I had started on an essay to describe this meteostatistical failure last night, but Lucia beat me to it, so the credit goes to her. She’s a sharp lady. Besides the fact that short term weather events are not climate you can’t apply the coin flip statistical logic to it like Weather Underground’s Jeff Masters did, citing a calculation that suggests a one in 1,594,323 chance heat wave. Lucia reduces this probability estimate calculation to rubble and writes:
In fact– the entire reason weather forecasting is possible at all is that we know weather patterns persist. Master’s calculation is based on the assumption weather patterns do not persist!.
As we’ve said many times before , the Eastern US heat wave was a result of a quasi-stationary blocking high pressure pattern that persisted a few days. It has already moved on and has been absorbed in the weather noise.
But the wailing about the significance of the recent heat wave has reached a fever pitch, blinding rational people who should know better in their quest to show that climate and weather are the same thing. They aren’t, and they never will be. The same folly of opinion occurred two years ago in the summer of 2010 during the Russian Heat Wave, with many of the MSM and pundits saying that its was a sure case of global warming affecting the weather. Then, NOAA published a peer reviewed paper holding global warming/climate change blameless, basically saying it was nothing more than a persistent weather pattern. A follow up paper by other scientists confirmed it was due to natural variability. But the people who believe that AGW will be dangerous and world changing can’t let go of the idea when it comes to blaming short term weather patterns on global warming.
Dr. Jeff Masters wrote of the recent heat wave:
Each of the 13 months from June 2011 through June 2012 ranked among the warmest third of their historical distribution for the first time in the 1895 – present record. According to NCDC, the odds of this occurring randomly during any particular month are 1 in 1,594,323. Thus, we should only see one more 13-month period so warm between now and 124,652 AD–assuming the climate is staying the same as it did during the past 118 years. These are ridiculously long odds, and it is highly unlikely that the extremity of the heat during the past 13 months could have occurred without a warming climate.
Lucia writes:
What this really is is a meaningless statistics.
and adds:
Let’s tweak Dr. Master’s rather imperfect calculation by retaining his assumption that “climate is staying the same as it did during the past 118 years” but accounting for “persistence”. More specifically we will assume that there is non-zero serial auto-correlation in the monthly data. Since he used “white” noise, I’m going to pick the next simplest model: Red noise (i.e. AR1 noise.)
She runs her calculations and concludes:
Taking the mean of the series, I found that “assuming the climate is staying the same as it did during the past 118 years” the probability of 10% ± 0.4% the final 13 months would fall in the top 1/3rd of historic temperatures observations.
A 1 in 10 (10%) probability is a statistical galaxy away from a one in 1,594,323 chance.
And even other warmists agree, Lucia adds in this update:
Update: I googled to read who’d blogged. Michael Tobis commented:
Actually that’s bad form from both Masters and NCDC.
1.6 million (more precisely, 1,594,323) to one is just the thirteenth power of 1/3, which overstates the case to the extent that successive monthly anomalies are correlated. (Also the 1/3 is somewhat arbitrary and could be a cherry pick, but leave that aside). I don’t doubt that something very odd is going on but the number represents a common elementary statistical error and is in this case excessively alarmist.
Is this the first time MT and I have agreed on something?
Unfortunately, the damage is done, and Dr. Jeff Masters million to one lie is all over the net, aided by an unquestioning press.
Read Lucia’s full explanation here.
I have calculated that there is a 1 in 1,594,323 chance that I will ever again visit the Weather Underground website.
Folks – there are many very good, alternative weather sites on the web (though it seems many are affiliated with the Weather Channel, unfortunately). Please don’t give Jeff Masters any more funding than he already has by visiting his site. And suggest to others that they switch too.
I have 2 legs this is higher than the average number of legs people have – statistically speaking.
I keep seeing the lower 48 states being referred to as North America. What I would like to see is the same 13 month period for the real North America which includes Canada and Alaska which we all know has had an much lower than average few months.
Stats really isn’t my thing but I know the basics and what bothers me most about the discussion is how easily a stats discussion gets divorced from the physics.
1. The earth has been warming for the last 400 years, a fact accepted for the most part by alarmists and skeptics alike. That being the case, we would EXPECT more highs and more clusters of highs in the last number of years just from the NORMAL TREND.
2. A high by how much? Let’s say the previous high was +40C. Over a period of time, we see new highs of +41, +41.2, +41.1 and plus 42.05. Wow, that’s four new highs! But to anyone with a bit of understanding of physics and the cyclical nature of physical processes, that looks like a peak that is slowing down and soon to be reversed.
