Support the Arctic Sea Ice Forum and Blog

Author Topic: GCM data and code  (Read 1571 times)

NeilT

  • Nilas ice
  • Posts: 1314
    • View Profile
  • Liked: 111
  • Likes Given: 8
GCM data and code
« on: September 01, 2014, 12:25:44 AM »
I was reading the statements on the 2014 melting season thread and thought I create this one here.

Over the years I've read quite a lot about the models used for GCM and I've noted that RealClimate has a page dedicated to the presentation of the model code and the data used.

That page is here.  The more specific model being talked about is the GISS GCM ModelE used by the IPCC.

Now I'm not a scientist but I've spent quite a lot of my life writing code and also interpreting peoples requirements. As far as I can see, the models are physical models which take input data and apply both rules and physics to produce results.  Gavin Schmidt has talked about this many times if you want to search RC.

I believe it would make sense to read the descriptions, if not the code, to understand what these models are doing.  To my understanding they are models which work over hundreds or thousands of years to predict the physical interaction of the climate to the introduction of modifying factors such as greenhouse gasses.  They take into account reflectants, sea heat absorbtion inertia and many other factors.

However they are not a tool to say what the climate will be like one decade from now.  They are not a tool to predict tipping points or even sudden change. They are a tool to give a broad overview of the changes which will happen in the following centuries.

Of course they rely heavily on the mechanics of how the earth climate changes and what it releases in terms of natural gasses which impact the climate.  They even include ocean acidification and breakdown of the ability to absorb CO2.  They are very sophisticated.

However, only time will tell as to how accurate they are and also they will continue to evolve every year.  Even the politicians cannot avoid the fact that even the models become worse at every adjustment which includes new data on climate impacts of GHG increases.

That is their role.  Not to predict what will happen in the Arctic or with Arctic ice over the next decade.  Although they can do that too, but with the expected variance in results and reality....

Just my twopenneth worth.
Being right too soon is socially unacceptable.

Robert A. Heinlein