A Question for Global Warming Deniers

I have a question for global warming deniers. If you were a Martian, and you wanted to know if Earth was undergoing global warming, what kind of evidence would be sufficient for you? My guess is that the reams of data gathered by scientists all over the world on this subject would be more than sufficient to convince you. So why is it that, as an Earthling, you refuse to accept the reality of global warming? I think it has something to do with human capacity for denial, especially when it comes to worst-case scenarios that we simply find too unpleasant to contemplate. Sort of like the person who just can't admit to themseleves that their kid is doing drugs, despite overwhelming amounts of evidence from all angles (kids he hangs out with, smells coming from room, drop in academic performance, money missing from your wallet, etc. etc.). Thoughts?

Ice Cream, Banks, and Pharmacies

Have you every noticed how there seems to be an over-abundance of certain things on the market?  Take ice cream for example.  At my local supermarket, there is an entire freezer (one aisle long) dedicated to ice cream.  There must be at least fifteen different brands.  Each brand has at least five varieties.  Ben and Jerry's probably has like, twenty.  When I was kid in the early 80s I think there were like three brands at the supermarket, and the flavors were vanilla, strawberry, and chocolate (and mint chocolate chip, if you were lucky). 

On a similar note, why does it seem like there's a bank on every block in town?  And not just big name banks, but little guys (local banks, too).  Why the abundance?  I mean, why hasn't online banking and the financial crisis diminished their presence?  Same thing with pharmacies.  Seems like every corner has a Walgreens, Rite Aid, CVS, or maybe even an Eckerd.  That's not to mention the pharmacies INSIDE the supermarkets.  What's the deal?