I don't want to get involved in the discussion, other than to point out this statement, which I'm guessing is just a typo, since the "fact" contained within it is impossible.
If 2008 was the coolest year out of the past 10, then the prior 9 years (1999-2007)would have all had to have been hotter than 2008.
While your statement is factually accurate, your beef should be with the original poster, not me; that was a direct quote from RTW's first post.
I took the word "decade" to apply to this decade (in contrast to, say, the '90s), which is obviously incomplete. This point would have been more apparent had you not substituted "the coolest year out of the past 10" for "the coolest year of the last decade".
But yes, you are technically correct to point that out, in the same sense that the Yankees have technically won two World Series "this decade."