Subject: Is the Earth, on average, moving closer to the sun?

Is the Earth moving closer to the sun? Answers to this question generally include ideas about the 
elliptical orbit of the Earth, however I'd like to know on average. Is the closest point getting closer? Is the 
furthest point also getting closer? Other answers I have had generally conclude that we are moving 
further away due to the big bang theory, however I believe this cannot be the answer as the big bang 
theory states that the entire universe is expanding and says nothing about individual solar systems. 
Could this also be contributing to global warming?
Thank you in advance.

Re: Is the Earth, on average, moving closer to the sun?