Dozens of reports detail the growing threats of extreme heat, wildfires, drought, and rising seas – and provide communities with the science needed to prepare
Media Contact: LCI.press@lci.ca.gov
SACRAMENTO (10/19/2026) — As California faces unprecedented warming and increasingly severe climate impacts, the state is releasing new research from California’s Fifth Climate Change Assessment, which details how climate conditions are changing across the state and what communities can expect.
The Fifth Assessment brings together the latest climate science, data, research, tribal knowledge and community perspectives to help state and local leaders better understand the risks posed by climate change and take action to protect their communities. The research will inform efforts to strengthen climate resilience, guide local planning, and prepare for worsening climate impacts.
As the Trump administration turns its back on science, California is doubling down on climate action, on protecting our communities, and on building a safer future. We are putting the latest science to work so communities across the state have the tools to confront the climate crisis head-on.
Since 2006, California’s Climate Change Assessments have provided the scientific foundation informing state and localized plans, policies, investments and decisions about climate change. The Fifth Assessment builds on that work, bringing together the latest climate science, tribal knowledge, and community perspectives to help state and local leaders understand climate risks, strengthen resilience, and prepare for worsening impacts.
Funded by the California Legislature, the research underwent review by scientific experts, Tribal Advisory Group members, and an external editorial board. Along with a statewide summary, the compilation of original climate research includes nine Regional Reports, 18 Tribal Research projects, 15 Core Climate Research Program reports, Statewide Topical Reports and more to help California communities prepare for climate change and build resilience.
The reports in the compilation reflect the individual authors’ and researchers’ conclusions, and they do not necessarily represent the state’s views; they are intended to inform future decisions rather than prescribe specific policies or actions. The peer-reviewed research translates global climate models into locally relevant reports to fill information gaps and support decisions at the local, regional and state levels.
The Climate Assessment includes three scenarios in its projections: SSP2–4.5 is an intermediate scenario where global CO2e emissions initially plateau at current levels, then start to fall after 2050; SSP3–7.0 is a less optimistic high emissions scenario that shows CO2e emissions doubling by 2100; and SSP5–8.5 is a more aggressive emissions scenario, which describes a very high and unlikely emissions pathway that shows CO2e emissions tripling by 2075.
The Fifth Assessment comprises years of research involving government, academic, tribal and community partners to shed light on the ways climate change could impact California’s diverse communities and help them take action. The assessment’s climate science and community-informed research can serve as the cornerstone for guiding smart policy and sound investment at the state, regional, and local levels to improve community resilience for years to come.
For decades, the State of California has been investing in cutting-edge science to answer some of the most pressing questions about climate change. California has completed four prior Climate Change Assessments – each building upon the last to expand our understanding about climate change triggers, impacts, risks and possible adaptation pathways, and inspiring some of California’s most significant climate policies, laws and programs. Since the release of California’s Fourth Climate Change Assessment in 2018, the state has experienced several of the most extreme events in its recorded history, including record-breaking wildfires, catastrophic atmospheric river storms, prolonged droughts, and increasingly frequent and severe extreme heat events.
Since 2006, California’s Climate Change Assessments have helped inform the plans, policies and investments that shape how we prepare for and respond to climate change. The Fifth Assessment brings together dozens of reports that provide the science we need to better understand how climate risks are changing, how those risks affect our communities, and what we can do to prepare. The future is not predetermined.
The Fifth Assessment provides further insight into how these events will continue to impact California in the decades ahead. Among the key findings:
- California will experience rising temperatures throughout this century. Average temperatures in California are increasing at an unprecedented rate, projected to rise by 3.5–4.3°F (1.9–2.4°C) by 2050 relative to the 1981–2010 baseline. By 2100, projected temperature increases range between 5.7°F (3.2°C) under an intermediate emission scenario to 8°F (4.4°C) under a high emission scenario.
