Note: I posted this originally early this morning, something happened with wordpress.com hosting (I’m not sure what) and it disappeared, here it is again. – Anthony
Christopher Monckton of Brenchley replies to readers
I am most grateful to the many kind readers of www.wattsupwiththat.com who have commented on my open letter to the Australian Prime Minister. If you want to see a real “hockey-stick” graph, just look at the record of this wonderful website’s monthly hit-rates over the past couple of years.
May I answer some of the scientific and economic points raised by your readers?
Several readers raised the question whether the function ΔT = (4.7 ± 1) ln(C/C0) (in Celsius degrees) that I have derived for the rate of warming predicted by the IPCC in response to any given proportionate increase in CO2 concentration takes account not only of the direct forcing from CO2 enrichment of the atmosphere but also of any net-positive temperature feedbacks.
In fact the Monckton function does take account of feedbacks as well as forcings. Broadly speaking, the IPCC assumes (though this is almost certainly a monstrous exaggeration) that temperature feedbacks approximately triple any externally-forced initial warming. For the sake of minimizing any dispute, and solum ad argumentum (only for the sake of argument), I have simply calculated the warming the IPCC’s way, exaggerations and all.
One can test the function by calculating that 4.7 ln 2 (for a doubling of CO2) equals 3.26, the precise equilibrium temperature change, in Celsius degrees, predicted by the IPCC as its central estimate. For US and UK readers, the Monckton function in Fahrenheit degrees is ΔT = (8.5 ± 1.8) ln(C/C0).
My purpose in deriving this function was to facilitate instant calculation of the equilibrium temperature change predicted by the IPCC for any given change in CO2 concentration, without having to take separate account of the magnitude of the CO2 radiative forcing, of the Planck no-feedbacks climate sensitivity parameter, or of the sum of climate-relevant positive and negative temperature feedbacks.
A related question, also raised by several readers, was whether I should have taken account of the fact that not all feedbacks are linear. Since the IPCC assumes that all feedbacks are either linear or close enough to linear to be linearizable, I have adopted the same assumption, again solum ad argumentum, even though it is clear that the water vapor feedback, for instance, cannot be strictly linear.
Another reader has asked why I have calculated the effect of implementing the Copenhagen Accord only as far as 2020. This is the time-horizon for the Accord. The effect of the Accord over ten years would be to forestall warming of just 0.2 C° (0.35 F°) forestalled even if everyone complies fully. This outcome is so minuscule that extending the analysis beyond that date would be pointless, not least because by ten years from now it will be blindingly obvious to everyone a) that the climate is simply not warming anything like as fast (if at all) as the IPCC had ambitiously predicted, and b) that compliance with Copenhagen was little better than compliance with Kyoto. By 2020, the climate scare will be all over bar the shouting, and no one will be cutting CO2 emissions any more.
Another query was about whether I should have done the calculation on the basis of 7.5% of total CO2 emissions, rather than 7.5% of the additional 20 ppmv that we will emit on the trend of the past decade unless we cut emissions. Here, the enquirer is confusing emissions with concentration. CO2 emissions are rising at a near-exponential rate, but over the past decade CO2 concentration has risen at a strictly linear rate of a fraction over 2 ppmv/year. The IPCC’s case is that without our emissions CO2 concentration would stabilize, and would only drop back to its pre-industrial 278 ppmv after hundreds of years: therefore it is appropriate – solum ad argumentum, as ever – to hoist the IPCC with its own petard and to attribute all of the 2 ppmv/year increase in CO2 concentration to our current emissions, from which the calculation in the letter to Mr. Rudd follows.
Dr. Patrick Michaels, one of the most distinguished commentators on the climate scam, has done some excellent work demonstrating that over the past 30 years the relationship between CO2 emissions and CO2 concentration has remained broadly constant at approximately 14-15 billion tons CO2 emitted per 1 ppmv increase in atmospheric CO2 concentration.
