From RICE UNIVERSITY
World Weather Attribution study: Climate change made Harvey 3 times more likely
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.
“The takeaway from this paper is that Harvey was more intense because of today’s climate, and storms like Harvey are more likely in today’s climate,” said study co-author Antonia Sebastian, a postdoctoral research associate with Rice’s Severe Storm Prediction, Education and Evacuation from Disasters (SSPEED) Center. “It highlights the need to consider that our hazards are changing over time, and that we should be considering those changes in the design of our infrastructure.”
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 climate 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.”
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 climate change 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.”
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The paper: http://iopscience.iop.org/article/10.1088/1748-9326/aa9ef2/meta
Attribution of extreme rainfall from Hurricane Harvey, August 2017
Abstract
During August 25–30, 2017, Hurricane Harvey stalled over Texas and caused extreme precipitation, particularly over Houston and the surrounding area on August 26–28. This resulted in extensive flooding with over 80 fatalities and large economic costs. It was an extremely rare event: the return period of the highest observed three-day precipitation amount, 1043.4 mm 3dy−1 at Baytown, is more than 9000 years (97.5% one-sided confidence interval) and return periods exceeded 1000 yr (750 mm 3dy−1) over a large area in the current climate. Observations since 1880 over the region show a clear positive trend in the intensity of extreme precipitation of between 12% and 22%, roughly two times the increase of the moisture holding capacity of the atmosphere expected for 1 °C warming according to the Clausius–Clapeyron (CC) relation. This would indicate that the moisture flux was increased by both the moisture content and stronger winds or updrafts driven by the heat of condensation of the moisture. We also analysed extreme rainfall in the Houston area in three ensembles of 25 km resolution models. The first also shows 2 × CC scaling, the second 1 × CC scaling and the third did not have a realistic representation of extreme rainfall on the Gulf Coast. Extrapolating these results to the 2017 event, we conclude that global warming made the precipitation about 15% (8%–19%) more intense, or equivalently made such an event three (1.5–5) times more likely. This analysis makes clear that extreme rainfall events along the Gulf Coast are on the rise. And while fortifying Houston to fully withstand the impact of an event as extreme as Hurricane Harvey may not be economically feasible, it is critical that information regarding the increasing risk of extreme rainfall events in general should be part of the discussion about future improvements to Houston’s flood protection system.
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The bullwhips are cracking! It MUST be Mankind’s Fault. Must, Must, Must…
+1
Would be much more believable if the number was 15.332%
Even more believable if the number was 0.000…01%
from The World Weather Attribution
Really. And what does the WWA … ALWAYS … attribute as the cause of all “extreme” weather events ? If the answer is ALWAYS Global Warming … then you know EXACTLY WHY this org. was formed. To shill for Global Warmism. Period. Meaning … they don’t DO science … they DO political policy.
bingo, note Heidi Cullen is an author of this paper
You don’t say, so how worse would it have been if Heidi’s dog didn’t eat all that global warming lost during the hiatus? hmmm tough question.
Heidi has stated patent falsehoods repeatedly.
She also testified before congress that Atlantic hurricanes out at sea increased in number (in rebuttal to Dr Spencer, but failed to mention monitoring captures more of those than in the past due to advances).
Cullen also says things completely contrary to the IPCC position, these loons do not like AR5 at all, not enough terror in it, same for SKS
kenji – Come on, they couldn’t very well attribute any “extreme” weather to natural variation, could they? I mean, really! They wouldn’t get any traction in the media, and their funding sources would dry up faster than you could say “perpetual drought”. Their docile peer reviewers might even find fault with their attribution methodology
And as for ignoring the fact that “unprecedented” weather events are not actually without precedent, well, the same argument applies. Best not to look at that possibility, who’s going to notice other than those darned skeptics?
As scientists, these people may be a bit deficient, but they do know how to run a profitable business.
So, we have a study that says that “storms like Harvey are more likely in today’s climate”.
And fact database that say that storms like Harvey are less numerous than in previous period.
Another instance of IPCC logic, by which less happening things are more likely…
“Storms like Harvey are more likely in today’s climate.”
So…where were they the last 10 or years?
They were waiting for the headlines to change from “Global Warming” to “Climate Change”?
But that already happened 10 or so years ago.
Hmmm…., well, this is all political science. Maybe bureaucratic red tape slowed them down?
How can these storms become more likely when Texas was in a permanent drought just a few years ago. Maybe they should have asked Hayhoe to join their team.
I thought climate change made Harvey less predatory !
Might Harvey have been predatory whatever the weather?
I suggest this as a possibility, no more.
Auto
I think these “researchers” at Rice University are in the wrong business; they should start raising cattle. They seem to be excellent bull shippers.
