# So with dual Super-hurricanes this year, is it conclusive that it's from global warming? **URL:** \ **Category:** Factual Questions\ **Created:** [September 7, 2017, 5:13pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745 "2017-09-07T17:13:37Z")\ **Posts on this page:** 16\ **Page:** 3
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [September 8, 2017, 10:30pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/41 "2017-09-08T22:30:42Z")
Try me … what exactly is the correlation between the instantaneous water temperature in the western Gulf of Mexico, where Harvey formed, and the instantaneous water temperature in the eastern Atlantic, where Irma formed … and please do explain in simple terms how these are connected in temporal terms … looks to me like their paths cross in Illinois … I don’t know what you’re trying to say here … we take a grossly invalid statistic A, add it to another grossly invalid statistic B, and you seem to be saying that the result is grossly invalid because of some imagined correlation (which you haven’t specified yet) … Maybe you’re not using “correlation” properly … there’s an over 90% correlation between having daylight in Chicago and having daylight in Des Moines … that does NOT mean daylight in Chicago causes daylight in Des Moines … please explain how the causation of flooding in Houston is exactly the same as the causation of flooding in Miami _in each and every circumstances_ of flooding in either … And gee whiz … could you please define what amount of area we’re talking about … dA or a hundred million square miles … ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [September 9, 2017, 10:31am UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/42 "2017-09-09T10:31:36Z")
> [@watchwolf49](#): > > … a 500 year flood in Miami _or_ Houston is 0.4% give or take 0.2% … Did you mean to write “0.3% give or take 0.1%” ? > [@watchwolf49](#): > > Try me … what exactly is the correlation between the instantaneous water temperature in the western Gulf of Mexico, where Harvey formed, and the instantaneous water temperature in the eastern Atlantic, where Irma formed … and please do explain in simple terms how these are connected in temporal terms … looks to me like their paths cross in Illinois … I won’t Google to look for temperature correlations between Western and Eastern Atlantic, but your post indicts itself! Why “instantaneous”? Did Harvey really “form” in the western Gulf? Do you deny that late August temperatures are correlated with early September temperatures? _Do you deny that hurricanes acquire more energy after they’re formed?_ What does Illinois have to do with it? In the following I’ve taken the liberty of painting red the text I’ll comment on. > [@watchwolf49](#): > > … please explain how the causation of flooding in Houston is **exactly the same** as the causation of flooding in Miami _ **in each and every circumstances** _ of flooding in either … Here you are addressing a Doper who asserts the _correlation is exactly one_. Who is that Doper you are addressing? **Marvin the Martian** asserts that the _correlation is non-zero_. ---
**Author:** ![Jim\_s\_Son](https://avatars.discourse-cdn.com/v4/letter/j/e19adc/32.png) [@Jim\_s\_Son](https://boards.straightdope.com/u/Jim_s_Son)\ **Post date:** [September 9, 2017, 12:21pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/43 "2017-09-09T12:21:40Z")
“Rolling Stone” magazine said Hurrican Katrina in 2005 was the harbinger of strong hurricanes due to global warming. The United States promptly went on a decade scarcity of strong hurricanes not since since Rutherford Hayes was President. When a cold spell hit New York last month, sports writer Peter Botte of the Daily News said it was due to global climate change, the other name used when some one has an agenda to push. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [September 9, 2017, 1:11pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/44 "2017-09-09T13:11:16Z")
There is a core of unassailable and well understood science here, stuff that is not in the least controversial. We have a very good understanding of how hurricanes work. They are powered by warm water, and there is a well established direct link from the sea surface temperature to the existence and strength of hurricanes. This is why hurricanes occur in specific regions on the planet and not others. And why they die out when they run up over land - and simply turn into big rain storms. The upshot is that if sea surface temperatures rise - hurricanes will have a wider spread over the globe, and may become, on average, stronger. If sea surface temperature drops, the converse happens. There is no politics or agenda here. Simple physics. Sea surface temperature has other very significant influences on weather - el Nino, la Nina is basically sea surface temperature. As are other oscillating effects - Antarctic Annulus, Indian Ocean Dipole, and so on. Each of these effects causes significant changes to the weather for those regions where the weather is generated over those seas. The most noticeable is rain versus drought, but bouts of cold and bouts of heat come as well. What bothers climate scientists is that a general rise in sea surface temperature is likely to mean greater variation in the weather controlled by sea surface temperature. So more and worse extreme weather. So far there is no mention of anthropogenic warming. What is described above is simply a reasonable expectation about that will happen, and noting that a key part of the problem is the temperature of the sea surface. The only point where any controversy might come to play is whether the observed severe weather seen is evidence of a general rise in global temperature. Temperatures have risen, that is not in dispute. Whether they have risen enough to