I'm not a climate scientist and only got into it to win an Internet Argument. It was very important, at the time. ;-)
Basically, I'd worked with modeling large data sets in a chaotic system (traffic) and knew that 'adjusting the data' was legitimate. This was when people were complaining about the scientists changing the data they used in their models.
So, I started poking. I spent about two years poking at it. I also learned that the rumors seemed to be untrue. I was able to email and get unadjusted data - even without credentials. I say 'seemed' because this was after the email disclosures.
If you just want a copy of a paper and you don't feel like paying for it or hitting up your local university library, you can even just email one of the authors. I did that a couple of times and have had nothing but cooperation.