Hi.
Earth is not a constant distance from the Sun. The closest it gets is 91,405,436 miles in early January and 94,511,989 miles in early July You can read more about that here:
http://www.windows.ucar.e...re.html&edu=elem

So you see over the course of a year Earth's distance from the sun changes by around 3 million miles, much more than a few thousand feet, and it does not have an terrible effect on our environment.

If the earth were closer to the sun on average though, that would increase the total heat input energy over the course of a year. That would tend to make a difference in climate. I doubt a few thousand feet would make a difference, bu I am not sure how far it would have to change before it made a difference. The distance to the Sun makes a difference in temperature, but other things related to how Earth's climate reacts makes a difference too, so it is not a simple thing to figure out.

Terry