Feasibility of air capture

Abstract

Capturing CO2 from air, referred to as air capture, is being proposed as a viable climate change mitigation technology. Technically, air capture is not a new technology; industrial applications can be traced back to the 1930s. This paper explores the feasibility of this technology as a climate change mitigation option. Two different pathways of air capture are assessed: direct air capture, which uses a chemical process to capture CO2, and biomass coupled with CO2 capture and storage (CCS), which utilizes the biological process of photosynthesis to remove CO2 from the air. We find that direct air capture has prohibitively high mitigation costs compared to the costs of climate change mitigation options being considered today. The pathway of biomass coupled with CCS has much more reasonable costs and could be used to offset certain emissions. However, the large land requirement may limit the amount of offsets available. We conclude that relying on air capture technology to play a major role in mitigating carbon emissions is a very risky policy decision.