Guest post by David Middleton
My State is currently in the grip of a very severe drought…
Professor Andrew Dessler, an atmospheric sciences professor at our nation’s greatest university, recently authored a column about our drought in the Bryan-College Station Eagle…
Published Tuesday, August 30, 2011 12:05 AM
Paying the price for climate change
By ANDREW DESSLER
Special to The Eagle
Texas Gov. Rick Perry stirred up controversy on the campaign trail recently when he dismissed the problem of climate change and accused scientists of basically making up the problem.
As a born-and-bred Texan, it’s especially disturbing to hear this now, when our state is getting absolutely hammered by heat and drought. I’ve got to wonder how any resident of Texas — and particularly the governor who not so long ago was asking us to pray for rain — can be so cavalier about climate change…
[…]
I know that climate change does not cause any specific weather event. But I also know that humans have warmed the climate over the past century, and that this warming has almost certainly made the heat wave and drought more extreme than it would otherwise have been.
[…]
Dr. Roy Spencer had an interesting take on Dr. Dessler’s column in his blog…
Dessler vs. Rick Perry: Is the 2011 Texas Drought Evidence of Human-Caused Climate Change?
September 5th, 2011 by Roy W. Spencer, Ph. D.
One of the most annoying things about the climate change debate is that any regional weather event is blamed on humans, if even only partly. Such unscientific claims cannot be supported by data — they are little more than ambiguous statements of faith.
[…]
Andy Dessler recently made what I’m sure he thought was a safe claim when faulting Texas Gov. Rick Perry for being “cavalier about climate change” (as if we could stop climate from changing by being concerned about it).
Dessler said, “..warming has almost certainly made the (Texas) heat wave and drought more extreme than it would otherwise have been.”
This clever tactic of claiming near-certainty of at least SOME effect of humans on weather events was originally invented by NASA’s James Hansen in his 1988 Senate testimony for Al Gore, an event that became the turning point for raising public awareness of “global warming” (oops, I’m sorry, I mean climate change).
The trouble is that climate change theory predicts changes, up and down, in just about anything you can imagine. So, anything unusual that happens anywhere, anytime, is deemed “consistent” with global warming.
[…]
According to Dr. Spencer the current national drought conditions are not exceptional; nor is there any statistically significant trend…
And, while Texas is experiencing a record-setting drought; the “record” is just over a century-long and there is no trend at all…
The lack of a trend in the precipitation data made me wonder… Just how often should we be setting precipitation records if the annual variation is random?
The record only goes back to 1895. Does anyone know how often record highs and record lows should be broken in such a short time series?
At a record length of 117 years, there was a 1% chance of setting a new record high in the 117th year…
The probability, pn(1), that the nth observation of a series xm= x1, x2, … xn has a higher value than the previous observations [pn(1) = Pr(xn > xi |i < n)] can be expressed as:
pn(1)= 1/n (1)
provided the values in series are iid random variables.
(Benestad, 2003)
The cumulative probability says that 5 records should have been set between 1895 and 2011.
So, let’s have a look at the data. I downloaded the summer precipitation data for Texas from NCDC’s “U.S. Climate at a Glance” page…
In order to analyze the frequency of record excursions, I plotted the absolute value of the annual summer precipitation anomaly along with an “expected records” curve…
There have been 5 record excursions from the average annual summer precipitation – Exactly what there should have been in a random series of numbers. And the records have occurred with the expected frequency of a random series of numbers. The fifth record excursion should have occurred between 1945 and 2030 – It occurred in 2007.
If a person with general background in topography, prevailing wind direction, and orientation with respect to the tropics, but no knowledge of local climate history, were to look at a map of the US mainland, he would likely guess something like this:
From its location, east of the Rockies, northwest of the Gulf, south of almost all of the rest of the states, Texas can expect very warm to hot summers, mostly dry since moisture would have a hard time vaulting the Rockies and southeast winds don’t usually penetrate far from the coast. Winters can get chilly, since there are no major natural barriers between the north Texas plains and Canada; but the southern location should mitigate that to some extent.
I’d say those general expectations have been met this year, as during many past years. The wet years the state has enjoyed could be regarded as exceptional; and in some of those years, it was tropical cyclones that swelled the wetness of the statistics. This year has been unusually dry, in many places calamitously so; but given the expectations from the map, it would seem obvious that even a mild “blocking high” or similar event could produce a summer such as that now happening in Texas. It is sad; I wish I could send some of our Virginia moisture there (9.2″ last week); but it is well within the realm of possibility.
Those graphs really tell the story! In US overall, the trend is toward less extremes of precip, which is of course contrary to what the Holy Carbon Models tell us. In Texas, the trend is toward more extremes of precip, which would indicate that the jet stream is getting “locked in” more often. The latter seems to be a worldwide tendency, esp in last 30 years or so.
Having had the misfortune to spend much of the Summer and Fall of 1980 — also a drought year — in Texas, I’ve viewed the current situation with a mixture of amusement, sympathy, and thankfulness that I don’t live there.
