A new report by the California Environmental Protection Agency details the effects of climate change already being seen in the state, including the effects of higher temperatures, declining snowmelt runoff, more frequent and intense wildfires.
The report tracks 36 climate change indicators and how California is being impacted by each of them. A key element of the report highlights the effects of increasing temperatures on the state's water, vegetation and wildlife.
Throughout California, from the Pacific coast to the central valley to the rugged mountains along the state's east, the effects of climate change are observable, the report states, noting that the impacts of a warmer climate can be seen in decreasing spring snowmelt runoff, rising sea levels along the California coast, shrinking glaciers, increasing wildfires, warming lakes and ocean waters, and the gradual migration of many plants and animals to higher elevations.
California Gov. Jerry Brown called for action in a statement that ran alongside the Aug. 8 report.
"Whether you live in California, Texas or Timbuktu, climate change is real, and it's long past time for action," Gov. Brown said.
The new report acts as a complement to a consensus statement released by the state's highest office in May identifying climate change as one of five key threats to the environment that require immediate action.
Titled "Indicators of Climate Change in California," the report, compiled by 51 scientists from a variety of leading institutions including the University of California, Scripps Institution of Oceanography, Lawrence Berkeley National Laboratory, US Geological Survey and the National Oceanic and Atmospheric Administration, goes on for 258 pages, detailing what it calls "climate change drivers," which include greenhouse emissions, black carbon concentrations, acidification of coastal waters, as well as the observable impacts of climate change on physical and biological systems.
"Climate change is not just some abstract scientific debate," California EPA Secretary Matt Rodriquez told the San Jose Mercury News. "It's real, and it's already here."
Key findings of the report include:
- Temperatures: The state's high, low and average temperatures are all rising, and extreme heat events also have increased in duration and frequency. The rate of warming has accelerated since the mid-1970s, and night time (minimum) temperatures have increased almost twice as fast as maximum (daytime) temperatures.
- Wildfires: The number of acres burned by wildfires has been increasing since 1950. The size, severity, duration and frequency of wildfires are greatly influenced by climate. The three largest fire years on record in California occurred in the last decade, and annual acreage burned since 2000 is almost twice that for the 1950-2000 period.
- Water: Spring snowmelt runoff has decreased, indicating warmer winter temperatures and more precipitation falling as rain rather than snow. Earlier and decreased runoff can reduce water supplies, even when overall rainfall remains the same. This trend could mean less water available for agriculture, the environment and a growing population.
- Coast and Ocean: A number of indicators reflect physical and biological changes in the ocean, impacting a range of marine species, including sea lions, seabirds and salmon. And data for Monterey Bay shows increased carbon dioxide levels in coastal waters, which can harm shell-forming organisms and have impacts throughout the marine food chain.
- Species Migration: Certain plants and animals have responded to habitat changes influenced by warming. For example, conifer forests in the Sierra Nevada have been moving upslope and certain small mammals in Yosemite National Park have moved to higher elevations compared to the early 1900s.