After more than half a decade of rule-making, court challenges, and a failed proposition to suspend action until the state unemployment rate fell to 5.5 percent, the signature piece of California’s effort to reduce greenhouse gas emissions has finally became the law of the land. Beginning this year, the Global Warming Solutions Act of 2006 calls for reducing, by 2–3 percent annually, emission allowances for entities such as refineries and electricity-producing facilities that have previously emitted more that 25,000 metric tons of carbon dioxide a year.

Since its passage, the act has been a boon for firms with California environmental practices, including Latham & Watkins, Bingham McCutchen, Manatt Phelps & Phillips, and Alston & Bird. Demand has been especially high this year as companies geared up for California’s first-ever carbon emissions auction in November. “For those who aren’t dealing with it every day, it’s hard to appreciate just how much work has been spawned [from the legislation],” says Robert Wyman, the Los Angeles–based chair of Latham’s environment, land, and resources department. (The auction resulted in the sale of 23.1 million permits—each allowing for the release of one ton of carbon in 2013—for $10.09 apiece.)