Monday, April 13, 2009

California Impacts Under Climate Change

A biennial report released today by a team of experts that advises California’s governor suggests that climate changes are poised to affect virtually every sector of the state’s economy and most of its ecosystems. Significant impacts will likely occur under even moderate scenarios of global greenhouse emissions and associated climate change, but without action, severe and costly climate change impacts are possible across the state.

The state Climate Action Team (CAT) report uses updated, comprehensive scientific research to outline environmental and economic climate impacts. Its authors include Dan Cayan, a climate scientist at Scripps Institution of Oceanography, UC San Diego, and a member of the CAT steering team.

A broad collaboration of scientists, mostly from state academic and government agencies, provided a large set of technical papers that form the underpinnings for much of the CAT report. Assessments include the impacts of sea level rise, higher temperatures, increased wildfires, decreased water supplies, increased energy demand, among others, on the state’s environment, industries and economic prosperity. Each of the papers has undergone peer review by technical experts in private, public and governmental entities.

Impacts of climate change to California’s coast, agriculture, forest and communities have been known and studied for years; however the studies that support the CAT report suggest that actual greenhouse gas emissions are outstripping 2006 projections. Of particular interest are the several papers focusing on the impacts of a rise in sea levels to coastal communities and increased potential of wildfires to residential areas.


Key Findings:

* Water Supply Impacts: A group of researchers at UC Davis investigated the effect of potential climate-induced reductions in water supply to the agricultural sector. One of their findings is that the lack of water would result in reductions in irrigated crop area contributing to the loss of agricultural lands in the Central Valley. Under the particular climate change scenario investigated, the researchers also found that changes in yields (mostly negative) and changes in water availability could result in gross revenues losses of up to $3 billion by year 2050. (Source: Effect of Climate Change on Field Crop Production in the Central Valley of California; California Perennial Crops in a Changing Climate; Estimating the Economic Impacts of Agricultural Yield Related Changes for California)
* Electricity Demand Impacts: To estimate potential impacts of climate change on electricity demand for the residential sector, researchers at UC Berkeley used a comprehensive household level billing data set for California. This highly detailed study found much larger effects of climate change on electricity demand than previous studies. Statewide electricity demand may increase by up to 55 percent by the end of the century. However, policies aimed at reducing the weather sensitivity of demand can play a large role in reducing future electricity demand. (Source: Impact of Climate Change on Residential Electricity Consumption)
* Wildfire Risks: Scientists at UC Merced and Pardee RAND Graduate School performed a novel analysis of wildfire risk in California. They estimated that wildfire risk would increase throughout the end of the century. Average annual monetary impacts due to home loss may plausibly to be on the order of 2 billion dollars per year by mid-century and up to $14 billion per year by the end of the century. (Source: Climate Change, Growth, and California Wildfire; Potential Effects of Climate Change on Residential Wildfire Risk in California)
* Ecosystem Impacts: The Nature Conservancy’s research has determined that California's historic ranching culture, and a source of local, grass-fed beef, is at significant risk from climate change. (Source: The Impact of Climate Change on California's Ecosystem Services)

To view each of the draft papers and a list of authors, visit

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