Michael Mann’s Hockey Stick Rules out CO2 as Cause of Global Warming


It appears that the #1 requirement to succeed in the field of Climate Science is the inability to read very simple graphs and understand their meaning. Al Gore first demonstrated this requirement when he produced the Ice Core data to defend his CO2 drives temperature theory. The problem is, the chart he used as evidence ruled out CO2, it didn’t implicate it. 100% of temperature maxima in Al Gore’s charts are above current temperatures and we have higher CO2 levels today. Additionally, CO2 lags temperatures from between 800 and 1500 years. For CO2 to be the cause of the temperature variation, the cause always has to lead the effect. Lastly, there is absolutely no defined mechanism where CO2 would increase before temperatures to pull the globe out of an ice age, and no mechanism by which CO2 would decrease before temperatures to end an ice age.


Michael Mann, apparently inspired by the complete and utter ignorance of Al Gore, decided to improve upon this concept and manufactured the “Hockey Stick” to make his case that CO2 drives temperatures. In fact, it does just the opposite. If Michael Mann understood how to read a chart, he would understand that his “Hockey Stick” rules out CO2 as the cause.

CO2 between 1000 and the start of the industrial age was extremely stable. According to ice core records it bounced around in a very narrow range of 275 to 285 ppm. In other words, CO2 was a constant for the vast majority of the time covered in the Hockey Stick. As a refresher, constants in a model can’t cause variation in the dependent variable. That is why they are called constants. Constants cause shifts in, not movements along the chart. The standard deviation of a constant is zero, and the variation it causes to the dependent variable is zero. Let me say that one more time for emphasis. For the vast majority of the time covered in Michael Mann’s Hockey Stick chart, CO2 was effectively a constant.1ac

Now, with an understanding that a constant can’t cause a variation, just look at the Hockey Stick chart. It suffers from the most extreme case of Heteroscedasticity I have ever seen in a chart claiming to support a theory that passed “Peer Review” and was accepted as the basis for a “Consensus.” That chart would fail any econometrics 101 class, and most likely fails other tests to qualify as a BLUE Variable (Best Linear Unbiased Estimator). In the year 1000 temperatures range from +0.4 to -0.8, around the year 1350 temperatures range between +0.6 and -1.0. By the time we get to 1902, variations are down to -1.0 to -0.7. In other words, as CO2 increased, temperature variation DECREASED!!! And was still falling until 1902.


Suddenly then, at year 1902 in the chart, Michael Mann discovered something called a thermometer and started adding instrumental data. The chart immediately dog-legs. There is nothing about the physics of the CO2 molecule that would support a dog-leg in temperatures with an increase in CO2. CO2’s absorption of LWIR demonstrates a logarithmic DECAY!!! Temperatures wouldn’t dog-leg up, they would gradually flatten. They must not teach how to use MODTRAN or Quantum Physics where Michael got his Ph.D. Either that, or he failed both miserably.


Many things can cause warming, not just CO2. H2O is by far the most abundant and potent GHG. It is so potent that it makes CO2 irrelevant in the lower atmosphere. No that is not a typo, CO2 is irrelevant in the lower atmosphere. H2O saturates the absorption of the same wavelengths CO2 absorbs. Had Michael Mann taken a course on MODTRAN he would have known that. 100% of the proxies and instrumental records Michael used are taken from the layer of the atmosphere unaffected by CO2. Don’t take my word for it, here are the MODTRAN results for doubling CO2 near the surface. There is a 0.00 change in the Upward IR Heat Flux.

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In reality, because Michael doesn’t understand basic science, what his chart really measures is the impact of non-CO2 factors like the Urban Heat Island Effect and atmospheric H20. Because CO2 evenly blankets the globe, CO2’s influence is evenly distributed. Multiple sources only complicate the issue and greatly increases the error of models and data. Had Micheal controlled for such factors, his instrumental data post-1902 would have been flat and showed no warming at all. Antarctica is the ideal control for the Urban Heat Island Effect and atmospheric H2O and it shows no warming since 1902.

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While CO2 doesn’t correlate well with temperatures controlled for H2O and the Urban Heat Island Effect, the sun is highly correlated.


Most ironic however is that the layer of the atmosphere that CO2 does affect, the Stratosphere, its influence is to COOL, not warm. No that isn’t a typo or a joke, CO2, through its rapid radiative effect, speeds transport of energy into outer space.

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Michael must also have failed Geology 101. CO2 has been as high as 7000 ppm and never caused catastrophic warming, and shows no relationship to temperatures on a geologic scale. The globe also fell into an ice age when CO2 was 4000 ppm, or 10x the level it is today.

