If greenhouse gasses didn't cause "Greenhouse Effect"

[AncientHumanoid]

Assume the atmosphere of the Earth is still the same, except that certain properties of some of the gasses didn’t exist.

Namely, the Greenhouse Effect™
If this wasn’t a property of our atmosphere, what would be the temperature of Earth?

Would it be hotter or colder overall? Or, would it still all average out with some horrendous winds?

Remember, I’m not talking about an airless Earth. Just no greenhouse effect for atmospheric gasses.

[Motog]

Just a clarification - are you talking about the greenhouse effect or the enhanced greenhouse effect?

If you’re talking about the greenhouse effect then we would be very, very bloody cold, a similar sort of temperature to that of, say Mars (The average surface temperature on Mars is about 220 Kelvin (-53 degrees Celsius, or -63 degrees Fahrenheit). but note that Mars is a further from the sun than earth so it is a bit cooler than earth would be.

If you’re talking about the enhanced greenhouse effect then that’s a very difficult and contentious question.

[AncientHumanoid]

Well, an article (from an Scientific American ) on global warming is what got me thinking about this in the first place.

So, I would really like to hear a discussion of man’s role in this too.

Here are the definitions I’m using:

from The Australian Academy of Science

greenhouse effect: The trapping and build-up of heat in the lower atmosphere near a planet’s surface. Some of the heat flowing back towards space from the Earth’s surface is absorbed by water vapour, carbon dioxide, methane and other gases in the atmosphere. If the atmospheric concentrations of these gases rises, then theory predicts that the average temperature of the lower atmosphere will gradually increase.

enhanced greenhouse effect: An increase in the natural process of the greenhouse effect, brought about by human activities, whereby greenhouse gases such as carbon dioxide, methane, chlorofluorocarbons and nitrous oxide are being released into the atmosphere at a far greater rate than would occur through natural processes.

This might turn into a debate, I think.

If man had no part in the climate, you’ve already answered my hypothetical question. Looks like water in its three states wouldn’t exist on the surface of Earth, so I’m guessing Man would not exist either.

But, to take it further, is this one animal, Man, really changing the environment that much? Are the effects of these gasses that powerful? And, if there was no Greenhouse effect, would this kind of atmospheric pollution cause any other differences in climate?

Sorry for the multiple questions and posts, I think in spurts…