Your reasons for excluding Mars ignore the fact that terraforming Mars gets rid of those problems (except the 34 million miles away problem). Antarctica can be

Your reasons for excluding Mars ignore the fact that terraforming Mars gets rid of those problems (except the 34 million miles away problem). Antarctica can be terraformed too and would become a much more livable place. But, I think the current effort is to prevent/stop the terraforming of Antarctica due to the effects on the rest of Earth.