Fourth Column

Climate’s Uncertainty Principle

Whether we should do anything now to limit our impact on future climate boils down to an assessment of a relevant cost-benefit ratio. That is, we need to put a dollar number to the cost of doing something now, a dollar number to the benefit thus obtained by the future generations, and a number to a thing called “discount for the future”—this last being the rate at which our concern for the welfare of future generations falls away as we look further and further ahead. Only the first of these numbers can be estimated with any degree of reliability. Suffice it to say, if the climate-change establishment were to have its way with its proposed conversion of the global usage of energy to a usage based solely on renewable energy, the costs of the conversion would be horrifically large. It is extraordinary that such costs can even be contemplated when the numbers for both the future benefit and the discount for the future are little more than abstract guesses.

This essay appears in April’s Quadrant.
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Assessment of the future benefit is largely based on two types of numerical modelling. First, there are the vast computer models that attempt to forecast the future change in Earth’s climate when atmospheric carbon dioxide has increased as a consequence of the human activity of burning fossil fuel. Second, there are the computer-based economic models which attempt to calculate the economic and social impact of the forecasted change of climate. Reduction of that impact (by reducing the human input of carbon dioxide to the atmosphere) is the “benefit” in the cost-benefit calculations.

Taking the climate change calculations first, it should be emphasised that in order to be really useful, the forecast must necessarily be of the future distribution of climate about the world—on the scale of areas as small as individual nations and regions. Calculating only the global average of such things as the future temperature and rainfall is not useful. The economic models need input data relevant to individual nations, not just the world as a whole.

Which is a bit of a problem. The uncertainty associated with climate prediction derives basically from the turbulent nature of the processes going on within the atmosphere and oceans. Such predictability as there is in turbulent fluids is governed by the size (the “scale”) of the boundaries that contain and limit the size to which random turbulent eddies can grow. Thus reasonably correct forecasts of the average climate of the world might be possible in principle. On the scale of regions (anything much smaller than the scale of the major ocean basins for example) it has yet to be shown that useful long-term climate forecasting is possible even in principle.

To expand on that a little, the forecasts of the global average rise in temperature by the various theoretical models around the world range from about 1 degree to 6 degrees Celsius by the end of this century—which does little more than support the purely qualitative conclusion from simple physical reasoning that more carbon dioxide in the atmosphere will increase the global average temperature above what it would have been otherwise. It does little to resolve the fundamental question as to what fraction of the observed rise in global surface temperature over the last thirty or so years (equivalent to a rise of about 1 degree Celsius per century if one is inclined to believe observations rather than the theory) is attributable to the human-induced increase in atmospheric carbon dioxide. There is still a distinct possibility that much of the observed rise in global temperature may be the result of natural (and maybe random) variability of the system.

While the forecasts of future global average climate are not really trustworthy and would probably not be very useful even if they were, the potentially much more useful forecasts of regional climates are perhaps just nonsense. A good example supporting this rather negative view of the matter is the variability of the set of hundred-year forecasts of the average rainfall over Australia. Each forecast was produced by one of the many climate models from around the world. The present-day measured average is about 450 millimetres per year. The forecasts for the next century range from less than 200 mm to more than 1000 mm per year. That sort of thing makes finding a model to support a particular narrative just too easy.

As a consequence, the economic models of the future of regions and nations are highly unreliable if only because their regional and national inputs of forecasted climatic “data” are unreliable. But to make matters vastly worse, the economic models themselves are almost certainly useless over time-scales relevant to climate. Their internal workings are based on statistical relations between economic variables devised for present-day conditions. There is no particular reason why these relations should be valid in the future when the characteristics of society will almost certainly have changed. As Michael Crichton put it: “Our [economic] models just carry the present into the future.” And as Kenneth Galbraith once remarked: “Economic forecasting was invented to make astrology look respectable.”

There is a lot of discussion among academics as to what should be an appropriate “discount for the future” to apply in the cost-benefit calculations associated with human-induced climate change. The discussion quickly becomes incomprehensible to the average person when phrases such as “cross generational wealth transfer” and “intergenerational neutrality” and so on appear in the argument. These are fancy terms supposedly relevant to what is essentially a qualitative concept of fairness to future generations. The concept is so qualitative that there is virtually no hope of getting general agreement as to how much we should spend now so as not to upset the people of the future.

There are two extremes of thought on the matter. At one end there are those who tell us that the present-day view of a benefit for future generations should be discounted at the normal rate associated with business transactions of today. That is, it should be something of the order of 5 to 10 per cent a year. The problem for the academics is that such a discount would ensure virtually no active concern for the welfare of people more than a generation or so ahead, and would effectively wipe out any reason for immediate action on climate. At the other end of the scale, there are those who tell us that the value of future climatic benefit should not be discounted at all—in which case there is an infinite time into the future that should concern us, and “being fair” to that extended future implies that we should not object to spending an unlimited amount of present-day money on the problem.

Academics tie themselves in knots to justify the need for immediate action on climate change. For example, we hear argument that “discounting should not be used for determining our ethical obligations to the future” but that (in the same breath) “we endorse a principle of intergenerational neutrality”—and then we hear guesses of appropriate discount rates of the order (say) of 1.5 per cent a year.

