Greenhouse-gas emissions in California were up sharply last year as compared to 2011, leading to doubts that the state will be able to meet an ambitious pollution target set in 2006.

Part of the problem is short-term in nature and can be traced to the sudden shutdown of the San Onofre Nuclear Generating Station in northern San Diego County early in 2012. Loss of the plant's 2200 megawatts of power (equivalent to the output of four large-scale conventional power plants) caused the state to rely heavily on natural gas for electricity generation. While cleaner than the coal burned in other states, the immediate pollution is much higher than that of a nuclear operation.

A second culprit, suggests the National Resources Defense Council, is a decrease in hydroelectric power generation. After a particularly wet 2011 caused power generated through this low-pollution method to spike, a much drier 2012 brought about a drop in production almost equal to that caused by the shuttering of San Onofre.

While these setbacks do pose a problem in finding a long-term replacement to San Onofre's power, a study released November 4 from the Lawrence Berkeley National Laboratory suggests the state should still be able to meet a goal of reducing greenhouse gas emissions to 1990 levels by 2020, as required by 2006 legislation. An executive order from then-governor Arnold Schwarzenegger requiring an additional 80 percent drop by the year 2050, however, seems more daunting.

The Berkeley study considers three possible scenarios for every contributing factor to greenhouse-gas pollution: existing policies that have already drawn commitments from legislators and industry, proposals to more aggressively cut emissions, and anticipation of future technologies that will allow for even further reductions.

Even under the most optimistic scenarios, however, researchers say it's unlikely that the 2050 target will be met. The state's population is expected to expand as high as 50 million by mid-century, and new consumers will bring more demand for energy, as will the industries they'll be working in.

Back in San Diego, the challenge of reducing pollution while facing a rising population is facing similar problems. The San Diego Association of Governments, responsible for implementing a regional transit plan through 2050, has been under fire since 2011, when a lawsuit was filed against the plan's implementation. Plaintiffs Cleveland National Forest Foundation and the Center for Biological Diversity, with support from state attorney general Kamala Harris, point out that the local plan calls for increased pollution, rather than reductions.

The SANDAG case continues to wind its way through court, with the latest briefs for a state appeals court action after the government body's plan was struck down filed in early October.

The pressing nature of the report's implications seems to be lessened by the reaction of the agencies responsible for meeting the pollution goals.

"Even if we aggressively expand our policies and implement fledgling technologies that are not even on the marketplace now, our analysis shows that California will still not be able to get emissions to [target levels]," says Berkeley researcher Jeff Greenblatt in a release that accompanied the report.

"Building programs and putting them in place in concrete now for that purpose would really not achieve much," countered Dave Clegern at the California Air Resources Board in an interview with Capital Public Radio. Clegern says that he believes there's still plenty of time to make corrections to meet the pollution reduction goal.