GCM IPCC Climate Models

These General Circulation Models are 3D models which attempt to solve a number of fluid dynamic equations over space and time.   There are a large number of them, more than 100 independent models with ranges of assumptions and algorithms.  Not much review of the models or the code has been performed, and the results are poor especially over the last 20 years.    See the GCM results page.   Also to have an overview of this topic see the slide presentation starting with this slide.


It is the aim of these models to be able to accurately predict climate well into the future, at least as far away in time as the end of this century.  The errors that are estimated by r Franks are quite relevant, but so are the comparison of results versus GCM models.  See the video on the Model Error page.


These models suffer not just from the above systematic errors but fall short of predicting the past nearly as well as the models termed here as the alternative models


The basic problems in the GCM models include the following:

Grid size and

physics included as well as the assumptions made.  

The largest assumption is that CO2 dominates GHG which in turn dominates the heating of the atmosphere by OLR (outgoing long-wave radiation).  

The natural causes detailed elsewhere are also assumed relatively constant such as solar irradiance.

There is also an issue with compute power available. 


Judith Curry has more to say about the basic structure of these models at this Page.  These assumptions are explored in more detail on the page Key Assumptions.    


It is also apparent from the literature and private communication

with Patrick Michaels that the tuning of the models is also done, as the model outputs a hotter climate than makes sense in observation.    There is independent study that shows that the models do tend to overstate warming.


There is also the point that needs to be made that the GCM models do also violate the laws of thermodynamics, and cannot model convection due to the large grid size, another indication that the models do not represent well the energy transfer and the chaos of the atmosphere.


Judith Curry speaks to the validity of the models below.   Dyson also has some observations on this page, as does Prof Soon


Judith Curry on the GCM Models and the Politics of Academia



The Chaos Not Modeled

https://wattsupwiththat.files.wordpress.com/2017/09/firedog-ii.png?w=300&h=172&crop=1Into The Vortex

Guest Post by Willis Eschenbach I came across a lovely photograph of a “fire devil”, also called a “fire whirl”. I liked it because the photo perfectly exemplified what is wrong with the current generation of climate models. What is wrong with the models is that they don’t include any of the vortex-based emergent atmospheric…

September 8, 2017 in Climate News, Emergence.


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