Harvey-Like 'Biblical' Flooding Will Become More Common in Texas Because of Climate Change, Study Says

Pam Wright
Published: November 14, 2017

Texas faces a sixfold risk of hurricane flooding similar to that experienced during Hurricane Harvey in the next 25 years, a new study says, a risk that will again triple by the turn of the century thanks to global warming.

Published Monday in the Proceedings of the National Academy of Sciences, the study led by Massachusetts Institute of Technology meteorology professor and hurricane expert Kerry Emanuel found that extreme weather events with 20 inches or more of rain could become far more common over Houston and other parts of Texas in the decades to come. 

According to Emanuel, the chances of "biblical" amounts of rain totaling 20 inches or more falling over Texas from 1981 to 2000 were only 1 in 100 or less. Today, the probability is 6 in 100 and will likely grow to 18 in 100 by 2081.

Homes are surrounded by water from the flooded Brazos River in the aftermath of Hurricane Harvey Friday, Sept. 1, 2017, in Freeport, Texas.
(AP Photo/Charlie Riedel)

“You’re rolling the dice every year,” Kerry Emanuel, the Cecil and Ida Green Professor of Atmospheric Science and co-director of the Lorenz Center at MIT, said in a press release. “And we believe the odds of a flood like Harvey are changing.”

Emanuel said looking at historical data to determine when the next big flooding event will occur does little good thanks to climate change so he developed an innovative modeling technique that combined six global climate models used for future warming studies with hurricane models to draw his conclusions.

He used the model to plug in thousands and thousands of possible storm “seedlings” to see what would happen "under a future scenario in which the world’s climate changes as a result of unmitigated growth of greenhouse gas emissions."

“When you take a very, very rare, extreme rainfall event like Hurricane Harvey, and you shift the distribution of rain toward heavier amounts because of climate change, you get really big changes in the probability of those rare events,” Emanuel said in the MIT press release. “People have to understand that damage is usually caused by extreme events.”

John Nielsen-Gammon, the state's lead climatologist, told weather.com authorities this study confirms existing evidence for future heavy rainfall totals.

"In the case of heavy rain in general, we do already have lots of evidence from a lot of different angles," Nielsen-Gammon told weather.com in an email. "So I think it’s time to figure out the best way to allow for increases in frequency of heavy rains for both new construction and existing infrastructure."

Hurricane Harvey slammed into the Texas coast on Aug. 25, dropping 40-61 inches of rainfall in southeast Texas and southwest Louisiana as it hovered over the region for days. Numerous all-time U.S. tropical cyclone rain records were broken, including a two-day rainfall record by almost 8 inches at Houston's Hobby Airport, where 23.06 inches of rain fell Aug. 26-27.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

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