Hansen’s Temperature Analysis: Today’s Normal is Yesterday’s Extreme–and Nobody Cares

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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49 thoughts on “Hansen’s Temperature Analysis: Today’s Normal is Yesterday’s Extreme–and Nobody Cares

  1. Very true. What’s more is that people live all around this planet from very low temperatures to very high temperatures. Folks living in Ahwaz and Kuwait deal with average highs of 46.7oC (116.1oF). DC has a long way to go before they reach that still-liveable-level. And thanks to cheap electricity, everyone spends most of their day in comfortable climate controlled environments.

    But where Hansen and his ilk will take this argument is that it’s all about the rate of change…the so-called fact that temperatures are going up and they aren’t coming back down unless we take action, while positive climate feedbacks will accelerate this temperature increase to a tipping point from where there is no return from becoming a climate like Venus.

    And that requires a crystal ball, or a couple climate models, or both. And like the soothsayers of the past, there is big money in making predictions and scaring people.

  2. 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.

  3. The greater metropolitan District of Comedy is a massive Urban Heat Island, as are most major metropolitan areas. While Hansen attributes the changes to CO2, it is likely that UHI has had a greater impact, particularly on Tmin, as noted by Dr, John Christy in two posts on Dr. Spenser’s blog.
    It appears that Dr. Hansen is having increasing difficulties discerning the difference between “what he knows”, “what he thinks he knows” and “what he believes”.

  4. Even taking figure 1 as scientifically supportable, it’s zohneristic to highlight the increase in extreme warmth without highlighting the decrease in extreme cold.

  5. When the world was passing in and out of MWP/LIA/stable climate periods people were subject to these statistical artifacts multiple times. People with no education, kings, and paupers, survived. Since the last true climate change we have learned to fear what those people adapted easily to. We have also learned to exploit the information, promulgate fear, and grow powerful from controlling that fear. Not unlike the old Chicago mobs.

    Someone should plot the growth of scientific corruption in the field of climate and the growth of fear mongering over time. Toss in government money spent on this over the same time frame.

  6. I take umbrage with this article because it relies on a statistics to arrive at frequency of extremes in a warmer world while ignoring the laws of physics which dictate changes in the variability that the statistics are trying to predict.

    The laws of physics require that low temperatures (night time, winter, high latitude) will see MOST of the change and high temps (day time, summer, low latitude) will see the LEAST change. So on that basis alone it does NOT follow that an “average” temperature increase will drive high temperature extremes commensurate with the statistical analysis shown.

    FURTHER, if we’re talking extremes in terms of temperature, we must consider both ends of the scale, which means that we must also ask; What happens to extreme lows? The answer is that since the physics requires that temperature increases be heavily weighted toward low temps, that means fewer extreme lows. Going back to the same statistical analysis and applying it to both ends of the spectrum with the physics in mind, we’d see more extreme highs, but no nearly so many as predicted, and we’d see fewer extreme lows by several times that amount. By looking at both ends of the spectrum we would expect to see FEWER extremes as a total, not to mention that extreme heat kills a tiny fraction of the number of people that extreme cold kills every year.

    But let’s not stop there, let’s consider OTHER forms of extreme weather. Temperature differentials are what drive the wind and all the extreme weather associated with it. The daily heating and nightly cooling due to the planet’s rotation is part of the story, the other part being that heating in the tropics is much higher than heating in the high latitudes. This creates energy imbalances that try to even themselves out by moving energy from high concentrations to low via air and ocean currents. Going back to the physics, since the least warming happens in the tropics and day time highs, while the most happens in the high latitudes and at night time lows, the temperature of the planet becomes more uniform. The more uniform the temperature, the fewer extreme events we see that are driven by temperature differential. Indeed, we’ve been measuring Total Cyclone Energy for about 30 years now and it has been steadily dropping.

