More people moved into high flood zones, exposing larger populations to water disasters: World Bank

Most countries, especially in East Asia, saw more settlements in regular flood zones, ultra-high flood zones than in dry areas
Photo: iStock
Photo: iStock

Human settlement in the world’s riskiest flood zones increased 122 per cent since 1985, making a lot more people vulnerable to water disasters from climate change, according to a study by the World Bank. 

The growth was 80 per cent for the safest areas, the report published in Nature journal October 4, 2023 stated. The study authors looked at settlement extent and expansion using satellites instead of population. The world’s overall built-up regions grew 85 per cent from 1985 to 2015.

“People are on a search for better lives and better jobs and then sort of get stuck in bad lands because that’s what they can afford,” said study co-author Stephane Hallegatte, as quoted by international news agency Associated Press (AP). “They know it’s dangerous when they arrive.” Hallegate is a World Bank senior climate adviser and expert on disaster economics.

As per the study findings, the problem is driven by middle- and low-income countries. “Richer countries like the United States and parts of Europe are seeing more growth in safer areas than flood-prone ones,” it highlighted.

China and Vietnam both saw their settlement extent more than tripling in the past 30 years, increasing far more than their dry land areas, the authors noted.

The study also pointed out: 

  • Most countries, especially in East Asia, saw more settlements in regular flood zones and ultra-high flood zones than in dry areas 
  • Libya, which suffered from devastating flooding last month, had an 83 per cent increase in settlement extent in the worst flood zones 
  • Pakistan, also affected by catastrophic flooding both last year and this year, had an 89 per cent increase

“What’s happening is that as a nation grows a bit wealthier, there’s a change from rural to urban and people leave the country to go to cities, which are often near waterways that flood in places,” said the study lead author Jun Rentschler, as quoted by AP. Rentschler is a World Bank economist.

“What you would expect is that initially you settle in a safe space, but as the city expands, it’s more likely to grow into areas that it previously avoided, flood zones for instance.”

Reportedly, the study researchers go on to raise the issue: “Is it cheaper to fortify these dangerous areas or better to move people out?”

As per the study report, Dar es Salaam, Tanzania, is a poster city for this problem. “It boomed from a fishing village of about 83,000 people in 1950 to more than seven million people now, according to World Population Review,” the study authors told AP.

On the other hand, the United States saw dry settlements increase 76 per cent and the highest flood settlements go up only 46 per cent, the report pointed out. Other countries with more dry settlements than ultra-wet include France, Sweden, Austria, Finland, Japan, Canada and India, it also stated.

Populations growing into flood zones doesn’t mean that climate change isn’t a major problem, the study authors were further quoted as saying. “In fact, they are intertwined,” Rentschler added.

“And in both cases, poorer countries could keep from falling into a trap middle-income countries are doing now,” Hallegatte was quoted as saying by AP. With urban development, smart planning can prevent some of those moving into the riskiest places, he added.

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