Climate Change in California

California is experiencing significant damages from climate change, including increased heat-related mortality, more frequent and severe wildfires, and rising sea levels. The state faces critical water shortages, record-low snowpacks in the Sierra Nevada, and a high risk of extinction for 83 percent of its native freshwater fish species.

• Climate change has severely impacted public health in California, evidenced by the July 2006 heat wave which caused 140 deaths and over 16,000 excess emergency department visits. Vulnerable populations, including the elderly, infants, and African Americans, face higher risks of hospitalization for conditions such as stroke and acute kidney failure, while residents in socioeconomically disadvantaged areas of Los Angeles, Sacramento, San Diego, and San Francisco are more susceptible to the "urban heat island effect". Additionally, rising temperatures have led to the discovery of the Asian tiger mosquito in Los Angeles County and worsened respiratory health through increased ground-level ozone and particulate pollution from wildfires.
• Wildfire activity in California has intensified, with ten of the state's 20 largest fires occurring since 2005. The 2013 Rim Fire burned over 257,000 acres, resulting in nearly $126 million in suppression costs and between $50 million and $265 million in private property destruction. Approximately 375,000 residential properties are currently classified as being at very high risk of wildfire damage.
• Sea levels along the California coast rose approximately seven inches over the last century and are projected to be 10-18 inches higher by 2050 and 31-55 inches higher by 2100 compared to 2000 levels. A 55-inch rise by 2100 could put $100 billion of property and 480,000 people at risk along the California coast and San Francisco Bay. By 2050, storms that currently occur once every 100 years could happen annually.
• Water security is declining due to drought and reduced snowpack; the average early spring snowpack in the Sierra Nevada fell by about 10 percent over the last century, and April 1, 2015, recorded a 500-year low in snow levels. These conditions have led to desiccated wells and dry faucets for some residents of the San Joaquin Valley.
• Biological systems in California are shifting, with terrestrial and aquatic species moving toward cooler regions or changing growth timing. Among California's 121 native freshwater fish species, 83 percent are considered at high risk of extinction.

APA

Union of Concerned Scientists (2016). Climate Change in California. https://www.ucs.org/about/news/climate-change-california

Chicago

Union of Concerned Scientists. Climate Change in California. 2016. https://www.ucs.org/about/news/climate-change-california.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Climate Change in California |date=29 March 2016 |url=https://www.ucs.org/about/news/climate-change-california |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2016climate, author = {{Union of Concerned Scientists}}, title = {{Climate Change in California}}, institution = {Union of Concerned Scientists}, year = {2016}, month = mar, url = {https://www.ucs.org/about/news/climate-change-california}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }