California will be the first U.S. state to cap greenhouse gas emissions, including those from industrial plants, under a landmark deal reached Wednesday by Gov. Arnold Schwarzenegger and legislative Democrats [more | more2]. The bill is designed to cut California's emissions of carbon dioxide and other greenhouse gases 25% by 2020.

"The bill would require the state's major industries _ such as utility plants, oil and gas refineries, and cement kilns _ to reduce their emissions of the pollutants widely believed to contribute to global warming. The key mechanism driving the reductions would be a market program allowing businesses to buy, sell and trade emission credits with other companies."

This monumental step is great news for efforts to establish mandatory greenhouse gas emission caps globally.