AFAICS, the current situation is little different than 1980 except that Texas finally got a little rain in September 1980 when Hurricane Gilbert came ashore in the Western Gulf. Is there a case for climate change making the temperatures a little (not much) higher than they were in 1980? Probably. Drier? You’re kidding, right? No rain is no rain. Is there any reason to believe that Climate Change has made any significant difference? Not that I can see.
Dessler? Not impressed. Comes across as every bit as faith based as Perry. Just worships at a different alter. Surely “Climate Science” must include a few actual scientists. Might be time to dust a few off and let THEM talk to the public.
Crispin in Waterloo says: September 13, 2011 at 8:57 pm
What you say rings true.
Indeed a great post and totally debunks the claim that the extreme dry weather is a result of MGW. How would we explain the extreme wet weather of 2007 … and as you point out there is no trend.
The only possible argument might be that there is increased chaos in the system leading to greater extremes at both ends of the spectrum. Can you also analyse for increased variability or chaos in the system ? Is there any trend there ?
SteveE says:
September 14, 2011 at 1:54 am
Roger Carr says:
September 13, 2011 at 10:41 pm
Nailed it for me, Mike; and one can expand that question into how a fraction of a degree of warming over a century can even raise a pulse, let alone catastrophic panic and billions of dollars.
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The reason is it’s an average increase of a fraction of a degree over the whole globe over a whole year. That doesn’t mean that every day will be half a degree hotter everywhere.
Read up on some basic maths of averages if you still have trouble with this.
——————————————————————-
Hi Steve. You know that axe cuts both ways? The normals that anomalies are compared to are averages, and so it’s normal to have highs and lows in the meteorological record.
Whoop! 🙂
SteveE tells me to: “Read up on some basic maths of averages if you still have trouble with this.”
No trouble with averages, Steve — but some trouble with you missing the point I made; or perhaps choosing to misrepresent what I said for your own (or for AWGers in general) reasons.
Who is denying this general rise in temperatures of a fraction of a degree? Certainly not me; and that being said I repeat: “…how (can) a fraction of a degree of warming over a century even raise a pulse, let alone catastrophic panic and billions of dollars.”
We have to have been bored, or asleep, on the day…
Seriously, though, Dessler really is an embarrassment. Dr. Spencer has been exceptionally nice to him despite his undeserving stance as of late.
Gary Turner says:
September 13, 2011 at 9:32 pm
Gary, cut Roger some slack…he’s one of the good guys :). I’ve read some of his writings on the internet and I’d take him any day over Dessler by a country mile.
There has always been “Climate Change”. There will always be “Climate Change”. The problem is that the “warmest s” have taken the high ground by a clever technique of automatic association. In the general public’s mind, the words “Climate Change” are now linked to man made actions!
“But I also know that humans have warmed the climate over the past century, and that this warming has almost certainly made the heat wave and drought more extreme than it would otherwise have been.” [Dessler]
This is the statement that we (via GOOD [non-biased] Scientific Research) must adamantly oppose. How does HE “know that humans have warmed the climate”????? Faith in the money stream??
– Neil: Kudos, that comment was worth the read!
@Stephen Fisher Rasey,
“For one thing, Negative rainfall is impossible by definition, yet must be possible if it is a Noral Distribution. — You asked.”
Well, you got one thing correct. Negative rainfall is rather scarce. However, it is quite possible to run a statistical analysis (a simple one) for data distribution on the total annual precipitation. I suspect that any introductory statistics class will teach this.
I provided a tinypic above for the distribution curve for annual precipitation in Texas. Again, the data is almost normally distributed around the mean of 28 inches per year.
Excellent post. Sent link to friends and relatives, with this subject and comment:
/Mr Lynn
Couple comments and questions:
Since the warmists claim an increase in extreme events, does the texas data show a divergence between max and min? Is it statistically significant on such a short record?
Isn’t Texas always a dry, hot state?
It seems clear to me that human industrialization has destroyed the natural environment of Texas. The lush tropical rainforests of Texas are no more, and the Texas gorillas are extinct. Weep for the Earth. /sarc Seriously… I’m pretty sure the natural vegitation in Texas are types that can withstand severe drought. That’s probably because this happens there a lot. Just sayin’
@polistra,
“In Texas, the trend is toward more extremes of precip,. . .”
Actually, no, the NCDC data for Texas’ annual precipitation shows fewer extremes since 1959.
I chose 1960 as the boundary in the data because an eye-ball analysis indicates that’s about where the data quit bouncing around as much. The smoothed trend line also
One measure of variability is standard deviation. Using that metric, pre-1960 annual precipitation for Texas has a standard deviation of 5.7 inches. For 1960 and later, the standard deviation is lower at 4.2 inches.
The annual average also increased by almost one inch per year, comparing the period pre-1960 to the period of 1960 to 2011. In Texas, at least, it is not getting drier nor is the rain/drought cycle getting “wilder” or more extreme. Quite the opposite. Meanwhile atmospheric CO2 level continues to increase.
