New research, published in the journal Nature and co-authored by a UW School of Environmental and Forest Sciences Ph.D. graduate, reports that 24 percent more of the world’s population is exposed to flooding since 2000.

Catherine Kuhn, who graduated from SEFS in spring 2021, assisted in gathering the direct satellite observations of floods to inform the research. The percentage increase is 10 times higher than scientists previously thought, and it has been caused by increased flooding and population migration.

Other key findings of the new study include, according to the University of Michigan:

• 58 million to 86 million people moved into observed flood regions between 2000-15, a 20%-24% increase in the proportion of the world’s population exposed to floods.
• 2.23 million square kilometers (~861,000 square miles) were flooded between 2000-2018, affecting between 255 million and 290 million people.
• By 2030, the Cloud to Street model estimates that climate and demographic 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 proportion of 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.
• Nearly 90% of flood events occurred in South and Southeast Asia, with the large basins (Indus, Ganges-Brahmaputra, Mekong) having the largest absolute numbers of people exposed and increased proportions of population exposed to inundation.
• The satellite data also uncovered previously unidentified increases in flood exposure in southern Asia, southern Latin America and the Middle East.

Read the Nature article here.