From Master Resource, by Chip Knappenberger
Yesteryear’s climate extremes are today’s climate normals. Yet we are largely oblivious and better off. A hundred years from now the same will be true. Ho hum….
But not everyone thinks this way. Take NASA’s James Hansen for example.
Hansen has recently published a prominent paper (in the Proceedings of the National Academy of Sciences, PNAS) and placed a prominent op-ed (in the Washington Post) that are aimed at raising the public’s awareness of the impacts of climate change, both now and in the future. In a rather candid admission for a scientific paper (and one which in most cases would have resulted in an immediate rejection), Hansen (and co-authors) proclaim that “…we were motivated in this research by an objective to expose effects of human-made global warming as soon as possible…” To drive the point home further, Hansen’s op-ed was headlined “Climate change is here — and worse than we thought.”
What Hansen wants us to know, is that as temperatures increase, temperatures at the high end of the scale that were once statistically very rare (i.e., extreme) will become considerably less rare.
I agree completely.
However, Hansen is of the opinion that once this knowledge becomes widely known and associated with human greenhouse gas emissions (one of the many ways that human activity can alter the climate), that the majority of people will hasten to support actions (legislative, regulative) aimed at curtailing such emissions.
I completely disagree.
For one thing, it is not clear to me that warmer (and higher atmospheric CO2 levels) isn’t in many ways better. Robert Murphy pointed to recent economic analyses that found this to be the case, at least for some additional warming. And there are plenty of other potential benefits.
For another, as Roger Pielke Jr. points out, there is a lot of evidence that folks who already accept that human activities are impacting the climate still don’t clamor for actions to mitigate that influence—at least very expensive ones.
And thirdly, a changing climate is quickly and thoroughly absorbed in everyday life such that no one really cares about how it used to be and simply adjusts to how it is.
…
“Extreme” Temperatures
In his PNAS paper, Hansen defines “extreme” high temperatures as being at least three standard deviations above the average—an event which should only occur about 0.13% of the time based on a normal (bell-shaped) distribution. Hansen points out that as the average temperature increases, the distribution of observed temperatures will shift to the right (toward higher temperatures), with the consequence that the occurrence of extremes will increase dramatically when judged by the old distribution. Figure 1 shows this.
Fig. 1 The left hand (blue) bell curve represents the distribution of a set of temperature observations from some period in time. The average (or “mean”) temperature is indicated by the red vertical line. The standard deviation (and its multiples) are indicated on the x-axis. Only 0.13% of the data points exceed (lie to the right) a value of three standard deviations from the mean. The right hand (red) bell curve represents the distribution of a set of temperature observations from a warmer climate. The shape of the distribution is the same, but the average temperature (red vertical line) is higher (by a value of one standard deviation) from the original climate. In the warmer climate, the number of observations that exceed three standard deviations from the original climate (region filled in dark red) has greatly increased (to a value of 2.28% of the observations).
Let’s look at the numbers in Figure 1 a bit more closely. I’ll use an example of climate change where the average temperature increases by an amount equal to the value of one standard deviation (a standard deviation is a measure of variability such that two-thirds of all observations fall within one standard deviation of the average of all observations). In this new, warmer climate (with a variability the same as the old, cooler climate) the occurrence of events exceeding three standard deviations above the old average increases by about 17.5 times. Specifically, a high temperature event that used to occur only about 0.13% of the time, now occurs about 2.28% of the time. Or, if you wanted to add a more attention-getting spin, you could say that the occurrence of extreme events has increased by over an order of magnitude.
Temperatures in the real world over the past 50 years or so have behaved somewhat like my example.
In his paper, Hansen notes that globally, since the 1950s, the average temperature has increased by about a standard deviation, and as expected, the occurrence of extreme (greater than 3 standard deviations above the old mean) temperatures has increased considerably.
Here is how Hansen et al. describe their findings:
The most important change…is the appearance of a new category of extremely hot summer anomalies, with mean temperature at least three standard deviations greater than climatology. These extreme temperatures were practically absent in the period of climatology, covering only a few tenths of one percent of the land area, but they are occurring over about 10% of global land area in recent years. The increase of these extreme anomalies, by more than an order of magnitude, implies that we can say with a high degree of confidence that events such as the extreme summer heat in the Moscow region in 2010 and Texas in 2011 were a consequence of global warming.
Several commentators around the web have taken umbrage to the final sentence above, arguing that the role of global warming in those specific weather events has been overstated, and/or improperly calculated. Others are fully supportive. But rendering an opinion about this is not the subject of my commentary.
