World's Biggest Weather Threat Isn't Hurricanes

Big storms steal the headlines in the U.S., but flooding puts far more people at risk. And it's going to get worse.

It's time to prepare ourselves.

Photographer: Ye Aung Thu/AFP/Getty Images

The National Oceanic and Atmospheric Administration this week released its list of climate events that have had the greatest economic impact on the U.S. from 1980 to 2017. At $306 billion, last year’s sustained costs due to weather disasters was 43 percent higher than in 2005, which had hurricanes Katrina, Rita and Wilma. Hurricane Harvey alone caused $125 billion in damage, only $1 billion less than all of 2012 (which included Hurricane Sandy).

A Record, and It's Not Even Close

Annual cost of billion-dollar weather disasters in the U.S.*

Source: National Oceanic and Atmospheric Administration


Tropical cyclones are the most damaging weather events that threaten the U.S. Since 1980, weather disasters have incurred just over $1.5 trillion in costs, with hurricanes making up 55 percent, followed far behind by droughts and then severe storms. Flooding is a distant fourth, followed by cold and fires.

First Hurricanes, Then Droughts

Billion-dollar weather disasters by type since 1980, as a percent of total damages

Source: National Oceanic and Atmospheric Administration

Globally, however, flooding is an enormous weather risk. New research from the Potsdam Institute for Climate Impact Research suggests that we must start taking it far more seriously -- not just in terms of costs, but also in terms of the enormous risk to populations. In its analysis, just over 100 million people are affected by river floods today. Double that many will be affected by 2040, according to the institute’s calculations.

Today, the top 10 countries most at risk of river flooding make up about two-thirds of the global total population at risk of floods -- and eight of the 10 countries are in Asia, and two in Africa. Brazil has the largest population exposed to river floods in the Americas, and Ukraine the largest in Europe. China, with nearly 24 million people exposed to river floods, is the wealthiest country in the top 10. China is an “upper middle income economy,” according to the World Bank; each of the others is a lower-middle-income or low-income country. But China also has immense engineering resources to mitigate what might come.

Asia's Huge Threat

Number of people currently facing risk of river flooding, by country

Source: Potsdam Institute for Climate Impact Research, 2018

By 2040, those top-10 countries will have more than twice as many people at risk of river flooding as now -- amounting to more than 70 percent of the at-risk global population. India, sadly, will leap from seventh to the second-largest population at risk of such flooding.

A Bleak Future

Number of people facing risk of river flooding in 2040

Source: Potsdam Institute for Climate Impact Research, 2018

Hurricanes may dominate the news in the U.S., and for good reason, but hundreds of millions of people around the world live in countries that remain ill-equipped to deal with flooding, which remains a far greater threat to their populations and economies.

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