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Climate Change

Climate change is having a profound impact on California water resources, as evidenced by changes in snowpack, sea level, and river flows . These changes are expected to continue in the future and more of our precipitation will likely fall as rain instead of snow. This potential change in weather patterns will exacerbate flood risks and add additional challenges for water supply reliability.

The mountain snowpack provides as much as a third of California's water supply by accumulating snow during our wet winters and releasing it slowly when we need it during our dry springs and summers. Warmer temperatures will cause what snow we do get to melt faster and earlier, making it more difficult to store and use. By 2050, scientists project a loss of at least 25 percent of the Sierra snowpack. This loss of snowpack means less water will be available for Californians to use.

Climate change is also expected to result in more variable weather patterns throughout California. More variability can lead to longer and more severe droughts. In addition, the sea level will continue to rise threatening the sustainability of the Sacramento-San Joaquin Delta, the heart of the California water supply system and the source of water for 25 million Californians and millions of acres of prime farmland.

The Department of Water Resources (DWR) is addressing these impacts through mitigation and adaptation measures to ensure that Californians have an adequate water supply, reliable flood control, and healthy ecosystems now and in the future. Below are some of DWR's climate change activities.

  • In 2014, DWR released up-to-date climate change information, including hydrologic impacts and projections at the statewide and regional levels, adaptation strategies, and energy intensity of water supplies in California Water Plan Update 2013
  • In 2013, DWR completed its ownership divestment of a coal-fired power plant in Nevada and ceased taking electricity from it. By replacing this electricity with electricity generated by high-efficiency gas-fired power plants and renewables, DWR reduced its GHG emmissions by over 800,000 metric tons per year (equivalent to removing 170,000 cars from the road).
  • In 2012, DWR adopted phase 1 of its Climate Action Plan, a Department-wide Greenhouse Gas Emissions Reduction Plan
  • In 2011, DWR in cooperation with the U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, and Resources Legacy Fund completed the Climate Change Handbook for Regional Water Planning
  • In 2010, DWR adopted an Environmental Stewardship Policy which supports a Department-wide "Total Resource Management" approach to planning activities and projects. Clear and measurable Goals for sustainability implementation were also adopted in 2010 following the 2009 adoption of DWR's Sustainability Policy to promote a departmental change in the way DWR does business. (Visit DWR's Sustainability Portal and Watch DWR's Sustainability Videos)
  • Between 2007 and 2009, DWR was a member of the California Climate Action Registry and made the list as a Climate Action Leader by reporting its GHG emissions and having the data verified through a third party audit. In 2010, DWR transitioned to The Climate Registry, a North America-wide climate registry, and continued to provide third party verified GHG emissions inventory data.
  • DWR adopted a Climate Change Adaptation Strategy (2008)

Other Climate Change Activities

Adapting to the current and future effects of climate change is essential for DWR and California's water managers. DWR addresses climate change in its California Water Plan, which is updated every five years. The California Water Plan provides a framework for water managers, legislators, and the public to consider options and make decisions regarding California's water future. DWR continues to improve and expand the analysis of climate change in the California Water Plan. The 2013 California Water Plan Update includes multiple scenarios of future climate conditions and stresses the inclusion of uncertainty, risk, and sustainability.

Climate Change Technical Advisory Group

Featured Link
Paleoclimate (Tree-Ring) Study Released
New Hydroclimate Reconstructions have been released, using updated tree-ring chronologies for these California river basins; Klamath, San Joaquin and Sacramento. The report, prepared by the University of Arizona, allows assessment of hydrologic variability over centuries to millennia, gives historic context for assessing recent droughts, and can be used in climate change research.