Economic growth rates in some parts of the world could shrink by as much as 6% by 2050 as water supplies dry up from climate change, according to a report released Tuesday by the World Bank.

“Growing populations, rising incomes and expanding cities will converge upon a world where the demand for water rises exponentially, while supply becomes more erratic and uncertain,” warns the report entitled High and Dry: Climate Change, Water and the Economy.

The regions at risk of “sustained negative growth” are northern Africa, the Middle East, India and China, according to the report.

It notes that efficient water management could help mitigate or even offset the impact. But if nothing is done, areas where water is plentiful, like Central Africa and East Asia, will see supplies dwindle, while countries that are already water-scarce will suffer even more.

No matter where scarcity hits, the report says, strained water supplies will hurt the poor the most. In addition to slowing economic growth, water scarcity also threatens to drive migration and ignite civil conflict.

Write to Mark Rivett-Carnac at mark.rivett-carnac@timeasia.com.