On Numerical Models, etc.

[5stringJeff]

An excellent article on how climate change models work and how much trust we ought to put in them: not much.

http://www.americanthinker.com/2007/...grated_ci.html

Numerical Models, Integrated Circuits and Global Warming Theory
By Jerome J. Schmitt
Global warming theory is a prediction based on complex mathematical models developed to explain the dynamics of the atmosphere. These models must account for a myriad of factors, and the resultant equations are so complex they cannot be solved explicitly or "analytically" but rather their solutions must be approximated "numerically" with computers. The mathematics of global warming should not be compared with the explicit calculus used, for example, by Edmund Halley to calculate the orbit of his eponymous comet and predict its return 76 years later.

Although based on scientific "first principles", complex numerical models inevitably require simplifications, judgment calls, and correction factors. These subjective measures may be entirely acceptable so long as the model matches the available data -- acceptable because the model is not intended to be internally consistent with all the laws of physics and chemistry, but rather to serve as an expedient means to anticipate behavior of the system in the future. However, problems can arise when R&D funding mechanisms inevitably "reward" exaggerated and alarming claims for the accuracy and implications of these models.

[MtnBiker]

Solar flux
Gravity, Pressure
Temperature
Density
Humidity
Earth's rotation
Surface temperature
Currents in the Ocean (e.g., Gulf Stream)
Greenhouse gases
CO2 dissolved in the oceans
Polar ice caps
Infrared radiation
Cosmic rays (ionizing radiation)
Earth's magnetic field
Evaporation
Precipitation
Cloud formation
Reflection from clouds
Reflection from snow
Volcanoes
Soot formation
Trace compounds

How accurate are scientist in predicting volcanoes or solar flux?

[5stringJeff]

What I found interesting is that chemical engineers put so little trust in small models, with variables that they can completely control, that they sometimes scrap them and just use the trial-and-error method of doing stuff. And we're supposed to buy a computer-model of global warming?

[MtnBiker]

None of the global warming crowd has cared to dispute this.

[manu1959]

interesting quotes from the article...

In this competitive environment, one can imagine climate modelers justifying their work by citing the possibility of global change, the further study of which requires, of course, "more research". One can further imagine that in the inchoate communication between university researcher, funding agency, congressional staffer and congressmen that "possibility" eventually became "probability" and then "probability" morphed into "certainty" of global warming, especially if there was potential for political advantage.

This has resulted in an inadvertent funding-feedback mechanism that now resonates in largely unjustified alarm and also seeks to quash scientific dissidents who indirectly threaten to throttle the funding spigots.

The UN's distortion of historical climate data should further undermine our faith in climate models because such models can only be "tested" against accurate historical data.