San Francisco - Seven US West Coast states and four Canadian provinces are to introduce a market-based emissions-trading scheme aimed at reducing carbon dioxide emissions, news reports said Thursday.

The Western Climate Initiative - comprised of the US states of California, Arizona, Montana, New Mexico, Utah, Oregon and Washington and the Canadian provinces of British Columbia, Manitoba, Ontario and Quebec - released a draft proposal for the programme Wednesday, the San Francisco Chronicle newspaper said.

Trading was to officially start in 2012.

The initiative was launched in February 2007 with the aim of dramatically reducing greenhouse gas emissions on a regional level by 15 per cent from 2005 levels by 2020.

California Governor Arnold Schwarzenegger in 2006 signed strict greenhouse gas legislation, introducing the strictest measures in the United States. Emissions are to be cut by 2020 to 30 per cent below 1990 levels.

Plans to introduce climate legislation on a federal level fell through in Washington in June, owing to strong Republican resistance. The draft, which proposed clear-cut rules for emissions cuts, would increase already skyrocketing energy costs, the Republicans said. (dpa)