How is climate data relevant for decision-making in California?
Topics covered in this article:
- How is climate data relevant for decision-making?
- California’s changing climate
- Using climate data in adaptation planning
How is climate data relevant for decision-making?
Characterizing climate conditions is important when planning for the future in a variety of sectors, including municipal planning, natural resource stewardship, utility management, public health and safety programming, and private industry. By assessing the range of possible future conditions under a changing climate, you can plan adaptations that reduce the impacts of climate change and safeguard lives, livelihoods, and landscapes for decades to come.
California’s changing climate
The California Fourth Climate Change Assessment produced updated climate projections that provide state-of-the-art understanding of different possible climate futures for California. The science is highly certain that California (and the world) will continue to warm and experience greater impacts from climate change in the future. Projected statewide climate change trends are listed in the table below:
| Climate variable | Cal-Adapt symbol | Projected change | Scientific confidence | Cal-Adapt tools |
|---|---|---|---|---|
| Temperature |  | Warming | Very high | Annual averages, Extreme heat, Maps of projected change, Local climate change snapshot, Cooling degree days and heating degree days, Extended drought |
| Sea levels |  | Rising | Very high | Sea level rise – CalFloD-3D Hourly projections of sea level |
| Snowpack |  | Declining | Very high | Snowpack |
| Heavy precipitation events |  | Increasing | Medium high | Annual averages, Maps of projected change, Local climate change snapshot, Extreme precipitation events |
| Drought | | Increasing | Medium high | Local climate change snapshot, Extended drought |
| Wildfire |  | Increasing | Medium high | Local climate change snapshot, Wildfire |
Table: projected climate change trends in California, from Fourth Assessment key takeaways report
These trends will vary in magnitude and impact across California, so it’s important that adaptation planning uses data that are specific to the planning location and the climate hazards of concern in that location. To explore climate projections for a specific area, check out the Cal-Adapt tools associated with each climate variable. For additional information on the impacts of climate change in California, you can explore California’s Fourth Climate Change Assessment.
Using climate data in adaptation planning
Cal-Adapt data can be used in combination with other data sources to inform a climate vulnerability assessment, which combines projections data, historical data, and other qualitative and quantitative sources to identify how specific climate-related risks will impact a community. Vulnerability assessments are commonly used to identify the populations, infrastructure, and natural systems most at risk of climate change impacts and evaluate the severity of their vulnerability and their ability to adapt. Climate change vulnerability analysis and adaptation planning methods can vary by sector. Regardless of the context, using climate change data to understand vulnerability is an important cornerstone of identifying the best adaptations to undertake to address the projected risks.
The 2020 Adaptation Planning Guide (APG) provides guidance to local governments on local adaptation and resiliency planning in California, including how to use Cal-Adapt to inform a vulnerability assessment. The APG breaks down adaptation planning into four phases:
- Explore, Define, and Initiate
- Assess Vulnerability
- Define Adaptation Framework and Strategies
- Implement, Monitor, Evaluate, and Adjust
While following this process, it is most useful to start examining climate change data from Cal-Adapt in a preliminary analysis during Phase 1 to understand the scope of the assessment you are about to undertake, and then to conduct a more thorough technical analysis as you move into Phase 2. Explore each phase, broken down into manageable smaller steps in the online Adaptation Planning Guide.
Cities and Counties in California are required to address climate adaptation and vulnerability in their safety elements. For more information on the requirements see the State's 2020 Adaptation Planning Guide, the General Plan Guidelines Chapter 4, or Government Code section 65302(g). (Senate Bill 379, Jackson, 2015).
The way that you use climate data will depend on your particular needs, risk tolerance, and planning context. To support adaptation planning, the State of California has produced guidance materials, including:
- 2020 Adaptation Planning Guide
- State of California Sea Level Rise Guidance, 2018 Update
- Planning and Investing for a Resilient California: A Guidebook for State Agencies
- General Plan Guidelines and Technical Advisories (See Chapter 4, Safety Element, and Chapter 8 for specific guidance on addressing climate change).
- Defining Vulnerable Communities in the Context of Climate Change
- Various state agencies produce regional, topical, and impact-specific guidance documents and technical resources that are compiled and highlighted on the State Adaptation Clearinghouse as Featured Resources, organized under Topic Areas.
You can find a list of additional climate change adaptation planning resources on the California Adaptation Clearinghouse Resources Page and example plans and strategies by exploring the database search page, which can filter resources by the topics, climate impacts, regions, and resource types most relevant to you. Additionally, the Governor’s Office of Planning and Research regularly conducts an inventory of local adaptation efforts and related documents, which are displayed for public access on the ResilientCA Adaptation Planning Map (RAP-Map), also housed on the Adaptation Clearinghouse.