Tuesday, March 27, 2012

The Heat Is On

The question of what is happening to our planet is really one of thermodynamics; studying the effect of the amount of heat stored by Earth. I once had a thermodynamics instructor who would set up an equation, cross out all the numbers, and then work the equation using only the units of measure. He said that “in the study of thermodynamics numbers don’t really matter.” That’s why the heat wave in the Eastern US is irrelevant; temperature is just a number, while heat is something quite different.

Quite simply, temperature is a measure of the quality of a form of energy, while heat is a measure of the quantity of that same form of energy, and more heat does not by any means necessarily mean hotter.

Natural gas burns at about 3000 degrees, but that doesn’t tell you how rapidly a furnace will warm up your home. A furnace rated at 90,000 BTU will do so a lot faster than one rated at 40,000 BTU, but both are burning natural gas at 3000 degrees. That’s because the larger one has more burners and is delivering a larger quantity of heat, even though both are operating at the same temperature.

So how does that relate to the state of our planet? I’m glad you asked.

The Sun is very hot, but that doesn’t matter to us very much because none of that heat reaches the Earth. Heat cannot travel through a vacuum, which is why the coffee in your thermos stays hot. What does reach us is a different form of energy radiated by the Sun; light, and one whole hell of a lot of it. A good bit of that light energy which reaches Earth is re-radiated back into space. Some of it bounces (is reflected), some is radiated as infrared light on the night side, and some of it remains as heat in our atmosphere.

As the amount of CO2 and Methane in our atmosphere has increased the planet’s ability to radiate infrared light back into space has been diminished, and more of the absorbed light energy is being retained and stored, mostly, as heat. So our planet is storing more and more heat energy. Do you notice I haven’t used the word “temperature” yet?

So what does that heat do, if not make us hotter? Another good question.

I’m sure you’ve watched a pan of water boil. At first nothing happens, then a bubble appears on the bottom of the pan, then a few more; those bubbles rise to the top. More bubbles appear and rise, then bigger bubbles and more of them, and at the end the pan is a violent roiling mass of activity. The period of interest is the time between when that first bubble appeared and the end stage.

Water boils at 212 degrees, and that first bubble did not appear until the water in the pan reached that temperature. Because it boils, water can never get any hotter than 212 degrees, unless you prevent it from boiling by pressurizing it, which we didn’t, so at the end stage our pan of water was still at 212 degrees. But it certainly changed, didn’t it? That’s because we continued to add heat to it. The additional heat made the water much more violent, but it didn’t raise its temperature by a single degree.

Just as the addition of energy changed the state of that pan of water without raising its temperature, the extra energy being added to our planet is changing the state of our planet. It may or may not be raising the planet’s temperature, and while a temperature change might affect man, that is not really the main issue. The added energy is most certainly is doing other things to our planet, and we may not even be aware of some of them yet.

When a person gets overheated, that is absorbs too much heat on a sunny day, he sweats, which is the human body’s natural cooling mechanism. When the overheating goes too far the person stops sweating, and when that happens the person almost always dies very quickly.

Our planet also has some natural ways of keeping the extra heat from overheating Earth; for instance the melting of planetary ice fields. When ice melts it absorbs energy and keeps that energy from turning into heat. One whole hell of a lot of ice has already melted, and much more will do so, but what happens when all of the ice has melted? All of that energy will start going into our atmosphere. That is not going to be fun.

Our atmosphere may be becoming warmer or may not. It probably is, but that's not the important point. Like that pan of water, as more and more energy is stored within our atmosphere, it is unquestionably becoming more and more vigorous. Storms are more frequent, move more rapidly and are more violent. Where does that end?

Actually, the added energy is changing our atmosphere in a number of ways which we are only beginning to discover and some of which we don’t understand at all. Why, for instance, is the average altitude of clouds becoming lower? There may well be other atmosphereic effects which we haven’t even discovered yet.

We know more about outer space than we know about our oceans. A great deal of energy is being absorbed by our oceans, known by those of us who live on the West Coast as “nature’s great air conditioner,” and we know almost nothing about the future effects of that energy gain on our oceans. How long can they condition our air?

These are the things we should be talking about, not how hot it got in Dubuque, IA on Wednesday of last week. Temperature is just a number.

1 comment:

Bartender Cabbie said...

Looks like you have been spammed. Interesting post.

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