Number of the Month

February  2008

Thoughts on thermal inertia

When the central heating comes on in the morning, the temperature of the house rises exponentially towards its new equilibrium with a time constant of the order of an hour. The process of heat conveyance is inefficient because the medium of transfer, air, has a low heat capacity, while the recipients, walls and furnishings, have a high one.

Half a century ago a research student colleague of your bending author constructed a thermal oscillator comprising a lamp bulb and a thermistor. The equivalent circuit was a very high inductance and a very high capacitance, with the negative slope resistance of the thermistor cancelling out the positive one of the bulb. Light from the bulb pulsed with a period of several seconds.

The thermal capacity of water is much higher than that of air (not only is it considerably denser, but it has about four times the specific heat).  The specific heat of liquid water is much higher than that of any other common substance. Thus it is unsurprising that relatively minor perturbations in the oceans produce major effects on the atmosphere. The oceans exhibit oscillatory behaviour with periods measured in years. There is the El Niño phenomenon, the Pacific Decadal Oscillation and the North Atlantic Oscillation. It is not unreasonable to suppose that, because of the huge discrepancy in volumetric thermal capacities, the influence of water on air is very much greater and more immediate than vice versa. A change in atmospheric temperatures might take centuries to affect the oceans, but a relatively small convective disturbance in the water has an almost immediate effect on the air. Thermal inertia of the seas accounts for the difference between, for example, the clement climate of an island like Great Britain and the harsher continental extremes of central Europe.

Given all this it is somewhat surprising that there is so much discussion of the atmospheric climate that more or less ignores the contribution of the oceans. Furthermore, as we have recently remarked, it is a major error (or is it fraud?) to ascribe the apparent high global temperature associated with the strong El Niño in 1997-1998 to global warming. That phenomenon tells us that the apparent global atmospheric temperature is a rather poor indicator of the heat content of the planet. Furthermore, it is grossly misleading to use that isolated outlier as the end point of a trend calculation, but this has been done on a grand scale. That, however, is what happens when propaganda replaces science.

Footnote: Number watcher Fred Langford draws attention to this relevant paper.


Contrasts: local propaganda versus global reality

Once more a revelation to a prophet of the new religion shows an interesting disparity with events in  the real world. They don’t have a lot of luck, do they, these prophets of doom? There has been the near universal operation of the Gore effect, the BBC’s ill fated Springwatch and many other examples of the curse of the phenologists. You have to admire the way the faithful soldier on, completely ignoring what is actually going on, pursuing undaunted their doomladen visions. Still if faith can move mountains it ought to be able to shift a bit of ice.

Just a couple of thoughts

If it's settled it's not science.

They used to disembowel animals in an attempt to forecast the future. Now they disembowel trees in an attempt to aftcast the past. Funny old world!


Heartland heartbreak

Your bending author was devastated to have to decline a generous invitation to attend the Heartland Conference on Climate Change on the grounds of ill health. It is wonderful to see science at last making a fight of it against the new religionists, and the speaker list includes most of the heroes of the resistance. Let us hope that it has the success that it merits.

Footnote: Our man in Puerto Rico points out that the greatest hero of the resistance has been busy doing nothing.


It starts!

This is a truism

Wind power is unavailable when it is very hot or very cold.

The reason is that extremes of temperature in winter and summer occur when there is a stationary high and when there is a stationary high the wind does not blow.  We can put it another way

The only reliable thing about wind power is that you know it will not be there when you really need it.

A significant event occurred this month and like so many significant events it had to happen in Texas. For the first time, major power cuts were suddenly implemented because of a drop in the wind. Since the birth of Number Watch it has been going on about the insanity of energy policy (see for example, Power Mad) with reminders on roughly an annual basis that power cuts are inevitable and that people are going to die. The Texas incident is just a small taster of what is to come, but the frenetic erection of those modern religious icons, wind turbines, means that successive incidents can be expected to get worse.

The least stupid way of utilising wind power is to pump water up hills. At least the energy is then available when you need it. But religion never had much to do with common sense.

Link to this piece

Number of the month 1,400

This is the loss of power production in Megawatts resulting from the sudden drop in the Texas wind.



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