The leaders of 6 western states and 2 Canadian provinces have set formal targets for the reduction of greenhouse gases.

Dubbed the Western Climate Initiative (WCI) , California, Washington, Oregon, Arizona, New Mexico, Utah, British Columbia and Manitoba have agreed to reduce the region's emission to 15% below 2005 levels by 2020.

Though the figure above represents an overall goal, individual states will vary according the policies they have already established. Arizona and New Mexico are promising reductions over their 2000 emissions, while Washington and California used 1990 as a base year, promising 15 percent reductions. Oregon used 1990 as a base year and promised a 10 percent cut by 2020, as did BC.

The key point in the announcement is the agreement to establish a carbon market and cap-and-trade system over within the next year - a key peice of the puzzle that is needed before any region of North America can make substantial progress on climate change.