Here are some things to know about California Gov. Jerry Brown's new target for reducing carbon emissions that contribute to climate change.
WHAT DO THE NUMBERS MEAN?
Brown set a goal for the state to reduce emissions to 40 percent below what they were in 1990. Countries set that year as a benchmark for climate change when they signed on to the U.N. Kyoto Protocol, an international treaty to address global warming.
The rules will likely apply to California municipalities and businesses rather than residents. Business groups warn that tougher standards will drive up the cost of fuel, housing, transportation and other necessities, hurting the working poor.
WHAT DID HE DO?
Brown's executive order is more symbolism than substance. It is equal to taking about 36 million cars off the road, nearly reaching the number of residents in the state, 39 million.
Brown did not spell out how to do it, but he supports pending legislation aimed at doubling electricity from renewable sources, halving the amount of gasoline used on roads, and making buildings twice as energy efficient.
WHY DID HE DO IT?
Like his predecessor, Gov. Arnold Schwarzenegger, Brown wants California to be seen as an international leader on climate change. He has signed carbon-reduction treaties with foreign countries, states and provinces Brown says unchecked climate change is an economic and social threat to California.
WHAT HAS CALIFORNIA DONE?
California has already cut its emissions and is on track to meet its goal of reaching 1990 levels by 2020. It gets a quarter of its electricity from sources such as wind and solar and has stringent vehicle-emissions rules.
The state's landmark cap-and-trade program limits the amount of heat-trapping gases companies can emit by requiring them to pay for each ton of pollution. Companies that cut emissions below the cap can sell their leftover pollution credits to companies that release more greenhouse gases. The program was expanded this year to include gasoline, natural gas, propane and heating oil.
The state could expand programs offering rebates for installing solar panels, incentives to buy electric vehicles or dumping gas-guzzlers, and building more charging stations for electric vehicles. Such programs are paid for by fees on polluters.
Business leaders say expanding costly programs could drive manufacturers out of California because of higher prices.