When someone is explaining global warming, he might mention a pot of water on a stove, which some frogs have jumped in. Frogs, the writer asserts, don’t realize the heat is rising until it’s too late and they are boiled alive. If they’d only had the sense to jump out of the pot!
We are not frogs, however. We have the science and the observations of climate from many years to consult. From the recorded data, we know the earth’s temperature is rising, fast. We are not frogs, but our oceans are warming although certainly not boiling. The oceans do not need to be hot to bring very serious effects; and our “pot” has a lid and we couldn’t jump out if we tried.
1. The Lid
Return for a moment to that simple image of the stove and pot. If you need to heat a big pot of water and you want it to boil quickly, just put a lid on it. A lid keeps the hot air above the water inside and increases the pressure, so the water gets hot much faster.
Our planet Earth has its own lid: It’s the magnetic field. That is basically a force field which holds the ozone layer in place, and all the air beneath it.
If we didn’t have the magnetic field, Earth would be like the Moon, and you’d need a spacesuit and oxygen tank to breathe, because the air would drift away. There would be no atmosphere, no blue skies or sky of any color.
We’re incredibly lucky. Astrophysicists scour space looking for planets like ours, and I’m not certain any — at all — have been found. Where else could we live?
The answer is nowhere. This planet is what we need. Conditions right here, right now are what we require to keep existing as a species; it’s what plants and animals on Earth need to continue existing, too.
2. Why is it getting so hot here? Why is the globe warming?
It’s because of the atmosphere under that lid I talked about. A few hundred years ago the atmosphere was quite different. It didn’t have nearly so much greenhouse gas in it as it does today. Between that time and now, greenhouse gases have been created at a very high rate. They’re created both by nature and by mankind.
Greenhouse gases you’ve heard of already: carbon dioxide, methane, and a bunch of manmade gases. These are the ones spoken of as the major initiators of the greenhouse effect.
Ideally, sunlight shines down through the atmosphere, warms the earth up, makes daytime and so forth, but then most of its rays bounce off the earth, pass through the atmosphere again and go harmlessly back out into space. Not now. Carbon dioxide and water vapor tend to absorb huge amounts of heat. Both the cloud layer and the carbon gases in the air act like a cap, because it’s more difficult for these substances to release heat. The heat is held closely to earth, warming the land and oceans.
Heat is building up, under our lid. It hasn’t escaped, and it’s starting to cook.
It’s not a cozy greenhouse here anymore. It’s more like the pot of water with frogs inside, with a lid on it. And we’re the frogs after all. We’re just frogs with big brains.
3. Heat and Weather
Weather is made by interaction with the oceans, the friction of the atmosphere scraping across the earth, as well as tidal forces from Moon and Sun. Mostly, however, it changes with temperature. Unusual temperatures produced by global warming disturb the usual, seasonal patterns of weather and bring about heightened frequency of massive storms, including catastrophic storms such as have been experienced worldwide in recent years.
In future posts we can discuss the mechanisms of heat and weather, and how they tie in with global warming.