The problem about per capita is that a country faces less repercussions for their policies that add to the CO2 load of the world via population. If you currentl

The problem about per capita is that a country faces less repercussions for their policies that add to the CO2 load of the world via population. If you currently cap everyone, Y, to some per capita value of emissions, X, (total emissions Y * X). Then if some country adds 1m to their population, Y + 1m, everyone else then goes to X * 95% emissions, by the fault of those people.