Simple Climate Models

This web model uses an efficient Java implementation of simple carbon and climate models, the same as those used to create many of the smooth-curve plots and quoted predictions in the recently published Intergovernmental Panel on Climate Change Third Assessment Report (IPCC-TAR)

Note this does not mean that it contains the same computer code, only that we try to match the same specification, as described in published scientific papers and IPCC reports.

The good fit to published data from IPCC can be shown by comparison with the data from the WG1-SRES appendix which can be superimposed as circles on the plots.
  • Check the correspondence with IPCC data.

    Components

    The Carbon cycle, Atmospheric chemistry, and Radiative Forcing calculations are based on the Bern model. The temperature and sea-level calculations are based on the Wigley/Raper UDEB model parameterised to fit a range of GCM predictions according to appendix 9.1 of IPCC-TAR-WG1.

    Both models incorporate upwelling-diffusion multi-layer oceans to account for the slow uptake of heat and carbon into the deep water. These systems are solved using an eigenvector method which is more efficient than direct integration and more flexible than pulse response functions.

    The code also has a flexible modular structure, whose components are only calculated if they are both needed for output, and have changed due to parameter adjustments or feedbacks.

    Specific details of how the calculations are made are now given in the documentation for each Module, see

  • Module Menu

    Related general topics:

  • How does it work so fast?
  • Code Structure
  • About the Java language
  • References

    Note, to explore the details, it is recommended that you switch the version (top panel menu) to "expert" mode!

    Types of models

    Note that this is a "simple" model which generates smooth curves, useful for comparing scenarios and understanding key processes. It cannot generate intrinsic climate variability, or regional climate variations, for which it is necessary to use much more sophisticated, but very slow "General Circulation Models" (GCMs).

    Between these two extremes are also emerging "Earth System Models of Intermediate Complexity" (EMICS) which may be particularly useful for integrated assessment, for investigating non-linear "surprises", and for simulations over longer timescales (glacial interglacial cycles).

    IPCC-TAR considered all these types of model -you can tell the difference by how smooth or "noisy" the plots are.