Expert Voices

Climate Change Has Arrived in California (Op-Ed)

view of Earth and cloud cover
Perception of climate change may be influenced by the frequency that climate-science words appear in the popular literature. (Image credit: Nicolle Rager Fuller, National Science Foundation)

Adrienne Alvord is the director for California & Western Statesat the Union of Concerned Scientists(UCS). This piece is adapted from one that appeared on the UCS blog The Equation. Alvord contributed this article to LiveScience's Expert Voices: Op-Ed & Insights.

A new State of California report, released Aug. 8, verifies what scientists have been telling the public for some time — climate change is here, and it is now affecting California's water supplies, farm industry, forests, wildlife and public health.

The California Environmental Protection Agency Office of Environmental Health Hazard Assessment (OEHHA) is sounding the alarm in a report that compiled 36 indicators of climate change. The report draws upon monitoring data from throughout the state and a wide variety of research studies carried out by 51 scientists from the University of California, Scripps Institution of Oceanography, Lawrence Berkeley National Laboratory, the U.S. Geological Survey and the National Oceanic and Atmospheric Administration, among other agencies and institutions.

[MORE: Burning Question: How Will Climate Change Impact Western Wildfires? ]

The report says, categorically, that climate change is "an immediate and growing threat," with indicators including state greenhouse-gas emissions and temperature data and measurements of impacts on California's physical environment, people, vegetation and animals. The report concludes that climate change is occurring throughout California, from the Pacific Coast to the Central Valley to the Sierra Nevada Mountains.

Among other findings, the report concluded that:

  • Warming temperatures have accelerated since the 1970s, with nighttime temperatures increasing much faster than daytime;
  • Changes in precipitation patterns have had the effect of decreasing water supplies, even when overall rainfall remains the same;
  • Carbon dioxide levels in coastal waters are harming species and having effects throughout the marine food chain;
  • Over the past century, water levels have risen along the California coast by an average of 7 inches (18 centimeters), and levels have risen by 8 inches (20 centimeters) at the Golden Gate; and
  • Annual acreage burned by wildfires since 2000 is double the rate of the previous 50 years, from less than 300,000 acres to almost 600,000.

As California Department of Forestry and Fire Protection Chief Ken Pimlott pointed out at a UCS forum in Pasadena on June 28, "Twelve of the 20 most-damaging wildfires in California occurred in the last 10 years." Pimlott said there will never be enough engines and firefighters to put out all the wildfires in the state — not now and not in the next few decades, when global warming is expected to get much worse. "We have to learn to be resilient and live with fire," he said at the UCS forum.

The report comes on the heels of a recent survey by the nonpartisan Public Policy Institute of California, which found that the public already understands these impacts — 63 percent of the state's residents said the effects of global warming are already being felt.

One of the most hopeful findings of the OEHHA report is that "since 2000, despite a 49 percent increase in economic output (as measured by the gross state product or GSP), and a 10 percent increase in population, [greenhouse gas] emissions per $1,000 GSP — also known as emissions intensity — have declined." And California's overall emissions have decreased by more than 7 percent since 2008, two years after California passed Assembly Bill 32 (AB 32), the Global Warming Solutions Act.

These data demonstrate the false premise presented by fossil-fuel lobbyists who claim California can't cost-effectively reduce emissions and grow the state's economy, or that the state has to "go slow" so the changes don't harm state growth.

There is no evidence our low-carbon policies have caused harm to the economy — quite the contrary. If anything, the report shows the urgent need to do much more, and more quickly, to reduce the intensity of future impacts. Clean-energy policies haven't hurt the statewide economy in California, but widespread climate impacts certainly will.

The new findings represent a call to action to state leaders to better prepare California for impacts people are now facing while aggressively maintaining the course charted by AB 32. The findings defend policies for reducing global-warming emissions while also encouraging preparedness for climate change so communities can become more resilient to increasingly severe wildfires , rising sea levels and longer, summer heat waves.

This piece was adapted from Climate Change in California: Ready Or Not, It's Here on the UCS blog The Equation. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on

Union of Concerned Scientists