Global Warming: Man or Myth?

Scientists can also wear their citizen hats

Little Ice Age vs. Global Warming

with 40 comments

On Friday, September 24, 2010 I gave a public presentation on The Little Ice Age (LIA).  Click to view the presentation (PDF format).  Much of the historical information comes from my Little Ice Age in Europe Web page published quite a few years ago.

The LIA (a general cooling of the climate between the years 1150 and 1460 and a very cold climate between 1560 and 1850) brought dire consequences to its peoples. The colder weather impacted agriculture, health, economics, social strife, emigration, and even art and literature. Increased glaciation and storms also had a devastating effect on those that lived near glaciers and the sea.

So how does the climate change experienced during the LIA compare to what lies ahead?

Please view the presentation and consider the following:

  1. The climate in Western Europe was about 0.7C (1.3F) cooler than in the warmest part of the Medieval Warm Period.
  2. This apparently “slight” climate change had profound and devastating impacts on European civilization.
  3. It is expected that the global average temperature increase by the year 2100 will be 4C (7.2F).
  4. The climate change expected by 2100 is about 6 times greater than that experienced during the LIA.
  5. The causes of the LIA, if repeated today, may only put a dent in the expected warming heading our way.
  6. Although our modern technologically-driven society is better equipped to respond to climate change than our ancestors, is it reasonable to assume that such a large expected climate change will be beyond our ability to adapt resulting in biblical implications for this century?

Your opinions on the last question are welcomed.

Written by Scott Mandia

September 25, 2010 at 1:35 pm

Posted in Uncategorized

40 Responses

Subscribe to comments with RSS.

  1. What do you mean by “biblical implications for this century”?

    Mandia: Massive death, suffering, and hardship on a global scale. Essentially, a Mad Max scenario where society breaks down.

    Hunt Janin

    September 26, 2010 at 5:53 am

  2. Hunt,

    Pestilence is one of the biblical terrors. Australia is facing its biggest threat of locust plagues in decades. (A good season for crops is also a good season for these marauders.) We’re starting a huge spraying campaign in my own state this week – the others soon – and there are television ads telling people what to watch for and who to call if flighting is spotted.

    That’s fine for us. What if the same thing were happening in a poor country without the surveillance and control facilities we have? The locusts would wipe them out. Have you ever seen what the aftermath of a locust swarm over a crop or a garden looks like? It’s not pretty.


    September 26, 2010 at 10:33 am

    • Adelady makes a great point here. A few months ago, while travelling to the Riverland for Adelaide, I hit one of the swarms which took nearly an hour to drive through and caused driving conditions similar to driving through a heavy storm (I was unable to catch this, as I was driving, but caught results to the vehicle). They tell us to pull over and wait for it to pass, but I came back down this road around 5hrs later and had the same conditions again – this swarm was immense and did an incredible amount of damage to crops (the hatching of their eggs is having an effect now).
      Also climate zones suitable for malaria are increasing.
      The reason these were mentioned in the bible is likely to be because they did so much damage, leading to so many deaths historically. We’ve forgotten these fears with the relative ease of life in western societies (although not in most other regions). Ignorance of environmental degradation coupled with a changing climate will certainly lead to a re-cap of such lessons.


      September 26, 2010 at 7:32 pm

  3. Global warming has stopped. Objective application of science and engineering reveals the significant sources of temperature trends since 1895 including the temperature run-up late in the 20th century and the flat temperatures since. The predictions, by some in the Climate Science Community, of future warming (4C° by 2100) are high by a factor of about 5. Without human-caused global warming there can be no human-caused climate change or human-caused Global Climate Disruption.

    Research, with findings regarding measured and projected temperature trends is reported at The 6/27/10 pdf there presents a rational equation that accurately calculates the average global temperatures since 1895 with a coefficient of determination of 0.88. That means that it explains 88% of the measured temperatures for 114 years and counting. The best that GCMs have done is significantly less than this. The equation shows that CO2 is a minor (about 20%) contributor to the measured increase in average global temperature and predicts that the future trend of average global temperatures will be down. The above link and sub links, including links to the temperature data reported by the five reporting agencies, track the data back to the published credible sources. The work can be verified by anyone competent with a spreadsheet.

