Background

At the 2015 climate summit in Paris, in Glasgow in 2021, and in Sharm el-Sheik in 2022, world leaders committed to limit warming to well below 2°C. Unfortunately, it is increasingly implausible this can be achieved by emissions reductions alone. Today, almost all scenarios that have a reasonable chance of not breaching a 1.5 or even 2°C warming threshold require Carbon Dioxide Removal (CDR) technologies. These are techniques that actively remove CO₂ from the atmosphere for long-term storage. Many different CDR methods have been proposed, each with advantages and disadvantages. In section 3.3 we build on our expertise in weathering and Critical Zone processes and currently focus on a promising CDR technique: Enhanced (silicate) weathering (EW). EW refers to the distribution of powdered silicate rock that reacts with atmospheric CO₂, thus removing it from the atmosphere. EW also releases P, Mg, Ca, K and other nutrients, giving EW the potential co-benefits of enhanced crop yield and elevated crop nutritive status.

Scientific key questions

• How can we monitor, report and verify (MRV) CO₂ removal processes?
• Which kinds of landscapes are most suited for CO₂ removal?
• What are the potential trade-offs and co-benefits for CO₂ removal processes?