Floods endanger millions more people than previously estimated

Satellite imagery allowed researchers to gather previously unused information

A recent study has revealed that flooding is a threat to tens of millions more people than previously believed.

The journal Nature published the findings, revealing that up to 86 million more people are living in areas at danger of flooding around the world in 2015 than in 2020.

Researchers compiled what they call the most comprehensive data of observed floods ever developed, showing that more people have moved into areas where flooding is a major risk.

Because city planners and insurance companies have been using old datasets while developing policies, the risk of floods to people around the world may be significantly underestimated.

The study comes in the wake of severe floods in locations around the world. People in Germany, Belgium and China were killed when massive floods washed through towns, destroying homes and leaving motorists stranded in their cars.

Most of the flooding is a result of record-breaking rainfall, caused at least in part by climate change resulting in warmer air. Warm air holds more moisture, which results in heavier rainfall.

“It just really hits home, the urgency of the issue,” Colin Doyle, one of the authors of the new study told The Verge. “It’s urgent now that we deal with the resilience issue — both adapting to the events and also creating infrastructure as a safety net.”

The new research suggests that previous estimates detailing people who live in flood prone areas may be underestimating those numbers by 10 times the actual amount.

According to the study, people living in at-risk areas increased by 20 to 24 per cent since 2000.

Using satellite data allowed the researchers to include more types of floods than commonly used flood maps. Floods from snow melts, surface water floods, and dam failures were included in the group's study.

The research has found that the changes are not just indicative of better monitoring technology; it also reveals that human development is concentrating in areas that are at-risk of significant floods. Part of that worldwide trend is caused by poverty and a lack of access to less risky areas.

Brendan Jongman, a senior disaster risk management specialist with The World Bank who reviewed and wrote an accompanying piece to the study in Nature, told The Verge that for some communities the only solution to avoiding flood risks is to leave.

“The only option for some communities will be to manage their retreat out of flood-prone areas,” he said.