    So while I understand the author’s premise that yesterday’s extremes are today’s normal, it simply doesn’t follow that we’ll see more extremes in a warmer world. Will see marginally more extremes of some specific types, but for the majority of the extremes that matter, extreme lows and extreme storms, the physics says we will see less.

  7. The problem with people like Hansen is and always has been that they assume that linear projection they are plotting will continue on its present course forever. Tain’t so.

    As long as the temperatures remain in the range we now enjoy, food production will support this rather large human population. The bad part is going to be when the temperatures begin to drop again. Then humanity — and all life — will be facing a challenge. Only the most adaptable and durable will survive.

  8. davidmhoffer (# August 23, 2012 at 9:15 am),

    I my article I am talking about seasonal (summer) average temperatures. So an extreme event, in my analysis, is an unusually warm summer. Which will (without a shrinking of the variance) become more frequent as the average temperature increases.

    I am making no comment here as to the impacts of a changing climate on other types of extremes, although I have discussed them on other occasions in the back issues of both at Master Resource and World Climate Report.

    -Chip

  9. pcknappenberger says:

    August 23, 2012 at 9:27 am
    dp (# August 23, 2012 at 8:56 am),

    Except that we are not croaking, but thriving.

    And only the warmists say we’re in a cooking-pot (a closed system).

  10. “Cheere up Brian. You come from nothing, you end up as nothing. So what’ve you got to loose? Nothing!”

    From “Always look on the bright side of life – Eric Idle”

  11. “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.”

    Even frogs are smarter than whoever thought up this silliness…

  12. Perhaps it should be noted that Hansen’s “climatology”, only includes 30 years, if it had included 60 years, i.e., an earlier positive phase of the PDO, the increased frequency of extreme events might also have been closer to the real normal and warming might have been more realistically seen in the perspective of natural variation.

  13. pcknappenberger says:
    August 23, 2012 at 9:27 am

    dp (# August 23, 2012 at 8:56 am),

    Except that we are not croaking, but thriving.

    We’re not in the end game yet. But there may not be one. The end game in this context means the temperature continues in one direction until it annihilates humanity as Hansen suggests. Neither of us thinks that is going to happen, but your depiction doesn’t make a case for that. You’ve best described the frog in the pot by suggesting we’ll quietly adapt, giving no thought to the change or the consequences.

    I suggested in my second post that this has been going on for a long time and agree it is part of the natural adaptability of many species, but to describe it as an idyllic unnoticed byproduct of climate evolution seems to me a poor argument. It is the path of the uninformed and I think more than ever skeptics need to present an informed perspective.

    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.

    It is true that nobody I’m aware of anyway craves the temperatures common during the LIA, and the subsequent warming is now ho hum. For how long will this be true? It cannot be forever, obviously, because life is not compatible when the temperature rises above a certain level. We will certainly notice. Why introduce this unsupportable position?

  14. “dp says:
    August 23, 2012 at 8:56 am
    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.”

    Like many analogies, this steaming, overheated one comes from the anal region.

    How about a frog in a pot of cool water? As the water warms to room temperature, the frog will likely find a mate, reproduce and soon tadpoles will be swimming around in the pot.

    That’s the last 20,000 years in a nutshell.

  15. Figure 1 caption confuses the vertical mean lines being compared, calling them both “red vertical lines”, one in parentheses and the other not.

  16. It seems to me that the assumption of a Gaussian distribution for temperatures isn’t necessarily valid. I think a Levy distribution (long tailed) is most likely the case. In other words, year after year the climate doesn’t change much but the climate can change in large amounts, and we really can’t say it’s changing infrequently, at least in the last 500K years.

  17. pcknappenberger says:
    August 23, 2012 at 9:36 am
    davidmhoffer (# August 23, 2012 at 9:15 am),
    I my article I am talking about seasonal (summer) average temperatures. So an extreme event, in my analysis, is an unusually warm summer
    >>>>>>>>>>>>>>>>>

    Yes, I get that. But your statistical model is linear and so results in a frequency of unusual summer temps that is too high, and focusing on summer events alone is misleading. In fact, it is a fallacy.

