Seeing the environmental forest

It's nice when a topic for a new post lands in your lap.  Or, in this case, in the comments of one of your old posts.  An anonymous commentator made several statements concerning RSS that warrant a longer explanation than is possible in a reply on the comment section.  This is going to be a long, stats-heavy post.  You've been warned.

While browsing a climate change article on Huffington Post, I noticed a global warming denier using a Watts Up With That post by Lord Monckton as "evidence" that global temperatures haven't changed since September 1996.  In it, Monckton uses least squares regression to show that satellite data from RSS is flat (trend: -0.0001394ºC per year) between September 1996 and January 2014.