OG Verbal TC Medium Q8

Here, in the first blank I chose B instead of OA A, and got the remaining 2 correct. Can anyone expain this? I thought that if in blank 1, if somehow the loss of heat from earth’s surface would be made worse, then wouldn’t it be warmer (say, for humans?) because the heat is coming out of the surface

I think humans are considered to be living on the surface where they need the heat to stay there