LOS ANGELES (Reuters) - Most Californians won't support the state's ambitious efforts to fight global warming if they lead to sharply higher energy costs, according to a survey commissioned by a pro-business group released on Thursday.

Sixty-three percent of 1,000 registered California voters surveyed this month said they supported the goal of cutting greenhouse gases, but that support fell to 47 percent when the question included the likelihood of higher energy costs.

"This is an example of when you add the potential costs of the potential solutions, voters are going to back off from their support of ideals," said Alex Evans, president of EMC Research, which conducted the survey.

About 80 percent of the respondents said they had not heard about California's landmark legislation passed in 2006 and signed by Gov. Arnold Schwarzenegger that mandates a cut of global warming gases to 1990 levels by 2020.

The survey was sponsored by the AB32 Implementation Group, named for that 2006 legislation.

Stanley Young of the California Air Resources Board said that state agency's early assessments are that implementing the legislation will save money by improving energy efficiency and promoting development of renewable resources.

Some environmentalists said the survey is flawed.

"I don't see any merit in a survey that lacks credibility. The questions are so leading and misleading," said Wendy James, manager of the Global Warming Action Coalition based in Southern California.

Shelly Sullivan, executive director of AB32 Implementation Group, defended the survey, saying it was fair questioning of a random sample of Californians. Sullivan says the group wants the state to reduce greenhouse gas emissions while maintaining a strong economy.