    From 2001 through August 2010 the atmospheric CO2 increased by 21% of the total increase from 1800 to 2001 while the average global temperature has not increased significantly and the trend of yearly averages from 2001 through 2009 is down. The El Nino that made early 2010 appear to be a bit warmer than the down trend, peaked in March, 2010 and average global temperature is now declining.

    This El Niño warmed the air enough for NOAA to announce the warmest ever period. They failed to say that ‘ever’ includes only the last 130 years or so. They also failed to mention that the new record was only 0.02C higher than their previous record. A more correct announcement would have been that average global temperature has not changed significantly for over a decade. Saying that the average global temperatures are the hottest on record is about as profound as saying that you drove 10,000 miles last year and the last 10 days were among the greatest distance traveled since the beginning of the year

    Dan Pangburn

    September 26, 2010 at 12:21 pm

    • Where do I begin?

      1. Anybody who states that global warming has stopped since 2001 does not understand the basic statistics of climate trend calculations. Please see: Global Cooling.
      2. Air temperature is but one measure of warming. There are multiple indicators (ocean heat, ice melt, etc.) that show warming has gone unabated. It is incorrect to claim that warming has stopped given that each of the past three decades has been warmer than the one before and each has set a new record in the modern era. Please see: Modern Day Climate Change
      3. There is about a 30-40 year lag between CO2 emissions and the subsequent increase in global T because the oceans take in more than 90% of the excess heat and oceans vent that heat very slowly. Again, there is a fundental lack of understanding if one tries to correlate CO2 levels in the past decade with the T during that time frame. See: Climate Change: The 40 Year Delay Between Cause and Effect
      4. Whether Dan knows this or not, claiming that T has decreased between 2001 and 2009 is a classic “cherry pick”. I have an entire blog post on cherry picking data called Chopping Down the Cherry Tree.

      Dan, you need to do some reading.

      Scott Mandia

      September 26, 2010 at 2:42 pm

    • I hadn’t bothered reading you comment right through until just now. But instantly, I noted a blatant lie.

      “The El Nino that made early 2010 appear to be a bit warmer than the down trend, peaked in March, 2010 and average global temperature is now declining.”

      That’s simply not true. If you look at AMSU data for the past decade, you find that 2010 global temperature didn’t peak until 15-16th of July and until about the 7th of September, this year was almost entirely warmer than the previous decade. At this point it’s dancing around with last years values, which is still above the pack.

      As for discussing that this temperature difference is small, that truly ignores the many biophysical indicators that clearly demonstrate that this apparently small change has indeed disturbed the timing of events (Rosenzweig et al 2008. or Thackeray et all 2010. being probably the most well known papers on this, but there are a few – for long term trends see Amano et al. 2010.)


      September 27, 2010 at 11:44 pm

  4. Hi Scott, I just saw that post and thought, geez, where do ‘you’ begin 🙂

    Too many are still in a state of confusion about trends analysis, context and relevance. Continued cherry picking of data sets without examining the whole picture seems to be the method of choice and those that simple don’t know how the science is done do tend to latch onto whatever meme suits their particular fancy.

    Dan Pangburn

    Context will get you relevance. Don’t get caught up in less relevant or irrelevant minutia. If you don’t look at the whole earth system, you will get stuck in a gully somewhere. If you don’t climb out of the gully, you won’t see what the scope of the science is telling us. The cooling thing is a dead end, unfortunately (though I do wish it were true). But my wishes or anyone’s opinions have little to do with science.

    The problem is that the climate system is now positively biased above thermal equilibrium. That means the earth now has to work out a new equilibrium based on the new bias. But there are other dominoes in the system that have yet to fall. so the new equilibrium can only occur once all the dominoes have fallen and found their new equilibria state.

    I guess the only way you could be right is if all the maths and the physics are wrong on the major climate signal above the noise. What do you suppose the odds are that your calculation trumps the body of evidence including the observations, trends analysis, physics, maths and models?

    Just remember, natural variability is not going to stop. It will just occur on a new path and that path has a positive radiative forcing bias. Positive does not mean cooling, no matter how fanciful our wishful thinking may be.

