Cap-and-trade sets a limit, or cap, on emissions of heat-trapping gases and requires companies to pay for each ton of pollution they emit, the price of which is determined in an allowance auction. Polluters that cut emissions below the cap can sell their leftover pollution permits, called allowances, to companies that need extra.
The program is a central part of AB32, the greenhouse gas reduction law that passed the Legislature and was signed by former Gov. Arnold Schwarzenegger, a Republican, in 2006. But it is just one of several provisions of the law — such as requiring lower-carbon fuels — meant to prompt Californians to change their transportation and energy consumption habits as the state seeks to reduce emissions of heat-trapping gases to 1990 levels by 2020.
The California Air Resources Board, which designed and implemented cap-and-trade, differs with Steinberg's assessment and projects no noticeable increase in gas costs after Jan. 1. But the board's own economic analysis of AB32 from 2010 shows that diesel prices could rise from 3 percent to 23 percent, with gasoline prices rising 5 percent to 32 percent, depending on market factors associated with the global warming law's programs.
The industry and some economic forecasts have predicted a 10- to 12-cent increase in the price per gallon at the pump, and Steinberg says those prices could spike as high as 40 cents a gallon.
Still, Mary Nichols, chairwoman of the Air Resources Board, said oil companies have had since 2010 to prepare and are not required to pass on the costs to consumers.
"It would appear to be some deliberate measure on their part if there were to be a sudden rise in (fuel) prices on Jan. 1," Nichols said. "I would expect that they would incorporate the cost of the allowances into their pricing."
Steinberg's idea of charging a flat tax on carbon — rather than having the price change regularly because of cap and trade auctions — does not force polluters to reduce their emissions, Nichols said, which is key to the state's greenhouse gas law.
But it does allow for more stable pricing, said Steinberg, a Democrat from Sacramento.
"Under cap-and-trade, no one can tell us whether fuels will trade at 10 cents or 40 cents a gallon in 2015 or 2016, at any given timing and without a warning. On the other hand, a carbon tax is stable," he said.
He proposed a 15 cent-a-gallon carbon tax to offset what he said would be the indirect tax on consumer fuels once the companies that produce those fuels go into the cap-and-trade program next year.
Under his proposal for a flat carbon tax, introduced in the Legislature as SB1156, the tax would rise to 24 cents a gallon by 2020 and more than 40 cents a gallon by 2029.
About two-thirds of the estimated $3.6 billion raised by Steinberg's carbon tax would go back to households earning less than $75,000 a year in the form of a state-level Earned Income Tax Credit. The rest would go toward mass transit programs with the goal of getting more Californians out of their automobiles.
The legislative prospects for Steinberg's tax proposal, especially during an election year, are uncertain. But the oil industry has greeted his plan warmly.
Catherine Reheis-Boyd, president of the Western States Petroleum Association, said the cost of cap and trade allowances will add $2 billion to the costs of gasoline and diesel, or about 12 cents per gallon.