全球不平等与经济增长：新冠疫情前的三十年与之后的三十年

11093 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 theincome gap with richer parts of the world. Growth in aver-age incomes played a critical role in this reduction, withdifferences within countries contributing relatively little.The Covid-19 pandemic abruptly halted the reduction inglobal income inequality and was responsible for the largest 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 thantheir richer peers, global inequality could continue to fall.Climate adaptation and mitigation challenges will play anincreasing role in shaping country-level growth trends andthus the changes in global income inequality. 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 thoseof the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank andits affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent. Global Inequality and Economic Growth: The Three Decades before Covid-19 and Three Decades After Diana C. Garcia RojasⓡNishant YonzanⓡChristoph Lakner1 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 capturesdifferences in mean incomes across countries, with each country weighted by its population. Bothconcept 1andconcept 2do not account for individuals’ personal income, and thus ignore theinequality among individuals within a country.Concept 3considers the interpersonal incomes ofeveryone around the world, and thus incorporates both inequality between countries and inequalitywithin a country. For the discussion below, unless otherwise mentioned, any reference to globalinequality implies this interpersonal version. 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 theyare largely non-existent (except for a few surveys in Western countries) before that. So, researchershave relied on historical per capita GDP and population estimates to calculate global inequality forthe period before 1990. This evidence inevitably relies on strong assumptions. Nevertheless, thehistorical estimates of global inequality reported above, based on work by Bourguignon &Morrisson (2002), have been corroborated by others (Lakner & Milanovic, 2016; Van Zanden etal., 2014). 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) re