Climate change made Harvey rainfall 15 percent more intense

December 14, 2017 by Jade Boyd, Rice University
Climate change made Harvey rainfall 15 percent more intense
Hurricane Harvey over the Gulf of Mexico Aug. 24. Credit: NASA

A team of scientists from World Weather Attribution, including researchers from Rice University and other institutions in the United States and Europe, have found that human-caused climate change made the record rainfall that fell over Houston during Hurricane Harvey roughly three times more likely and 15 percent more intense.

The study is available online in Environmental Research Letters.

Sebastian's co-authors included Dutch researchers from both the Royal Netherlands Meteorological Institute (KNMI) and the Red Cross Red Crescent Climate Centre in The Hague, Netherlands, and English and U.S. researchers from the University of Oxford, Princeton University and Princeton-based Climate Central. The team is part of World Weather Attribution, an international effort to analyze and communicate the possible influence of change on extreme weather events, such as extreme rainfall, heat waves and droughts. SSPEED is not affiliated with World Weather Attribution.

Sebastian has spent a decade studying urban flooding and flood risks in Houston, first as a doctoral student at Rice and later as a research associate at SSPEED. She was completing a one-year visiting appointment at Delft University of Technology in the Netherlands when Harvey struck Houston, and she was asked to participate in the World Weather Attribution study by lead author Geert Jan van Oldenborgh, senior researcher at KNMI, and Maarten van Aalst, director of the Red Cross Red Crescent Climate Centre.

Van Oldenborgh said, "This multimethod analysis, drawing upon both observed rainfall data and high-resolution climate models, confirms that heavy rainfall events are increasing substantially across the Gulf Coast region because of human interference with our climate system."

Houston flooding from Hurricane Harvey. Credit: Rice University

Harvey made landfall Aug. 25 near Corpus Christi, Texas, as a Category 4 hurricane and stalled. As a tropical storm, it dropped more than 30 inches of rain on Southeast Texas and caused record catastrophic flooding in Houston and the surrounding region. In east Harris County, a record 51.89 inches of rain—the highest storm total in U.S. history—was recorded over the six-day period from Aug. 25 to 30. During the first three days of the storm, 41.07 inches fell over Baytown.

For a specific location like Houston, the study found that the maximum observed rainfall is still extremely rare in today's climate – less than a one-in-9,000-year event. However, the chances of seeing this much rain over a three-day period anywhere over the entire Gulf Coast region are much higher, but still small—less than once every 100 years.

"These results make a clear case for why information should be incorporated into any plans for future improvements to Houston's flood infrastructure," Sebastian said. "The past is no longer an accurate predictor of present or future flood-related risks."

Due to global warming, global temperatures in today's climate are about 1.8 degrees Fahrenheit higher than pre-industrial temperatures, the researchers said. They estimated that even if Earth met the global targets set by the Paris Agreement of limiting warming to 3.6 degrees Fahrenheit, an event like Harvey will see a further increase of about a factor of three in probability.

"But if we miss those targets, the increase in frequency and intensity could be much higher," said study co-author Karin van der Wiel, a postdoctoral researcher at KNMI.

"Although the rainfall levels from Harvey are extremely rare, additional factors, such as rapid population growth, urban growth policies and aging water-management infrastructure, further exacerbated the ultimate impacts of this storm," van Aalst said. "Damage from storms like Harvey, Ike in 2008 and the Tax Day Flood of 2016 illustrate the importance of managing exposure and vulnerability when reducing the level of flood impacts in Houston."

Explore further: Studies: Warming made Harvey's deluge 3 times more likely

More information: Geert Jan van Oldenborgh et al. Attribution of extreme rainfall from Hurricane Harvey, August 2017, Environmental Research Letters (2017). DOI: 10.1088/1748-9326/aa9ef2

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12 comments

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SamB
1.3 / 5 (12) Dec 14, 2017
human-caused climate change? How about 'naturally caused climate change' or maybe just a weather anomaly?
Pretty bold to suggest that humans had something to do with a rain storm without proof.
leetennant
5 / 5 (14) Dec 14, 2017
human-caused climate change? How about 'naturally caused climate change' or maybe just a weather anomaly?
Pretty bold to suggest that humans had something to do with a rain storm without proof.


