全球不平等与经济增长：新冠疫情前的三十年与后三十年

Policy Research Working Paper Global Inequality and Economic Growth The Three Decades before Covid-19 and Three Decades After Diana C. Garcia RojasNishant YonzanChristoph Lakner Policy Research Working Paper11093 Abstract Global income inequality captures income differencesamong all individuals around the world. Global inequalityaround the world increased from 1820 to 1990 as incomesin richer countries grew faster than incomes in relativelypoorer countries. However, these trends were reversedover the three decades starting in 1990. Inequality amongall citizens of the world decreased as populous and rela-tively poorer countries, in particular China, reduced the increase in global income inequality in at least three decades.The future of global inequality largely depends on howincomes grow in various parts of the world. If the trendsof the last three decades continue, inequality may increaseas growth in those countries that drove the reduction ininequality now contributes to increasing inequality, sincethese countries are in the upper part of the global distribu-tion. However, if poorer countries today grow faster than The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about developmentissues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry thenames of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those Global Inequality and Economic Growth:The Three Decades before Covid-19 and Three Decades After Diana C. Garcia RojasⓡNishant YonzanⓡChristoph Lakner1 Keywords: Global inequality, economic growth, shared socioeconomic pathways.JEL codes: D30, D31, O40 1Introduction Global income inequality is the inequality in income among all citizens of the world. The levelsand trends of global inequality differ depending on the precise concept used (for example, seeAnand & Segal, 2008; Deaton, 2021). Milanovic (2005) has defined three ways to think aboutglobal income inequality:Concepts 1,2,and3inequalities.Concept 1inequality considers onlythe differences in mean incomes across countries, or just the inequality between countries.Concept2adjusts the former for population differences across countries. In other words, it captures differences in mean incomes across countries, with each country weighted by its population. Bothconcept 1andconcept 2do not account for individuals’ personal income, and thus ignore the The Gini index of the global income inequality was around 50 in 1820 and continuously increasedover the next 170 years to peak at around 70 right before the fall of the Berlin Wall (Milanovic,2024). This increase in global inequality is largely explained by relatively faster income growth intheWestcompared to other parts of the world. Between 1820 and 1990, per capita GDP in WesternEurope grew over 1,000 percent compared to roughly 300 percent in Asia and 125 percent in Sub-Saharan Africa (Bolt & van Zanden, 2020). The increase in global inequality before 1990 wasentirely due to the differences in income between countries (i.e., Concept 2 inequality) as there islittle data on individual incomes. There are only a few household surveys in the 1980s and they The focus of this paper is the period after 1990, for which there is more household survey data andwe can thus capture globalinterpersonalincome inequality. Lakner & Milanovic (2016) relied onsurveys conducted around reference years spaced 5 years apart from 1988 to 2008 to constructtheir global interpersonal income distribution. In all their reference years besides the first year,more than 90 percent of the global population was covered by these household surveys. Using anupdated methodology, Mahlerⓡal. (2022) construct annual distributions of global incomes The underlying survey microdata in PIP uses income aggregates to capture household welfare formost industrialized countries as well as countries in Latin America and Europe. For most otherparts of the world, the surveys use a consumption aggregate to capture welfare. Inequalitymeasured by income tends to be higher than inequality measured by consumption (see Jenkins2015; Haddad et al. 2024). While thelevelsof inequality are most likely different, there is evidencethat thetrendsmay be similar (Alvaredo et al., 2023; Kanbur et al., 2022; World Bank, 2024b). Inwhatfollows,we combine the income and consumption distributions to create a global This paper first outlines the trends in global income inequality from 1990 to 2019, then discussesthe changes in global inequality due to the Covid-19 pandemic in 2020, and finally, providespotential pathways for global inequality in the coming decades. We use the income distributionfrom PIP to report estimates of global income inequality from 1990 to 2024. For the years after2024, we draw on growth and population forecast