Maybe the researchers did not know about the Cuba and Jamaica flooding rains, when carbon dioxide was lower…..
“Cuba got hammered by more than 100 inches of rain when Hurricane Flora sat over the island for four days in 1963. And even earlier, in 1909 before hurricanes were named, a storm dropped more than 96 inches of rain on Jamaica. In more recent history, Wilma dumped more than 62 inches of rain on Mexico in 2005 and Hurricane Mitch, blamed for killing more than 11,000 in Central America in 1998, soaked Nicaragua with more than 62 inches, according to records compiled by National Oceanic and Atmospheric Administration forecaster David Roth.”
http://www.miamiherald.com/news/weather/hurricane/article170512137.html
Maybe the researchers just hoped that nobody would fact-check their ludicrous claims – and unfortunately, in the case of far too many serving as “useful idiots,” they’re right.
The authors of this paper are all devout climate alarmists. One is doing so in a German weather forum is particularly special. So, strictly speaking, I do not believe the contents of this paper. It fits seamlessly into the tailor-made climate alert paper. Not to be confused with the Panama papers.
Hard to accept any results that claim more extreme hurricane activity after the lengthy period of
non-extreme hurricane activity. These claims seem to be relevant, if at all, to offshore storms
that sit and suck up sea watr andthen come ashore. Believe it or not, but a 15% increase in
precipitation is not much and occured in a very unusual storm scenario, which had the cane stalling, moving north and then reversing course and hitting the same spot. If the precipitation had been 15% less, does anyone believe that the results would have differed to any significant extent?
It is also true that you cannot assume that if changes had been present, everything ese would have remained the same. And , as I recall, the temps in the Gulf were higher than the norm and were not typical Gulf temps.
“The past is no longer a predictor of the future.”
No longer? Never was.
They dont really have any idea do they.
Funny, if I was to make a claim that “The Wrath of God over abortion and gay marriage made Hurricane Harvey 3 times as likely” I would be denounced as a bigoted extremist.
But there’s no real difference between that claim and the claim made by the climatista’s here. Neither one is falsifiable, and both rely on faith, not evidence.
Bingo!!
I knew the instant we had a busy hurricane season, the Eco-Fascists would tell everyone who’s listening that it is human activities that (a) caused it, (b) made it worse, or (c) all of the above. Looks like my “hypothesis” is not only testable but 100% accurate and verified!
If they want to BLAME Harvey et al from this most recent hurricane season on “global warming/climate change,” then they ALSO have to CREDIT “global warming/climate change” for the LONGEST PERIOD ON RECORD WITH NOT A SINGLE MAJOR HURRICANE HITTING THE U.S., which appears to fly in the face of these types of “worse and more frequent” BS claims, now doesn’t it?!
We STILL have not had a MAJOR hurricane hit in the recent decade or so..
Harvey was Cat2 at landfall.
So, we’ve had 5 CAT3(?) hurricanes landfall and cause major damages in 12 years. That’s 2 a year. 2005 had 4 of them, including the two worst, Katrina, and Wilma. Hurricanes are expensive, and getting more so because so many people live and rebuild in the worst areas for hurricane damage, mostly courtesy of the US government(taxpayers).
That kind of summarizes the solutions- don’t build in flood plains, don’t allow building that were total losses to rebuild on location at all, and start increasing flood insurance cost to at least break even over the next 10 or so years.
Hurricane Harvey barely was CAT 3 at landfall and dropped rapidly to a tropical storm, while still pulling moisture from the Gulf. The rainfall RATES for Harvey were nothing special. The major cause of the flooding was the storm stalled over the Houston watershed for three days, all the while dropping rain at typical hurricane rates around 2in/hr, 24in/day. The authors of this hit piece don’t even mention that Harvey stagnated in one area, well within reach of the coast to draw moisture to maintain the rainfall.
Abysmal science.
Just build a model of The Wrath of God over abortion and gay marriage, when an university employee, and it will work.
Besides, their claim IS falsifiable, and indeed is even proven wrong by the dataset.
It’s always handy when they have a computer model to fictionalize any result they choose to report. Science you say??
There’s more science in witch doctor rituals than in that precious bit of wankery.
wankery. That’s gone into my dictionary. Nice one.
Computer Climate Models: Witch Doctors are Cheaper
Cheaper, and more efficient. They DO useful advices, lest they be pushed out of business by one or the other competitor. They do not depend on public money, just on customers’, and those are demanding.
The climate changed around Houston from quite dry to very wet for several days and back to very dry. Ouch, fingers slapped for calling weather climate. Hmm didn’t weather use to be what defined climate? It seems that climate now defines weather and somehow imposes limits or excesses on it. Apparently, Harvey could not have happened if the climate hadn’t warmed a tiny bit. No point looking at data.
