Major props to Seattle mayor Greg Nickels who recently started the US Mayors Climate Protection Agreement. It is becoming something of a smackdown to federal leadership that refuses to take global warming seriously. The idea is simple: if the US government won’t ratify the Kyoto Protocol, then the constituent parts of the nation will.

So Seattle made the pledge to meet Kyoto’s standards (reduce greenhouse gas emissions 7 percent from 1990 levels by 2012); and then Nickels started rounding up other cities to join in. The response has been overwhelming, and not just from small-fry or blue-state cities either. The full list is here. Following are a few of my favorites:

New York, Los Angeles, San Francisco, Oakland, Miami, Newark, Denver, Salt Lake City, Minneapolis, Little Rock, Louisville, New Orleans, Boston, Kansas City, Albuquerque, Austin, Portland, and Tacoma.

It’s a surprisingly diverse list, drawing together nearly 31 million Americans from 36 states—everywhere from Cambridge, Mass to Macon, Georgia to Gary, Indiana. Nickel’s initiative picked up some nice media coverage in the New York Times recently, among other places.

For Cascadia counters: The list includes 12 cities in Washington, 3 in Oregon, 2 in Montana, and 30 in California. None, so far, in Idaho or Alaska.

UPDATE:Some other non-Cascadian pledges worth noting: The states of New York, Massachusetts, and Maine have all pledged to reduce statewide greenhouse gas emissions by 10 percent by 2020. New Jersey has pledged 5 percent reductions by 2005. Taken together, these northeast state initiativesadd up to more than 35 million Americans who are pledging to Kyoto-like carbon targets.