If a tax is not imposed on carbon-dioxide emissions, gas is artificially underpriced.

Former Treasury Secretary Henry Paulson says we need a carbon tax to prevent a global-warming catastrophe. But if Congress won't act?

The official news agency in China is reporting that the government will tax carbon emissions.

Among the world's most developed countries, Turkey and the Netherlands tax gas and carbon use at the highest rate; the U.S., Mexico and Canada tax carbon and gas at the lowest rates.

It's official: Companies must now purchase permits to emit excess levels of carbon dioxide and other greenhouse gases in the state of California.

In Australia, Aussies are getting used to the first week under a new carbon tax. The country's biggest polluters are paying a steep $24 per ton of carbon emitted -- that's more than twice the cost of carbon permits in…