Climate Statistics Prof rips climate model claims: Certain Trade War over Uncertain Models — a response to Professor William Nordhaus,

June 8, 2015: Certain Trade War over Uncertain Models — a response to Professor William Nordhaus, sent to the New York Review of Books.

                                                                                                June 5, 2015
Letter to the Editor, New York Review of Books:

William Nordhaus must really be convinced that a catastrophe will unfold if, as the UN’s Intergovernmental Panel on Climate Change predicts, industrial emissions of carbon dioxide raise the concentration in the atmosphere of this generally beneficial warming gas from four hundredths of one percent to eight hundredths of one percent over the next 100 years   (A New Solution: The Climate Club, June 4, 2015).

After all, Professor Nordhaus is willing to start a global trade war by forming a “Climate Club” of governments who agree to place heavy tariffs on the products of governments who refuse to join them in sharply restricting their emissions.  (One hopes that the Club would exempt Africa from this trade war, since life expectancy there hovers in the mid-50’s, and at present only carbon-based energy can deliver electricity to the 75 percent of homes that currently lack it.)

What is the basis for Professor Nordhaus’ conviction?  Like the UN, President Obama, and members of the Democratic Party as a rule, it’s the models: “Scientists are increasingly confident that the basic results of climate modeling are accurate.  Climate models calculate that past emissions have contributed to warming of almost one degree centigrade over the last century, with rapid continued warming projected over the present century and beyond.”  Professor Nordhaus claims that there have been “disruptions” of the climate to date due to this tiny warming, and that there are “potential dangers” to come.

As someone who has helped students in math modeling and statistics classes sort through these sorts of hypotheses over the past decade, I cannot share Professor Nordhaus’ certainty on either the causes or the effects of the warming to date and the predicted warming to come.  The models do not, in fact, attribute the recorded 1.2 degree Fahrenheit (or .7 degree Celsius) rise in temperature since around 1880 entirely to human-based emissions of warming gasses.  (And remember, this is a very rough estimate of the rise, since methods of producing a “global mean temperature” have varied widely in global coverage and accuracy over this period.)

Fully half of the rise came before human-based emissions were large enough to have much effect.  The computer models attributes that warming, from 1880 to 1940, to the very difficult-to-measure variables of solar power and decadal ocean oscillations that they choose to exclude as causes in more recent years.  The IPCC’s finding is only that it is “extremely likely” that “most” of the half a degree rise from 1960 to 2000 (when a 15-year “pause” ensued) was due to human-based sources.

Even that claim is highly suspect.  The “time-step” computer models of the climate that predict conditions in the near future, and then use those predictions to estimate conditions in the next near-future, have not, in fact, gotten fundamentally more convincing since the 1950’s.  There was a reason that Cold War professor John von Neumann gave up trying to use climate models to prepare a U.S. “climate war” that would cause drought and starvation in the Soviet Union.  Models of our complex and chaotic climate system simply don’t make useful predictions after a few days’ time.

The climate models have gotten more complex, for sure, with thousands of estimated parameters for warming potential, vorticity, circulation patterns, absorption of heat, pressure, energy, and momentum by various layers or atmosphere, land, ocean, and sea-ice.  But they are still like models of the stock market, based not just on theoretical causations, but on correlations in conditions that will never be repeated.  This makes prediction, well, unpredictable.  A climate model runs on many imperfect assumptions, including crucially the precise warming potential of carbon dioxide.  It must be constantly “tuned” to control its predictions, since slight changes in any of the thousands of assumptions and parameters can cause it to explode upwards or nose-dive to zero in future time periods.

The modelers themselves call their future estimates “scenarios” and not “predictions.”  They agree that their models’ workings are partially based on ideal theory and partially based on “opaque” equations, since they must play with the levels of parameters representing the unknown effect of the interaction of numerous variables until they get a nice “back-fit” with previous temperature records.  What the models are not based on is a sound knowledge of what in the world causes our global temperature to move the way it does.

