The 1.5°C target will require removing at least some of the carbon dioxide (CO2) previously emitted. Knowledge on how this can be done has been increasing, though barriers remain concerning governance, policy, and acceptability. For the 26th session of the Conference of the Parties (COP26) to move beyond an academic debate on CO2 removal (CDR), a broader alliance of research and policy communities, industry, and the public is needed.
Three decades ago, we could still gradually reduce emissions to avoid the strongest effects of global warming. Today, however, continued growth in emissions and stringent climate targets through the Paris Agreement require a new type of mitigation pathway: moving beyond zero emissions to net-negative emissions by removing more greenhouse gases (GHGs), specifically carbon dioxide (CO2), from the air than are emitted. Because temperatures generally stabilise when CO2 emissions reach net zero but emissions are unlikely to be comprehensively reduced to zero, net-negative emissions are required in most emission pathways consistent with 1.5 C or 2 C warming. Not only can CO2 removal (CDR) offset residual emissions, but it can also be used to bring temperatures down after an overshoot of the target.