Up to 86 million people around the world, driven by economic necessity, moved into known flood regions during the same period
Amid a growing number of natural calamities including those involving water-related hazards, a new study reveals that the number of people exposed to flood-affected areas in Bangladesh has increased up to 14.3 million from 2000 to 2015.
The study, published in the British journal Nature on Wednesday, found that up to 86 million people around the world, driven by economic necessity, moved into known flood regions during the same period – a sharp 24% increase, reports The Washington Post.
The number is as much as 10 times higher than previously thought.
In late December last year, another study predicted that Bangladesh could see a seven-fold increase in climate migration, forcing 3 million people to migrate from their homes due to climate disasters by 2050.
"People die and lose their homes and livelihood," said Beth Tellman, a human-environmental geographer at the University of Arizona and lead author of the latest paper.
Tellman and her colleagues collected satellite imagery of 913 large flood events around the world, from 2000 and 2018. They then compared the population of the flooded areas between 2000 to 2015.
The change in population in flood zones varied by location, the latest study shows. In Russia and Sri Lanka, for instance, the number of people living in those areas shrank. Jamaica stayed about the same. However, in India, the number of flood-affected population increased up to 44.8 million.
A total of 2.23 million square kilometres -- more than the entire area of Greenland -- were flooded between 2000 and 2018, affecting up to 290 million people, AFP reports citing the research.
And it's only going to get worse.
Computer modelling produced estimates that climate change and shifting demographics would mean an additional 25 countries facing a high risk of flooding by 2030.
"We are able to map floods that are often unmapped or not typically represented in flood models, such as ice melt floods or dam breaks," Beth Tellman told AFP.
"Dam breaks are especially impactful. In these dam overflow or dam break events, up to 13 million people were impacted, across just these 13 events," she said.
Most flood events in the database unveiled on Wednesday were caused by excess rainfall, followed by storm surges, snow or ice melt, and dam breaks.
Tellman said the research showed the benefit of building in flood prevention measures to rural and urban planning.
"It is well known that spending $1 on disaster management and prevention can save up to $6 on relief and recovery efforts," she said.
In a linked comment, Brenden Jongman, an expert at the World Bank, said the flood database was a "crucial step" in understanding the link between climate change and socio-economic development.
"Satellite technology can track changes in protective ecosystems, similarly to its use in monitoring flooding and population changes," he said.
"However, even the best combination of infrastructure and nature-based approaches might be insufficient to deal with rising sea levels -- the only option for some communities will be to manage their retreat out of flood-prone areas," added Jongman.