In breathless anticipation of what SamB would accept as "proof".
rodkeh
1.3 / 5 (12) Dec 15, 2017
human-caused climate change? How about 'naturally caused climate change' or maybe just a weather anomaly?
Pretty bold to suggest that humans had something to do with a rain storm without proof.


The AGW frauds don't need proof, they have consensus!
Maggnus
4.7 / 5 (12) Dec 15, 2017
human-caused climate change? How about 'naturally caused climate change' or maybe just a weather anomaly?
Pretty bold to suggest that humans had something to do with a rain storm without proof.


The AGW frauds don't need proof, they have consensus!

Consensus among scientists is proof dumdum..
Anonym
1.3 / 5 (13) Dec 16, 2017
Consensus among scientists is evidence of delusion, or collusion. Nothing in real science is deterministic, as Einstein noted 100 years ago: "As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality. "

The (19th century) idea that "climate science" can determine anything with certainty --- let alone climate's causative relationship to weather --- is as fundamentally flawed as the idea that "normal weather" exists. Normality is not reality; reality is not normative. So, no, it's not possible to quantify how much (15% no less!) the weather events of the past year might have been exacerbated by "climate change." You've got to be a real scientific dumdum (or a grant recipient) to claim it could be. But then, these are the same folks who blithely posit a "global average temperature" that can be determined to a decimal place!
Shootist
1 / 5 (9) Dec 16, 2017
The Sun is blank and dimming

https://wattsupwi...dimming/

The ice returns.
leetennant
5 / 5 (12) Dec 16, 2017
Consensus among scientists is evidence of delusion, or collusion. Nothing in real science is deterministic, as Einstein noted 100 years ago: "As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality. "


This is why I don't take planes or drive a car. Who knows when all this "science" will stop working?
Pumastar
5 / 5 (7) Dec 17, 2017
Consensus among scientists is evidence of delusion, or collusion. Nothing in real science is deterministic, as Einstein noted 100 years ago: "As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality. "

The (19th century) idea that "climate science" can determine anything with certainty --- let alone climate's c......

Your entire argument against climate change is delusional, You are a fraud, a lier, a propogandist for big oil because guess what all you care about is cheap money nothing more nothing less, the more oil sells, the more money you get, a cheap life for a shallow mind, not caring for the planet, not caring for it's future, only caring for your pathetic reasons to keep betraying yourself and everything else for money and greed.
Pumastar
5 / 5 (8) Dec 17, 2017
Consensus among scientists is evidence of delusion, or collusion
Consensus among scientists is an oxymoron, because scientists are supposed/payed for doubting. Whole the article title is nonsensical: how single hurricane (which had no predecessor) could indicate the climate change trend? And just by 15%? With compare to what?

The AGW alarmisms is very strong with this one and whole the article smells with fraud.


Opening your mouth smells of fraud with every word you type because that's all you have of proof about your delusional opinions, proven your own stupidity.
Pumastar
5 / 5 (8) Dec 17, 2017
The Sun is blank and dimming

https://wattsupwi...dimming/

The ice returns.


Thee only thing that is blank and dimming is the singularity between your ears. Not allowing for any constructive thinking nor understanding of science.
leetennant
5 / 5 (3) Dec 17, 2017
Main reason, why I'm getting so upset with "renewables" is just their increased demand for fossil fuel consumption. The actual greediness in on the side of "renewable" ideologists, who ignored (and indeed still ignore) the overunity and cold fusion research the most


They refuse to fund my unicorn research as well.
phprof
1 / 5 (1) Dec 18, 2017
Ah, yes, the old "if it pours it must climate change". One storm recorded in a tiny slice of history indicates total destruction. Watch climate change claims is depressing yet still more entertaining than the latest Star Wars film. Mostly because the Star Wars film is more realistic.

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