In Northern Illinois, you get cold winters and hot summers. On some nights you can strongly experience firsthand the global warming effects of water versus CO2.
Some of us interested in amateur astronomy have long been aware that the best nights for viewing are in the winter. The humid summer nights add a milkiness to the sky when streetlights illuminate it. I do not recall a single summer night that was truly dry enough to lack this milkiness. But in the winter, the sky does lose moisture, allowing us to see more stars as well as faint nebulae and galaxies. These very dry nights are also the times that heat from the ground radiates directly into space, yielding subzero temperatures. This weeds out the weaker astronomers.
A cold nights can occur when we get a cold blast of Canadian air (the Canadians probably just call it 'air'). But on a clear, windless night, meteorologists point out that infrared heat will escape directly into space, leaving us with bitter cold temperatures. Yet many local residents I've asked are unaware of the connection. I recommend everybody take note of this effect, both on cloudy nights and clear nights. You will find the effect to be quite dramatic, differing by thirty or so degrees F.
The same thing happens in daytime, it gets colder than usual under clear skies, but the effect is lessened while the sun is simultaneously heating the ground.
Carbon dioxide blankets the earth evenly, it does not form "fronts" and "systems" the way clouds do, so a night without moisture still has plenty of CO2 present. Stepping outside, we learn that the effects of water vapor dominate temperatures while present levels of CO2 do little to counteract the absence of water.
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