LOS ANGELES (CBS / AP) – California will further slash greenhouse gas emissions after Gov. Jerry Brown extended the nation's most ambitious climate change law by another 10 years.

The Democrat signed the legislation Thursday at a park in Los Angeles amid opposition from the oil industry, business groups and Republicans.

Lawmakers last month approved a 10-year extension of the state's landmark climate change law. It set a new goal to cut emissions 40 percent below 1990 levels by 2030.

California is on track to meet the current target set a decade ago to reduce emissions to 1990 levels by 2020.

Brown also signed a bill that would provide greater oversight of the appointed Air Resources Board, which is in charge of climate policy.

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