3. At what humidity? The amount of energy it takes to increase temps by a given amount on a dry day is a fraction of the amount required to raise the temp by the same amount of on humid day. So a new record temp wise combined with a low humidity could well mean that the earth LOST energy rather than gained it!
4. The practice of using anomalies and records masks the fact that the raw temps themselves have meaning. Let’s say we set a new day time high in January at a high latitude. For example purposes, the old record is -20 C and the new record is -19C. Wow, that’s a whopper of a temperature change. It equates to record change of +1 which is pretty big. Using SB Law, convert that to w/m2 and you get a change of 3.7 watts. Now let us assume also that somewhere in the tropics the temperature was 3/4 degree below the day time average high of +40. Well gosh golly be, that would be a drop from average of 5.2 w/m2. So, between the two we have a n INCREASE in temperature but a DECREASE in energy flux! Which is it? did the earth warm? or cool?
Applying simple statistical analaysis…. or even highly sophisticated statistical analysis in absence of an understanding of the underlying physics is so stupid that there ought to be a special category in the Darwin Awards to accomodate them.
I will gladly bet Dr Masters $10 million he is wrong. If we never have a similar situation for another 1,594,323 months I promise to pay up.
Wow! I didn’t realize the US temperatures had such low serial auto-correlation.
Hey, the climate, you found it!
To me this example shows that there is something seriously wrong with post hoc assigning probabilities to single events. Suppose, you walk on the street and meets a friend you haven’t seen for ten years. Depending on all arbitrary elements you use in your calculation the probability of this event may be as low as one in a trillion. Your whole day is filled with these extra ordinary cherry-picked events. If you use an infinite amount of aspects for the event, each associated with a number between 0 and 1, the end result will be zero anyhow. That is also the probability of your own existence.
Not Lucia’s finest hour it seems… Here is the risk of treating numbers out of their meteorological context.
What is probability that dozens of statistical errors in climate “science” (Mann, Rahmstorf, Steig, Santer, Gergis, NCDC, and many others.) all promote global warming alarmism ?
The odds of something happening in any 2% of the Earth’s surface are about fifty times greater than the odds that event happening in a specific 2% and that assumes that the 2% areas you can pick can’t overlap and remain a fixed set.
To pick a particular small area will make events seem much more unlikely than they actually are.
hmm, I always thought the probability of an already observed event happening was … 1.
But what do I know, I always had problems getting probabilities right when predicting coupled dynamic chaotic events anyway – things that weren’t even on the radar keep happening.
Pokerguy:
No, you are absolutely right about the odds of any hand. In addition to yours I count five comments so far from folks who actually understand the post-hoc fallacy (the Feynman comment is right on, as is Mindert Eiting’s analysis). After the Russian heatwave article on Realclimate, I posted comments there stepping through the basic tenets of a post hoc fallacy, and got one of the scientists (I am not sure I remember correctly which one) to agree that each one was in fact operative in their probabilistic assessment. I even tipped my hand at the beginning as to what I was doing, yet absolutely no one there caught on that they were basically espousing a post hoc fallacy. I cannot say that I am always impressed by the WUWT readership, but this time I am!
Pokerguy;
But does it really matter? I play poker and there’s a very low probability of every hand I play coming out just as it does among a 6 man table. But so what?>>>>
Exactly. The odds of rolling a 6 on a six sided die are 6:1. The odds of rolling 6 twice in a row are 36:1 and the odds of rolling a 6 three times in a row are 216:1.
Now, if I’ve ALREADY rolled two sixes in a row, what are the odds that my NEXT role will be a six?
Answer: 6:1
The results of the past do not change the odds of the future.
Only when weather patterns persist long enough do they become climate.
Aside from the ‘presume the heat still radiates away ‘ I think this is the crux of the issue; how likely are we to have the highs and lows (La Nina and El Nino et al) in confluence together again; otherwise this is just an ‘odds’ (or statistics) game (with no real exhibited skill; no knowledge of the underlying processes that work to bring a ‘heatwave’ event to fruition).
The real question is where and when will the ‘highs’ come together. Speaking basic meteorlogically as subsidence in a high warms the air by compression: “In high-pressure centers, descending air is compressed and warmed; therefore, cloud formation and precipitation are unlikely … ” … for a heatwave a little more orchestration is called for, however.
