The California Nevada Applications Program (CNAP) and the California Climate Change Center (CCCC) aim to develop and provide better climate information and forecasts for decision makers in California, Nevada and the surrounding region. By working directly with users, CNAP and CCCC are working to evaluate climate information needs and utility from the user perspective.
Projected monthly precipitation. These data layers were downscaled using a bias correction and spatial downscaling (bcsd) approach and include data for four different models (PCM1, CCSM3, GFDL, CNRM) for two different scenarios (A2, B1).
In order to create data layers used in this visualization tool, we have averaged each month of each year (1950-2099) by decade. This process was done for each model for both the A2 and B1 scenarios. Lastly we have averaged the decadal results for all four models to create the "all" models category.
Zoom to the full extent of California
Change the opacity of the overlay
Using the Area Selection Type Menu to the left, edit types of selection areas:
Select various chart options in the dropdown menus to the right, which can include Month, Model, and Temperature ranges (High, Low, or Average).
Note: The first set of chart options control the variables being viewed on the map.
Click "Add Chart" to create an additional chart to compare with. After creating the new chart, click on a new area of the map to view a chart for the same options in another location. Or change an option in the dropdown menu to view the chart for the same location, with different settings.
To edit the first chart again, either directly edit the dropdown menus, or click on the Location Name and then click on a new location on the map.
Click "Predefined boundaries" in the Area Selection Type Menu to the left before clicking on an area of the map, if you'd like to compare counties to one another.
Fix the locations of the graphs to one area by clicking this toggle.
The following map displays the projected annual precipitation totals across the state at decadal averages. On average, the projections show little change in total annual precipitation in California. Furthermore, among several models, precipitation projections do not show a consistent trend during the next century.
The Mediterranean seasonal precipitation pattern is expected to continue, with most precipitation falling during winter from North Pacific storms. One of the four climate models projects slightly wetter winters, and another projects slightly drier winters with a 10 to 20 percent decrease in total annual precipitation. However, even modest changes would have a significant impact because California ecosystems are conditioned to historical precipitation levels and water resources are nearly fully utilized.
Use the slider bar to the left to visualize the projected change in precipitation, as seen in the low and higher emissions scenarios. Adjust the options below to view different models, and months.
Create a chart by clicking a location on the map and altering one of the dropdown option boxes.
Create a chart by clicking a location on the map and altering one of the dropdown option boxes.
The data presented in this tool represent a projection of potential future climate scenarios, they are not predictions. These data are meant to illustrate how the climate may change based on a variety of different potential social and economic factors. The default visualizations in this tool are comprised of the average values from a variety of scenarios and models. Find out more about climate change data.
This information is being made available for informational purposes only. Users of this information agree by their use to hold blameless the State of California, and its respective officers, employees, agents, contractors, and subcontractors for any liability associated with its use in any form.
This work shall not be used to assess actual coastal hazards, insurance requirements, or property values and specifically shall not be used in lieu of Flood Insurance Studies and Flood Insurance Rate Maps issued by the Federal Emergency Management Agency (FEMA).
Data Set Contributed: Projected Precipitation
Projected monthly precipitation. These data layers were downscaled using a bias correction and spatial downscaling (bcsd) approach and include data for four different models (PCM1, CCSM3, GFDL, CNRM) for two different scenarios (A2, B1).
2011 April 12
Continued global warming will increase pressure on California’s water resources, which are already over-stretched by the demands of a growing economy and population. Decreasing snowmelt and spring stream flows coupled with increasing demand for water resulting from both a growing population and hotter climate could lead to increasing water shortages. By the end of the century, if temperatures rise to the medium warming range and precipitation decreases, late spring stream flow could decline by up to 30 percent. Agricultural areas could be hard hit, with California farmers losing as much as 25 percent of the water supply they need.
2011 April 13
In central and southern Sierra, the giant sequoias, which are among the biggest living things on Earth, might be in threat. As precipitation continues to become more and more irregular, longer drought periods are expected in various regions of the state. Along with the sequoias, there are other kinds of vegetation which are at a risk of drying out.
2011 April 13
Climate change may significantly affect the operation of California's electric power system, in both the demand and supply sides. As temperatures rise, electricity demand will also increase to meet air conditioning and other cooling requirements. This in turn will further escalate the emission of greenhouse gases and the air pollution due to use of unclean sources of energy.
