Critics point out that capturing, purifying, and compressing CO2 for tyre inflation would require significant energy
A reader’s question explores whether inflating all vehicle tyres with carbon dioxide could meaningfully lower atmospheric CO2 levels by storing the gas in rubber. The idea, posed by Chris Coldwell from Lancaster, considers the scale of carbon that might be trapped if every tyre on Earth were filled with CO2 instead of air, and whether the process itself would generate more emissions than it saves. The concept hinges on the sheer number of vehicles globally—over 1.4 billion cars alone, not counting trucks, buses, and other machinery—each with four tyres holding roughly 30 to 40 litres of gas. If filled with pure CO2 instead of nitrogen-oxygen air, each tyre could store about 0.08 to 0.1 kilograms of carbon dioxide. Multiplying that across all tyres yields a theoretical storage capacity in the millions of tonnes, though still a fraction of the 36 billion tonnes of CO2 emitted annually from fossil fuels.
Critics point out that capturing, purifying, and compressing CO2 for tyre inflation would require significant energy, likely sourced from fossil fuels, creating a carbon cost that could offset or exceed the storage benefit. Additionally, CO2 permeates rubber faster than air, meaning tyres would lose pressure more quickly, reducing fuel efficiency and increasing wear, which in turn raises emissions from manufacturing replacements. Practical Challenges of Gas Replacement in Tyres Beyond environmental trade-offs, safety and performance concerns arise. Tyres rely on stable internal pressure for optimal grip, braking, and handling. CO2’s higher solubility in rubber leads to faster diffusion, necessitating more frequent re-inflation. This maintenance burden would fall on drivers or service stations, adding logistical complexity. Furthermore, in cold temperatures, CO2 pressure drops more sharply than air, risking underinflation and potential tyre failure.
Experts note that while nitrogen is already used in some high-performance and aircraft tyres for its slower leakage
Experts note that while nitrogen is already used in some high-performance and aircraft tyres for its slower leakage, CO2 offers no such advantage and introduces new drawbacks. The energy-intensive process of isolating CO2 from industrial emissions or air capture plants would likely negate any atmospheric benefit unless powered entirely by renewables—a condition not yet scalable. Could This Idea Ever Be Viable? Even under optimistic scenarios, the carbon stored in tyres would represent less than 0.1% of annual global emissions. The temporary nature of the storage—since tyres degrade and are discarded every few years—means the CO2 would eventually be released back into the atmosphere during recycling or incineration. Thus, the approach functions more as a delayed emission than a true removal strategy.
Scaling such a system would also demand unprecedented infrastructure for CO2 distribution, tyre modification, and monitoring, diverting resources from proven climate solutions like renewable energy adoption, reforestation, or direct air capture with geological storage. Frequently Asked Questions How much CO2 could realistically be stored in all vehicle tyres? Estimates suggest filling every tyre on Earth with CO2 would store roughly 20 to 30 million tonnes of gas—equivalent to less than one year’s emissions from a single large coal power plant. Would CO2-filled tyres affect fuel efficiency? Yes, due to faster pressure loss, tyres would run underinflated more often, increasing rolling resistance and reducing fuel economy by an estimated 3–5%, counteracting any carbon storage benefit. Is there any scenario where this could help the climate?
Only if the CO2 used were sourced from excess capture powered by renewables and the tyre’s lifetime extension offset emissions from replacement—but current technology and scale make this implausible as a climate solution.