This page quotes what the IPCC says about its own models - basically, in my opinion, these experts admit that the entire theory of Human Produced Global Warming is based on models that don't work.

Please, don't just read the few quotes I've included below - read the entire report. (I've only read parts of it.) It is painfully obvious that none of the models are very good ... and clouds are almost ignored.

Thus, before you even consider the models, it should be obvious that the basic premise of this section is wrong.

7.2.2.4 Cloud-radiative feedback processes

In response to any climate perturbation the response of cloudiness thereby introduces feedbacks whose sign and amplitude are largely unknown.

The sign of the cloud cover feedback is still a matter of uncertainty and generally depends on other related cloud properties.

Cloud optical feedbacks produced by these GCMs, however, differ both in sign and strength.

7.2.2.5 Representation of cloud processes in models

In spite of these improvements, there has been no apparent narrowing of the uncertainty range associated with cloud feedbacks in current climate change simulations. A straight-forward approach of model validation is not sufficient to constrain the models efficiently and a more dedicated approach is needed.

Note - Section 7.2.2.5 has a graph showing which models consider clouds as positive or negative feedback mechanisms.

It is unbelievable that the most important feedback could make human produced Global Warming extremely serious or just a lot of nonsense - but they still can not determine even the sign of the feedback.

At least there is a consensus so that there is no longer a need for scientific inquiry.

7.2.3 Precipitation

... the associated heating rates often dominate all other effects and strongly influence local and global circulations.

These aspects have been explored only to a limited extent in climate models. No studies deal with true intensity of rainfall,

However, estimates of precipitation and surface long-wave radiation suggest that the sensitivity of the hydrological cycle in climate models to changes in SST may be systematically too weak. Accordingly, it is important that much more attention should be devoted to precipitation rates and frequency, and the physical processes which govern these quantities.

It is interesting that cloud physics (inhomogeneities) is not in the existing models.

In feedback theory

• Positive feedback makes a system unstable
• Negative feedback makes a system stable

• In a swing, positive feedback makes you go higher.

• When starting a fire, a small amount of energy (a match) lights a piece of paper ... the paper starts the twigs ... and those start the charcoal. In each case a small amount of energy starts something else burning, and that releases more energy, and so forth. This process applies to all fires - in the grill, starting a forest fire, or burning gas in your car. This basic sequence even applies to firing a gun or setting off an explosion.

• A shock absorber provides negative feedback to stop a car from bouncing. When you hit a bump, the wheel moves and compresses the spring - storing mechanical energy. Without a shock absorber, the car will move up and down until the energy is converted to heat. A shock absorber provides a quicker way to convert the mechanical energy into heat and the car quits bouncing much faster.

• A furnace uses negative feedback to keep the temperature stable. When it gets too hot, the furnace turns off. When it gets too cold, it turns back on.

In the case of Global Warming, positive feedbacks will make a little heating get even hotter and negative feedbacks tend to make temperature changes very difficult.

The same applies to cooling, with positive feedback a little cooling will cause more cooling until everything freezes. With negative feedback, again, temperature changes (in this case cooling) are very difficult.

One of the major problems with the IPCC report is that the models can not even agree on the sign (plus or minus) of the most powerful of all the feedback systems - humidity and clouds.

What I can't believe is that anyone would suggest a course of action based on a climate model that completely ignores clouds.

Apparently, Dr. Richard S. Lindzen, one of the contributors to chapter 7, agrees that the IPCC has misrepresented chapter 7.

What no one seems to realize is that, with few exceptions, everything that is "known" about the climate is actually based on models

• Past global temperatures are based on ice cores and models to "adjust" the data
• Past atmospheric CO2 concentrations are based on ice cores and additional models
• Even the current estimate of the global temperature is based on a few measurements (thousands) and a model that gives a single number. Without models there is no way to know if the global temperature is increasing or decreasing - there is actually no way to measure the temperature of the Earth ... so we use a model for even that.

• The increase in atmospheric CO2 concentrations since 1952 - these are measured (and filtered to remove some percentage of the data)
• Humans burn fossil fuel (duh)

However, the accuracy of these most basic models is never addressed.

Thus the IPCC hysteria report is based on models that are based on models - and I thought they claimed that the science was done. I guess that they did not read their own report.

URL: http:// questionable-science.com / Global_Warming / IPCC.html