  5. Great short piece here Scott.
    When I read Dan’s first line, I thought, “Geez, a Jo Nova/Monckton parrot…”
    But you’ve provided some excellent grounds for Dan to start being acquainted with the relevant evidence-based conclusions.
    I recently watched that documentary, Jesus Camp – the home schooling part was disturbing. The mother tells the child that there’s nothing to worry about with climate change because the temperature anomaly is so small, but as you show here, “This apparently ”slight” climate change had profound and devastating impacts on European civilization.”
    I guess this is yet another point that needs to be emphasised more.


    September 26, 2010 at 7:39 pm

  6. Read my post again and this time look at the link. What part of a coefficient of determination of 0.88 on average global temperature since 1895 do you not grasp?

    The conflicting information, misinformation and obvious nonsense extant caused me to do my own research which involved thousands of hours over several years. My findings are completely documented at the link and sub links. Complete information is provided so anyone competent with a spread sheet can check them. Also at the link is a list of some of the mistakes that some Climate Scientists have made; apparently because they don’t understand a lot of the relevant science very well and are unaware of their lack of knowledge.

    The Argo Floats data at shows that the oceans abruptly stopped warming in about 2004. The sun hasn’t been this quiet this long since about 1913.

    I wonder how large the measured separation between the rising atmospheric carbon dioxide level and not rising average global temperature will need to get before some begin to realize that climate related papers that have been published in what have been called reliable sources are not reliable and that so-called peer review of climate related papers has been de facto censoring.

    Mandia: Dan, because your first comment here is filled with many mistakes, why should I believe anything I read in your link? We are all busy here and cannot respond to every equation that comes along that appears to be fringe science. The true test is to publish your work in a respectable journal and let the scientific community vet it there. Good luck.

    Dan Pangburn

    September 27, 2010 at 12:31 am

    • I can not find any mistakes in my first comment. Perhaps you could be more specific.

      You should not believe anything that I say without checking it. All the links and data sources are provided so you can do that. You can spot check the results by picking points off the graphs.

      Dan Pangburn

      September 27, 2010 at 9:50 pm

  7. Have you seen these, Dan?

    Click to access Recent_AABW_Warming_v3.pdf

    The ocean has been warming. Out of reach of a lot of the instruments, which weren’t doing a very good job. Seeing as they weren’t designed for this purpose that’s not surprising, but people who really know what they’re doing are gradually sorting it out.


    September 27, 2010 at 2:13 am

    • Effective Sea Surface Temperature (ESST), as described in the link, has accurately accounted for the complexities of the oceans for over a century. Any error in it is part of the 12% of average global temperature that the equation does not explain.

      Dan Pangburn

      September 27, 2010 at 10:36 pm

  8. Re Dan’s comments, in a recent post, Bob Grumbine makes the excellent point that science must be coherent. Climate science does not exist in some vacuum distinct from other areas of scientific inquiry — if our current scientific understanding of the climate system were wrong, then there’s a lot of other stuff that wouldn’t work either. As Bob states:

    “I think a crucial part of that error is a failure to understand how science works. While you and I (and others) look at it and see masses of scientists from different areas and reach a conclusion, others don’t. The extra piece of knowledge we have is that science has to hang together as a coherent picture. If climate people were seriously wrong about the radiative properties of CO2, then CO2 lasers would not work. And so on through a very, very long list. Conversely, if climate types were seriously wrong about CO2’s radiative properties, laser specialists would look at the climate work and point to the errors and that’d be the end of the wrong climate CO2 work.

    “Instead, they take the view that science is story-telling. Laser physicists go along with the climate people because the climate folks are telling a story that the laser folks like, not because there’s any particular evidence in favor of it. The “It’s a liberal conspiracy”, or “They only say this because they want to impose one world government” responses are part of this. The he said — she said journlistic line is exactly this, as the science is presented as two stories the reader is choosing between. They think the scientists are doing the same thing. (How would they know differently?)”


    September 27, 2010 at 2:42 pm

    • I don’t think that there is much disagreement about the radiative properties of CO2 among knowledgable people.

      As to climate science and specifically the GCMs and AOGCMs, the parameterization of clouds is a known source of uncertainty and possible bias. Several mistakes are discussed in the pdf published 8/11/10 at the above link.

