California

Global climate change poses risks to human health and to terrestrial and aquatic ecosystems. Important economic resources such as agriculture, forestry, fisheries, and water resources also may be affected. Warmer temperatures, more severe droughts and floods, and sea level rise could have a wide range of impacts. All these stresses can add to existing stresses on resources caused by other influences such as population growth, land-use changes, and pollution.

Climate Change in California

Below are some of the potential impacts:

• By 2100 temperatures in California could increase by about 5°F (with a range of 2-9°F) in the winter and summer and slightly less in the spring and fall.
• Higher temperatures and increased frequency of heat waves may increase the number of heat-related deaths and the incidence of heat-related illnesses. Cities such as Los Angeles that experience occasional very hot, dry weather may be especially susceptible.
• Water resources are affected by changes in precipitation as well as by temperature, humidity, wind, and sunshine. Changes in streamflow tend to magnify changes in precipitation. Water resources in drier climates tend to be more sensitive to climate changes. The seasonal pattern of runoff into California’s reservoirs could be susceptible to climatic warming. Winter runoff most likely would increase, while spring and summer runoff would decrease. This shift could be problematic, because the existing reservoirs are not large enough to store the increased winter flows for release in the summer.
• Increases in climate variability could make adaptation by farmers more difficult. Warmer climates and less soil moisture due to increased evaporation may increase the need for irrigation. However, these same conditions could decrease water supplies, which also may be needed by natural ecosystems, urban populations, and other economic sectors.
• Along much of California’s coast, sea level already is rising by 3-8 inches per century (3 inches at Los Angeles, 5 inches at San Francisco, and 8 inches at San Diego), and it is likely to rise by another 13-19 inches by 2100. The beaches stretching from Santa Barbara to San Diego have been replenished with sand, and undoubtedly will be replenished further or protected with structures if threatened by sea level rise. Cumulative costs for sand replenishment to protect California’s coastline from a 20-inch sea level rise through 2100 could be $174 million to $3.5 billion. sea level rise update
• Hotter, drier weather could increase the frequency and intensity of wildfires, threatening both property and forests. Along the Sierras, drier conditions could reduce the range and productivity of conifer and oak forests. Farther north and along the northern coast, drier conditions could reduce growth of the Douglas fir and redwood forests. A significant increase in the extent of grasslands and chaparral throughout the state could result. These changes would affect the character of California forests and the activities that depend on them.

The above are based on from the Environmental Protection Agency's report on climate change, which uses data from the Third Assessment Report of the Intergovernmental Panel on Climate Change (2001).

For more info on climate change impacts on California's water resources, agriculture, forests and ecosystems, you can download pdf of full EPA Report.

CO2: How Does Your State Rank?

California is the highest emitter of C02 of all 50 states and the most populous.

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Maps

See CO2 output by sector, coastal population maps, and maps of regional initiatives.

Regional Initiatives

In the absence of federal action, many U.S. states are banding together to explore and employ greenhouse gas-reducing policies.

California participates in the following:

West Coast Governors' Global Warming Initiative

Western Governors' Association (WGA): Clean and Diversified Energy Initiative

Western Regional Climate Action Initiative

Learn about climate initiatives in all U.S. states and regions

Your Impact

Estimate your CO2 footprint by using a carbon calculator such as the one on the Inconvenient Truth web site.

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