1937 co2

Lastly, Michael must have failed or never took ethics. He conveniently Cherry-Picked the past 1000 years to reconstruct, ignoring hundreds of years of instrumental data. Ice core, tree ring, and coral proxies go back much further. He also chose the N Hemisphere, whose temperature has a much greater chance of being influenced by non-CO2 factors. Had he chosen to reconstruct a more appropriate time, the entire Holocene, he would have found that we are nowhere near the peak in temperatures for the current warming period, and all previous Holocene temperature optima occurred at lower CO2 levels. Had he chosen a location that controlled for H2O and the Urban Heat Island effect, his chart would be sending the warning that we may be slowly sliding into the next Ice Age.


In conclusion, Michael Mann is an expert in sophistry, not science. It is that simple. The biggest crime, however, isn’t the piece of garbage Michael Mann produced, it is that his piece of garbage passed “Peer Review” and is the foundation of the “Consensus.” Everyone on the “Peer Review” panels that reviewed this piece of garbage should be charged with criminal incompetence, and barred from ever reviewing scientific literature. As a remedy, Michael Mann should be forced to return any Federal Dollars he used to create this piece of garbage, as well as being barred from ever receiving Federal Dollars in the future. Michael Mann and his cabal of “Peers” are the scientific equivalents of FBI Agent Peter Strzok. They were granted a position of public trust and betrayed that trust on a scale rarely seen in history. Time for Trump to do what he is doing to the FBI to the field of Climate Science.

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And as for those Yamal tree samples, they came from only 12 specimens of 252 in the data set… while a larger data set of 34 trees from the same vicinity that weren’t used showed no dramatic recent warming, but warmer temperatures in those Middle Ages.

Scientific critics have also raised another looming question. Since Mann’s 1,000-year-long graph was cobbled together using various proxy data derived from ice cores, tree rings and written records of growing season dates up until 1961 where it then switched to using surface (ground station) temperature data, then why change in 1961? Some theorize that maybe it’s because that’s when other tree ring proxy data calculations by Keith Briffa at the East Anglia University Climate Research Unit (CRU) began going the other way in a steady temperature decline.

After presenting these unwelcome results to Mann and others, Briffa was reportedly put under pressure to recalculate them. He did, and the decline became even greater.  As recorded in ClimateGate e-mails, this presented what Mann referred to as a “conundrum” in that the late 20thcentury decline indicated by Briffa would be perceived by IPCC as “diluting the message”, that there was a “problem”, and that it posed a “potential distraction/detraction”. Mann went on to say that the warming skeptics would have a “field day” if Briffa’s declining temperature reconstruction was shown, and that he would “hate to be the one” to give them “fodder”.

In an e-mail sent to Mann and others, CRU’s director Dr. Philip Jones reported“I’ve just completed Mike’s [Mann’s] Nature [journal] trick  of adding in the real temps to each series for the last 20 years (i.e., from 1981 onwards) and from 1961 for Keith’s  [Briffa’s] to hide the decline [in global temperatures]…”  Then all of the proxy and surface measurement chartings were presented in different colors on a single graph, and Briffa’s were simply cut off in a spaghetti clutter of lines at the 1961 date.


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11 thoughts on “Michael Mann’s Hockey Stick Rules out CO2 as Cause of Global Warming”

      1. It reduces his silly papers impact since HALF of the world was never covered, after all he made it seem like his half backed paper was global in coverage with his 1998 as being hottest year on record babble (purportedly based on global temperature coverage), yet his paper isn’t global at all and in fact barely cover any part of Northern Hemisphere either.

        Bristlecone Pine trees inhabit a tiny spot in Western America in a niche climate slot, that doesn’t come close to being a representative sample of the climate in Western America. That alone should have been enough to show how absurd his claims were.

        I knew it was JUNK when it first came out, by this alone.


  1. Very nice! … I would add that, there is no such thing as a “greenhouse gas” … no gas in the universe can “add” additional heat to our atmosphere and especially cause an object (the surface) to heat itself.

    But otherwise, fantastic article! … very well done!


    1. Squid, thanks for the comment. I hear what you are saying, but this isn’t Newtonian Physics, it is Quantum Physics. Yes, it can’t add energy to a system, but it can change in form. The radiation from the sun travels through space at 0.00 K, but once it hits something that absorbs it, it converts that EM radiation to heat. In that sense, through the conversion of one form of energy EM Radiation, to kinetic heat energy, it can in fact add heat to a system. Same thing happens when you strike a match and burn a fire. You are converting chemical energy into heat/kinetic energy. If you look at the stratosphere, the coolest it gets is the temperature consistent with thermalizing 13 to 18 micron LWIR. That is the contribution of CO2 in the atmosphere. Thanks for the comment.


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