Re: News from Canada: Global Warming Ice Ages Out

On Feb 25, 8:50 am, Skipper <dadwri...@xxxxxxxxx> wrote:
http://www.nationalpost.com/opinion/columnists/story.html?id=332289

When I was in the Canadian Dept of the Environment (it has a different
name now), people were always coming around trying to sell us computer
models for fisheries, climate, ocean circulation, whatnot. These
models appealed wonderfully to managers, who like nice clean computer
outputs to wave around. They were especially likely to buy them if the
results supported their own views.

When I first encountered these, one of the things that amazed me was
the sensitivity of all environment models to the initial assumptions.
But you wouldn't see this until you got up real close and studied the
model and its documentation (and the data they plugged into it)
literally for weeks. For example,

""We missed what was right in front of our eyes," says Prof. Russell.
It's not ice melt but rather wind circulation that drives ocean
currents northward from the tropics. Climate models until now have not
properly accounted for the wind's effects on ocean circulation, so
researchers have compensated by over-emphasizing the role of manmade
warming on polar ice melt." -from the citation.

If you look at the available models, you'll find that most use density
driven (ice melting) circulation assumptions, which you can derive
from basic physics. Someone, looking for a unique approach to
modeling, looks at wind effects on circulation (which have
historically been regarded as minimal), and has to make the following
assumptions and measurements:
- Air to water transfer of kinetic (wind) energy - probably easiest to
estimate by measuring the slowing of wind over water.
- Partitioning of transferred wind energy into water movement and heat
- Effect of wave height, type, pitch, and direction on transfer of
energy from wind to water.
- Transfer of energy from surface to deep water. Very hard to model or
measure in the environment. An old oceanographer's rule of thumb is
that no wave energy is transferred deeper than 1-1/2 wave heights
below wave troughs. But this diffusion is also a function of time,
temperature, salinity, type of wave (smooth, breaking, etc).
- A whole shitload more variables.

The special feature of all computer models, too, is that tiny changes
in the input numbers often have outsized effects on the results -- the
so-called butterfly effect. Input data from two equally trustworthy
sources, in other words, may give opposite results.

Computer models used to predict fisheries are a major reason for the
disappearance of cod and other Atlantic fisheries, not because the
models were 'wrong' but because each party in international
negotiations selected their models to support their own interests.

So it is with climate change. No expects Joe Six-Pack to understand
any of the computer modeling arcana, which is why it breaks down into
a simple political choice-- If Al Gore is for it, wingnuts are agin'
it.

Dangerous Bill
.

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