The number of people living in flood-threatened areas is increasing worldwide. And according to researchers, this development will only intensify.
New York / Washington – The number of people in flood-prone areas is growing particularly rapidly worldwide. This is shown by a study in the journal “Nature”, which combines satellite images with population data.
Since the turn of the millennium, their share of the total population has grown by almost a quarter and will continue to increase until 2030, according to the forecast of the scientists.
Floods are among the most frequent and devastating natural disasters, as the floods in North Rhine-Westphalia and Rhineland-Palatinate demonstrated. Just recently, scientists “Science Advances” had warned of an increasing number of extreme weather events worldwide as a result of climate change, while a study recently published in the journal “Geophysical Research Letters” predicted that Europe too will have to prepare for increased storms in summer and autumn in the future. This makes it all the more important to record flood risks as precisely as possible. A team led by geographer Beth Tellman from Columbia University in New York used high-precision, daily satellite images to develop the “Global Flood Database”: a database that shows the footprint of 913 major floods that occurred between 2000 and 2018 .
Population in endangered areas is growing
For each event, the researchers estimated the flooded area and the number of people living there by using geospatial data sets of population density for different years. The analysis of a total of 12,719 images revealed that between 255 and 290 million people from 2.23 million square kilometers were directly affected by flooding during the study period.
The scientists also found that the population in flood-prone areas had increased by an estimated 34.1 percent, or 58 to 86 million people, during the study period. In contrast, the world population grew by only 18.6 percent in the same period. The researchers assume that this trend will intensify by 2030: in particular for 57 countries, including North America, Central Asia and Central Africa, they forecast a significant increase in the proportion of the population exposed to flooding. The reasons they give include the increasing sealing of the soil and climate change. In addition, the population is growing in some regions, particularly in areas at risk of flooding.
Commenting on the study, Brenden Jongman, World Bank specialist in disaster risk management, praised the authors’ approach: They mapped an unprecedented number of validated events, including various types of floods that had not been taken into account in previous analyzes, including those caused by dam bursts, local ones Precipitation events and snowmelt: “As a result, the authors’ estimate of the increase in the percentage of people affected by floods worldwide is ten times higher than in previous estimates.”
The trends identified would be daunting, but they also contain good news: “The ability to deal with and respond to floods has increased over time.” Jongman identifies many factors that could both prevent and mitigate floods . This includes investments in flood protection, drainage infrastructure and early warning systems together with improved building standards, programs to support people affected by floods and, finally, a reinforced policy to implement risk-oriented land use planning. For such measures, however, robust models are necessary, according to Jongman: “The improved global risk estimates by Tellman and colleagues are a decisive step in this direction.” Dpa