Instead, I want to show that it really doesn’t matter. While these events may be noteworthy now, if temperatures continue to rise into the future, they will eventually become status quo and ho hum. And while that that may sound frightful now, by then, we’ll not even notice.
So, don’t worry.
Case and Point: Temperatures in Washington DC.
Over the past 142 years (from official records starting in 1871), the average summer temperature in our nation’s capital has increased by about 4.5°F from a variety of causes (Figure 2).
full story at Master Resource
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on a logical point of view, one thing seems clear to me, anyone who says that extreme cold weathers are caused by climatic disruption is nonsense.
And what about places on earth where températures decreased over the last century…is it a statistical anomaly or and effect of the pattern of circulation? and then is there a global warming or climate disruption?
It’s definitely not a Gaussian bell curve. The tails are heavier than a Gaussian would predict.
There’s code to look at corresponding distributions for HadCRUT here: http://wattsupwiththat.com/2012/08/12/a-quick-look-at-temperature-anomaly-distributions/ There’s a comment down near the bottom that shows the distribution is not Gaussian. Using standard deviations when you’ve got heavy tails is a bad idea.
It’s actually a case of a frog in water that has been warmed by 0.5 C over a period of several years. People seem surprised that the frog did not notice.
Hansen’s Temperature Analysis: Today’s Normal is Yesterday’s Extreme–and Nobody Cares
WUWT cares, or it would not be making such an effort to convince you.
So what’s your prediction on when the ocean’s are going to start boiling? This decade or next?
Entropic says:
“WUWT cares, or it would not be making such an effort to convince you.”
Once again you’ve got it upside down. It is you who are trying to convince the rest of us that black is white, down is up, ignorance is strength, and Hansen’s GISS is not mendaciously inventing the past.
So far, you are failing.
Can we bury this frog meme, please? From Wikipedia:
Modern sources tend to dispute that the phenomenon is real. In 1995, Professor Douglas Melton, of the Harvard University Biology department, said, “If you put a frog in boiling water, it won’t jump out. It will die. If you put it in cold water, it will jump before it gets hot—they don’t sit still for you.” Dr. George R. Zug, curator of reptiles and amphibians at the National Museum of Natural History, also rejected the suggestion, saying that “If a frog had a means of getting out, it certainly would get out.”[2]
In 2002 Dr. Victor H. Hutchison, Professor Emeritus of Zoology at the University of Oklahoma, with a research interest in thermal relations of amphibians, said that “The legend is entirely incorrect!”. He described how the critical thermal maximum for many frog species has been determined by contemporary research experiments: as the water is heated by about 2 °F, or 1.1 °C, per minute, the frog becomes increasingly active as it tries to escape, and eventually jumps out if the container allows it.[3][20]
http://en.wikipedia.org/wiki/Boiling_frog
Corio37 – I think you are taking the frog story too seriously. It is a fable used as a prop to make a point. I doubt anyone thinks the frog is actually going to sit still long.
Burden of proof shall always lay with the conjecturer. Empirical data have not been supplied to back up the conjecture. Why nitpick the frogs? The petrie dish is empty!
“…To be honest, you are describing the frog in a pot of slowly heating water. The frog, unaware of the ultimate end game, sits quietly and croaks…”
I’ll have to try that. Get a frog, put it in a pot of room temp water (21C), and raise the temp of the water slowly at the estimated IPCC value of global warming – 0.2°C per decade (0.02 per year, or 0.00005479C per day). If boiling is 100 degrees, it could take about 395 decades for the water to boil.
You’re probably right. It would croak – of old age.
For you people who are too totally distracted by the frog fable to follow the OP’s badly constructed story and inevitable consequences, let me recap:
What he said:
Notice that he conjures a future, duration unspecified, where temperature continues to rise. Because he does not specify an end point we have to assume he believes this ho hum adaption will always work. Actually I doubt he’s thought it that far ahead as the entire premise is simplistic. If the world warms unabated it will kill everything but extremophiles at some point. Enter the frog fable – except being smarter than frogs (yes, it is a fable – in real life the frog will also notice) at some point we’re going to notice because we’re not extremophiles. And in the case of the frog fable, for those of you who are thinking of boiling water, just think about the temperature at which incompatibility with life is reached. It is not much higher than ambient, and far lower than boiling. I’ve never seen such loopy linear thinking. Summary: This is the OP’s scenario, not mine.
Perhaps he intended but failed to put a limit on increasing temperatures. Perhaps he assumed we readers would silently put a limit on increasing temperatures for him. Guesses aside regards his assumptions and intentions, his statement is juvenile as it stands.
My own analysis is this has already happened (limited warming and cooling) and world has already survived it and the mathematics in the shifting bell curves. The whole Hansen argument is vacuous and specious, and his conclusion is spurious. Condemning Hansen for this the OP got right. The warming forever without consequences he got wrong, frogs or no frogs.
