Seven Western states and four Canadian provinces proposed a sweeping plan to crack down on global warming emissions today, across a region that represents 20% of the U.S. economy and 73% of Canada's economy.

The Western Climate Initiative, endorsed by the Western governors and Provincial leaders, would slash regional greenhouse gas emissions by 15% below 2005 levels in the next 12 years.

"We're sending a strong message to our federal governments that states and provinces are moving forward in the absence of federal action," said California Gov. Arnold Schwarzenegger, adding that the effort would spur renewable energy development and create "green jobs."

The initiative calls for a program to cap emissions that contribute to global warming, grant industries fixed numbers of permits to pollute, and allow them to trade the permits among themselves, so the emissions can be achieved in the cheapest way possible. Such a cap-and-trade program has been adopted in Europe, and the Northeastern U.S. is unveiling a more restricted version limited to power plants.

However, President Bush has opposed any national climate legislation, and a comprehensive global warming bill that would have set up a national cap-and-trade program failed in Congress earlier this year.

The Western initiative comes as studies have shown that the Western region of the U.S. is likely to suffer severe effects from expected climate change: water shortages, increased wildfires, coastal flooding and species die-offs.

California passed a global warming law in 2006 and is well ahead of its neighboring states in setting up a program to cap emissions. A regional program is designed to prevent industries from relocating to states that have less strict emission regulations.

But the recommendations issued today are no guarantee that state legislatures outside California will adopt the program.

Affected industries, from electrical plants to cement factories, are hoping to postpone or weaken state rules until a national program is adopted.

The Western initiative, however, gives industries considerable flexibility by allowing up to 90% of pollution permits to be given to industry, rather than auctioned off as environmentalists and consumer advocates had hoped. An auction would create funds to subsidize clean energy and prevent what environmental groups call "a free ride for polluters."

Rather than reduce all their own emissions, industries could reduce only 51% of them and then purchase "offsets" in other ways, such as planting trees, or paying to capture landfill emissions, under the Western initiative. Economists have expressed concerns that many offsets used in the European cap and trade program have proved to be bogus. In many cases, they have not reduced pollution beyond what was already planned.

The seven states are Arizona, California, Montana, New Mexico, Oregon, Washington and Utah. Environmentalists fear that polluting industries could flee to Nevada, Colorado or other non-member states. The four Canadian provinces are British Columbia, Manitoba, Quebec and Ontario. All together, the participating jurisdictions have a population of 84.6 million people.