – sometimes enabling long-distance links, sometimes blocking or scattering signals. 

Because Es layers flicker in and out with winds, tides, and geomagnetic conditions, they are a perennial wildcard for air-to-ground links, maritime channels, emergency services, and broadcasters.

Chemistry from ground to space

Using a whole-atmosphere model, Liu and her team developed simulations of the upper atmosphere under two different CO2 concentrations.

The simulations included normal concentrations of 315 ppm, and then at 667 ppm (the average atmospheric CO2 level in 2024 was 422.8 ppm). The researchers evaluated changes in vertical ion convergence (VIC), which drives Es.

The experiments employed a coupled atmosphere-ionosphere framework that moves energy, winds, tides, and chemistry from the ground to space.

The key diagnostic – VIC – captures how winds push long-lived metallic ions (like Fe⁺ and Mg⁺ from meteors) into razor-thin sheets that become radioactive Es layers.

CO2 emissions and communications

The simulations revealed that, at higher atmospheric CO2 levels, VIC is enhanced globally at altitudes of 100-120 kilometers. The Es hotspots shift downward by approximately five kilometers; and their diurnal patterns change.

Further investigation revealed that these changes were caused by lower atmospheric density and wind disturbances.

Stronger shears and altered tides compress ions more efficiently. Lower density helps layers form at reduced altitudes, where collisions and chemistry differ.

Nightside persistence increases as cooling reshapes the daily wind cycle. For operators, that means more frequent and longer nighttime Es, at heights that interact with different signal paths than today.

Real-world systems in the crosshairs

“As the name suggests, Es are sporadic and difficult to predict. However, when they occur, they can disrupt HF and VHF radio communications,” Liu said.

“Our results revealed that, at high CO2 levels, Es tend to become stronger, occur at lower altitudes, and persist longer at night.”

Aviation still leans on HF as a resilient, beyond-line-of-sight backup – especially over oceans and polar routes. Shipping, fishing fleets, and coastal services depend on HF/VHF every day.

Broadcasters and emergency networks use the same bands for wide-area reach when satellites are overloaded or unavailable.

More robust Es doesn’t automatically spell outages, but it shifts the baseline, increasing the odds of fading, multipath, and unexpected skip distances right when reliability matters.

Satellites aren’t spared from CO2

Thinner air at 100–120 km reduces drag on objects that skim the upper atmosphere – good for keeping cubesats aloft, bad for clearing debris.

At the same time, wind changes and density spikes during storms can still create sudden drag events. 

The combined picture is a more variable environment: slower, longer decay on average, punctuated by sharper perturbations, and with more radio-noisy layers below.

Effects of global warming in space

The research shows that global warming affects not just the Earth but extends well into space.

Based on the findings, the telecommunications industry will need to develop a long-term vision that accounts for the impacts of global warming and climate change in their future operations.

That roadmap can start with better monitoring. Ground networks that ionosondes, GNSS scintillation monitors, and HF beacons already feed can be tuned to track Es trends, not only flares and storms. 

Propagation models should incorporate climate-driven winds and density, not just solar and geomagnetic inputs.

Equipment can hedge with frequency agility, polarization diversity, and adaptive link budgets. And training can treat Es as a climate-sensitive risk, not just a “space weather” oddity.

Future of CO2 and satellites

“These findings are the first of its kind to show how increasing CO2 affects the occurrence of Es, revealing new insight into cross-scale coupling processes between neutral air and ionosphere plasma,” said Liu.

“In other words, they show how global climate-driven changes can impact small-scale plasma phenomena in space.”

That cross-scale insight matters. It connects the arc of emissions policy to the physics of a pilot’s radio check. It also widens the scope of climate adaptation – from seawalls and heat plans to spectrum planning, antenna siting, and satellite end-of-life strategies.

As CO2 climbs, the ionosphere will not stand still. Neither should the communication systems that depend on it.

The study is published in the journal Geophysical Research Letters.

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