Every 100,000 years the earth experiences a swing of 20 degrees Fahrenheit down and up.  Atmospheric physicists agree that this swing is very likely caused, at some remove, by one of the “Milankovitch cycles,” because the earth’s orbit oscillates between a nearly-perfect circle to a five percent oval and back during this period.  As Oxford physicist Fred Taylor has written, however, the amount of solar power reaching the earth is not significantly affected by this change in orbit, and nobody has identified either the initial mechanism or the feedback mechanisms by which the temperature responds.  Given the difficulty of identifying the source of a 20-degree oscillation, a little humility is in order about our knowledge of the cause of a fairly typical change of one degree in one hundred years.

Caleb Stewart Rossiter

Adjunct professor, Department of Mathematics and Statistics, and
School of International Service, American University, Washington, DC


6 Responses

  1. “a little humility is in order about our knowledge of the cause of a fairly typical change of one degree in one hundred years.”

    A little humility…from liberal despots? NOW you are asking ENTIRELY too MUCH! If they did that, they wouldn’t be liberals anymore because being arrogant is part and parcel of being a liberal.

  2. Professor Rossitor evidently assumes that our current warming (such as it is) began in 1800s, but it started, by the very definition,

    at the bottom of the Little Ice Age (mid 1600s). That’s two centuries of really significant warming before co2 moved off the dime.

    But, even the most rabid alarmists are forced to agree that co2 level would not have had a measurable impact on global temperature until about 1950 (else they have other problems explaining the 1930s warming). So, there was actually 300 years of natural warming before any blame can be laid at human activity.

    We know the 40s to the 70s was a cooling period. Then from the 70s to about 1998 there was warming. Since then, no additional warming reported by satellite measurements. There are only 5 global data sets, 3 terrestrial, 2 satellite. For some reason both NASA and NOAA insist on using the terrestrial data which covers less than 20% of the earth’s surface, actually much less than that due to the large distances between many weather stations. (Could this have something to do with the consistent “corrections” to older temp data (always dropping temperature), whereas “corrections” to more current data invariably increase temperature?

  3. The sad fact is that Rossitor’s sensible and well-reasoned efforts are crushed by all the mainstream publications when they refuse to print what he submits. They are rational in their response because they are asking for trouble when they don’t tow the environmentalist line. It is the enviros who have poisoned the discussion. Fanaticism has been the stock-and-trade of the green movement from the beginning. They want to smash the machines. They think that somehow if humanity could turn back from technology and reduce the dreaded “human footprint” we would all be better off. Of course, this is utter nonsense, but it is a view that is also popular on the right, not simply the “extreme” right but let us call them the “Religious Right.” If you take the Bible literally, you will also hear the clarion call, “Turn back, Oh Man, forswear thy foolish ways.” Authoritarian extremism has no left or right. Liberals who have joined the Green crusade are the real fools. Liberal rationalists who truly believe that scientific method is the only way to seek truth, like me and, I think Rossiter, where do we go? Do we join the spewers of hate on the right, just because they happen to agree with us on this? Not me.

  4. Isn’t it bizarre …

    It is accepted by the UN’s IPCC that earth’s climate system is a coupled non-linear, chaotic system … highly complex and utterly unpredictable. It is also accepted that scientists cannot explain, for certain, what changed the climate in the past or what is changing the climate, presently. They can only speculate as to the likely causes of climate change. Scientists just do not know enough about earth’s climate system.

    Yet despite all this indisputable uncertainty, individuals like President Obama know, without any doubt, that carbon dioxide emitted by human activity is the key driver of climate change, and this human carbon dioxide is causing catastrophic global warming, dangerous rising sea levels, etc etc etc etc … claims that are simply not evident from real world observational data.

    Obama and the green environmental elites want to destroy the global energy system, all for the sake of a rare, harmless, odourless, colourless trace gas, that is the elixir of life … and all because of the human contribution of carbon dioxide to the atmosphere, which, by the way, is only responsible for a minuscule 0.11% of the total atmospheric ‘greenhouse heat effect’. Compare that to the water in the atmosphere responsible for 95% of the total atmospheric ‘greenhouse heat effect’.

    Who is the nutcase in the White House advising Obama?

    You would not want any of these idiots to be in charge of a corporation. They’s be charged with engaging in misleading and deceptive conduct, promoting fraud and malfeasance, and for engaging in racketeering.

    1. “or what is changing the climate, presently”, or is the climate even changing all that much. If it is, then it has become more benign than previous centuries.

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