idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
A new study visualizes three decades of income inequality data, the most comprehensive worldwide mapping to be done at a subnational level. The results confirm worsening income inequality for areas with over 3.6 billion inhabitants but also reveals hidden ‘bright spots’ where policy may be closing the gap.
Income inequality is one of the most important measures of economic health, social justice, and quality of life. More reliably trackable than wealth inequality, which was recently given a gloomy report card by the G20, income inequality is particularly relevant to immediate economic relief, mobility and people’s everyday standard of living.
The new study, from an international team led by Aalto University and Cambridge University, and also including IIASA authors, is the first to comprehensively map three decades of income inequality data in 151 nations around the world. Despite finding that income inequality is worsening for half the world’s people, the study also indicates that effective policy may be helping to bridge the gap in regions such as Latin America, highlighting ‘bright spots’ in administrative areas that account for around a third of the global population.
“This research gives us much more detail than the existing datasets, allowing us to zoom in on specific regions within countries,” says lead authors, Matti Kummu, from Aalto University. “This is significant because in many countries national data would tell us that inequality has not changed much over the past decades, while subnational data tells a very different story.”
The new data is particularly relevant in light of recent failings around wealth inequality, given that it could help shed light on what policy levers might be pulled to address inequality in the short-term.
“We have vastly more complete data on income than we do on wealth, which tends to be much harder to uncover and track,” explains co-lead author Daniel Chrisendo, Assistant Professor at Cambridge University. “Especially given that income inequality leads to wealth inequality, it’s critical to tackle both forms, but income inequality is perhaps the easiest to address from an immediate policy perspective.”
The study, published in Nature Sustainability and the new global subnational Gini coefficient (SubNGini) dataset, spanning 1990-2023, is publicly accessible online. Global annual data and trends can be explored visually using an Online Tool, which enables users to explore how income inequality has played out in regions around the globe and also download the data for further analyses.
This study complements earlier work by IIASA authors that used subnational household survey data to reveal persistent gaps in living standards across 75 low- and middle-income countries, underlining how inequalities in basic services and material wellbeing often mirror income disparities at finer geographic scales.
Pinpointing the role of policy
“By revealing where inequality is worsening and where it is being successfully reduced, this dataset helps policymakers move from broad national strategies to much more tailored, locally grounded interventions. This level of precision is essential if we want to design policies that actually reach the people who need them most,” notes coauthor Roman Hoffmann, who leads the Migration and Sustainable Development Research Group in the IIASA Population and Just Societies Program.
There are many examples where regional efforts have shone more brightly than is revealed by national statistics, say the researchers. However, India, China, and Brazil all present interesting case studies that affect large swathes of the global population. In India, for example, relative success in the south is linked to sustained investments in public health, education, infrastructure and economic development that have benefited the local population more broadly.
Meanwhile, in China, market-oriented reforms and open-door policy have driven economic growth and dramatically reduced poverty since the 1990s, but the authors point out that this growth has been uneven, likely due to the Chinese government’s ‘Hukou’ policy limiting rural migrants' access to urban services. In response, the government has implemented various policy measures, such as regional development programs and relaxed Hukou restrictions to address disparities and support internal migrants.
In Brazil, the mapping shows a potential correlation between reduced inequality and a regional cash transfer program providing cash to poor families on condition of their children attending school and receiving vaccinations.
Income inequality rising for half the world’s people
Relative income growth for the world’s poorest 40% is one of the UN’s Sustainable Development Goals (SDGs), yet the study confirms the collective failure to meet this goal by 2030.
“Unfortunately, not only are we quite far from that goal, but the trend for rising inequality is actually stronger than we thought,” says Kummu.
The researchers are now expanding the data visualization to encompass a vast range of other socioeconomical indicators, from how populations are aging, to life expectancy and time spent in schooling, to improved access to drinking water using the extensive new datasets slated for public launch in 2026. The authors hope the new datasets can be used to better understand, for example, the linkages between development and environmental changes. The recent study revealed links between more unequal regions and lower ecological diversity, which they would like to explore further.
“It’s ambitious, but to have subnational, high quality data spanning over three decades is crucial to understand different social responses to environmental changes and vice versa. It gives us the means to start understanding the causalities, not just the correlations, and with that comes the power to make better decisions,” Kummu concludes.
Reference
Chrisendo, D., Niva, V., Hoffmann, R., Masoumzadeh Sayyar, M., Rocha, J., Sandström, V., Solt, F., & Kummu, M. (2025). Rising income inequality across half of global population and socioecological implications. Nature Sustainability DOI: 10.1038/s41893-025-01689-4
About IIASA:
The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, and Europe. www.iiasa.ac.at
Contacts:
Roman Hoffmann
Research Group Leader and Senior Research Scholar
Migration and Sustainable Development Research Group
Population and Just Societies Program
hoffmann@iiasa.ac.at
Press Officer
Ansa Heyl
IIASA Press Office
Tel: +43 2236 807 574
Mob: +43 676 83 807 574
heyl@iiasa.ac.at
https://www.nature.com/articles/s41893-025-01689-4#citeas
https://iiasa.ac.at/news/dec-2025/subnational-income-inequality-regional-success...
Merkmale dieser Pressemitteilung:
Journalisten, jedermann
Gesellschaft, Politik, Wirtschaft
überregional
Forschungsergebnisse
Englisch
Sie können Suchbegriffe mit und, oder und / oder nicht verknüpfen, z. B. Philo nicht logie.
Verknüpfungen können Sie mit Klammern voneinander trennen, z. B. (Philo nicht logie) oder (Psycho und logie).
Zusammenhängende Worte werden als Wortgruppe gesucht, wenn Sie sie in Anführungsstriche setzen, z. B. „Bundesrepublik Deutschland“.
Die Erweiterte Suche können Sie auch nutzen, ohne Suchbegriffe einzugeben. Sie orientiert sich dann an den Kriterien, die Sie ausgewählt haben (z. B. nach dem Land oder dem Sachgebiet).
Haben Sie in einer Kategorie kein Kriterium ausgewählt, wird die gesamte Kategorie durchsucht (z.B. alle Sachgebiete oder alle Länder).