    If you surveyed people in the temperate zones (where the physics requires that the bulk of these effects be their most pronounced) and asked them if they thought that 5% more extreme high summer temps per year was a bad thing, you would get one result. If instead you asked if 40% fewer extreme lows in winter but the price is 5% more extreme highs in summer was a bad thing, you would get a completely different answer. If you broke the results down by latitude, they’s be increasingly skewed toward “are you kidding me? that’s a GOOD thing” at higher latitudes.

    Per Einstein, every problem should be made as simple as possible, but no simpler. I understand and even agree with your sentiment, but I think it over simplifies the issue and leads to a perspective that excludes the MOST important aspects of warming that the public in general needs to understand.

  18. Doug Huffman (#August 23, 2012 at 10:16 am ),

    Thanks. I fixed it in my original post over at Master Resource.

    -Chip

  19. I’m not so sure that bell curves apply in this case. And I’m absolutely sure that global warming will NOT shift the curve in the simplistic manner shown. The right hand side of the curve would move a tiny bit to the right; the left hand side could move a little farther to the right. The putative mechanism for global warming is via radiation, which is driven by T^4. The high temperature hand side of the curve therefore resists moving to the right, the low temperature side, not as much.

  20. pcknappenberger,

    Allow me an analogy to go along with my earlier comment.

    If you were told that there would be an extra $1,000 in tax deductions on your next pay check, I’m guessing you would think that is a bad thing.

    If you were told that your next pay check would be an extra $4,000, less $1,000 for taxes, I’m guessing you would think that is a good thing.

    Your article focuses on the extra tax, and that is my problem with it.

  21. Record extremes are so full of artifacts the results are meaningless. The only way to determine high-max and high-min record increase is with long standing well maintained sensors, with filters added to remove El Nino and La Nina immediate affects and echoes. The timing and location of station drop-out and new station add-on, not to mention poor station quality control will muddy the results and produce spurious statements like Hansen’s.

  22. davidmhoffer (# August 23, 2012 at 10:37 am ),

    I don’t think we are in disagreement. Recall, from my article that I stated:

    “For one thing, it is not clear to me that warmer (and higher atmospheric CO2 levels) isn’t in many ways better.”

    You’re discussing detals that I just didn’t go into for the purposes of my article…although you clearly thought that I should have :^)

    -Chip

  23. Hansen thinks that:

    The most important change…is the appearance of a new category of extremely hot summer anomalies

    Supposing global warming does start up again (unlikely in my opinion), the most important change will be the disappearance of an old category of extremely cold winter anomalies. It is very clear that in terms of human impact, cold extremes do more harm than hot extremes at current tempertures.

  24. When dealing with extremes, one should be using an extreme value distribution (rather than normal) in their statistical analysis. Record temperatures are extreme values. The time between an old record and a new one follows an extreme value distribution rather than the shifting of the tail of a normal distribution. The length of the period that records are kept is another factor to consider.

  25. 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?

  26. 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.

  27. 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.

  28. dp says:
    August 23, 2012 at 8:56 am
    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.

    So what’s your prediction on when the ocean’s are going to start boiling? This decade or next?

  29. 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.

  30. 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

  31. 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.

  32. 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!

  33. “…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.

  34. 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:

    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.

    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.

  35. Vince Causey says:
    August 23, 2012 at 9:43 am

    “Cheere up Brian. You come from nothing, you end up as nothing. So what’ve you got to loose? Nothing!”

    From “Always look on the bright side of life – Eric Idle”

    OOg. If yer gonna quote a master, at least spell it right.
    “Cheer” and “lose”.

  36. 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.

  37. 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.”

  38. 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…

  39. 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.

  40. 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

  41. 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?”

  42. “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.

  43. 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.]

  44. 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

  45. 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.]

  46. 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.

  47. 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)

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