Doer signed the Midwestern Regional Greenhouse Gas Reduction Accord with seven American governors in November 2007. The following month, he announced that Manitoba would introduce vehicle emission standards similar to those in California. In late January 2008, he agreed to a blueprint proposal with the premiers of British Columbia, Ontario and Quebec for a market-based trading system to cut greenhouse gas emissions. He later became an enthusiastic supporter of North American cap and trade programs to reduce energy emissions, while at the same time criticizing the idea of a carbon tax.