A reader has asked whether filling all vehicle tyres with carbon dioxide (CO2) could meaningfully reduce atmospheric carbon levels, a question that touches on the broader feasibility of carbon capture and storage in everyday objects.
Chris Coldwell from Lancaster posed the question to The Guardian's long-running 'Notes and Queries' series, inviting readers to consider the potential climate impact of such a scheme. The query asks if the CO2 locked inside tyres would be enough to lower atmospheric concentrations significantly, and whether the energy cost of capturing and compressing the gas would offset any benefits.
Scientific Feasibility and Scale
The proposal faces a fundamental challenge of scale. While a single car tyre holds only a small volume of gas, the global vehicle fleet numbers in the billions. However, even if every tyre on Earth were filled with CO2, the total mass of gas contained would be a tiny fraction of the annual emissions produced by human activity.
For context, global CO2 emissions exceed 36 billion tonnes per year. The combined internal volume of all vehicle tyres worldwide is estimated at well under one million cubic metres, which would hold less than two million tonnes of CO2 at standard pressure—equivalent to less than one hour of global emissions.
Energy Costs and Practical Issues
Beyond the scale problem, the energy required to capture, compress, and pump CO2 into millions of tyres would itself generate significant emissions. Carbon capture and compression is energy-intensive, and unless powered by renewable sources, the process could add more CO2 to the atmosphere than it sequesters.
There are also safety and operational concerns. CO2 behaves differently from air when heated, potentially affecting tyre pressure stability and durability. Moreover, tyres are regularly replaced and recycled, meaning the stored CO2 would be released back into the atmosphere at the end of each tyre's life, unless the gas were captured during recycling—a process that would require additional energy.
Broader Carbon Storage Context
The idea highlights a wider debate about the role of novel carbon storage methods. While geological storage and direct air capture are being developed, the scale of the climate challenge demands solutions that can handle billions of tonnes of CO2, not millions.
Readers are invited to submit their answers to this question, as well as new queries, to The Guardian's Notes and Queries series. A selection of responses will be published the following Sunday.