sheet home this year’s hurricanes to that rise is probably a lot harder to nail down. Indeed I doubt a definitive answer to that will be known for some time. Still no actual mention of anthropogenic warming. So, the difficult question is how much of a risk anyone is willing to take. Politicians are driven by many factors, and sadly political ideology seems to be one that is capable of directing their actions even when it flies in the face of reality. Neither side is immune. Whether you believe that human CO[sub]2[/sub] emissions are the key cause of any global rise in temperature, or believe that it is a natural cycle of weather we have no control over, or believe that it is statistical glitch, and on average the global temperature is not rising and will not rise, the simple reality of weather is that the temperature matters, and matters in a big way. Very small changes in sea surface temperature make for dramatic changes in weather patterns. YMMV. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [September 9, 2017, 1:55pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/45 "2017-09-09T13:55:04Z")
> [@septimus](#): > > Did you mean to write “0.3% give or take 0.1%” ? > > I won’t Google to look for temperature correlations between Western and Eastern Atlantic, but your post indicts itself! Why “instantaneous”? Did Harvey really “form” in the western Gulf? Do you deny that late August temperatures are correlated with early September temperatures? _Do you deny that hurricanes acquire more energy after they’re formed?_ What does Illinois have to do with it? > > In the following I’ve taken the liberty of painting red the text I’ll comment on. > Here you are addressing a Doper who asserts the _correlation is exactly one_. Who is that Doper you are addressing? **Marvin the Martian** asserts that the _correlation is non-zero_. Are you addressing **Buck Godot’s** post #32? … if not, please do … ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [September 9, 2017, 2:29pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/46 "2017-09-09T14:29:41Z")
> [@watchwolf49](#): > > Are you addressing **Buck Godot’s** post #32? … if not, please do … 😕 I see nothing in post #32 relevant to my questions directed at you. Please address _my_ post. 🙂 ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [September 9, 2017, 3:23pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/47 "2017-09-09T15:23:49Z")
> [@septimus](#): > > 😕 I see nothing in post #32 relevant to my questions directed at you. Please address _my_ post. 🙂 Please describe the context you wish me to answer, being the intended context is unacceptable to you … ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [September 10, 2017, 3:20am UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/48 "2017-09-10T03:20:08Z")
> [@Chronos](#): > > The jury might still be out on what global warming would theoretically be expected to do to hurricanes, but we’re getting close to the point where that doesn’t matter, because we’re finding out empirically what it does. Global warming is not something that will happen; it’s something that is happening right now, and has been for a century. I am curious what you think it is that global warming does wrt hurricanes, esp North Atlantic? We’ve had some very quiescent recent years, and in the last 70 years at least I don’t see much evidence that suggests anything “empirically.” [![](http://www.atmo.arizona.edu/students/courselinks/fall16/atmo336/lectures/sec2/Atlantic_ace_2015.png) ](http://www.atmo.arizona.edu/students/courselinks/fall16/atmo336/lectures/sec2/Atlantic_ace_2015.png) And note that the first half of the 20th century had some doozies… I do see an incredible amount of confirmation bias. If we have a quiescent season, then global warming did something to create more saharan dust and chill out the hurricanes. If we get some biggies, lo and behold those stupid Deniers cannot see the writing on the wall. As to Irma being superly massive…she is currently a 3. She was incredibly powerful for 37 hours–a “record.” But do you have some kind of idea what that record was 100 years ago? I have trouble believing we would have known, given the state of technology at the time to measure hurricanes that remote. Wouldn’t she have been just another big hurricane since the measurements were not as precise or comprehensive over the life of a hurricane as they are now? Yet everyone seems super excited to mention this “biggest hurricane on record”–without mentioning that it’s a pretty recent record set against which we are measuring hurricanes. For me, as a skeptic of human nature (not necessarily AGW itself, but skeptical of what happens to our reason when we are behind a Great Cause), it’s pretty easy to see people get caught up in the hoopla of hurricanes without much supporting data… ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [September 10, 2017, 11:05pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/49 "2017-09-10T23:05:03Z")