Therefore, if we ignored the IPCC’s belief – which certainly does not represent the consensus in the scientific literature – that CO2 lingers in the atmosphere for hundreds of years, then the correct calculation would be to assume that without our current emissions CO2 concentration would fall swiftly back to 278 ppmv from its present 388 ppmv – a drop of 110 ppmv. Then, if we saved 7.5% of total emissions, we should reduce CO2 concentration by 7.5% of 110 ppmv, or around 8 ppmv, in which event the warming forestalled over the next ten years would be 0.1 C°, still not worth all those trillions.
Next, a reader says he will not believe the UN’s computer models until they are capable of modeling all of the natural as well as anthropogenic causes of “global warming”. However, even then modeling is of limited value, because the climate is not merely complex and non-linear but mathematically chaotic. Therefore, as Lorenz (1963) proved in the landmark climate paper that founded chaos theory, unless we know the initial state of the climate at any chosen moment to a precision that is forever unattainable in practice, reliable, very-long-term weather prediction is not available “by any method” – and “very-long-term”, as the Met Office in the UK has learned to its cost in each of the past three summers and in the current winter, means just a few weeks. It is better to rely upon observation and measurement than upon models.
Which leads to my next answer. A reader says he wishes I had supplied references to support my statements in the closing paragraphs of the letter that the measured radiative forcing from changes in cloud cover between 1983 and 2001 was at least five times greater than that from CO2. The forcing from CO2 over that period – the only period warming that we could have influenced even in theory – was just 0.8 Watts per square meter. The forcing from decreased cloud cover, expressed as the sum of 19 annual means, was 4.5 Watts per square meter.
A recent blog posting by me at www.scienceandpublicpolicy.org explains the theory behind the radiative influence of changes in cloud cover. Briefly, where low-altitude, low-latitude cloud cover diminishes, more short-wave radiation hits the Earth rather than being reflected harmlessly back to outer space. When it hits the Earth, it is displaced to the long wave and then heads back towards outer space. Therefore, the ERBE and CERES satellites, whose data is publicly available, will show simultaneous decreases in outgoing short-wave and increases in outgoing long-wave radiation if decreases in cloud cover are the cause, and vice versa for increases in cloud cover.
There are several good papers on this measured phenomenon. See e.g. Palle, E, Goode, P.RT., Montañes-Rodriguez, P., and Koonin, S.E., 2004, Changes in the Earth’s reflectance over the past two decades, Science 304, 1299-1301, doi:10.1126/science.1094070; or Pinker, R.T., Zhang, B., and Dutton, E.G., 2005, Do satellites detect trends in surface solar radiation?, Science 308, 850-854. It is also worth looking at the data from the International Satellite Cloud Climatology Project, a “Mark-I-Eyeball” methodology which confirms the short-wave and long-wave measurements of the ERBE and CERES satellites.
My letter to Mr. Rudd also referred to measurements showing that outgoing radiation from the Earth’s surface increases as sea-surface temperatures increase, and does not diminish as all of the IPCC’s capable of being forced with changes in sea-surface temperatures predict. These measurements are reported and analyzed in Lindzen R.S., and Choi, Y.-S., 2009, On the determination of climate feedbacks from ERBE data, Geophysical Research Letters. I do not have the page reference, because I have the preprint that the authors kindly sent to me.
Another reader asked whether my letter had been “peer-reviewed”. Yes, I asked an eminent Professor in Australia to read it for me before it was sent to the Prime Minister and to other party leaders. Any errors, however, are mine alone.
A reader asks whether my letter to Mr. Rudd is available as a .pdf file. I have sent the file to Anthony Watts, who, I am sure, will kindly make it available to anyone who would like to see it. Thank you all very much for your kind interest: and, as always, thanks to Anthony for having given the letter a wider audience.
[Update: a pdf of Lord Monckton’s letter is available here. ]