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More People Live in Flood Zones Than Previously Thought

New research maps how urban development and migration patterns are exposing an increasing proportion of the world’s population to flood risk. 

Aerial view of a flooded crossroad on July 21, 2021 in Zhengzhou, Henan Province of China. The heavy rain across Henan Province began on July 16, with Zhengzhou being one of the hardest-hit areas. 

Aerial view of a flooded crossroad on July 21, 2021 in Zhengzhou, Henan Province of China. The heavy rain across Henan Province began on July 16, with Zhengzhou being one of the hardest-hit areas. 

Photographer: Jiao Xiaoxiang/VCG via Getty Images

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Even as climate change makes flooding more common and more deadly, the proportion of the world’s population living in flood zones has increased exponentially. And it will keep growing if cities continue to develop in risky areas, according to new research published Wednesday in the journal Nature. 

From 2000 to 2015, the number of people living in flood-prone areas increased by an estimated 58 million to 86 million, the study found. That marks a 24% increase since 2000 in the proportion of the world population exposed to floods — 10 times higher than what’s been projected by traditional predictive models that rely on terrain elevation data but don’t typically account for urban development and global migration.