The Global Warming Solutions Act, AB 32, was passed with bipartisan support and signed by Republican governor Arnold Schwarzenegger in 2006. The law—which requires state to reduce its greenhouse gas emissions—received strong majority support (65%) among Californians when the PPIC Statewide Survey first asked about it in July 2006, with strong majorities of Democrats (67%), Republicans (65%), and independents (68%) in favor.

Overall support for the law remains strong: in our July 2014 survey, 68 percent of Californians said they favored it. But the partisan makeup of the supporters has changed significantly. While support among Democrats and independents has remained solid, it has gradually decreased among Republicans. Today, 81 percent of Democrats and 62 percent of independents favor the law, but only 39 percent of Republicans do.

What happened?

We have found that this partisan divide is linked to two main factors. The first is the increasingly common belief among Republicans that global warming is not imminent. Fewer Republicans today say the effects of global warming have already begun (47% 2006, 35% today) or that global warming poses a serious threat to California (57% 2006, 48% today). Attitudes among Democrats and independents have not changed much.

The second factor is rising concern among Republicans that addressing global warming will affect the economy and jobs. From the beginning, proponents of AB 32 have argued that the threat posed by global warming requires immediate state action and opponents have expressed concern about the economic impact of regulating greenhouse gases. Our survey shows that during the Great Recession, support for taking action right away declined among all Californians. Support did not drop much among Democrats and independents, and it bounced back as the economy recovered. But immediate action on global warming was never popular among Republicans, so perhaps it is not surprising that even as the state’s unemployment rate declined from its peak in 2010 most Republicans continued to say the state should wait until the economy improved.

Their differences may be growing, but partisans do still agree on some aspects of addressing global warming. Majorities across parties continue to favor requiring increasing energy efficiency for residential and commercial buildings and appliances. They also favor requiring industrial plants, oil refineries, and commercial facilities to reduce their emissions.

These results show that policymakers face a challenge in forging compromises on the contentious aspects of climate change policy. But they also have areas of consensus to build on.

Cross-posted at PPIC.