In a statement, Fiorina called it "a Band-Aid fix and an imperfect solution," but she said she's supporting it anyway.
Proposition 23 would suspend implementation of the state's landmark climate change law until unemployment dropped to 5.5 percent or less for a full year. Critics say it's an attempt to gut the legislation.
"The real solution to these challenges lies not with a single state taking action on its own, but rather with global action," Fiorina said. "That's why we need a comprehensive, national energy solution that funds energy R&D and takes advantage of every source of domestic energy we have - including nuclear, wind and solar - in an environmentally responsible way. That said, AB 32 is undoubtedly a job killer, and it should be suspended."
Democratic Sen. Barbara Boxer chided Fiorina during the debate for declining to say whether she backed Proposition 23, and noted Thursday that "she's taken money from the very same oil and coal companies that are funding overturning AB 32."
PHOTO CREDIT: Republican candidate for U.S. Senate Carly Fiorina speaks during a debate with U.S. Sen. Barbara Boxer (D-CA) on the campus of Saint Mary's College September 1, 2010. Jeff Chiu-Pool/ Getty Images