Response to comment on "Fairness considerations in global mitigation investments".

We welcome the analysis of Semieniuk et al . ( 1 ) as an additional sensitivity to illustrate a more extreme distribution of regional contributions to climate mitigation investments that supports our main conclusion regarding the North-South divide in mitigation investment capabilities. In response to Semieniuk et al . we would like to first point out that, in defining the required global mitigation investments for the 2020 to 2030 period, our study relies on the estimates in the sixth assessment report (AR6) of the Intergovernmental Panel on Climate Change (IPCC) WGIII ( 2 ). These are based on diverse sources and underlying models that to varying degrees reflect regional differences in technology costs and consider both purchasing power parity (PPP) and market exchange rates (MERs). We use these IPCC estimates as a starting point and focus entirely on the question of how much of the needed regional investments, given different fairness considerations, should be financed from sources within a region.