@thomaspiketty.bsky.social
Professor at EHESS & PSE Co-Director, World Inequality Lab inequalitylab.world | WID.world http://piketty.pse.ens.fr/
Inequalities in exposure to environmental risks – flooding and subsidence – are high and vary across home ownership status in France (owner-occupants, and owners of rental, second, or vacant homes) [🧵1/6]
New study by Thomas Bézy 🔗 wid.world/news-article...
How should we analyze the new wave of trade tensions that gripped the world in 2025? To better understand the issues at stake, the World Inequality Lab @wid.world recently published a historical study on global trade and financial imbalances since 1800 www.lemonde.fr/blog/piketty...
17.07.2025 06:54 — 👍 20 🔁 3 💬 0 📌 0
This paper is the third in a series of research papers and technical notes that will form the backbone of the #GlobalJusticeProject, due to be released in June 2026.
Find out more inequalitylab.world/en/global-ju...
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📈 In a more optimistic scenario, if all countries invested 38% of GDP in health & education, global productivity could rise to 100€/hour. Everyone gains: North America could hit 120€/hour (up from 80€), Sub-Saharan Africa 100€ (up from 9€).
[9/10]
📉In a “business-as- usual” scenario where education & health spending stalls, the productivity gaps persists. By 2100, productivity would stay at ~9€/hour in Sub-Saharan Africa vs 80€ in Europe & North America.
[8/10]
Since 1800, human capital spending has driven productivity. Average return on human capital > 10%/year. Returns are highest for:
• education (vs. health)
• public (vs. private) spending
• poorer countries — with returns up to 20% a year
[7/10]
If we were to provide all children worldwide with the same average level of expenditure on education and health as is currently available in Europe and North America, it would cost 32% of the world’s GDP.
[6/10]
🏥Public health spending per person <65 ranges from 50€ in Sub-Saharan Africa to 3,198€ in North America (PPP € 2025) — a gap of 1 to 60.
The gap widens even more with private spending (though we know that high private health costs in the US don’t necessarily lead to better health outcomes).
[5/10]
Health and education have improved globally—but the spending gap between rich and poor regions is still enormous.
🎓Today, a child in Sub-Saharan Africa receives 220€ in public education spending compared to 9,025€ in North America – a gap of almost 1 to 50.
[4/10]
Total public expenditure rose from 3% of global GDP in 1800 to 31% today, largely due to rising spending on health, education, and social protection.
This reflects the expansion of the “global social state”, supported by states’ growing capacity to collect direct income taxes & social contributions.
The study draws on a new global historical database on public expenditure and revenue and their components, with a focus on education and health. This is the first database of its kind to cover all world regions over the period from 1800 to 2025.
[2/10]
Children in Sub-Saharan Africa receive just 3% of the public education funding available to their peers in Europe and North America.
🧵A thread on a NEW STUDY written with @nitin-k-bharti.bsky.social A. Gethin @markjmn.bsky.social @zhexunmo.bsky.social & L. Yang.
🔗 wid.world/www-site/upl...
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📄In this new theory working paper, S.Subramanian makes the case for combining across the board measures with tailender indices into a composite index to measure and mitigate inequality.
Read more: wid.world/news-article...
Congratulations @cmtneztt.bsky.social & co-authors for this study on wealth inequality in Spain - the first of its kind at the autonomous region level.
The new Spain Wealth Atlas will be a very useful tool to track the evolution of wealth inequality across space and time. spainwealthatlas.world
Are you a journalist or editor?
To receive embargoed copies of the #GlobalJusticeProject papers, sign up to our distribution list: forms.gle/U6dcuoBQv5JW...
📄 So far, 2 of 8 building blocks of the #GlobalJusticeProject have been published:
1️⃣Global Labour Hours in Paid and Unpaid Work wid.world/document/glo...
2️⃣Unequal Exchange and North-South Relations wid.world/document/une...
🗓️ #GlobalJusticeProject - Key dates:
🔸Dec 2024 – May 2026: Release of working papers & technical notes
🔸June 4–5, 2026: Launch of the Global Justice Report at the World Inequality Conference in Paris @PSEinfo
More details about the Conference: inequalitylab.world/en/event/wor...
The #GlobalJusticeProject is a new research initiative developed by @wid.world, and coordinated by @lucaschancel.bsky.social @cmohren.bsky.social @rowaida96.bsky.social @moritzoder.bsky.social @anmol-smnch.bsky.social and myself—along with contributions from 30+ researchers across the world.
19.06.2025 14:35 — 👍 1 🔁 0 💬 1 📌 0
What would a just distribution of socio-economic and environmental resources look like at the global level from 2025 to 2100 – both between and within countries?
From now to June 2026, the #GlobalJusticeProject will help provide answers.
inequalitylab.world/en/global-ju...
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By opposing the 2% minimum wealth tax on billionaires, the French Senate has revealed just how out of touch it is with the issues of our time.
www.lemonde.fr/blog/piketty...
En s’opposant à l’impôt plancher de 2% sur les milliardaires, le Sénat vient de montrer à quel point il était déconnecté des enjeux de notre époque.
www.lemonde.fr/blog/piketty...
This study is the first in a series that will form the backbone of the #GlobalJustice Project, due to be released in June 2026.
inequalitylab.world/en/global-ju...
[8/8]
A BAU scenario is unsustainable.
But if we invest in human capital and infrastructure in the Global South, the world in 2100 could look radically different:
💶 Productivity converging to ~€100/hour
🕒 Less working hours for all
♀️ Drop in gender gaps
🌍 Labor shift away from high-pollution sectors
[7/8]
💰Women are also paid less than men – far less than previously thought.
When unpaid domestic work is factored in, the “real” gender pay gap in hourly earnings rises to 40–50% in high-income countries—double the conventional estimates of 10–20%.
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⚖️ Women work longer hours than men - but much of that work is unpaid and invisible.
Women provide fewer hours of economic labour than men, but significantly more hours of (unpaid) domestic labour, particularly in low- and middle-income countries.
[5/8]
📈A steady rise in productivity has accompanied the long-term global reduction in working hours.
At the global level, hourly productivity (net domestic product per work hour) rose from 0.7€ in 1800 to 16€ in 2025 (PPP, 2025 €).
[4/8]
This graph shows the long-run decline in average economic labour hours per workers between 1800 and 2020.
📉 Over two centuries, global work hours have fallen significantly (-34%), from 3,200 hours (≈ 60-65 hours per week all year long) to 2,100 hours (≈ 40 hours per week including two weeks in paid vacation).
This happened through collective mobilizations, changing institutions and social norms.
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📊 This study draws on harmonized historical series on labour hours by gender, employment status and sector — covering 40+ countries from 1800 to today.
Based on these historical trends, we outline a potential path to a high-productivity, high-leisure future by the year 2100.
[2/8]
Work time reduction and gender equality should accelerate their historical trajectory in the 21st century.
🧵A thread on a study with @marie-andreescu.bsky.social, R. Loubes & A.S Robilliard [1/8]
wid.world/news-article...
We urgently need structural reforms to the international system - e.g.:
🔹 better terms of exchange for developing countries;
🔹 a global clearing union (in the spirit of Keynes 1943);
🔹 an international reserve currency;
🔹 major reforms of the governance of IMF and other post-war institutions 8/8