The significant point in this cost-benefit business is that there is virtually no certainty about any of the numbers that are used to calculate either the likely change of climate or the impact of that change on future populations. In essence it is simply assumed that all climate change is bad—that the current climate is the best of all possible climates. Furthermore, there is little or no recognition in most of the scenarios that mankind is very good at adapting to new circumstances. It is more than likely that, if indeed climate change is noticeably “bad”, the future population will adjust to the changed circumstances. If the change is “good”, the population will again adapt and become richer as a consequence. If the change is a mixture of good and bad, the chances are that the adaptive processes will ensure a net improvement in wealth. This for a population which, if history is any guide, and for reasons entirely independent of climate change, will probably be a lot wealthier than we are.

Perhaps the whole idea of being fair to the people of the future should be reversed. Perhaps they can easily afford to owe us something in retrospect.

The bottom line of politically correct thought on the matter—the thought that we must collectively do something drastic now to prevent climate change in the future—is so full of holes that it brings the overall sanity of mankind into question. For what it is worth, one possible theory is that mankind (or at least that fraction of it that has become both over-educated and more delicate as a result of a massive increase of its wealth in recent times) has managed to remove the beliefs of existing religions from its consideration—and now it misses them. As a replacement, it has manufactured a set of beliefs about climate change that can be used to guide and ultimately to control human behaviour. The beliefs are similar to those of the established religions in that they are more or less unprovable in any strict scientific sense.

Garth Paltridge is the author of The Climate Caper: Facts and Fallacies of Global Warming.


8 thoughts on “Climate’s Uncertainty Principle

  • Andrew Griffiths says:

    Thankyou for such a sensible story, there is so much scaremongering and nonsense about in politics and the mainstream media,Quadrant is a haven in these crazy times.

  • Charles says:

    Yes, you are quite correct, and what this gentle warming that w have no control over requires in the courage to do nothing. Unfortunately when you have an extremely timid political class who is addicted to virtue-signaling, you end up with the mess we have today.

  • Biggles says:

    Piers Corbyn has made a very pertinent statement about the likelihood of changes in CO^2 having an effect on temperature.
    Imagine the clock tower at the Palace of Westminster. If the height of the tower represents all the gasses in the atmosphere other than CO^2, the increase in height when CO^2 is added is only four centimetres or one and one half inches.
    Given this comparison do you really imagine that a small change will affect the global temperature? Bear in mind that geological records show that CO^2 concentration in past ice ages has been as high as 8000 ppm.

  • ianl says:

    I agree with the last paragraph in this essay and have often came to the same conclusion:

    homo sapiens is truly insane as a species

    As always with the evolutionary process, you never get something for nothing. Our species has the most developed cognition, self-awareness, imagination etc that has ever existed on the planet. This awareness has allowed us moon landings, Beethoven symphonies, da Vinci paintings, incredible surgical accomplishments …

    It also informs us from a really early age that we will die. That certain knowledge makes us insane.

    My name is Ozymandias, King of Kings. Look on my works, ye mighty, and despair.

  • Salome says:

    How do you calculate the global temperature, past, present or future? Different suburbs have different maxima, and the distribution of thermometers worldwide is most uneven (and this was even more the case the further back in the past you go). Global average temperature is a nonsense at any time, so any argument that seeks a global average as its point of departure is already in La La Land.

  • Bush1958 says:

    Man-made climate change is real, but it has nothing to do with greenhouse gasses.

    There is a simple, alternative explanation for climate change, which is easily proven to be correct, but which is ignored by all.

    Whenever there is a large volcanic eruption, Megatons of SO2 are spewed in to the stratosphere, where it is converted into dimming SO2 aerosols (small droplets of sulfuric acid), that cool the earth’s surface for a year or two, usually causing a La Nina

    When these aerosols settle out, as they all eventually do, temperatures warm up to pre-eruption levels, or higher, simply because of the cleansed air (which allows sunshine to strike the earth’s surface with greater intensity, causing increased warming)

    Anthropogenic SO2 aerosol emissions, from the burning of fossil fuels, have the same effect: cooler temperatures resulting from their presence, and warming temperatures when their concentration is intentionally reduced (by Clean Air efforts).

    Circa 1975, anthropogenic SO2 aerosol emissions peaked at ~131 Megatons, and by 2014, due to Clean Air efforts, they had fallen to ~ 114 Megatons. As with volcanic aerosols, warming HAD to occur because of the cleaner air.

    The warming expected from the 25 Megaton decrease in SO2 emissions (plus ~ 0.20 deg. C of natural recovery from the Little Ice Age cooling) so closely matches the anomalous rise in average global temperatures over the period that there is no room for any additional warming due to “greenhouse” gasses.

    Thus, the bulk of the warming that has occurred, along with many associated climate-related disasters, has unwittingly been CAUSED by the environmental movement!.

    All of the above refutes the insane nonsense that rising CO2 levels are the cause of our warming planet, and suggests that the judicious re-introduction of SO2 aerosols into the atmosphere could be used to lower our rising temperatures.

  • rod.stuart says:

    A theory that warrants some thought to be sure.
    But a recent paper (Goddard et al) determines that the urban heat island effect in the UK amounts to about 1.7 C.
    Since this is a whole degree more than any supposed “warming” in the past hundred years, and since temperatures measured in major cities the world over represent the lion’s share of measured temperatures, I theorise that in fact THERE HAS BEEN NO BLOODY WARMING AT ALL!,

  • Bush1958 says:


    Earth’s temperatures are pretty much regulated by the temperature of the Pacific Ocean, whose temperature has been rising. Its area is probably thousands of times greater than the area of all of the cities of the world, and thus has a FAR greater effect.

    In addition, its surface temperatures are measured independently, completely unaffected by any “heat island” effect. See plots of ERSST sea-surface temperatures.

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