Global Income Convergence in a Climate‐Constrained World

Abstract

Global economic convergence is critical for international justice and increasingly called for in in‐ternational policy discourse. Research has explored various climate‐economic scenarios, but littlehas been said about how radical and universal income convergence, to levels such as those in Europe,may impact the climate. Taking into account both between‐country and within‐country inequality,I explore the carbon emissions of stylized global income convergence scenarios in a deterministicdata‐driven model. I find that global emissions depend on the desired income level, the time horizonand assumptions about carbon intensity evolution. Moreover, I find that income reductions of high‐income groups could contribute to climate mitigation in convergence scenarios but only extremelyfast, economy‐wide, decarbonization can make climate targets fully achievable in those scenarios.This is especially true if the level of income convergence is very high. For example, if the entireworld were to converge to the current level of income in Denmark by the year 2100. In this case,the model shows that the convergence process alone would overshoot the 2 degree budget by 60%without reaching net‐zero emissions, even assuming a long‐run carbon‐intensity reduction rate of ‐5% for all countries, currently the best empirically observed value. Only a long‐run average carbonintensity reduction rate of approximately ‐11% or faster each year, seven times the historical globalaverage, enables the Denmark‐level convergence scenario to stay within the two‐degree budget whilealso reaching net‐zero emissions.

Keywords: North-South convergenceClimate economicsSocio-economic scenariosEcological economics