> [@Chief\_Pedant](#): > > I do see an incredible amount of confirmation bias. If we have a quiescent season, then global warming did something to create more saharan dust and chill out the hurricanes. If we get some biggies, lo and behold those stupid Deniers cannot see the writing on the wall. Actually, and there were many previous discussions on this, it is clear that most scientists think that there is little to say about the number of hurricanes. I have seen that while some do propose that the numbers will increase they point out that the effect will possibly be seen in the middle of the century if nothing is done to control emissions. What it is clear is that the hurricanes are getting more intense and that is based on one item that deniers have not been able to dismiss: > **[The One Number That Shows Why Climate Change Is Making Hurricane Season Worse](https://time.com/4931586/irma-hurricane-season-climate-change/)** > > Hurricanes Irma and Harvey have reignited discussions about the link between global warming and extreme weather. This one number shows why > [@](#): > > [The One Number That Shows Why Climate Change Is Making Hurricane Season Worse](https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation) > > Hurricanes Irma and Harvey have reignited discussions about the link between global warming and extreme weather, with climate scientists now saying they can show the connections between the two phenomena better than ever before. > > Scientists’ explanation of how they do that involves a complex discussion of climate models, historical temperature data and probability. But understanding the link really comes down to one figure: the air can hold 7% more water with every degree Celsius that the temperature rises. That figure comes from the [Clausius–Clapeyron equation, a widely accepted physical law established centuries ago long before any politicized debate on climate change.](https://blogs.scientificamerican.com/observations/what-we-know-about-the-climate-change-hurricane-connection/) > > “A warmer ocean makes a warmer atmosphere, a warmer atmosphere can hold more moisture,” says Gabriel Vecchi, a professor of geosciences at Princeton University who studies extreme weather events. “So, all other things equal, the same storm in a warmer planet would give you more rainfall.” > [@](#): > > “You fit all the data together and ask what is the likelihood for 100 millimeters, 200 millimeters of precipitation,” said study co-author Sarah Kapnick, a researcher at the NOAA, before the Harvey hit Texas. “As you get to higher and higher values of precipitation it becomes less and less likely without climate change.” > [@Chief\_Pedant](#): > > For me, as a skeptic of human nature (not necessarily AGW itself, but skeptical of what happens to our reason when we are behind a Great Cause), it’s pretty easy to see people get caught up in the hoopla of hurricanes without much supporting data… One more thing about supporting data, again it is clear that there are many doubts about how many hurricanes we can expect on a warming world, but as pointed many times before: besides the increase in water vapor in the atmosphere, hurricanes become more intense because the oceans are rising. Again, thanks to global warming due to humans not controlling global warming gas emissions. > **[What We Know about the Climate Change–Hurricane Connection](https://www.scientificamerican.com/blog/observations/what-we-know-about-the-climate-change-hurricane-connection/)** > > Some links are indisputable; others are more subtle, but the science is improving all the time > [@](#): > > For example, even if we could say nothing else, we can conclude that sea level rise has contributed to the coastal flooding associated with recent major hurricanes: nearly a foot at Battery Park in New York City in the case of 2012 Superstorm Sandy and roughly half a foot in the case of Hurricane Harvey. The seemingly modest 1 foot of sea level rise off the New York City and New Jersey coast made a Sandy-like storm surge of 14 feet far more likely, and led to 25 additional square miles of flooding and several billion extra dollars of damage. ---
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [September 10, 2017, 11:24pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/50 "2017-09-10T23:24:22Z")
> [@watchwolf49](#): > > Right … if we divide up the world’s land mass into 500 equal-area chunks (a little bigger than Arizona) … _on average_, one of these chunks will experience a 500-year flood somewhere in its area every year … keep in mind, if a tiny tickle of water runs every 500 years in Central Antarctica, that’s a 500 year flood event … the statistical arts are useful, but there are some drawbacks … > > **Buck Godot** used as an example Houston and Miami … these two locations are far enough apart where just adding the probabilities is valid enough … as valid as can be had until we have 500 years of good scientifically accurate data … we’re just guessing at this point … It’s fairly common for hurricanes to cross over FL and make a second landfall on the Gulf Coast. Miami and Houston’s flood probabilities are co-related because they could easily be hit by the same hurricane. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [September 10, 2017, 11:50pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/51 "2017-09-10T23:50:53Z")
> [@boffking](#): > > It’s fairly common for hurricanes to cross over FL and make a second landfall on the Gulf Coast. > Miami and Houston’s flood probabilities are co-related because they could easily be hit by the same hurricane. Yes, after we add the probabilities, we would then subtract the probability of those events that are directly linked … However … consider the probability of one tropical storm: stalling over Miami and producing a 500-year flood, then moving off to the west and stalling over Houston to produce a 500-year flood there … seems very unlikely to make any difference … ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [September 11, 2017, 3:43am UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/52 "2017-09-11T03:43:20Z")
> [@Johnny\_L.A](#): > > Not to worry. Harvey and Irma are once-in-500-year storms. One study by [Metstat](http://metstat.com/hurricane-harvey-extraordinary-flooding-for-houston-and-surrounding-areas/) is saying Harvey brought 1,000-year rain over a 24-hour period over much of the area, widespread 25,000-year rain over a 120-hour period, and 500,000-year rain over 120 hours in some isolated locations. ---