This would make quite an interesting study to use the available data for other regions / states and confirm or debunk the warmists’ claim of wilder and more extreme rain / drought.
I’ve come to understand that the habit of comparing a day’s, month’s or season’s weather to the “average” leads to misconceptions about the weather and climate. Often this mistake is compounded by using the term “normal” instead.
When we compare weather to the “average” it makes our daily highs and lows appear more extreme. But by looking at the record highs and record lows, we see that our weather usually sits comfortably within that range.
Dear Dr. Dessler,
You seem to a glutton for punishment, a mouth awaiting a foot. You might want to act more like a scientist and check the data BEFORE you come to a conclusion.
Since you are so enthused about the Texas Drought situation, here is the data for the history of drought in Texas. The long term (100+ years) shows drought is improving in Texas and the current drought is moderate at best.
http://tinyurl.com/3f53gr6.
We’ll await you apology letter.
“Does anyone know how often record highs and record lows should be broken in such a short time series?”
As temp increases, both should be broken more often. Variability increases. Deeper and more prolonged droughts as well as more precipitation when it rains.
Netherlands were typical this year. Record dry spring. Record wet summer. Records set as of 1901.
Dessler said, “..warming has almost certainly made the (Texas) heat wave and drought more extreme than it would otherwise have been.”
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Yep, that 1/10th of a degree pushed it over the top…………………/snark
Sorry Roger Sowell, AusieDan & Stephen Rasey are right. Rainfall does not have a normal distribution. I have found that the distribution of my area of Australia is close to a Poisson distribution where the standard deviation is close to the average. The peak or record rainfall (monthly values from 1893) is five to seven standard deviations (eg January av 235mm SD 205 record 1384mm, August av 59 SD 52 record 375mm, December av 173mm SD 121mm record 668 mm latter in 2010 when there were floods in January with normal rainfall for that month- the wettest month is actually February)
Mentioned the Poisson distribution for rainfall in a post by Willis E sometime ago and he suggested it was actually a Chi square distribution.
Love Governor Perry or hate him, he is still the only politician smart enough or with courage enough to speak the truth: AGW is a hoax and Social Security is a Ponzi scheme!
Me, I’m sort of lukewarm on the Gov. Still I have to respect him for saying that the “Emperor has no clothes”.
By the way, the Gov is not the first Texan to speak up about Social Security. Watch these and weep for our children:
http://www.youtube.com/watch?v=6mqSXsNJzRM
Regards,
Steamboat Jack (Jon Jewett’s evil twin)
Full disclosure:
I went to a six day marine firefighting school at Texas A&M College Station. A friend says that makes me an Aggie. I even graduated!
Methinks the goddess of climate change, the beloved CO2, is lazy and only works to raise temperatures in some areas some of the time. Perhaps her motto should be “I can heat some of the air all of the time, and all of the air some of the time, but I cannot heat all of the air all of the time”. (My apologies to P.T. Barnum)
@ur momisugly Roger Sowell and Stephen Rasey
Stephen is certainly correct that the distribution is not (and cannot be) a normal distribution; on the other hand, Roger is correct that an eyeball look at the data distribution looks like a rough approximation of a normal distribution.
I admire the approach that David Middleton has come up with, but the question is, how close to ND is close enough?
SteveE says:
September 14, 2011 at 2:48 am
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Steve, are you intentionally missing the points of the comments or do you need an interpreter?
Roger didn’t imply the average was uniformly distributed. Why would you infer that he did? And Tom wasn’t stating that public opinion was a measure of truth, he was talking about the word “controversial” and how Dessler attached the word to Perry’s position.
Did you take a class from Dessler in interpretive reading skills? You seem to share the same characteristics
Now, could you direct me to one of the “experts” of the subject? I’m anxious to hear the thoughts of a person so well versed in physics, astrophysics, molecular chemistry, meteorology, geology, archeology, hydrology, statistics, history, botany, biology, etc…..
SteveE says:
September 14, 2011 at 2:48 am
Tom C says:
September 13, 2011 at 11:32 pm
I don’t think public opinion is a good measure on the truth of something though. A good measure might be the percentage of experts who have researched the subject in question.
True, public opinion by itself doesn’t tell you much about the truth. However, in the case of CAGW what we’re seeing is that despite a massive onslaught of Warmist propaganda for a number of years, plus a famous Nobel-prize-winning slideshow supposedly based on truth, public opinion is actually moving away from the Warmist ideology. Now, for a rational person, if the more and louder a “truth” is told, the less people believe it, then it would be logical to assume that there is something fundamentally wrong with said “truth”. Only those who are irrational, or have motives other than truth-telling would say that the failure lies with “the communication”, yet, amazingly enough, that is the general stance of the CAGW community.
Regarding “the percentage of experts who have researched the subject”, i.e. “the consensus” being a “good measure of the truth”, that is a logical fallacy trap that Alarmists fall into quite often. You might want to read up on logical fallacies, if you still have trouble with that.