"In many parts of the world, state and regional governments control much of the carbon infrastructure, from energy to transport, and have powers to develop policies including implementing emissions trading schemes," the report says.

"Sub-national governments, many of whom have globally significant economies in their own right, can also have a globally significant impact on climate change mitigation due to their unique position of influence on citizens and national goverments," The Climate Group CEO Steve Howard noted.

Howard added, "Many of these measures will deliver not only environmental benefits but also financial benefits, both to the individual consumer and the wider economy." "A further exciting development is that neighboring states have started to collaborate with one another, amplifying the emissions reductions that can be achieved."

The report cited the Regional Greenhouse Gas Initiative under which Northeast states will put a carbon cap-and-trade system for power plants at the start of 2009, and the Western Climate Initiative. WCI is developing a cap-and-trade program among Washington, Oregon, California, Utah, New Mexico, Arizona, British Columbia, and Manitoba. The Washington Climate Action and Green Jobs Bill before the 2008 Legislature prepares the state to enter into the WCI system.

"Low Carbon Leader" also features subnational initiatives in other nations that have not yet joined the global carbon framework, including China, India and Mexico.

• Guangdong, China's richest province, has launched a campaign aimed at making it China's most energy efficient province while saving 45 million metric tonnes of carbon dioxide equivalent emissions between 2005-10.
• Maharashtra, India's industrial leader, has also launched an ambitious efficiency program aimed at saving 20,000 gigawatt-hours of energy.
• Mexico Distrito Federal, home to one of the world's largest city-states, has instituted air quality measures that could save 2.2 mllion metric tonnes of carbon dioxide equivalent each year by 2010.

The report carries additional profiles including Tokyo; Victoria, Australia; Quebec province; Western Cape, South Africa; Scotland; and North Rhine-Westphalia, Germany.

This article originally appeared in Climate Solutions Journal.