Could tackling climate change and levelling inequality go hand in hand?

The world can raise income, reduce inequality and limit global warming, according to an ambitious roadmap presented this week by economists in France. Making the case for a radical transformation of economies and lifestyles, they call on rich countries to slow growth, phase out fossil fuels and tax the wealthiest to help poorer countries fund development and mitigate the effects of climate change.

Issued on: 06/06/2026 - 06:56

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Published on Thursday by the World Inequality Lab, the Global Justice Report presents a vision of a fairer world built within the planet's limits.

Based on data from around the world, it makes the case that it is possible to “reconcile planetary habitability with wellbeing for all” – but only by making deep structural changes. These include rapid decarbonisation, sharp reductions in wealth disparities and shifts in consumption patterns, particularly in high-income countries.

Co-directed by French economist Thomas Piketty, the Paris-based research group proposes a long-term scenario in which people around the world earn an average monthly income of around €5,000 by 2100. Currently, that figure ranges from roughly €290 in sub-Saharan Africa to nearly €4,600 in North America.

Under the plan, the share of global wealth held by the poorest half of the world’s population would rise from just 2 percent today to 30 percent, while the proportion held by billionaires would fall dramatically.

At the same time, the researchers argue, global warming could be limited to 1.8 degrees C – well below current trajectories that exceed 4 degrees.

They say this requires three major shifts: a rapid phase-out of fossil fuels in favour of renewable energy; rebalancing economic activity away from carbon-intensive sectors such as manufacturing and transport towards services like education and healthcare; and significant changes in diets, including cutting back on meat, to allow for large-scale reforestation.

The report also calls for a reduction in working hours in wealthier regions, alongside efforts to equalise incomes both within and between countries.

According to its authors, this would mean near-zero per capita growth in richer economies, while poorer regions would grow faster to close the gap.

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Taxing the rich

To finance the transition, the economists propose the creation of a “global justice fund”, initially funded through steep taxes on the wealthiest individuals – up to 20 percent annually on billionaires’ fortunes and income tax rates of up to 90 percent.

Over time, the fund would evolve into a global sovereign wealth mechanism, redistributing resources to support both social development and climate mitigation.

Spending from the fund would average more than 10 percent of global GDP annually between 2026 and 2060, with a strong focus on the Global South. Allocations would be tied to both social and environmental conditions, with priority given to health, education and energy transitions.

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With geopolitical tensions rising and international cooperation on the decline, the report's proposals may struggle to gain political traction.

The authors acknowledge resistance from wealthy individuals and governments is likely, and suggest that an initial coalition of willing countries could impose tariffs on non-participants.

They point to the dramatic reduction in inequality and working hours in 20th-century Europe as evidence that transformative change is possible.

The publication coincides with WIL's World Inequality Conference in Paris, where researchers and policymakers are set to debate the findings.

(with newswires)