- California’s snowpack will decline substantially, affecting downstream water systems, local economies, and ecosystems. Early April snowpack is projected to decrease by approximately 40% by mid-century (2041–2070) and approximately 60% by the end of the century (2071–2100) compared to the 1981–2010 average. Snowpack decline is due to rising temperatures and a greater amount of precipitation falling as rain.
- Wildfire smoke exposure and associated health risks are increasing. Models project that California will experience the highest increase in annual excess deaths from wildfire smoke of any U.S. state by 2050, reaching over 5,000 excess deaths per year compared to 2011–2020. Farmworkers alone are projected to experience a 190% increase in smoke exposure days considered “unhealthy for sensitive groups” by mid-century.
- Extreme heat events are growing longer and more frequent, resulting in prolonged heat waves and more days above critical temperature thresholds. By end-of-century, the average longest heat wave of the year is projected to lengthen across all regions of the state, with durations ranging from six days in the Bay Area to as long as 19 days across the Sierra Nevada under a high emissions scenario.
- Marine and coastal ecosystems are being reshaped by marine heat waves, ocean acidification, and hypoxia. Ocean acidification along the California coast is occurring at twice the global rate due to upwelling. Combined with severe marine heat waves and low oxygen levels in California coastal waters, marine ecosystems and wildlife are facing devastating threats.
- With 3.3 feet of sea level rise, $78 billion worth of property and 201,000 people could be exposed to coastal flooding by 2100. This means five times the exposure expected in 2050. A 100-year storm could raise these estimates to 310,000 people and $122 billion in property exposed by 2100.
- California Native American tribes face disproportionate impacts from climate change yet are leading effective climate adaptation solutions. Historical land dispossession and criminalization of traditional practices have heightened tribal vulnerability to shifting seasons and climate-related hazards. Nonetheless, California Native American tribes are implementing strategies such as ecocultural restoration and cultural burning which can reduce the likelihood of catastrophic wildfires by up to 92% for a decade post-treatment. These practices strengthen ecosystems, communities, and California’s overall adaptive capacity.
- Climate hazards are increasingly interconnected, creating cascading and compounding risks. Major climate hazards in California are most destructive when they occur sequentially or simultaneously. For example, an exceptionally hot summer and fall in 2024 exacerbated fire conditions leading into the 2025 Los Angeles Fires, one of the most expensive natural disasters in U.S. history. Multi-benefit solutions can help address the complex and intersecting nature of climate hazards.
The latest reports also detail the unique and disproportionate climate threats to vulnerable communities and tribal communities, with a focus on working collaboratively with these communities on research and solutions for resilience.
We’re proud that this Fifth Assessment is the first to feature a Tribal Research Program. The program includes a Tribal Advisory Group, Tribal Research Grant Program, and a Statewide Report written by and for tribal communities. The program uplifts tribal expertise and examples of tribally led practices that are strengthening California’s climate resilience.
To access Fifth Assessment technical reports, regional reports, summary reports, online tools, climate projects and data, and other resources and information, please visit the website.
California is a global leader in climate action, including investing in and using research to advance proactive climate change policy. Its climate change assessments provide the scientific foundation for understanding climate-related vulnerability and how Californians may respond. The Climate Change Assessments directly inform state policies, plans, programs, and guidance to promote effective and integrated action to safeguard California from climate change.
California is playing a world-leading role in building strong coalitions of partners committed to curbing carbon pollution and building climate resilience in California, the United States and around the globe. From last month’s Climate Week NYC to the upcoming Resilient California Summit and U.N. Conference of the Parties (COP) and in our everyday work, California is joining local, state and international partners to take urgent climate action and make the case that even more must be done – led by science.
About LCI
The Governor’s Office of Land Use and Climate Innovation (LCI) oversees and administers programs, policies, and initiatives that chart California’s future through bold ideas, proven implementation, and scale. LCI’s leadership is provided by the Director, who is the principal advisor to the Governor on all matters relating to the programs and investments under LCI’s umbrella. LCI also provides ongoing operational support for the California Strategic Growth Council and the California Racial Equity Commission, with its Director acting as Chair of the Council.