The USEPA defines climate change as any distinct change in measures of climate lasting for a long period of time. In other words, “climate change” means major changes in temperature, rainfall, snow, or wind patterns lasting for decades or longer. Climate change may result from:
- Natural factors (e.g., changes in the Sun’s energy or the Earth’s orbit);
- Natural processes within the climate system (e.g., changes in ocean circulation);
- Human activities that change the atmosphere’s make-up (e.g, burning fossil fuels) and the land surface (e.g., cutting down forests).
The 2007 IRWM Plan reports that hydrologic conditions in the Region, California, and the Colorado River Basin will likely be altered as a result of global climate change (based on conditions observed over the past century). Key probable changes in hydrologic conditions forecast by DWR include:
Snowpack Changes — While snowpack represents a negligible component of the water balance within the Region’s local water supplies, snowpack in the Sierra Nevada Mountains represents California’s largest water storage component. Decreased snowpack in the Sierras will result in increased runoff, adversely affecting California’s water storage and potentially affecting the amount of imported water available to the Region.
Hydrologic Patterns — Global warming may result in a shift in storm tracks. Existing data show a trend of increasing precipitation in Northern California and decreasing precipitation in Southern California during the past century.
Storm Intensity — Flood management, erosion, and water quality impacts could occur if climate change results in increased precipitation intensity and reduced health plant cover.
Sea Level Rise — Sea level rises associated with global warming could increase coastal erosion, impacting ecosystems and tidal wetlands. Sea level rises would also increase salinity intrusion into the Delta, adversely impacting the quality of State Water Project supplies delivered to the Region.
Water Temperatures — Increased air temperatures and modified storm patterns may result in increased reservoir water temperatures, adversely affecting cold water and other species and increasing the intensity of algae blooms.
Water Demand — Further drying of climates in currently arid regions will result in increased human and environmental demands.
Energy Demand — Global warming effects may result in increased energy demands that will require increased conservation and efficiency measures. |
