The Greenhouse Theory is supported by a whole range of data of supposed climate properties. These data are paraded by the likes of Al Gore and Sir Nicholas Stern as being certain and not subject to controversy. Yet the more you examine these data the more dubious they appear, to the extent that it is necessary to question the value of most of them.
Let us start with the central proposition that so-called "well-mixed" greenhouse gases are increasing, .
Let us begin with carbon dioxide.
There are two major pieces of evidence for increases in atmospheric concentrations of carbon dioxide. The first is from the Mauna Loa volcano site, from 1974, extended backwards to 1957, from measurements at La Jolla, California. The other is from the world-wide measurements, made almost exclusively over the ocean from 1981 and the averages published by NOAA ESRL GMD Carbon Cycle (The US Government Agency responsible) from the Mauna Loa record the concentration of carbon dioxide in the atmosphere is rising by about 0.4% a year since 1975, with irregular fluctuations.
Most of the climate models assume 1% a year, and the predicted levels assume increases which include one even higher than this.
You calculate the "radiative forcing" (which is related to temperature change) for carbon dioxide from one of three formulae given in Table 6.2 of "Climate Change 2001" (page358). The simplest of these is
DF = 5.35 ln(C/Co), (where ln is the natural logarithm (to the base e)
This means that if you are to calculate the trend in radiative forcing from the concentration of carbon dioxide in the atmosphere you have to assemble a matrix of measured concentrations over a representative range of three dimensions of location, (geographical and vertical) and for a range of past time, and integrate the matrix according to this formula.
The data for this process to be carried out reliably simply do not exist. The existing samples are highly unrepresentative, as they hardly have any measurements over land surfaces where the supposed effects of greenhouse warming are most feared. The variability of the concentration in different places and different times is hardly documented, All we get are single point averages, which certainly vary with the seasons, and from different locations in the present network, but there is no appreciation that an apparent simple average is not relevant to a quantity whose effect depends on its logarithm. A logarithmic average might make some sense, but we have no evidence at all of the possible variability from which a daily average is obtained. Indeed the NOAA measurements are based on a daily sample, so we do not know if there is diurnal variability.
Then, the models use an overall arithmetic average, or, for most of the models, an assumption of an increase of 1% a year which is completely out of line even from the current unreliable measurements.. The IPCC even talks about "decadal" averages, which are also, presumably, arithmetical.
The problems with methane concentrations are, if possible, worse. NOAA ESRL GMD Carbon Cycle have only been measuring since 1984. Their published record shows a somewhat irregular, but steady decline in the "rate of increase" of globally averaged methane concentration, which is now hovering above and below the zero line, and from the last publicly available graph ( at the end of 2004) was well below it. This measurement is also subject to poor sampling and variability data.
The formula for calculating "radiative forcing" for methane is rather complicated, so I will refrain from overwhelming you with it by saying that it involves square roots as well as logarithms. But the same principle applies as with carbon dioxide, Before you can calculate the forcing you need to have a matrix of representative concentration measurement over the entire atmosphere over all time scales. It is even worse than carbon dioxide because there are even fewer sites, and for a shorter time. The variability seems to be greater. Only recently were we all surprised that methane is emitted from trees.
The treatment of methane by the models is so out of line that all of them assume the concentration is going up, when the flawed data indicate that it is actually going down.
The IPCC claims that carbon dioxide and almost all the other gases are "well-mixed" in the atmosphere. This is comparable to the term "likely" used for assessing models. How much is "well"? It matters.
The diagram purporting to list the various components of "radiative forcing" since 1750 given in "Climate Change 2001" (Fig 6.7, page 392) was put forward as evidence that the net "radiative forcing" might possibly be positive, and if so, possibly harmful.
The diagram omits the most important, and least characterised radiative forcing components, water vapour, and ordinary clouds, with the excuse that these can be treated as "feedbacks" to an overall positive result from the rest. There is virtually no theoretical or practical evidence to support this assumption.
The radiative forcing diagram shows "error bars" on each component, and in the caption it says:
"The uncertainty range specified here has no statistical basis".
On top of that, all of them are subject to different "Levels of scientific understanding" , so we can assume that none of the figures are believable.
Then, it says in the caption, that ".. the forcings shown here.. do not yield a complete picture... They are only intended to give... a first order perspective...and cannot be readily employed to give the total climate response...it is emphasised that the positive and negative global mean forcings cannot be added up....'
So the entire exercise is meaningless?
In the latest version of this diagram (Figure SPM-2 of the most recent version of the 2007 "Summary for Policymakers"), the error bars have suddenly acquired a statistical significance. Admittedly it does not aspire to the usual level of 95% confidence, only 90%. How did they do it?
Then, they have added and subtracted all the factors listed to give an overall figure, which they previously said was impossible. What is more, it was done after the last draft that was submitted to Government representatives only, in October 2006.
This is the sort of data which is being used to alter our whole lifestyle. Why does anybody believe it?
Wait for Part 2.