Modifying carbon feedback by transforming arctic soil into biochar

The escalation of global temperatures has heightened uncertainties in the Arctic, particularly regarding the potential release of greenhouse gases, such as carbon dioxide, through permafrost thawing. This phenomenon is primarily driven by positive carbon feedback, leading to 3.3 times faster Arctic warming rate than the global average. To address this challenge, this study proposes a proactive strategy for substituting Arctic underground soil with biochar to mitigate carbon dioxide emissions. Particularly, utilising carbon dioxide (CO 2 ) as a reactive feedstock to the pyrolysis system opens up opportunities to produce the functionalized biochar for adsorbing CO 2 , simultaneously enhancing energy recovery from other pyrogenic products, such as syngas and biocrude. Moreover, a comprehensive techno-economic analysis allowed to determine optimized pyrolytic conditions for biochar production. Despite the necessity of high reaction temperatures, the utilisation of carbon dioxide demonstrated superior performance in terms of energy recovery and carbon dioxide mitigation. The biochars produced represent a potential of offsetting CO 2 emission, with an estimated decrease rate of 51.6 Gt CO 2 yr −1 by 2100 over the next 75 years. Therefore, this study introduces a strategic approach to mitigate positive carbon feedback and slow global climate change by incorporating CO 2 for the biochar production. • Arctic carbon feedback has led to 3.3 times faster warming rate than the global average. • Conversion of Arctic underground soil into biochar offers a chance to mitigate CO 2 emission. • Using CO 2 as a reactive feedstock to the pyrolysis system produces the functionalized biochar. • A techno-economic analysis proved the functionality of biochar to slow global climate change.