      Dan Pangburn

      September 27, 2010 at 11:19 pm

  9. Dan Pangburn

    I did look at the link. You basically confuse natural variability with climate signal. You also don’t specify what you mean by the consensus. You then accuse scientists of doing what you are doing, that being “refuse to acknowledge some science” or ‘”not even be aware of some relevant science”.

    It’s an interesting argument technique that probably works on those less informed about the actual science (and the scientists), but it falls flat with those that know better. And you have just stepped into a web site where people know better.

    The obvious problems in your assertions are the ocean is in fact warming, both surface and deep ocean. The deep ocean measurements are a bit more challenging, but there is heat content that is unaccounted for and most scientists don’t think it is hiding under the bed, so probably in the deep ocean.

    As to the quite sun idea. I love the quiet sun. I hope it stays quiet for a long, long time. Unfortunately with this quiet sun NOAA/NCDC is reporting 4 months of this year with observed temps in those months as the highest in recorded history and the other 4 within the top 6 warmest.

    You need to understand what a positively bias in regarding radiative forcing compared to the relative thermal equilibrium of the Holocene.

    • Asserting that I “confuse natural variability with climate signal” is pretty vague. Perhaps you could be more specific. I derived a fairly simple equation, applied the best measured data to it and it calculated average global temperatures for over a century with an R2 of 0.88.

      The concensus is that dwindling group of climate scientist die-hards and their followers who still believe in AGW.

      I wonder how wide the separation will need to get between the rising CO2 and not-rising temperature for ‘people who know better’ to begin to realize that maybe they missed something.

      As to ocean temps, see my 10:36 post re ESST.

      As to observed avg global temps, see the last paragraph in my first post.

      “thermal equilibrium of the Holocene” sounds like you are trying to say that the MWP and LIA didn’t happen. I will settle for having discovered the cause of the 20th century temperature run-up.

      Dan Pangburn

      September 28, 2010 at 12:31 am

      • “The concensus is that dwindling group of climate scientist die-hards and their followers who still believe in AGW.”

        And you accuse others of being vague?

        “I wonder how wide the separation will need to get between the rising CO2 and not-rising temperature for ‘people who know better’ to begin to realize that maybe they missed something.”

        How about the fact that solar activity has slumped over recent decades? The temp anomaly may have slowed, but it’s still increasing and is really not following solar activity. Another great indicator of an amplifying greenhouse effect would be the number of warm nights per year (ie. more heat being trapped. See here.

        “As to observed avg global temps, see the last paragraph in my first post.”

        I also replied to that above.


        September 28, 2010 at 12:45 am

  10. Dan Pangburn

    The shear number of your incorrect statements and inferences is somewhat astounding. Let’s pick away though:

    I was specific enough in that you are mixing up natural variation with climate signal.

    You said “Global warming has stopped” and “flat temperatures since”

    Can you point out the flat part of this graph for me:

    You are saying it is flat ever since the late 20th century. What about the flat parts in

    1880 – 1919
    1920 – 1960
    1944 – 1989

    One can rejoice in the fact that global warming has stopped several times during the modern measured observation period. But that does not reverse or stop the upward trend.

    You may not know what natural variation, is so here’s a link to help:

    Your ‘flat part’ is within the natural variability signal range and still among the warmest decade in the climate trend.

    The climate signal is identifiable in the attribution

    Global warming does not stop natural variability.

    • Take the blinders off and look at the GISS data at
      It peaked in March 2010 and has been dropping steeply since.
      To avoid bias by using data from any one of the five reporting agencies I average them. If you had seriously looked at my stuff you would have known that. The graph of all five with some discussion is on page 9 of the pdf published 4/10/10.
      The significance is that this flat temperature period occurred during the 21% increase of CO2 (compared to prior rise which happened to concide with a temperature rise).

      Mandia: Have you learned nothing?

      To the rest of you: let us not keep going around in circles. I think it is clear that Dan is misguided so let us move on. If Dan mentions something new then by all means reply.

      Dan Pangburn

      September 28, 2010 at 8:23 am

      • And as I pointed out, repeatedly, you still don’t understand the difference between climate signal and natural variability.

