A reader has posed a speculative question regarding the potential climate impact of filling all vehicle tires globally with carbon dioxide (CO2). The inquiry, submitted by Chris Coldwell of Lancaster, explores whether this hypothetical scenario could sequester enough atmospheric carbon to measurably lower its concentration in the air. This question delves into the feasibility and effectiveness of using a common automotive component as a carbon storage mechanism, amidst the ongoing climate emergency. The core of the question examines two primary aspects: the volume of carbon that could be locked away and the net environmental benefit. It asks if the quantity of CO2 required to inflate all tires worldwide would be substantial enough to counteract existing atmospheric levels. Furthermore, it probes the carbon footprint associated with the process of trapping and containing this CO2 within the tires themselves. This includes considering the energy and resources needed for production, inflation, and maintenance, which could offset any carbon sequestration benefits. This question arises within the context of a series where readers respond to other readers' queries, often touching upon scientific and environmental themes. Previous questions in this series have explored topics such as the inevitability of consumerism leading to planetary overfill. The series aims to engage the public in scientific discourse and encourage innovative thinking about pressing global challenges, including climate change. The Guardian's "[email protected]" email address serves as the submission portal for both answers and new questions, with selected responses published weekly. The hypothetical scenario of CO2-filled tires prompts a consideration of alternative carbon capture and storage (CCS) methods. While current CCS technologies focus on industrial emissions and direct air capture, this question introduces a decentralized, consumer-level approach. The practical challenges of implementing such a system on a global scale would be immense, including the logistics of CO2 production and distribution, the integrity of tire materials under CO2 pressure, and the safety implications for vehicles and drivers. The question implicitly asks whether such a widespread, albeit unconventional, application of a common technology could contribute meaningfully to climate mitigation efforts, or if the associated costs and complexities would render it impractical.