One in three people globally live with threat of floods

More than 2.7 billion people globally live in areas vulnerable to coastal or inland flooding, research by risk analysis group Moody’s has found.

The proportion of people exposed to flood risk has also steadily increased since 1975, driven in part by climate change and urbanisation, the research said. The Middle East and South Asia, researched together as one region, was found to be at most risk for floods.

The Moody’s RMS study was published as central Europe reels from floods that caused billions of dollars worth of damage and the US recovers from Hurricane Helene, which spread destruction far inland.

The report took current population numbers and looked at projections for 10, 30, 50 and 100 years. More than one third of the global population live in areas vulnerable to inland or coastal flooding, Moody’s said.

Of those, 2.3 billion people are at risk from more than 10cm of inland flooding according to the 100-year forecast, and 240 million from coastal flooding.

“Flooding is a pervasive and recurrent natural hazard that has far-reaching consequences for both human communities and the environment,” Moody’s said.

“As flooding continues to pose a growing threat, understanding the populations most vulnerable to its effects is paramount for effective disaster management and mitigation efforts.”

More than 70 per cent of the people exposed to coastal flooding risks over the next 100 years are in five countries – India, China, Pakistan, Bangladesh and Indonesia.

“South Asia stands out as the most flood-prone region, with almost 40 per cent of its inhabitants susceptible to inland flooding at the 100-year return period level.” Moody's said. “South Asia also tops the list when it comes to coastal flooding with just over five per cent of its population at risk at the same return period.”

In the 100-year forecast, 25 per cent of the global population exposed to inland floods will be protected by flood defences, and 36 per cent for coastal floods.

Hurricane Helene showed the risk of flooding from major storms hundreds of kilometres away from the point where they first strike land.

Hurricane Helene leaves path of destruction – in pictures

Despite the storm coming ashore in Florida and travelling across all of Georgia – over land that slowed winds speeds – it still hit North Carolina with heavy rain and strong, but not hurricane strength, winds.

The storm dumped more than 35cm of rain over three days on to the western North Carolina, transforming mountainsides into mudslides and creeks into torrents.

Insured losses from floods in central Europe – areas of the Czech Republic, Austria, Poland, Slovakia, Hungary, Germany, and Italy – are could reach $3.9 billion, Moody's estimates. The widespread flooding was triggered by heavy and persistent rainfall which exceeded 40cm in places.