Clean technology: California combats carbon

California has kicked off its cap-and-trade programme to reduce carbon dioxide emissions amid speculation about whether it will nose-dive or become a national model.

The California Air Resources Board says that carbon credits were sold at auction for slightly more than the $10 opening.

"By putting a price on carbon, we know we are beginning the process of breaking our dependence on fossil fuels," says Mary Nichols, chair of the resources board, in the San Jose Mercury News.