For a quick review of this I would recommend a quick review of wiki (save for the preachy last sentence in this section about GW):
http://en.wikipedia.org/wiki/Heat_wave#How_they_occur
“Heat waves form when high pressure aloft (from 10,000–25,000 feet (3,000–7,600 metres)) strengthens and remains over a region for several days up to several weeks. This is common in summer (in both Northern and Southern Hemispheres) as the jet stream ‘follows the sun’. On the equator side of the jet stream, in the middle layers of the atmosphere, is the high pressure area.
Summertime weather patterns are generally slower to change than in winter. As a result, this mid-level high pressure also moves slowly. Under high pressure, the air subsides (sinks) toward the surface. This sinking air acts as a dome capping the atmosphere.
This cap helps to trap heat instead of allowing it to lift. Without the lift there is little or no convection and therefore little or no convective clouds (cumulus clouds) with minimal chances for rain. The end result is a continual build-up of heat at the surface that we experience as a heat wave.”
.
The whole charade is nothing more than a variation on the theme that they have been playing for several years now. This “1.6 million chance of 13 months …” blah, blah, blah is just another way of pretending that “has warmed” is the same as “is warming”. They have been playing that game ever since it became inconveniently difficult to deny that it has stopped warming.
Since then, they have been saying things like “seven of the ten warmest years on record were in the last decade”. Think about it. This current blathering about “13 months…” is nothing more than another way of saying that same thing, in a slightly different way. Ditto the “number of high record temperatures set is increasing vs number of new low record temperatures”, as well as the “Hottest year ever” fudged up for 2010. It sounds very mathematical and scientific, but it is meaningless prattle WRT their thesis. These sort of statistics are driven by the fact that it is relatively warm now WRT our very short period of record. These statistics are not driven by warming, and in fact are as likley to occur on the cooling leg of a cycle coming off a peak as they are to occur on the warming leg of a cycle coming up to a peak.
“Warm” is not “warming”, no matter how many ways they say it. It may be warm, but it is not warming, let alone warming at the rate predicted by the alarmists and their models. Expect these alarmist word games to persist as long as the temp estimates continue to be flat to declining as they are now.
Masters:
Isn’t it broadly accepted that there has been significant global warming since 1895, and don’t we have much better evidence for it than Masters’ assumption-ridden calculation based on the probabilities of temperature extremes?
What is truly silly is Masters’ pretense that the use of an inferior metric to say something utterly uncontroversial and non-alarming is somehow grist for alarm. He’s not offering any evidence that the planet is still warming, or how fast. Amazing what these people can go Chicken Little over.
The chances of Dr. Masters making another “Oh noes! More Global Warming!” post this week are nearing 100%. He’s bored because there are no hurricanes which would, among other things, indicate a decided lack of overall heat in certain parts of the atmosphere, methinks.
“Heat waves form when high pressure aloft (from 10,000–25,000 feet (3,000–7,600 metres)) strengthens and remains over a region for several days up to several weeks….”
LOL
Jim, what is the air density at this altitude? Have they ever watch satellite animations?
I see that Masters presumes knowledge of how the climate will behave over the next 122,640 years so as to make his point.
He can’t have been looking at tree rings; tea leaves, perhaps, or the front page of his next grant application.
When this story first popped up here, I noted that the odds of the monthly temps being in the middle 1/3 for 13 months is also 1 in 1.5 whatever million.
Sort of a vacuous statement, but so is Masters’.
I think I can clear up the scenario they are discussing, Tom; they are referring to a summer ‘heat wave’ much as what we just experienced here in the eastern US and how it came to be, and are describing ‘conditions aloft’. (IOW they are _not_ discussing a ‘heat wave’ simply forming aloft … hopefully that wasn’t your assumption b/c that was not the intended implication.)
(Tom, one doesn’t always expect the need to present a full meteorological ‘class’ or definition in a couple of paragraphs… it was mentioned this was a ‘quick review’ … sometimes one must assume his audience has some familiarity with the subject being presented (in a field like meteorology), or is going to at least click on a provided link for further explanation or clarification.)
.
In a world where “scientists” adjust past temperatures lower and lower and more recent temperatures higher and higher, do calculations like this have any meaning?
Ok, ya got me, Jeff Id. Although your probability proof is probability nonsense, I have to agree with your conclusion that the climate couldn’t be where it is today if it hadn’t warmed since the LIA. No question in my mind, the climate changes, and the 20th century was during one of the warming periods, albeit with significant ups and downs.
The great majority of skeptics I’ve ever talked to agree with this, and without having to resort to torturing probability, so…what’s your point, exactly?
It is amazing what can come from an “Air Pollution Meteorologist” , no?
Did I get that right?
It is tricky stuff!
Insert your own inference of character assignment to the following informational video 🙂