“… made the record rainfall that fell over Houston during Hurricane Harvey roughly three times more likely and 15 percent more intense …” … “The takeaway from this paper is that Harvey was more intense because of today’s climate, and storms like Harvey are more likely in today’s climate,”
Am I to understand “today’s climate” to mean 2017’s, but not ’16’s, ’15’s, ’14’s … ’08’s?
With this level of detailed attribution, they should now be able to assign a portion to George Bush and another portion to Rick Perry. After that they can assign a portion to all Ford F 150 owners or record and the BBQ place down the street.
No. Everyone knows it’s all Trump’s fault /s
If there’s a sitting Republican president, it’s his fault.
If there’s a sitting Democrat president, it’s the last Republican president’s fault.
;|
Right, but also the other way round. D and R are the same in that respect.
“We also analysed extreme rainfall in the Houston area in three ensembles of 25 km resolution models. The first also shows 2 × CC scaling, the second 1 × CC scaling and the third did not have a realistic representation of extreme rainfall on the Gulf Coast. Extrapolating these results to the 2017 event, we conclude…”
Is extrapolating models to reach a conclusion really reliable?
Three times?
I just ran the calculations through the calculator on my iPhone and came up with 2.795.
Harvey didn’t drop any more rain than is common with hurricanes…..the only thing that happened is a front blocked it and stalled it out…..and that’s just a coin toss
Since when did hurricanes become this susceptible to less than one degree?…
“”World Weather Attribution (WWA) is an international effort to analyze and communicate the possible influence of climate change on extreme weather events, such as storms, extreme rainfall, heat waves, cold spells, and droughts.””…..they are paid to find a global warming connection
More than that, they are paid to CREATE climate change/global warming connections, irrespective of reality.
Latitude
“Since when did hurricanes become this susceptible to less than one degree?…”
Since time immemorial.
The 50+ inches of rain in the small area was due to the cold front that came through and stopped harvey in its tracks. If the cold front had not come through the rain would have been dispursed over a much wider area resulting in rainfall in the 20-25 inch range over the 3 days.
Explain how Global Warming caused a strong cold front in the later part of august.
Oh come on now, you know “global warming” causes EVERYTHING, even things diametrically opposed to one another, the classic being “The children aren’t going to know what snow is” (when we were having winters with little snowfall) vs. “Heavier snowfalls are “consistent with” global warming” (when we started having winters where we were getting BURIED with snow). The story just adapts to whatever “bad” weather event is currently “in the news,” logic, scientific validity, and previous bogus claims be damned.
“Global Warming” has even caused this!
Awarded TOP 100 Status
“…the world’s most viewed climate website”
– Fred Pearce The Climate Files:
The Battle for the Truth about Global Warming
“…invaluable” – Steven F. Hayward, The Weekly Standard
“…changed the world and is one of the most influential resources on global warming. – Jonathon Moseley, American Thinker
“…flashy (apparently widely distributed)”- Michael E. Mann
Not only do you have to explain how global warming caused a cold front, but I recall the temperature in the Gulf was below normal, and even below what was thought to be necessary for hurricane formation. How can global warming explain that? I know it is much more complicated than that, but the simplistic attribution to global warming doesn’t make sense to me, even though they used computers and complicated models.
Agree. Doubtful that global warming is the reason Hurricane Harvey stalled over the Houston area. Texas state climatologist thought climate change over the last 100 years may have caused Harvey to drop 7% more rain in the Houston area then it would have a century ago. So rain fall amounts would have been 30 to 48 inches instead of 33 to 51 inches. You get 2.5 to 4 feet of rain in a relatively flat area in 3 to 4 days, it’s going to flood. Ray Charles could see that (or wade thru it.)
But that cold front was a result of Catastrophic Anthropogenic Global Warming. You have to believe.
Observations while real are not as real as models.
“High resolution climate models”
This is a relative term, high resolution compared to what? More obfuscation.
The models don’t have the resolution needed nor can they model clouds which happen to carry a bit of rain in them now and then 😀
Experimental sciences for me, everything else tends to be utter crap
Here they ran a model a number of times with changed parameters and called each run an “experiment”. Does that count?
“…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…”
Notably absent is the mention of Houston being founded on swampland.
Also notably absent is any mention of flooding in 1929, 1935, 1957 (Hurricane Audrey), 1961 (Hurricane Carla), 1983 (Hurricane Alicia), and 2001 (Tropical Storm Allison). Why only go back to 2008? What is the attribution of the previous flooding events that Houston could not handle?
I call shenanigans.
If global warming made harvey three times more likely, why was there a drought of landfalls when trends say we should have had more and of course, if GW made them 15% more likely, plus the trend norm, how in earth did that drought of landfalls hapeen
As usual attribution of things to a system you dont understand, yields politically solicited BS