        I’ll give you a hint though… one is long term trend and the other is short term variability. Can you guess which is climate signal and which is natural variation?

      • I’ve learned that some AGW believers apparently have logic and reading impairments.

        I’ve been aware for over a year that AGW believers apparently lack knowledge in a lot of relevant science and they are unaware of that lack of knowledge. Discussed further in the pdf published 8/11/10 at

        Dan Pangburn

        September 30, 2010 at 10:26 am

      • Dan,
        “I’ve learned that some AGW believers apparently have logic and reading impairments.”

        Note that Scott Mandia is a very relevant work scientist to this field.. I think I’m more likely to trust his interpretation of the data as well as the vast quantity of peer-reviewed literature that exists, also combined with the many experts in my own field of eddy flux micro-meteorology than one individual who claims his work “published” because it appeared on a guess post on another blog – by your standard, I must be a veteran science writer!

        You’re graphs are fascinating! Where the models used in many scientific papers have roughly matched fairly well with observed data and continue the upward trend, yours suddenly plummets based on the decrease in slope over the past decade – talk about wishful feeding.


        September 30, 2010 at 6:36 pm

  11. Dan Pangburn

    “That means that it explains 88% of the measured temperatures for 114 years and counting.”

    I agree with Scott here. Get it published in the peer reviewed literature and let’s see what the peer response is. You certainly have not scientifically supported your position though with your statement. Let’s see the paper.

    You claim CO2 increased from 2001 to 2010 by 21%? How did you arrive at this conclusion? What’s your base line? Since pre-industrial? Since 1880? 1850? 1750? 1958? Show your context.

    Then you ignore natural variation and say temps should have gone up in this short span (as I said)?

    Then you bring up El Nino, and again ignore natural variation.

    Your 10,000 mile analogy is worthless. For example: What do the last 10 days matter if at the end of the trip you fall off the edge of the earth because it is flat anyway?

    Everything needs context and you don’t have real context in your claims. If you have 10,000 good hours in a row and then a mugger shoots you, that last hour may have nothing to do with the previous 10,000 hours. Maybe you just went down the wrong alley that day. Or maybe, or maybe. Context gets you relevance.

    • Carbon dioxide levels:
      The years are all clearly stated. Here are the values:

      year, value ppmv, source
      1800, 281.6, avg of 2 at Siple2 and 1 at Lawdome
      2001, 371.1, Mauna Loa
      Aug 2010, 389.9, Mauna Loa

      (389.9-371.1)/(371.1-281.6)*100% = 21%

      Read it again, I said “the average global temperature has not increased significantly” [from 2001 to now according to the average of the 5 reporting agencies].

      The observation that something is warm has nothing to do with whether it is still getting warmer. The observation of melting ice indicates that it is warmer than it was. It does not prove that it is still getting warmer.

      Dan Pangburn

      September 30, 2010 at 8:05 am

      • Follow the logic.

        – Fill a pot of water.
        – Measure the temperature of the water.
        – Turn on the flame under the pot.
        – Measure again in 5 minutes.

        You notice a slight rise in water temperature. Now, without changing any conditions, would you guess that in 5 minutes it would be warmer or colder?

        David Archer did a wonderful video series covering the basics that will help you understand:

  12. Dan Pangburn

    Clouds do have uncertainty. But again context is key. Can you show me that it was not warmer in the Eocene maximum and quantify the relevant factors regarding clouds and for example Richard Lindzens iris Effect preventing that temperature increase? First you have to prove it was not warmer in the past though.


    The consensus among working climatologists is that we are warming ad it is human caused. The dwindling you are speaking of is coming from those that don’t work in the field.

    Again, what you or I believe has nothing to do with the reality of maths, physics, or the observations. Beliefs, die-hards, etc. are a non starter in the argument when it comes to science.

    “sounds like you are trying to say that the MWP and LIA didn’t happen.”

    Classic red herring spin. Of course the MWP and LIA happened. Context is key. Ever head of a D/O event?

    Start reading up on ocean currents and ‘ocean heat content overturn’.

    • It will be interesting to see what happens to this “The consensus among working climatologists is that we are warming” in 5 years or so. Trenberth already thinks it’s a travesty that he can’t explain the current separation between the rising CO2 and not-rising temperature.


