Does 2011 Start a New Decade?

Is this a new 10 years or just the second year of the '10s?


When the clock flips tonight will 2011 start a new decade or merely be the second year of the ’10s? As I wrote here and here, I maintain the former: “since our calendar goes from 1BC to 1AD, without a year zero, this is not technically the last year of the decade.”

When I made that argument a year ago, a reader responded with an interesting argument. Kevin S. of Ohio wrote:

I have to disagree that 2009 wasn't the last year of the decade. Unlike centuries and millennia, we don't number decades sequentially. We call our decades the 1980s, the 1990s, etc. While we call this century "the 21st Century," we know we won't call the past decade (even though its name is still up in the air) "the 201st Decade." Therefore, a strong case can be made that 2009 was the last year of the decade, since it was the last "200X" year. Granted, this causes some problems with the first decade AD, but nobody ever bothers with that period enough to want to give it a name.

I don’t think I agree, but it’s an interesting point.