CO2 in car tyres fails as climate solution
Using CO2 to fill car tires would store only a tiny fraction of annual emissions and presents practical and safety risks, calculations show.
Filling every car tyre on Earth with carbon dioxide would lock away only about 157,700 tonnes of CO2, a Guardian reader calculates. This amount is minuscule compared to the 38.1 billion tonnes of CO2 emitted globally in 2025, which equates to roughly 100,000 tonnes released every minute. For context, you can explore the detailed stats on global emissions.
Readers responding to a question in the publication's forum systematically dismantled the idea. They highlighted the trivial scale of potential storage, the temporary nature of any sequestration, and significant logistical hurdles.
The numbers show a negligible effect
One contributor provided the core calculation. An inflated car tyre holds about 14 grams of air. Because CO2 is denser, each tyre would contain approximately 21 grams of the gas. With nearly 1.5 billion cars worldwide, the total stored would reach 157,700 tonnes.
To contextualize this figure, another reader compared it to natural carbon capture. A rewilding project can sequester carbon per hectare annually. Storing an equivalent amount naturally would thus require a significant land area or an immense timescale, both dwarfed by ongoing emissions.
| Comparison | Figure |
|---|---|
| CO2 in all car tyres | 157,700 tonnes |
| Global CO2 emissions (2025) | 38.1 billion tonnes |
| Emissions per minute (2025) | ~100,000 tonnes |
| Natural sequestration rate | carbon/hectare/year |
Practical and safety concerns are significant
Several readers pointed out that any carbon stored would be released quickly when tyres puncture, wear out, or are changed. If they leak, they provide no lasting benefit to the carbon balance.
The process of capturing and compressing CO2 specifically for tyres would be complex and expensive compared to using air. Another noted that CO2 leaks through rubber faster than nitrogen, meaning tyre pressure would drop more frequently. This would lead to under-inflated tyres, reducing fuel efficiency and increasing emissions from the global vehicle squad.
Safety is another major issue. High concentrations of carbon dioxide can be hazardous. Creating a widespread infrastructure for public handling of compressed CO2 cylinders would introduce new risks.
Alternative solutions are more viable
Readers broadly agreed that the proposal is a distraction from more effective climate actions. Many advocated for natural solutions like planting more trees, a natural store of CO2.
Others suggested technological approaches like bubbling CO2 through algae, trapping it in basalt, or converting it to bicarbonate for ocean storage. Some lists included these ideas alongside social measures like educating more girls.
Some focused on personal responsibility, arguing for actions like not buying from the livestock industry and not buying air tickets, linking these industries directly to unsustainable carbon outputs.
Thermodynamic realities also undermine related technical fixes. Reacting captured CO2 with hydrogen to create synthetic methane for the gas grid was proposed. However, others countered that the energy required for electrolysis and synthesis would be immense, and it would be better to leave natural gas in the ground and use a heat pump instead.
The discussion concluded that the tyre idea is fundamentally flawed, as the total volume of every car tyre on the planet is so much smaller than the size of the atmosphere. One final, humorous note suggested it wouldn't help the environment if you filled your tyres with nitrous oxide, but it would be funny if they burst.