**Author:** ![ralfy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ralfy/32/600_2.png) [@ralfy](https://boards.straightdope.com/u/ralfy)\ **Post date:** [September 11, 2017, 5:33am UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/53 "2017-09-11T05:33:42Z")
The problem isn’t so much just hurricanes but the effects of multiple feedback loops. ---
**Author:** ![FlikTheBlue](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fliktheblue/32/10972_2.png) [@FlikTheBlue](https://boards.straightdope.com/u/FlikTheBlue)\ **Post date:** [September 11, 2017, 12:21pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/54 "2017-09-11T12:21:13Z")
> [@Jackmannii](#): > > One bad hurricane season does not make it “conclusive” that climate change is to blame, any more than having [a streak of 12 years without a major hurricane hitting the U.S.](http://dailycaller.com/2017/06/16/its-been-4253-days-since-the-last-major-hurricane-landed-in-the-us/) disproves climate change. > > Tempting as it is to assign definitive causes to isolated events, long-term trends are what count. > > As for severe seasons, one of the worst on record was [in 1780](https://en.wikipedia.org/wiki/1780_Atlantic_hurricane_season). Without looking it up I was going to post about this based on my memory. The way I remember it is that 2004 and 2005 were bad hurricane years but that things had otherwise been relatively calm since then until this year (other than Ike and Sandy). ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [September 11, 2017, 1:35pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/55 "2017-09-11T13:35:39Z")
> [@watchwolf49](#): > > Maybe you’re not using “correlation” properly … there’s an over 90% correlation between having daylight in Chicago and having daylight in Des Moines … that does NOT mean daylight in Chicago causes daylight in Des Moines … The correlation is high in your daylight case because they have the same root cause - the sun is up. > [@watchwolf49](#): > > please explain how the causation of flooding in Houston is exactly the same as the causation of flooding in Miami _in each and every circumstances_ of flooding in either … You are describing 100% correlation. I never said that. If surface water temperatures are rising in the Atlantic basin, it seems reasonable to assume that there is some correlation between the surface water temperature in the Atlantic itself and the Gulf. > [@watchwolf49](#): > > And gee whiz … could you please define what amount of area we’re talking about … dA or a hundred million square miles … Exactly the point I was trying to make. For two adjacent areas, the correlation between the weather is going to be near 100%. The further apart you measure, the weaker the correlation is going to get. If the correlation is 100%, then the probability of at least one of the two areas experiencing a 0.2% probability event is 0.2%. If the correlation is 0%, then the probability increases to 0.4%. If the correlation is in between, then the probability is in between. All I am doing is objecting to the statement that if you look at 500 places on earth you would expect a 500 year event on the average of once a year. That is only true if the probability of an event in every location is completely uncorrelated with the probability in every other location. For weather-driven events this is clearly not true. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [September 11, 2017, 3:05pm UTC](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745/56 "2017-09-11T15:05:07Z")
> [@Marvin\_the\_Martian](#): > > The correlation is high in your daylight case because they have the same root cause - the sun is up. > > You are describing 100% correlation. I never said that. If surface water temperatures are rising in the Atlantic basin, it seems reasonable to assume that there is some correlation between the surface water temperature in the Atlantic itself and the Gulf. Again the same root cause, the sun is up … and the correlation between sea surface temperatures and 500-year floods is quite thin … sometimes these flood events are due to rainfall + snowmelt … > [@Marvin\_the\_Martian](#): > > Exactly the point I was trying to make. For two adjacent areas, the correlation between the weather is going to be near 100%. The further apart you measure, the weaker the correlation is going to get. If the correlation is 100%, then the probability of at least one of the two areas experiencing a 0.2% probability event is 0.2%. If the correlation is 0%, then the probability increases to 0.4%. If the correlation is in between, then the probability is in between. I thought that was the point you were making … I think we both dove down our own private rabbit holes … which is why I referred back to **Buck Godot’s** post where he doesn’t exactly say we simply add the probabilities together, rather the probabilities of 500-year floods anywhere in the USA is higher than 0.2% … and considering the remnants of Hurricane Sandy in 2012, Baton Rouge 2016 and now Hurricane Harvey in 2017 … I can see where someone might agree … > [@Marvin\_the\_Martian](#): > > All I am doing is objecting to the statement that if you look at 500 places on earth you would expect a 500 year event on the average of once a year. That is only true if the probability of an event in every location is completely uncorrelated with the probability in every other location. For weather-driven events this is clearly not true. The challenge here is finding a 500-year flood event that covered more than 100 thousand square miles … not far out of Houston, say 100 miles, we didn’t even see a 100-year flood event … Correlation ≠ causation … when we look at what weather events that cause 500-year flood events we find them to be very localized … [Previous page](https://boards.straightdope.com/t/so-with-dual-super-hurricanes-this-year-is-it-conclusive-that-its-from-global-warming/795745.md?page=2)