Climate

is chaotic:

What is the import of Lorenz? Literally ALL of our collective data on historic “global atmospheric temperature” are known to be inaccurate to at least +/- 0.1 degrees C. No matter what initial value the dedicated people at NCAR/UCAR enter into the CESM for global atmospheric temperature, it will differ from reality (from actuality – the number that would be correct if it were possible to produce such a number) by many, many orders of magnitude greater than the one/one-trillionth of a degree difference used to initialize these 30 runs in the CESM-Large Ensemble. Does this really matter? In my opinion, it does not matter. It is easy to see that the tiniest of differences, even in a just one single initial value, produce 50-year projections that are as different from one another as is possible(see endnote 1). I do not know how many initial conditions values have to be entered to initialize the CESM – but certainly it is more than one. How much more different would the projections be if each of the initial values were altered, even just slightly?

This has always been pretty obvious to me. What does it mean? That we cannot model it into the future with any confidence whatsoever.

3 comments on this post.
  1. Ed Minchau:

    Add to Lorenz the Nyquist sampling criterion, and any hope of predicting climate in the future goes right out the window.

  2. Tom Billings:

    “That we cannot model it into the future with any confidence whatsoever.”

    But that leaves nothing for my grad students to be funded to do!

    Think of the Children!

    Think, gulp, ..of the administrative office’s cut of the research grants!

    Think of Tenure!

  3. PeterH:

    +/-0.1 degrees C is wildly optimistic. For instrumental readings prior to the age of satellites, and a great deal since, +/- 1 degrees C is a more realistic estimate of error margin.