In the late 1990s, the idea of directly removing CO2 from the atmosphere via large mechanical ‘filters’ first emerged. Since then, various direct air capture (DAC) concepts have been developed and several projects have been implemented worldwide. In recent years, DAC has increasingly drawn attention, provoking a broad range of reactions – from enthusiastic supporters of the technology to sceptics who criticize its high energy costs or the risks of mitigation deterrence it presents. How does DAC compare to other carbon dioxide removal (CDR) and carbon capture methods? Which role may this technology play in climate mitigation strategies? What are the key challenges for it to be deployed sustainably at large scale?