Okay, so imagine a situation where most of earth's atmosphere is lost, the pressure at sea level is somewhere around 0.3 atm. If it matters, let's say that this is the result of the gradual escape of air during a period of a few years. Disregarding the prospect of life under such conditions, I'm more interested in what would happen to the climate in such a situation.
So in this scenario, the total amount of water vapor in the atmosphere would be expected to rise a bit due to the decreased vapor pressure (at least that's what I think would happen, though this could probably be negated by things such as temperature changes).
What I'm looking for is mostly an idea of the most general effects on Earth's climate. How would such a change affect the average temperature, day/night temperature cycle, winds, rainfall, and anything else you might eventually think of?
Oh, and hi.