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Tim Ball's comment

Quote:Tim Ball says:
June 2, 2011 at 6:35 pm

It is useful to have a study that confirms the limitations of knowledge about various components of the earth atmosphere interface. The IPCC acknowledged the limitations but glossed it over in their Summary for Policymakers and few have bothered to look at what the Science Report of Working Group I actually says. In my opinion the downplaying of severe limitations of data and process was the intent. Here is what they said about carbon to climate models.
“Several other groups have evaluated the impact of coupling specific models of carbon to climate models but clear results are difficult to obtain because of inevitable biases in both the terrestrial and atmospheric modules (e.g., Delire et al., 2003).”

There are similar problems with an even more important greenhouse gas, water vapour.

“Since the TAR, there have been few assessments of the capacity of climate models to simulate observed soil moisture. Despite the tremendous effort to collect and homogenise soil moisture measurements at global scales (Robock et al., 2000), discrepancies between large-scale estimates of observed soil moisture remain. The challenge of modelling soil moisture, which naturally varies at small scales, linked to landscape characteristics, soil processes, groundwater recharge, vegetation type, etc., within climate models in a way that facilitates comparison with observed data is considerable. It is not clear how to compare climate-model simulated soil moisture with point-based or remotely sensed soil moisture. This makes assessing how well climate models simulate soil moisture, or the change in soil moisture, difficult.”

“The climate models employed in the IPCC’s Fourth Assessment are clearly deficient in their ability to correctly simulate soil moisture trends, even when applied to the past and when driven by observed climate forcings. In other words, they fail the most basic type of test imaginable; and in the words of Li et al., this finding suggests that “global climate models should better integrate the biological, chemical, and physical components of the earth system.”
Li,H.,Robock, A. and Wild, M. 2007. “Evaluation of Intergovernmental Panel on Climate Change Fourth Assessment soil moisture simulations for the second half of the twentieth century.” Journal of Geophysical Research 112

I believe these limitations are adequate in themselves to give any credibility to outputs from the IPCC computer models. Despite this they are used as justification for global policies.
It is our attitude toward free thought and free expression that will determine our fate. There must be no limit on the range of temperate discussion, no limits on thought. No subject must be taboo. No censor must preside at our assemblies.

–William O. Douglas, U.S. Supreme Court Justice, 1952

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