Saturday, July 10, 2010

A new and content-free model

In his article "A New and Effective Climate Model", Stephen Wilde (guest posting on Anthony Watts' blog) states his dissatisfaction with current climate models, and proposes another "model" for climate which he hopes will improve the state of climate modeling in general. In the article he has items like:

  1. Solar surface turbulence increases causing an expansion of the Earth’s atmosphere.
  2. Resistance to outgoing longwave radiation reduces, energy is lost to space faster.
  3. The stratosphere cools. Possibly also the number of chemical reactions in the upper atmosphere increases due to the increased solar effects with faster destruction of ozone.
  4. The tropopause rises.
  5. etc...

This list continues for 26 points, not an equation in the mix. So why am I so hooked on equations? Take the first item, and call "Solar surface turbulence" T, and the size of the atmosphere, A. Saying T goes up, so A goes up, could be like:


which would predict a nice linear response. What about this:


or this?


Each of these is a translation of "when T goes up, A goes up", but they have radically different forms, and they have radically different effects. You can't build a proper scientific model in words alone. Words are not precise, and there are many different ways to translate them into something that is precise, that can actually make meaningful predictions.

A model of just words is not really a model, in the scientific sense. Lord Kelvin said it best:

"In physical science the first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be."