Statewide summary: California’s fifth climate change assessment

This report synthesizes findings from California’s Fifth Climate Change Assessment, drawing on research and data across the assessment portfolio to examine climate-related hazards, vulnerabilities and adaptation approaches affecting the state’s natural, built and social systems. It presents climate projections and evidence on changing temperatures, precipitation variability, declining snowpack, seasonal shifts and ocean changes, alongside analysis of wildfire, extreme heat, drought, flooding and sea-level rise. The assessment includes statewide and regional research, climate projections under different emissions scenarios, and work addressing tribal communities, racial equity, climate justice and other cross-cutting issues. Its evidence base includes original climate research and contributions from researchers, agencies, communities and Tribal partners.

The report finds that California faces rising temperatures, greater swings between wet and dry conditions, declining snowpack and increasingly severe climate-related hazards. These risks vary across regions and communities, reflecting differences in exposure, vulnerability and capacity to prepare, respond and recover. It presents adaptation approaches and identifies the assessment’s findings as a resource for informed climate adaptation across California. The report emphasizes the importance of understanding overlapping risks and the differing circumstances of communities when planning for climate impacts.