An increasing proportion of the world’s population is exposed to floods, according to new research published by Willis Research Network partner Cloud to Street.
The research revealed that the share of the global population exposed to floods has grown by 24% since the start of the millennium – a tenfold difference from what scientists previously estimated. Growing exposure and a rising number of flood events are driving the increase, the report said.
The partnership between Cloud to Street and the Willis Research Network works to address the insurance gap in the developing world, where 90% of economic losses from disasters are uninsured, putting vulnerable households at greater risk and slowing recovery efforts after disasters.
Most modern flood maps rely on modelling that simulates floods based on ground data like elevation, rainfall and ground sensors, Willis Towers Watson said. Those models are time-intensive and can have significant limitations, sometimes completely missing flood events in regions not historically prone to flooding. That leads to a large coverage gap and low flood insurance penetration globally.
Cloud to Street’s Global Flood Database, in contrast to other models, relies on satellite observations of actual flooding over the past two decades. That allows additional analyses of the scope, impact and trends of recent flooding, Willis Towers Watson said.
“More people and more assets are impacted by flooding than any other climate-fuelled disaster,” said Bessie Schwarz, co-founder and CEO of Cloud to Street. “The Global Flood Database will help insurers understand the changing nature of flood risk and offer more competitive insurance coverage. We are proud to enable governments and insurers to protect millions of people and billions in assets they have never been able to before.”
“The collaboration between Cloud to Street and the Willis Research Network is already delivering beyond our expectations, particularly in the research and development of tools to better understand flood risk and mitigate the economic impact of flooding for communities throughout the world,” said Simon Young, senior director at Willis Towers Watson’s Climate Resilience Hub. “Alongside our Willis Re and Alternative Risk Transfer units, the Climate and Resilience Hub is also creating innovative parametric solutions building on this rapidly evolving flood mapping technology.”
The report looked at daily satellite imagery to estimate the extent of flooding and the number of people exposed to more than 900 large flood events between 2000 and 2018. It found that between 225 million and 290 million people were directly impacted, and that between 2000 and 2015, the number of people living in these flood locations spiked by 58 million to 86 million.
Other findings included:
- By 2030, the model estimates that climate and geographic change will add 25 new countries to the 32 already experiencing increasing floods
- Despite representing less than 2% of floods, dam breaks had the highest increased incidence (177%) in the proportion of the population exposed
- Population growth in flooded areas is driven by people moving into flood-prone areas and economic development in those regions. Vulnerable populations often have no choice but to settle in flood zones, the research found
- Nearly 90% of flood events occurred in south and southeast Asia, with the large basins in the regions (Indus, Ganges-Brahmaputra and Mekong) having the largest absolute numbers of people exposed and increased proportions of populations exposed to floods
- Satellite data also revealed previously unidentified increases in flood exposure in southern Asia, southern Latin America and the Middle East.