Introducing population-adjusted historical contributions to global warming

The 1997 Brazilian Proposal suggested that differentiated emissions reduction targets for Annex I parties of the UNFCCC should be based on the impact of their historic greenhouse gas emissions on global temperature rise. In this paper, we develop methodologies for (and undertake) population-adjusted historical responsibility calculations. These adjust national-level historical responsibility calculations for historical population trends. We find a weak correlation between current per capita emissions levels and population-adjusted historical responsibility. Our calculations may contribute to burden sharing schemes in future climate agreements.