Who published the study on the growth of major cities?

The study was published by a team from the Complexity Science Hub (CSH) and ETH Zurich, including Andrea Musso, Diego Rybski, Dirk Helbing, and Frank Neffke, in the journal PNAS.

According to the new projection, how many people will live in megacities in 2100?

According to the calculations, around 38 percent of the world's population will live in major cities by 2100 — about 450 million fewer people than a simple continuation of current trends would suggest.

What practical significance does the study have for decision-makers?

According to Frank Neffke, the findings can serve as a basis for infrastructure planning, climate adaptation strategies, and forecasts of future economic growth.

Major Cities in 2100: Study Expects 450 Million Fewer People

Vienna, June 29, 2026

A study by the Complexity Science Hub (CSH) and ETH Zurich concludes that the growth of major cities through the year 2100 will be weaker than previous projections have assumed.

Between 1975 and 2025, the population in cities with more than one million inhabitants worldwide rose from around eleven to about 24 percent, report the researchers, including Andrea Musso, Diego Rybski, Dirk Helbing, and Frank Neffke. By the end of the century, this share is expected to grow to approximately 38 percent.

Economic Effects of Major Cities

The analysis, published in the journal PNAS, draws on satellite and registry data on urbanization in numerous countries between 1975 and 2025. Compared with a simple extrapolation of current trends, this means: 450 million fewer people than previously projected will live in megacities in 2100 — a difference of four percentage points.

New Study: Major Cities Will Grow Significantly Slower Than Expected by 2100

Economic Effects of Major Cities

Health-Related Downsides

Regional Differences in Growth

Implications for Planning and Policy

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