Portland, Oregon is not the only city claiming significant greenhouse gas reductions. Seattle says its 2005 overall emissions are 8% below 1990 levels, down to 11.5 MT per capita. (That compares to Portland's claim of 14.4 MT/capita, and an overall United States average of 24.1 MT/capita.)
According to an email from John Fleck, Albuquerque is claiming a 6% reduction in greenhouse gas emissions from 1990 to 2005.
I don't know. It is not intuitively obvious that Seattle should have a 20% lower carbon footprint than Portland, especially when it is farther north and has noticeably cooler weather, especially in the winter. And when I hear traffic is significantly worse up there.