Ok… Let me see if I can explain my question all in one post and not have to clarify it later:
The Earth is covered with air. This air is either warm or cold depending on where it is, although if you were to take all the air and mix it together, you’d eventually get one average temperature.
Because there were times when large sections of the Earth were frozen solid, and I’m assuming that at the same time the warm regions didn’t jump up thirty degrees, I am guessing that the Earth’s average temperature can change.
Remembering grade school experiments done with a balloon and a radiator, not to mention checking the air pressure in my tires before and after driving 20 miles, I feel safe to say that warm air expands and cold air contracts.
How much does the athmosphere on the planet contract or expand? I remember creationists saying that if the athmosphere was -nth bits thicker or thinner it would not protect us from the sun (or else block out too much of the sun as the case may be) and this number is usually something like 1/10th to 1/4 of an inch. Granted, they might be full of BS, but that’s not the issue. The question is, does the athmosphere expand like that? And once the temperature has risen or dropped in a global level (naturally, not via ozone depleteing what’s-its) what was changing it back anyway? I can buy the “meteor hits earth, dust blocks sun, Earth cools” theory once, but hasn’t the Earth had many an Ice Age? Is there an average temp the Earth just tries to maintain, meteors be damned?
“I guess one person can make a difference, although most of the time they probably shouldn’t.”