OOg. If yer gonna quote a master, at least spell it right.
“Cheer” and “lose”.
I hypothesize that the correlation between warming (up to historical ranges well above any present prospect) have been very felicitous for human population and civilization. .
I’ve yet to see a smidgeon of contrary evidence. And lots of supporting.
OOg. Mentally mix-mashed two alternate sentences, above. Here’s a coherent version:
“I hypothesize that the correlation between warming (up to historical ranges well above any present prospect) and felicitous changes in human population and civilization is very high, and positive.”
There is about a 5 C difference between temperatures in mid-California coast and Portland Oregon. So a 2.5 C ‘global warming’ would be about the same as moving from Portland to Northern California…. In other words, imperceptible to most folks…
During summer, Sacramento can be 100 F when San Francisco is 70 F (or sometimes lower…) Call it 15 C. That’s also about 80 miles. So a 1.5 C warming would be about the same as moving 8 miles inland from San Francisco. I think that gets you all the way to the other side of the bay…
Yeah, I think folks can cope with that…
As you say in the caption of your Figure 1, increased temperatures will lead to more extreme events compared to the original curve. But as far as I can tell, Hansen is comparing temperatures using the original standard deviation, but the appropriate mean. As if the original curve were shifted appropriately to the right and you were comparing that curve to the second curve.
Still, my analysis suggests that he’s wrong. I wanted to avoid gridding of temperatures, so looked for all stations in GHCN v3 that had 27 or more (out of 30) observations in each of the eras 1920-1949, 1950-1979, and 1980-2009. In the US, there were 142 stations that met this requirement (i.e. had 90% coverage of July’s).
Then I detrended each era’s July temperatures and normalized them. The exception is that I normalized all three era’s data using the standard deviation of the 1950-1979 era, rather than using their own standard deviations. That way, it’s easy to compare which era had the most extreme high temperatures (positive normalized value) as compared to 1950-1979.
Then, I made a graph which uses color to indicate which era had the greatest normalized value and the size of the circle to give an idea of how many 1950-1979 SD’s the value was. In the bottom left of the graph are a tiny circle and a large circle, which indicate the values 0.1 SD and 6.0 SD (more extreme than any of the actual values) to give a sense of scale.
The resulting graph is: [IMG]http://i45.tinypic.com/148qrp.jpg[/IMG]
It looks like the 1920-1949 era was more extreme than the 1980-2009 era, though in different parts of the country. And the 1920-1949 era appears to have had larger extremes (larger diameter circles).
For what it’s worth.
We know that there was a certain amount of global warming in the last century. The official value is about 0.7 degrees C. Now, if we assumed that global warming is evenly spread over the globe (of course, in reality it isn’t) then you would expect lots of new record high temperatures, simply because of that added 0.7 degree. It would be a direct consequence of the original warming.
But suppose the global warming stopped precisely in 2000 and the average global temperature has been constant since then. Because of large short term variations that always happen, we could expect plenty of new temperature records since 2000, although the mean hasn’t changed.
In other words, talking about temperature records is meaningless in the context of global climate. The only thing that matters is the actual trend, which is easily seen merely by eye-balling the graphs. Unfortunately many people will think that new temperature records is proof that the world is still warming, while in fact it isn’t.
.
I think we face a similar problem in September. It looks like the Arctic will hit a minimum lower than 2007. You can be sure that we won’t hear the last of it. It will prove that the Arctic is in a death spiral and we really are all doomed. But if you forget the records and look at the trend, things look completely different. The ice extend did fall during the early noughties (ironically, precisely when global warming had stopped). But since 2007 it looks like it’s been bouncing along the bottom. As with temperatures, it’s been flat and close to the minimum so it’s extremely easy to set new short term records. Of course, earlier this year the Arctic ice actually reached the long term average but, by definition, it can’t set any new records.
As I said, I think we should forget short term records as they’re pretty meaningless. The trend is your friend, as the saying goes….
Chris
Someone correct me if I’m wrong, please. Doesn’t the global history of temperature – on a geological scale – vary about 7-8-9 degrees top to bottom, Jurassic Age to Ice Age? Isn’t it true on that scale, today’s temperature are slightly below average – maybe 3 degrees from Ice Age and 5 degrees from Jurassic? Shouldn’t this fact, if I am correct, make it somewhere into the modern day consciousness? As little as I claim to be an expert, I still know wayyyyy more about Climate stuff than your average Joe, just from memory, reading and interest. The average Joe, who is hit with Warmista stuff in the news every day, NEVER hears this is part of the story! If most skeptics are wrong (this slight increase is NOT mostly natural, CO2 signature trivial, third decimal place stuff) and most warmers are right (it’s predominantly man made, it’s a trend and it will accelerate), wouldn’t it STILL be prudent to wait 25-50-75 years until the mean temp reaches or exceeds average historical, before we start “changing things?”
