A week after taking aim at greenhouse gas emissions produced by chip makers, California has set its sights on a new target: climate change pollution generated by transportation fuels.

The California Air Resources Board (CARB) released proposed regulations for a Low Carbon Fuel Standard last week to reduce transportation fuel emissions 10 percent by 2020. By requiring fuel providers to sell cleaner fuels, regulators expect about 20 percent of fuel used in the state will be supplanted with alternatives, such as biofuels, hydrogen and electricity.

The public has 45 days to comment on the proposal but the new rules are already facing stiff resistance from the corn ethanol industry, which is urging CARB to reject its staff's recommendations and arguing the new rules unfairly penalize ethanol using unproven science.

"This is academics gone wild," said retired Gen. Wesley Clark, now a co-chair of Growth Energy, a coalition of ethanol producers, during a conference call with reporters Friday. "This is not common sense."

At issue is the CARB staff's recommendations to include greenhouse gas emissions from indirect land use change in the calculation of biofuel carbon intensity, even though similar impacts aren't used in the intensity calculations of other fuels.

Intensity is based on the amount of greenhouse gas emissions produced during the fuel's production, transportation and consumption. For biofuels, intensity will include additional emissions from worldwide price-induced land changes that may arise from increased biofuel production. This is based on the premise that more demand for feedstocks, such as corn, drives up prices worldwide, leading to deforestation as farmers clear land and forests to plant potentially profitable biofuel crops.

Blake Simmons, a scientist at Sandia National Laboratories, applauded the state's leadership in addressing climate change but said there were big deficiencies in how emissions from indirect land use changes were being applied in the proposed regulations. Simmons and more than 100 scientists wrote a letter to Gov. Arnold Schwarzenegger last week arguing the science is too limited for regulatory enforcement and should not be applied selectively when indirect land use change effects for all fuels are not completely understood.

The industry instead is calling for California to lead an international effort to study impacts from indirect land use changes in all fuels, and warned factoring in these emissions when calculating biofuel carbon intensity will have a chilling effect on investment in next generation biofuels.

Patricia Monahan, deputy director for clean vehicles with the Union of Concerned Scientists, argued the proposed rules would have the opposite effect and send a clear signal to investors.

"It's going to direct investment into truly clean biofuels in the future," she said.

There are no scientific studies showing other fuels generate significant indirect land use change impacts, she said, adding that these impacts may be unique to biofuels. She called the industry's argument a red herring.

"I think they're trying to dodge a significant source of emissions from biofuels by saying it's not fair," she said.

Corn ethanol interests have been treated remarkably well under the proposed Low Carbon Fuel Standard, said Dan Sperling, a professor of civil engineering and environmental science and policy at the University of California at Davis and founding director of the Institute of Transportation Studies.

The proposed regulations, for instance, deal with corn ethanol in California more favorably than corn ethanol from outside the state because production here tends to be more energy efficient and less reliant on coal, Sperling said. Also, the baseline blend will increase from E5.7 to E10.

"This is crucial because it means that the corn ethanol production can greatly expand in California (from 5.7 percent to 10 percent of total gasoline) without worrying about meeting the Low Carbon Fuel Standard carbon intensity reductions," Sperling said via email.

The ethanol industry wants the federal government to raise the baseline for most gasoline blends in the nation from 10 percent to 15 percent. Growth Energy petitioned the U.S. Environmental Protection Agency on Friday to raise the blend baseline in order to increase demand and create jobs, although some are raising questions about the impact on vehicle, boat and equipment engines. 

California's Low Carbon Fuel Standard, along with new regulations targeting highly potent gases used in semiconductor operations, are part of a series of early action steps undertaken by CARB to meet the goals of the Global Warming Solutions Act of 2006, also known as AB 32. The legislation aims to reduce emissions to 1990 levels by 2020.