Guest essay by Leo Smith – elevated from a comment left on WUWT on January 6, 2015 at 2:11 am (h/t to dbs)

As an engineer, my first experience of a computer model taught me nearly all I needed to know about models.

I was tasked with designing a high voltage video amplifier to drive a military heads up display featuring a CRT.

Some people suggested I make use of the acoustic coupler to input my design and optimise it with one of the circuit modelling programs they had devised. The results were encouraging, so I built it. The circuit itself was a dismal failure.

Investigation revealed the reason instantly: the model parametrised parasitic capacitance into a simple single value: the reality of semiconductors is that the capacitance varies with applied voltage – an effect made use of in every radio today as the ‘varicap diode’. for small signals this is an acceptable compromise. Over large voltage swings the effect is massively non linear. The model was simply inadequate.

Most of engineering is to design things so that small unpredictable effects are swamped by large predictable ones. Any stable design has to work like that. If it doesn’t, it ain’t stable. Or reproducible.

That leads to a direct piece of engineering wisdom: If a system is not dominated by a few major feedback factors, it ain’t stable. And if it has a regions of stability then perturbing it outside those regions will result in gross instability, and the system will be short lived.

Climate has been in real terms amazingly stable. For millions of years. It has maintained an average of about 282 degrees absolute +- about 5 degrees since forever.

So called ‘Climate science’ relies on net positive feedback to create alarmist views – and that positive feedback is nothing to do with CO2 allegedly: on the contrary it is a temperature change amplifier pure and simple.

If such a feedback existed, any driver of temperature, from a minor change in the suns output, to a volcanic eruption must inevitably trigger massive temperature changes. But it simply never has. Or we wouldn’t be here to spout such nonsense.

With all simple known factors taken care of the basic IPCC style equation boils down to:

∆T = λ.k.log( ∆CO2)

where lambda (λ) is the climate sensitivity that expresses the presupposed propensity of any warming directly attributable to CO2 (k.log(CO2)) radiative forcing and its resultant direct temperature change to be amplified by some unexplained and unknown feedback factor, which is adjusted to match such late 20th century warming as was reasonably certain.

Everyone argues over the value of lambda. No one is arguing over the actual shape of the equation itself.

And that is the sleight of hand of the IPCC…arguments about climate sensitivity are pure misdirection away from the actuality of what is going on.

Consider an alternative:

∆T = k.log( ∆CO2) + f(∆x)

In terms of matching late 20th century warming, this is equally as good, and relies merely on introducing another unknown to replace the unknown lambda, this time not as a multiplier of CO2 driven change, but as a completely independent variable.

Philosophically both have one unknown. There is little to choose between them.

Scientifically both the rise and the pause together fit the second model far better.

Worse, consider some possible mechanisms for what X might be….

∆T = k.log( ∆CO2) + f(∆T).

Let’s say that f(∆T) is in fact a function whose current value depends on non linear and time delayed values of past temperature. So it does indeed represent temperature feedback to create new temperatures!

This is quite close to the IPCC model, but with one important proviso. The overall long term feedback MUST be negative, otherwise temperatures would be massively unstable over geological timescales.

BUT we know that short term fluctuatons of quite significant values – ice ages and warm periods – are also in evidence.

Can long term negative feedback create shorter term instability? Hell yes! If you have enough terms and some time delay, it’s a piece of piss.

The climate has all the elements needed. temperature, and water. Water vapour (greenhouse gas: acts to increase temperatures) clouds (reduce daytime temps, increase night time temps) and ice (massive albedo modifiers: act to reduce temperatures) are functions of sea and air temperature, and sea and air temperature are a function via albedo and greenhouse modifiers, of water vapour concentrations. Better yet, latent heat of ice/water represents massive amounts of energy needed to effect a phase transition at a single temperature. Lots of lovely non-linearity there. Plus huge delays of decadal or multidecadal length in terms of ocean current circulations and melting/freezing of ice sheets and permafrost.

Not to mention continental drift, which adds further water cycle variables into the mix.

Or glaciation that causes falling sea levels, thus exposing more land to lower the albedo where the earth is NOT frozen, and glaciation that strips water vapour out of the air reducing cloud albedo in non glaciated areas.

It’s a massive non linear hugely time delayed negative feedback system. And that’s just water and ice. Before we toss in volcanic action, meteor strikes, continental drift. solar variability, and Milankovitch cycles…

The miracle of AGW is that all this has been simply tossed aside, or considered some kind of constant, or a multiplier of the only driver in town, CO2.

When all you know is linear systems analysis everything looks like a linear system perturbed by an external driver.

When the only driver you have come up with is CO2, everything looks like CO2.

Engineers who have done control system theory are not so arrogant. And can recognise in the irregular sawtooth of ice age temperature record a system that looks remarkably like a nasty multiple (negative) feed back time delayed relaxation oscillator.

Oscillators don’t need external inputs to change, they do that entirely within the feedback that comprises them. Just one electron of thermal noise will start them off.

What examination of the temperature record shows is that glaciation is slow. It takes many many thousands of years as the ice increases before the lowest temperatures are reached, but that positive going temperatures are much faster – we are only 10,000 years out of the last one.

The point finally is this: To an engineer, climate science as the IPCC have it is simplistic nonsense. There are far far better models available, to explain climate change based on the complexity of water interactions with temperature. Unfortunately they are far too complex even for the biggest of computers to be much use in simulating climate. And have no political value anyway, since they will essentially say ‘Climate changes irrespective of human activity, over 100 thousand year major cycles, and within that its simply unpredictable noise due to many factors none of which we have any control over’

UPDATE: An additional and clarifying comment has been posted by January 6, 2015 at 6:32 pm

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