The snowpack that refills Folsom Lake, Lake Oroville and Lake Shasta each spring — the reservoirs that supply roughly two thirds of California’s population with water — could shrink by about 40% within 25 years. As temperatures warm, more of Northern California’s water is set to arrive as rain instead of snow, with water running downstream instead of melting slowly into reservoirs as a stable water supply.
It is one of a dozen projections in California’s Fifth Climate Change Assessment, released Monday. The report estimates the state will warm to around 4 degrees by the 2050s, that heat waves will last far longer, that whiplash between drought and wet periods will be more extreme, and that wildfire smoke will kill more people in California than in any other state.
Although it is full of worrisome statistics and key findings, its creators also see it as a tool to help communities across the state better prepare for changing weather patterns in the decade to come. Helene Margolis, an epidemiologist at UC Davis who studies the intersection between public health and climate change and was the lead author for the Sacramento Valley section of the assessment, called it empowering…