From the Financial Times:

Five governors from western states, frustrated at the lack of administration and congressional action on climate change, yesterday agreed to work together to set a regional target in the next six months to cut greenhouse gas emissions.
Arnold Schwarzeneggar, governor of California and a member of the Western Regional Climate Action Initiative, told the National Press Club the target signalled to the federal government that if it did not lead, the states would: “We will create a cleaner environment, take care of our air and of our water, and follow the Kyoto treaty to a certain extent and really fight global warming.”
Mr Schwarzeneggar, who has spearheaded the most aggressive of the states’ efforts – to cut California’s emissions by a quarter by 2020 – has been joined by the governors of New Mexico, Oregon, Washington and Arizona. The group hopes to agree within 18 months on a market-based cap and trade programme to cut emissions across a range of sectors in each state and to set up a registry to track and manage emissions.
The western initiative, however, threatens to add to the patchwork of regulations that operate across the US, with different standards in different states. It follows a more limited gubernatorial initiative in December 2005 from the governors of seven north-eastern and mid-Atlantic states that targeted emissions from just the utility industry. Three more states are set to join that plan this year.