When I read through the data as follows, and it seems to be supported by so many of the other skeptics, I can't see why it shouldn't be included in the debate. This group does not deny that global warming is occurring no do they deny that at least some of it or maybe a lot of the CO2 levels in the atmosphere are a result of anthropogenic causes.
They strongly question the concusions of what the higher CO2 levels mean in the big picture, however. (Note to the consensus lovers: you might want to read through the HUGE number of people who signed onto this scientitic opinion that supported a petition for the USA to reject Kyoto. No idea whether any or all of the signatories are scientists however.)
The following is quoted from the website:
The computer climate models upon which ''global warming'' is based have substantial uncertainties. This is not surprising, since the climate is a coupled, non-linear dynamical system in layman's terms, a very complex one. Figure 10 summarizes some of the difficulties by comparing the radiative CO2 greenhouse effect with correction factors and uncertainties in some of the parameters in the computer climate calculations. Other factors, too, such as the effects of volcanoes, cannot now be reliably computer modeled.
Figure 11 compares the trend in atmospheric temperatures predicted by computer models adopted by the IPCC with that actually observed during the past 19 years those years in which the highest atmospheric concentrations of CO2 and other GHGs have occurred.
In effect, an experiment has been performed on the Earth during the past half-century an experiment that includes all of the complex factors and feedback effects that determine the Earth's temperature and climate. Since 1940, atmospheric GHGs have risen substantially. Yet atmospheric temperatures have not risen. In fact, during the 19 years with the highest atmospheric levels of CO2 and other GHGs, temperatures have fallen.
Figure 11:
Global annual lower tropospheric temperatures as measured by satellite MSU between latitudes 83 N and 83 S (17, 18) plotted as deviations from the 1979 value. The trend line of these experimental measurements is compared with the corresponding trend line predicted by International Panel on Climate Change (IPCC) computer climate models (14).
Not only has the global warming hypothesis failed the experimental test; it is theoretically flawed as well. It can reasonably be argued that cooling from negative physical and biological feedbacks to GHGs will nullify the initial temperature rise (26, 30).
The reasons for this failure of the computer climate models are subjects of scientific debate. For example, water vapor is the largest contributor to the overall greenhouse effect (31). It has been suggested that the computer climate models treat feedbacks related to water vapor incorrectly (27, 32).
The global warming hypothesis is not based upon the radiative properties of the GHGs themselves. It is based entirely upon a small initial increase in temperature caused by GHGs and a large theoretical amplification of that temperature change. Any comparable temperature increase from another cause would produce the same outcome from the calculations.
At present, science does not have comprehensive quantitative knowledge about the Earth's atmosphere. Very few of the relevant parameters are known with enough rigor to permit reliable theoretical calculations. Each hypothesis must be judged by empirical results. The global warming hypothesis has been thoroughly evaluated. It does not agree with the data and is, therefore, not validated.
Figure 12: Eleven-year moving average of global surface temperature, as estimated by NASA GISS (23, 33, and 34), plotted as deviation from 1890 (left axis and light line), as compared with atmospheric CO2 (right axis and dark line) (2). Approximately 82% of the increase in CO2 occurred after the temperature maximum in 1940, as is shown in figure 1.
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