The plans that were referenced, I believe, do have a base year. I'm not sure if it's specifically in the Japanese plan, but the Japanese Prime Minister had spoken about 2006 as a base year. Certainly in Canada's plan there's a base year, and certainly the Europeans have had a base year. The idea is that others would follow suit, follow the practice established by the three groupings: EU, Canada, and Japan, and put in place a framework for measurable reductions.
On June 19th, 2007. See this statement in context.