The Earth's atmosphere is not an easy thing to duplicate in the laboratory. One of its central features is decreasing pressure with altitude, with the pressure at each altitude being equal to the weight of the atmosphere above. Perhaps we could devise some way to build such a column on a smaller scale, with an ideal gas one thousand times more dense than air. But we know of no such gas.

And even if we could find such a gas, we would still need to duplicate the evaporation of water, its condensation into clouds, and the formation of snow and rain. Perhaps we could do this with some fluid other than water, which produces the same effects, but on a smaller scale. We know of no such fluid.

One day, some great experimental scientist may figure out how to build a model atmosphere in a laboratory, and so allow us to test our ideas about how the Earth's climate will respond to changes in solar power, cosmic ray flux, and carbon dioxide concentration. Until then, the study of long-term trends in the Earth's climate will be one of speculation, not experiment. No matter how sophisticated our theories about the climate's behavior, they will never deserve the credibility that we award to theories that have survived the test of thousands of independent experiments.

Nevertheless, the climate is a fascinating thing to think about. How does rain form? Why do clouds have often have flat bottoms and billowing tops? Why do hurricanes lose power when they strike land? Why does the air get colder as we ascend towards the tropopause? Why does it start getting warmer again when we ascend above that? We may not be able to devise and test a hypothesis about how the climate will evolve over the next hundred years, but we surely can provide ourselves with plausible answers to these questions, and as a result, enhance our enjoyment of the weather and of our view of the sky.

I'd like to say that this is the spirit with which we embarked upon our study of the climate. But I think that would be untrue. This is the spirit with which we continued and concluded our study. The reason I think we embarked upon the study was because we all heard on the radio and read in the newspapers that climate scientists were predicting a dire future for the Earth's climate unless we stopped using so much coal, gasoline, and oil. I expect that all of us experienced an acrimonious discussion in which our skepticism was ridiculed. I am confident that we all heard politicians suggesting public figures who doubted these predictions should be put in jail. And so we figured we should look into the matter for ourselves, to see if these dire predictions were indeed a necessary consequence of the laws of physics.

Over the course of two years, we built our own climate model. The model is crude, but it is effective. It is simple enough that you can download it an run it on your own computer. It cannot predict the future of the Earth's climate, but it does show that the dire predictions made by climate scientists are not a necessary consequence of the laws of physics. Indeed, the model suggests that the dire predictions cannot be true, and does so in what we find to be a most convincing manner. Thus we feel justified in our continued skepticism of anthropogenic global warming.

The real benefit of the model, however, is the tentative answers it provides to many basic questions we asked ourselves about the Earth's climate, and even the climate of Venus and the Moon. Where does the power for storms come from? Why is Venus so blisteringly hot? Why is a hazy day warmer than a clear day? Why does it get cold so suddenly at night in the desert? All these questions and many others we now feel we can answer. Our answers are not tested, but at least we have some basis upon which to discuss how these phenomena might manifest themselves.

It is more enjoyable, in our minds, to have a hypothesis that turns out to be wrong, than to have no hypothesis at all. So that is what you will find here: an accumulation of hypotheses, each of which we have tried to make as carefully as possible, but any one of which could turn out to be disproved by experiment, when some intrepid scientist figures out how to test them. We hope you enjoy reading them as much as we enjoyed writing them.

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