There's something about the mid-to-late summer that tends to bring extreme weather events of enormous magnitude. There was the 2010 Russian heat wave and Pakistan floods, which together killed tens of thousands, and the 2003 European heat wave. Of course, this year, there's the unprecedented Texas deluge from Hurricane Harvey.
While Harvey has garnered most of the attention in the U.S. -- and rightly so, given the extraordinary scope and scale of the disaster, a wider view of the world reveals that Houston is not alone. Flooding disasters have been taking place in large cities and rural towns across Asia and Africa.
These floods dwarf Texas' woes when it comes to the number of lives affected, and they also offer a foreboding glimpse into our future climate. Extreme events, including precipitation extremes, are only expected to worsen in coming decades, so we'd better start building communities that are resilient enough to handle the onslaught of water.
These floods carry with them a message for humanity that we are increasingly pushing the climate and population centers beyond their limits, and suffering blowback as a result. One of the more well-established findings from climate change attribution studies is that human-caused global warming is raising the risk of heavy rainfall events across much of the world.
Shane Hubbard, a meteorology researcher at the University of Wisconsin studying Harvey's floods, says there has been an observed shift in how places are getting their rain. Instead of coming in many lighter rainfall events, we're getting more rain in short, intense bursts, he said.
“We’re getting our rainfall quicker and in a fewer set of storms,” Hubbard said.
When these heavy rains fall on sprawling, low-lying cities, such as Houston, or in densely populated developing countries such as India, death and destruction can result.
Hubbard's work shows that Harvey was the most extreme rainstorm on record in the U.S. in terms of its magnitude and scope. He determined that an area just larger than the state of West Virginia received at least 20 inches of rain, and an area about the size of Massachusetts and Rhode Island combined was inundated with 30 inches or more of rain.
“It’s not even close, it’s not even in the same ballpark," as other rainfall events, Hubbard said of Harvey.
"This is an event that’s way on the end of the spectrum. We’re on the end of the curve,” he said, calling it a 1,000-year rainstorm, meaning it has about a 0.1 percent chance of occurring in any given year.
Beyond Houston, one need not scan headlines very far to come across stories of deadly flooding elsewhere. The worst monsoon rains in years slammed parts of India, Pakistan, Bangladesh, and Nepal during the past 2 weeks, killing at least 1,200 and affecting the lives of more than 40 million, according to news reports.
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Severe flooding brought the city of Mumbai to a standstill for days in late August, killing more than a dozen. As is the case in Houston, development patterns, such as the paving over of mangrove swamps and other naturally-occurring drainage systems, worsened the flooding there.
In Nepal, thousands have lost their homes and dozens have died in monsoon-related rains. Elephants were enlisted to help rescue people. And in Bangladesh, a low-lying, vulnerable nation under assault from global warming-related sea level rise, about one-third of the land is under water from intense monsoon rainfall, according to the New York Times.
Then there's the flooding in Niger, a developing country that typically sees heavy rains at this time of year. This rainy season has been unusually destructive, with more than 40 killed and thousands displaced.
These floods cap off another extreme summer.
It's not a coincidence that these are occurring at a time when planet-warming greenhouse gases in the atmosphere are at an all-time high during human history, and when we're settling in increasingly crowded megacities with inadequate infrastructure.
While the flood events in Houston, Asia, and Africa during the past few weeks cannot be directly connected, they all send the same blaring message: We're slipping blindly into the era of climate change consequences. The sooner we realize that, the better.
