Summary/Abstract
Owing to the small quantity of carbon dioxide (CO2) that can be emitted before we exceed the 1.5C–2C target of the Paris Agreement on climate change, signatories are increasingly likely to require ways of removing significant CO2 from the atmosphere. In addition to the biological options considered to date such as afforestation and bioenergy with CO2 capture, direct air carbon capture and sequestration (DACCS) is emerging as a potentially important synthetic CO2 removal technology. This paper explains how DACCS works, focusing on two major processes that have been developed into large-scale pilot plants. The paper discusses cost estimates and operational energy requirements, as well as ecological and ethical considerations. The paper also highlights the role of DACCS in the low-carbon transition and in meeting the Paris Agreement targets by discussing its benefits, while also noting potential trade-offs and uncertainties that deserve further investigation.