Scientific Confirmation Pending, But 4th Of July Floods Had Global Warming's Fingerprints All Over Them
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It will take some time for scientists to do proper “attribution” studies here, to say for instance how much extra rain they can blame on climate change. But generally speaking, this disaster has climate change’s marks all over it — a perfect storm of conspiring phenomena, both in the atmosphere and on the ground. “To people who are still skeptical that the climate crisis is real, there’s such a clear signal and fingerprint of climate change in this type of event,” said Jennifer Francis, senior scientist at the Woodwell Climate Research Center.
This tragedy actually started hundreds of miles to the southeast, out at sea. As the planet has warmed, the gulf has gotten several degrees Fahrenheit hotter. That’s turned it into a giant puddle of fuel for hurricanes barreling toward the Gulf Coast, since those storms feed on warm seawater. Even when a hurricane isn’t brewing, the gulf is sending more moisture into the atmosphere — think about how your bathroom mirror fogs up when you draw a hot bath. This pushes wet, unstable air higher and higher into the atmosphere, condensing into clouds. As these systems release heat, they grow even more unstable, creating a towering thundercloud that can drop extreme amounts of rainfall. Indeed, preceding the floods, the amount of moisture above Texas was at or above the all-time record for July, according to Swain. “That is fairly extraordinary, in the sense that this is a place that experiences very moist air this time of year,” Swain said.
That meant the system both had the requisite moisture for torrential rainfall, plus the instability that creates the thunderstorms that make that rain fall very quickly. This storm was dumping 2 to 4 inches of rain an hour, and it was moving very slowly, so it essentially stalled over the landscape — a gigantic atmospheric fire hose soaking Central Texas.
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This is exactly the kind of precipitation event that’s increasing fastest in a warming climate, Swain added. In California, for instance, alternating periods of extremely wet conditions and extremely dry ones are creating “weather whiplash.” As the world’s bodies of water heat up, more moisture can evaporate into the atmosphere. And due to some basic physics, the warmer it gets, the more moisture the atmosphere can hold, so there’s more potential for heavier rainfall. “The Gulf of Mexico has been going through several marine heat waves recently, and so it’s just adding that much more heat to the atmosphere, loading it up for more extreme rainfall events,” said Brett Anderson, senior meteorologist at AccuWeather. “A lot of these places, 1-in-100-year floods may be becoming more like 1-in-50, even 1-in-10.” AccuWeather’s preliminary estimate puts the economic damage of the flooding at between $18 billion and $22 billion.
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https://grist.org/climate/the-science-behind-texas-catastrophic-floods/
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