AB 32 requires California to reduce its GHG emissions to 1990 levels by 2020 — a reduction of approximately 15 percent below emissions expected under a “business AS usual” scenario. Pursuant to AB 32. ARB must adopt regulations to achieve the maximum technologically feasible and cost effective GHG emission reductions. The full implementation of AB 32 will help mitigate risks associated with climate change. While improving energy efficiency. Expanding the USE of renewable energy resources. Cleaner transportation. And reducing waste.