Mathematics of Global Warming?

One of the few dissidents in the climate debate is Lars Bern coauthor with Maggie Thauersköld of the Chill-Out - The Truth about the Climate Bubble, which questions the accepted truth that global warming is such a threat to humanity that in particular poor people should be prevented from increasing their energy consumption.  

Decisions aimed at controling global warming are based on predictions obtained by computational solution of basic equations of physics expressing conservation of mass, momentum and energy. Correct decisions require correct predictions and the question of the accuracy and reliability of the predictions must be addressed.

The Intergovernmental Panel of Climate Change IPCC  states in its Fourth Assessment Report (AR4) released in 2007 about Climate Models and their Evaluation:

• One source of confidence in models comes from the fact that model fundamentals are based on established physical laws, such as conservation of mass, energy and momentum,  along with a wealth of observations.  
• A second source of confidence comes from the ability of  models to simulate important aspects of the current climate. 
• A third source of confidence comes from the ability of models to reproduce features of past climates and climate changes. 
• Nevertheless, models still show significant errors. 
• This is partly due to limitations in computing power, but also  results from limitations in scientific understanding or in the  availability of detailed observations of some physical processes.  Significant uncertainties, in particular, are associated with the  representation of clouds, and in the resulting cloud responses  to climate change. Consequently, models continue to display a  substantial range of global temperature change in response to  specified greenhouse gas forcingof model development, they have consistently provided a robust  and unambiguous picture of significant climate warming in response to increasing greenhouse gases.
• In summary, confidence in models comes from their physical basis, and their skill in representing observed climate and past  climate changes. Models have proven to be extremely important  tools for simulating and understanding climate, and there is  considerable confidence that they are able to provide credible quantitative estimates of future climate change, particularly at larger scales. 
• Models continue to have significant limitations,  such as in their representation of clouds, which lead to uncertainties in the magnitude and timing, as well as regional details,  of predicted climate change. 
• What does the accuracy of a climate model's simulation of past or contemporary climate say about the accuracy of its projections of climate change? This question is just beginning to be addressed...
  
• Nevertheless, over several decades  of model development, they have consistently provided a robust  and unambiguous picture of significant climate warming in response to increasing greenhouse gases.
• Over several decades of development, models have consistently provided a robust and unambiguous picture of significant climate warming in response to increasing greenhouse gases.

We read that IPCC states that

• the models still show significant errors
• models continue to have significant limitations,

which expresses that the accuracy of the predictions is very questionable, according to the highest authority of IPCC. Compare with a Global Climate Modeling: Fate of Humanity?

The statement that the confidence comes from the fact that the models have physical basis, shows an alarming innocence as concerns computational mathematical modeling. Physical basis? What else? Religion or parapsychology?

This statement is aimed at impressing the uninformed, but is a triviality to the informed.  Is the message that the poor should feel the pressure of established physical laws and not ask for more?

The statement cited last is the key: models show response to increasing greenhouse gases.

Yes, but this is because they are so designed. Models are not reality. 

It may be that there is antropogenic warming derived from human activities, but statements that this is proved by simulations using Global Climate Models can be questioned.

 

If mathematical predictions are to serve as the basis of decisions influencing the lives of billions of people, the accuracy has to be improved. Suddenly nothing seems more important to humanity than computational mathematics, fluid dynamics and simulation technology ...because this is the only way to get information about the future we know of ...

Compare Climate Debate Daily and Resisting Climate Hysteria, Global Warming - Sensibilities and Science and Global Warming - A Peculiar Issue by Richard Lindzen stating:

• What was done by IPCC, was to take a large number of models that could not reasonably simulate known patterns of natural behavior (such as ENSO, the Pacific Decadal Oscillation, the Atlantic Multidecadal Oscillation), claim that such models nonetheless accurately depicted natural internal climate variability, and use the fact that these models could not replicate the warming episode from the mid seventies through the mid nineties, to argue that forcing was necessary and that the forcing must have been due to man. 
• The argument makes arguments in support of intelligent design sound rigorous by comparison.  It constitutes a rejection of scientific logic, while widely put forward as being ‘demanded’ by science.
  

If we reject scientifc logic, what shall we then rely on?