Another national poll confirms that Americans increasingly believe there is solid evidence of global warming and that human activities are mostly to blame for climate change.

In the second such survey released this month, the Pew Research Center for the People & the Press reported that 67 percent of U.S. residents now believe the earth’s average temperature has been getting warmer over the past few decades, which is four points from last year and 10 more than in 2009.

As I noted last week, a survey by the Yale Project on Climate Change Communication and the George Mason University Center for Climate Change Communication found a whopping 70 percent of Americans believe global warming is real, a substantial surge over the past two and a half years of polling.

Both surveys also reflected a growing consensus that humans are causing climate change:

  • The Yale-George Mason analysis said that for the first time since 2008, more than half of Americans (54%) blame human activities while those who fault natural changes in the environment declined to 30 percent – the lowest level since the survey began.
  • The Pew survey found 42 percent believe warming is mostly caused by human activity, such as burning fossil fuels, up four points from last year, while 19 percent say natural patterns are primarily responsible.

These reports follow earlier polling showing strong backing for initiatives to limit carbon pollution.

The nonpartisan Public Policy Institute of California survey this summer, for example, found 71 percent of adults support California’s groundbreaking AB 32 Global Warming Solutions Actto roll back greenhouse gas emissions to 1990 levels by 2020.

This month’s Pew and Yale-George Mason survey results come as California prepares to hold the first U.S. economy-wide auction of pollution credits next month as part of AB 32 policies to slash carbon pollution.

Meanwhile, the Pew survey said many people continue to see global warming as a problem: 64 percent of Americans say it is a very serious (39%) or somewhat serious (25%) problem.

This summer we experienced a heat wave that swept across the country, setting record high temperatures and contributing to the worst drought in 50 years. Millions of people without power were forced to sweat it out without air conditioning due to violent weather that, according to an increasing number of scientists, is the result of climate change. And with superstorm Sandy that packed a hurricane-sized punch to North Atlantic states this week, it’s difficult to ignore the evidence of climate change or the statistics that show more Americans it is occurring.

What’s important is not to lose sight of what California is doing to address climate change. We need to continue on the path of our state’s tradition of pioneering green policies like AB 32 that support efforts to reduce carbon pollution, protect our air and health with home grown jobs and companies that will help shape our clean energy future.