5th California Climate Change Assessment

Prepared by Dr. M. B. Rose for the 5^th California Climate Change Assessment. The figure shows the projected relative change in suitability-weighted plant richness under climate change for 116 plant species in the California Floristic Province (Mediterranean-type climate) Ecoregions in California. Shown is the relative change in suitability-weighted richness from a historical baseline period (1980–2010) to end of century (2070–2099) under a high greenhouse gas emissions scenario (RCP 8.5). Suitability-weighted richness is calculated as the sum of continuous habitat suitability values across 166 native plant species, and relative change is expressed as the proportional difference between future and baseline conditions for each grid cell. Projections represent the mean of two global climate models and assume that species are constrained to their baseline distributions (no migration).

Invited by the State of California, Janet Franklin was the lead author on the chapter “Climate Change and Terrestrial Ecosystem in California” prepared in support of the 5^th California Climate Change Assessment (to be released in summer 2026).