“Case and point”? No, no. The expression is “case of Point”, referring to a Wisconsin beer brand.
The US records are not very relevant to Hansen’s claim. If this is the global warming that Hansen predicted in 1988, though, then it is going to accelerate. It’s now at the edge of natural variability viewed locally, which is what matters for adaptation. But the expectation is for it to continue to accelerate.
This is another crucial aspect to Hansen’s data. The acceleration of the change, barely suggested by the 1990s data but striking in 2000-2010 is consistent with an increasingly dominant anthropogenic signal, and there aren’t any other serious candidates.
mtobis says:
“The acceleration of the change, barely suggested by the 1990s data but striking in 2000-2010 is consistent with an increasingly dominant anthropogenic signal, and there aren’t any other serious candidates.”
Admit it, you’re just making that up. [Note the green line: the trend is decreasing, not accelerating.]
Smokey says:
August 24, 2012 at 1:19 pm
mtobis says:
“The acceleration of the change, barely suggested by the 1990s data but striking in 2000-2010 is consistent with an increasingly dominant anthropogenic signal, and there aren’t any other serious candidates.”
Admit it, you’re just making that up. [Note the green line: the trend is decreasing, not accelerating.]
=============
Curious. This looks like acceleration.
http://www.woodfortrees.org/plot/best/mean:60/plot/best/trend/plot/best/last:360/trend
Entropic man shows that he does not understand the difference between a temporary fluctuation, and a long term trend. Here is another view of the same data. Note that the long term trend remains within the long term parameters. Thus, no real acceleration. Using a chart with a zero baseline only makes it appear that there is unusual acceleration.
More evidence.
And more.
I have much more, just ask and I’ll post it.
Also, CO2 follows temperature. It is not a cause of temperature. Sorry about debunking your CO2=CAGW conjecture. But a good scientist would admit the conjecture was falsified, and MoveOn. [Note: a ‘good’ scientist.]
Entropic Man: using straight lines on real-world time series is naive. It’s the first thing someone does when they first use Excel, perhaps, but with time series it leads to ridiculous extrapolations.
Hansen’s analysis is fundamentally flawed. I had at first given him the benefit of the doubt, and assumed that he was comparing standard deviations but with appropriate means, but it now appears that he didn’t do that. He tried to address criticisms regarding the 1930’s by adding it to the baseline, but this is backwards. When you compare the 1950-1980 baseline to both 1980-2010 and 1920-1950, you find that 1980-2010 looks a lot like 1920-1950, except less extreme. It is the 1950-1980 era which is different from the rest of history, variance-wise, not the 1980-2010 era.
That doesn’t mean that warming has not occurred, just that the claims of increased extremes are erroneous because of improper statistics and because of the way stations are handled over time. Which is basic enough that it calls into question everything Hansen’s done.
I was really, really disappointed by Hansen’s analysis. The summary would be: “If it’s warmer now than it was 60 years ago, then when it’s hot it will be hotter than it was 60 years ago.” How easy it is to get published!
He throws a lot of text and graphs at it, but that’s basically it. Which I guess would be okay, except that he also talks about detrending data and shows graphs that would suggest that he’s doing more than that.
I had assumed that he was actually comparing volatility of temperatures, which is what I’d say a reasonable person’s understanding of “extreme” would mean. But after spending hours analyzing the GCHN v3 data (thanks, Steven Mosher for RghcnV3) and his paper, it’s obvious that Hansen was simply looking at 1980-2010 data using the 1950-1980 mean and standard deviation
So, having looked at June, July, and August in the US for the eras 1920-1950, 1951-1980, and 1981-2010, comparing appropriately-detrended values for each era normalized by the 1951-1980 era’s SD, it’s obvious that the 1980-2010 volatility was larger than than the 1920-1950’s era, but so was the 1920-1950’s. Which shows that the 1951-1980’s were actually an exceptionally torpid era.
(Maximum normalized June temperatures were 25% more likely to exceed 3 (1951-1980 sigma’s) in 1981-2010 than in 1920-1950, but July was 260% more likely to exceed 3 in 1920-1950 than in 1981-2010, and August was 38% more likely to exceed 3 in 1920-1950 than in 1981-2010. It’s really rather remarkably different from what Hansen presents. I suspect both his odd comparison and also effects of temperature infilling and and homogenization)