Since the middle of the twentieth century, the global population has experienced rapid improvements in its quality of life. Incomes, wealth, life expectancy, and educational attainment have risen at historically unprecedented high rates, and poverty and hunger have declined. However, one dimension of human welfare has not improved: contemporary global income inequality is similar to the level estimated for the beginning of the twentieth century. The study of inequality has been hampered by a lack of internationally comparable time series for the distributions of income and wealth. To remedy this neglect, the World Inequality Laboratory (WIL) at the Paris School of Economics hosts the rapidly expanding World Inequality Database. This public database has been developed by an international network of over a hundred researchers which collaborates with statistical institutions, tax authorities, universities, and international organizations to harmonize, analyze, and disseminate comparable international inequality data. The 2022 report is the flagship product of the WIL and provides a comprehensive and concise overview of the latest findings on inequality covering most of the globe.

The report has three main findings. First, contemporary income and wealth inequalities are very large. On average, an adult from the top 10% of the global income distribution earns $122,100 per year (at purchasing power parity), whereas an adult from the poorest half of the global income distribution makes only $3,920 per year. Global wealth inequality is even more pronounced. The poorest half of the global population barely owns any wealth at all, possessing just 2% of the total. On average, this half owns $4,100 per adult while the top 10% owns $771,300 per adult. The second conclusion is that income inequality has risen within countries over the past two decades (as the number of multimillionaires and billionaires has expanded at an extraordinary rate) while inequality between countries has declined due to the fast growth of the largest emerging economies. These two effects balance each other out so that in the past few decades global inequality has been more or less stable at a very high level. The third key finding is that inequality varies widely among countries and regions. The Middle East and North Africa, sub-Saharan Africa, Latin America, and South and South-East Asia have the most unequal incomes, while Europe is the most equal. In addition to detailed discussions of these main issues, the report includes sections on the impact of the COVID epidemic, public versus private wealth, female versus male labor incomes, inequalities in carbon emissions, and tax policies to redistribute wealth and income. Throughout this highly accessible report masses of statistics are presented in numerous well-designed figures and tables. An appendix provides country-level inequality statistics. —J.B.

自二十世纪中叶以来，全球人口的生活质量迅速提高。收入、财富、预期寿命和受教育程度以前所未有的高速度增长，贫困和饥饿现象有所减少。然而，人类福祉的一个方面并没有改善：当代全球收入不平等与 20 世纪初的估计水平相似。由于缺乏国际可比的收入和财富分配时间序列，对不平等的研究一直受到阻碍。为了弥补这一疏忽，巴黎经济学院的世界不平等实验室 (WIL) 拥有快速扩展的世界不平等数据库。这个公共数据库是由一百多名研究人员组成的国际网络开发的，该网络与统计机构、税务机关、大学和国际组织合作，以协调、分析和传播可比较的国际不平等数据。2022 年报告是 WIL 的旗舰产品，全面而简明地概述了全球大部分地区不平等的最新发现。

该报告有三个主要发现。首先，当代收入和财富的不平等非常大。平均而言，来自全球收入分配前 10% 的成年人年收入为 122,100 美元（按购买力平价计算），而来自全球收入分配最贫困的一半的成年人年收入仅为 3,920 美元。全球贫富差距更加明显。全球人口中最贫穷的一半几乎没有任何财富，仅占总人口的 2%。平均而言，这一半人每个成年人拥有 4,100 美元，而前 10% 的人每个成年人拥有 771,300 美元。第二个结论是，在过去二十年中，国家内部的收入不平等加剧（因为千万富翁和亿万富翁的数量以惊人的速度增长），而国家之间的不平等由于最大的新兴经济体的快速增长而下降。这两种效应相互抵消，因此在过去几十年中，全球不平等一直或多或少稳定在一个非常高的水平。第三个重要发现是，不同国家和地区之间的不平等差异很大。中东和北非、撒哈拉以南非洲、拉丁美洲以及南亚和东南亚的收入最不平等，而欧洲最平等。除了对这些主要问题的详细讨论外，该报告还包括有关 COVID 流行病影响、公共财富与私人财富、女性与男性的劳动收入、碳排放的不平等以及重新分配财富和收入的税收政策。在这份易于访问的报告中，大量统计数据以众多精心设计的图表形式呈现。附录提供了国家层面的不平等统计数据。—JB