Following up its good news/bad news report on Lake Tahoe, the California Office of Environmental Health Hazard Assessment paints a bleaker picture in its August 2013 Indicators of Climate Change in California.
To sum it up, analysis of monitoring data and scientific research from throughout the state outlines the effects of climate change: The spring runoff in the Sierra Nevada has declined over the last century. The period of time when winter temperatures in the Central Valley are cold enough for the development of fruit and nut tree flowers has been decreasing since 1950. River runoff declined during the 20th Century:
|River Runoff||Percent Decline
in 20th Century
|Sacramento River System*||9%|
|San Joaquin River System||6%|
|Carson and Walker rivers||5%|
|*includes the Sacramento River and major tributaries, the Feather, Yuba and American rivers.|
Changes in average temperatures have led to die-offs of native vegetation at the lower range of various species’ elevation range (during the last six decades Sierra Nevada conifers have clearly retreated upslope) and is pushing about half of the small mammals in Yosemite National Park to higher elevations. The annual acreage burned by wildfires in the state increased since 1950, with the three largest fire years occurring during the last 10 years. The acidity in the coastal waters around Monterey Bay is increasing at a rate greater than that in the open ocean near Hawaii. The average annual temperature in mountain lakes, including Lake Tahoe, has risen over the last few decades.
And butterflies are emerging earlier during the spring in the Central Valley.
Yet, there’s no real trend that can be discerned from the data. The rise in the sea level rise along the California coast is bucked the global pattern and has be relatively constant during the last two decades.