> The water already present in the atmosphere absorbs almost all IR radiation This does not seem to be correct. The earth's is gaining a significant amount of

> The water already present in the atmosphere absorbs almost all IR radiation This does not seem to be correct. The earth's is gaining a significant amount of energy from the sun. Since temperature is at an equilibrium we can assume it is losing a very similar amount of energy. We know that the earth gives off less (visible) light than it receives so the obvious explanation is that the earth is giving off a significant amount of heat. We can also directly observe heat leaving the earth from IR cameras in orbit. > No. It's just a hypothesis that greenhouse effect takes place. > And there goes f*ck your claim that it was a fact. You misunderstand me. It is a fact that the green house effect is happening. You yourself continue to insist that is is happening with statements like "The water already present in the atmosphere absorbs almost all IR radiation". Observing it happening is not the same as knowing how it would change in different conditions. That part is theory. Let me give a similar example: We can observe that the sun heats the earth. That is a fact. We have a theory that if the sun were to go out, the earth would get colder. Since the sun is still shining we cannot observe what would happen if the sun went out, so we deploy reason instead of direct observation. You could insist that the earth would stay the same temperature without the sun shinning and point out that we can't know for sure because it hasn't happened yet. Any statement we make about the future is not an observed fact because the future has not happened yet, but e can draw reasonable conclusions about the future.