      See my post at 10:36 on 9/27

      Oops, day job is calling . . .

      Dan Pangburn

      September 30, 2010 at 8:23 am

      • As I recall, Trenberth was referring to is the fact that we don’t yet have a handle on the natural variability, which is pretty much what every climate scientist says. So that’s not news.

        It’s important to distinguish that between short term weather and long term climate, there is natural variability, which does not have strong predictability in the relevant intra or inter-decadal time periods as yet.

  13. I should add to the context for LIA with Maunder and Dalton minimums.

    It seems that altering radiative forcing even a little bit for an extended period of time can have a strong impact… as Scott so clearly pointed out in his presentation ‘Little Ice Age vs. Global Warming’.

    What we should be thinking about is that if a 0.2 W/m2 change has that large an impact on the downside. What sort of impacts and magnitudes are expected with a 1.6W/m2 increase in radiative forcing?

    Well at least some of us are thinking about it.

  14. Moving back to the original post (which was an excellent piece of context – if the LIA is the effect of 0.7ºC cooling, then what will be the effect of 2, 4 or 6ºC warming?), I was interested in the claim at the end that our modern technologically-driven society is better equipped to respond to climate change than our ancestors. On the one hand, you could argue that we are better equipped, on the other, that we have much, much more to lose. Global population is many times what it was during the LIA and the total value of sunk costs in infrastructure is orders of magnitude greater. We’re trying to protect a much larger target.

    Byron Smith

    September 28, 2010 at 3:09 pm

  15. Byron Smith,

    Thank you for bringing up relevant considerations. As I mentioned above. The radiative forcing change to create that temperature change was only 0.2 W/m2.

    Given that such a small change can produce relatively large impacts for the human race. +’s and -‘s all in, we are looking at +1.6 W/m2 on the mean of the estimations within the error bars and this does not yet include all slow feedbacks.

    Now add to this the fact that Net Primary Production is not holding up as many of us expected and we’ve got an interesting scenarios unfolding here:

    Unfortunately, that’s only part of the problem.

  16. Reisman 9/30 8:46

    And if the water temperature does not increase significantly the heat must have been turned way down or off. (I think that this is a dopy analogy to climate or even weather)

    Dan Pangburn

    September 30, 2010 at 11:17 am

  17. I wonder how much longer the increasing separation between the rising CO2 and not-rising temperature will be rationalized by “…we don’t yet have a handle on the natural variability…”

    Mandia: By the end of this decade we will have set another new warmest decade and likely be smashing the previous decade. The warmth of the past decade is due to the CO2 emitted from the 60s and 70s. Our current decade is warming from the CO2 of the 80s and earlier. This is the reason that each of the past three decades set records and why the long-term warming trend will increase non-linearly. If India and China ever regulate their pollution, we are really in big trouble because pollution from these two countries in particular is offsetting some of the GHG warming.

    Dr. Hansen predicts that 2012 will likely set a new global T record.

    Dan Pangburn

    October 2, 2010 at 9:45 am

    • The observation that temperatures rose does not prove that they will continue rising. It’s not that complex of a concept. See my post at 9/30, 8:05 am.

      Currently, measurements show that the CO2 increase (see my first post above) added about 20% to the temperature rise in the 20th century. I expect that future measurements will show this to be high. A graph showing the declining trend of calculated CO2 influence is included on page 4 of the pdf that was made public 6/26. Next calculation awaits completion of 2010 measurements.

      Dan Pangburn

      October 2, 2010 at 12:02 pm

  18. […] Hockey stick shape.  Warmer Medieval Warm Period (MWP) followed by cooler Little Ice Age (LIA) and significantly warmer temperatures in the modern […]

  19. Reading these comments from last year piqued my curiosity as to “who is Dave Pangburn.” A quick search brings him up on Facebook. He shows just one title under books, you guessed it – the Bible.
    A little knowledge is a dangerous thing.

    Ross Cann

    May 23, 2011 at 1:51 pm

    • To quote Dan above, “I’ve learned that some AGW believers apparently have logic and reading impairments.”

      Seems even more comical in response…


      May 23, 2011 at 7:06 pm

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: