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Global cost of flooding to increase tenfold by 2030

Kashmiri people wade along a water-logged street in the Lal Chowk area of Srinagar, Kashmir following heavy floods.

DIBYANGSHU SARKAR/AFP/Getty Images

The numbers of people impacted by floods around the world could nearly triple to 54 million by 2030, driven in part by climate change and unchecked development, according to a new study.

The findings come from the Aquaduct Global Flood Analyzer, an interactive online flood-tracking tool developed by the World Resources Institute and four Dutch research organizations. They also found a similar trend with regard to the economic impact. It concluded that, today, economic activity to the tune of $96 billion in GDP is disrupted annually and that number could increase more than five times to $521 billion by 2030.

Poor countries in Asia would be hit hardest of the 170 countries analyzed. India is by far the most vulnerable with 4.8 million citizens put at risk by flood waters followed by Bangladesh, Vietnam, Pakistan and Indonesia.

"Our analysis shows a clear trend across the world. In lower- and middle-income countries, socioeconomic development is expected to concentrate more people, buildings, infrastructure and other assets in vulnerable regions," the researchers wrote in a blog post. "So, the developing world is expected to see more GDP exposed to flood risks in 2030, driven largely by socioeconomic change."

India, for example, faces more potential change in exposed GDP than any other country. Using a middle-of-the road scenario, the analysis estimates that $14 billion of GDP is already exposed annually with that number rising tenfold to $154 billion in 2030.

Researchers said the findings demonstrate that climate change will worsen flood risk as a result of rising sea levels. But they acknowledged the impacts of global warming would be dwarfed by socioeconomic growth, in particular due to the concentrated growth of Southeast Asia's megacities in flood-prone areas.

The only developed nation in the top 20 countries most vulnerable to flooding damage was the the United States. It came in 18th just behind Mexico and ahead of Sudan with 170,000 residents and $7 billion in GDP at risk. By 2030, that figure is expected to rise to 262,000 people and the GDP impact will more than double.

Breaking it down further, the analysis found that Florida ($890 million in lost GDP) was currently most at risk of all U.S. states. It was followed by Louisiana, California, Texas, Pennsylvania, Michigan, Illinois, Ohio, Indiana and New York.

By 2030, Florida continues to be the most at risk with as much as $5.5 billion in GDP at stake. But Oregon, Washington, Nevada and Tennessee replace Michigan, Indiana, New York and Ohio in the top 10.

The flood analyzer is the first publicly available online tool to assess current and future river flood risk - measuring the flood risk in dollar amount, including urban damage, affected GDP and affected population. Users can also look at flood risk by country, river basin or state and see the extent that floods will inundate any given place.

"Through this flood analyzer, the complex data really comes alive and becomes available to a nonspecialist audience far beyond the research arena," Hessel Winsemius, a researcher with Deltares, one of the four Dutch organizations, told reporters.

"It really transforms these data layers into actionable information informing users like governments and businesses which developments in their region are at risk," he said. "On the positive side, the user can actually see a first cut of how much benefit flood protection can provide in reducing this risk both at present day as well as in future in real economic dollars values. This really opens the door to actions, how to achieve this protection."

Erin Coughlan, a program officer at the International Federation of Red Cross and Red Crescent's Climate Center, said the tool would be a great benefit for the disaster response community, noting that almost half of the natural disasters in 2013 were floods.

"As the Red Cross, we often find ourselves in the place of firefighting and responding to these disasters after people have been surprised by the flooding event itself," Coughlan said. "A tool like this is incredibly useful to us because it does take into account how extremes can change in the future ... This powerful tool helps us focus our efforts on flood early warning systems or resilience building interventions in these flood-prone areas to reduce the actual damage which will ensure over time."

Alanna Simpson, a specialist at the Global Facility for Disaster Risk Reduction, also said the tool will be helpful for city planners and developers who are already thinking about projects decades into the future. With this tool in hand, Simpson said they can better plan evacuation routes, designate which areas are safe and those which are not and it could motivate them to consider smarter building design.

"We need to be able to show decision makers what Dhaka (Bangladesh) will look like in 50 years because they are building for the Dhaka of 50 years from today, not the Dhaka of today," she said. "We need to be able to help them visualize what their future looks like and, therefore, what action they can take today to mitigate the risk in the future."

  • Michael Casey

    Michael Casey covers the environment, science and technology for CBSNews.com