About Maps of Projected Change

California is already experiencing climate change and its effects will increase over the coming decades1. These maps show projected changes in long-term (30 year) annual averages of maximum temperature, minimum temperature and precipitation rate in California. Data is shown for Historical Baseline (1961–1990) and two future periods: Mid–Century (2035–2064) centered on the year 2050 and End of Century (2070–2099). Data is available for two different Representative Concentration Pathways (RCP): RCP 4.5 (medium emissions scenario) and RCP 8.5 (high emissions scenario).

How to use

Users can explore projected absolute values or explore projected changes in value from the historical baseline. Select from a list of overlays for different scenarios and time periods. View the data in a single map (SINGLE) or create a layered map view (SWIPE) to compare different scenarios and/or time periods. The layered view shows two maps layered over each other with a vertical bar that can be swiped back and forth to reveal different parts of the map below. Click on the map to a get popup box with data value for a grid cell. If a boundary layer is selected, the data value returned on map click is spatially aggregated over a polygon area.

Data

Daily downscaled climate projections generated to support climate change impact studies for California’s Fourth Climate Change Assessment by Scripps Institution of Oceanography. 32 coarse-resolution (~100 km) Global Climate Models (GCM) from the CMIP5 archive were bias-corrected and downscaled to a resolution of 1/16° (about 6 km, or 3.7 miles) using the Localized Constructed Analogues (LOCA) statistical method2.

Methodology

We calculated annual average values for each 30 year period for 10 of the 32 LOCA downscaled GCMs under both RCPs. This averaging helps eliminate year-to-year variations in the climate projections. We then averaged these values over all 10 models for each 30 year period.

References

  1. California’s Fourth Climate Change Assessment.
  2. Pierce et al. (2018). Climate, drought, and sea level rise scenarios for California's fourth climate change assessment. California’s Fourth Climate Change Assessment, California Energy Commission. Publication Number: CNRA-CEC-2018-006.