Fair-share carbon dioxide removal increases major emitter responsibility

The Paris Agreement long-term temperature goal is to be achieved on the basis of equity. Accomplishing this goal will require carbon dioxide removal (CDR), yet existing plans for CDR deployment are insufficient to meet potential global needs, and equitable approaches for distributing CDR responsibilities between nations are lacking. Here we apply two common burden-sharing principles to show how CDR responsibility could be shared between regions in 1.5 degrees C and 2 degrees C mitigation pathways. We find that fair-share outcomes for the United States, the European Union and China could imply 2-3 times larger CDR responsibilities this century compared with a global least-cost approach. We illustrate how delaying near-term mitigation affects the CDR responsibilities of major emitters: raising emission levels in 2030 by one gigatonne generates about 20-70 additional gigatonnes of CDR responsibility over this century. An informed debate about equitable CDR contributions will be essential to achieve much-needed progress in this area. Carbon dioxide removal (CDR) will be required to achieve 1.5 degrees C or well below 2 degrees C climate targets. Analysis of equitable distributions of CDR responsibility shows 2-3 times larger responsibility on large emitters such as the United States, China and the European Union than under a least-cost approach.