This technical report from California’s Fourth Climate Change Assessment advance the understanding of what types of heat waves pose public health risks for communities across California and examines how the frequency and severity of local heat waves are expected to change over time do to climate change. The report also provides a description of the methods, findings, and limitations behind the building of an online interactive tool, the California Heat Assessment Tool (CHAT) that supports the inclusion of extreme heat considerations into long-term policy and planning decisions throughout California.
Climate Impact Tags
Adaptation Planning Guide Phases
Phase 1: Define, Explore, and InitiatePhase 2: Assess VulnerabilityPhase 3: Define Adaptation Framework and Strategies
Resource Type Tags
Data and toolsScientific study
Last updated: July 5, 2022
Severe flood levels with a one-in-100 likelihood of occurring in any given year.
Affordable Housing Sustainable Communities
Adaptation Planning Guide
Adapting to Rising Tides
Making changes in response to current or future conditions (such as the increased frequency and intensity of climate-related hazards), usually to reduce harm and to take advantage of new opportunities. Climate change adaptation describes actions that address the projected impacts on all aspects of community function that may result from climate change. This can include impacts related to hazard events (flood, wildfire, drought, severe storms), as well as slow changes that affect agricultural, forestry, and fisheries productivity; ecosystem structure and function; and public health.
The “combination of the strengths, attributes, and resources available to an individual, community, society, or organization that can be used to prepare for and undertake actions to reduce adverse impacts, moderate harm, or exploit beneficial opportunities”. The ability to adjust to potential damage, to take advantage of opportunities, or to respond to consequence.
San Francisco Bay Conservation and Development Commission
Best Management Practice
The practice of adding sand or sediment to beaches to combat erosion and increase beach width. It is not a long-term solution; eventually waves and storms will erode away the additional sand, and nourishment will have to be repeated.
The ability of tidal wetlands, seagrass, and mangrove habitats to sequester and store carbon dioxide and other greenhouse gases from the atmosphere, helping to mitigate the effects of climate change.
Climate Action and Adaptation Plan
California Department of Forestry and Fire Protection
California Building Officials
climate action plan
California Air Resources Board
Cost-Benefit Analysis or Community-Based Adaptation
community-based participatory research
Community Choice Aggregation
Community Choice Energy
Carbon Capture and Storage
Center for Disease Control (Federal)
Consecutive Dry Days
California Department of Food and Agriculture
Coastal Data Information Program
California Department of Public Health
California Energy Commission
Continuous Emissions Monitoring System
The Council on Environmental Quality (White House)
California Environmental Quality Act
Compact Fluorescent Lamp
California Heat Assessment Tool
Combined Heat and Power
capital improvement program
Compressed Natural Gas
California Natural Resources Agency
Carbon Dioxide Equivalent
council of governments
California Public Utilities Commission
Climate Smart Agriculture
California Solar Initiative
California Independent System Operator
Governor’s Office of Emergency Services
California Building Resilience Against Climate Effects
California Certified Energy Rating & Testing Services
California Environmental Protection Agency
California Department of Forestry and Fire Protection
The process of removing carbon from the atmosphere and storing it in a carbon sink, a fixed molecule in soil, oceans or plants. Because of the amounts of carbon that are stored in soils, small changes in soil carbon content can have major impacts on carbon dioxide levels in the atmosphere.
A natural or artificial reservoir that accumulates and stores carbon for an indefinite period of times; the absorption of more carbon than can be released.
Climate change refers to a change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions, and persistent anthropogenic changes in the composition of the atmosphere or in land use.
Climate justice is defined as “the concept that no group of people should disproportionately bear the burden of climate impacts or the costs of mitigation and adaptation."
A plausible and often simplified representation of the future climate, based on an internally consistent set of climatological relationships that has been constructed for explicit use in investigating the potential consequences of anthropogenic climate change, often serving as input to impact models. Climate projections often serve as the raw material for constructing climate scenarios, but climate scenarios usually require additional information such as the observed current climate.
Climate models use quantitative methods to simulate interactions of the important drivers of climate, including atmosphere, oceans, land surface, and ice. Climate models are used for a variety of purposes from study of the dynamics of the climate system to projections of future climate.
An integrated approach to achieving greenhouse gas (GHG) reductions while also ensuring food security in the face of climate change.
The benefits of policies that are implemented for various reasons at the same time including climate change mitigation acknowledging that most policies designed to address greenhouse gas mitigation also have other, often at least equally important, rationales (e.g., related to objectives of improving public health, economic benefits and equity).
California Coastal Commission
A valued feature of a community that may be harmed by climate change. Community assets may include buildings and facilities, key services, ecosystems, economic drivers, and infrastructure.
A group of individuals organized by and for a particular community of people based on shared interests and/or attributes. The community could be defined geographically (e.g. a neighborhood), could contain members from diverse backgrounds, and/or could be defined on the basis of something like religious beliefs or a shared condition. Members may include various stakeholders, such as the public, elected officials, advocacy groups, and business leaders.
Roof surfaces designed to reflect radiation from the sun, reducing heat transfer into the building. Roof materials are typically light in color and have a high thermal emittance and solar reflectance.
Database for Energy Efficient Resources
Distributed Energy Resources
Department of Energy (U.S.)
Disaster Risk Management
Disaster Risk Reduction
Database of State incentives for Renewable Energy
Demand Side Management
Department of Water Resources (California)
Areas disproportionately affected by environmental pollution and other hazards that can lead to negative public health effects, exposure, or environmental degradation, or with concentrations of people that are of low income, high unemployment, low levels of homeownership, high rent burden, sensitive populations, or low levels of educational attainment.
The general name for a procedure to take information known at large scales to make predictions at local scales. The two main approaches to downscaling climate information are dynamical and statistical.
Energy Action Plan
U.S. Environmental Protection Agency
Electric Program Investment Charge
Energy Savings Assistance Program (IOU low income weatherization program)
Energy Use Intensity
Electric Vehicle Supply Equipment
Uses biodiversity and ecosystem services as part of an overall adaptation strategy to help people and communities adapt to the negative effects of climate change at local, national, regional and global levels.
The processes by which the environment produces resources utilized by humans such as clean air, water, food and materials. Ecosystems can be classified as: 1) Supporting services - the services necessary for the production of all other ecosystem services, 2) Provisioning services - the products obtained from ecosystems, 3) Regulating services - the benefits obtained from the regulation of ecosystem processes, and 4) Cultural services - the non-material benefits people obtain from ecosystems.
El Niño and La Niña are opposite phases of what is known as the El Niño-Southern Oscillation (ENSO) cycle. The ENSO cycle is a scientific term that describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific. The term El Niño refers to the large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific. La Niña episodes represent periods of below-average sea surface temperatures across the east-central Equatorial Pacific.
The fair treatment of people of all races, cultures, and incomes with respect to the development, adoption, implementation and enforcement of environmental laws, regulations, and policies.
Equity is just and fair inclusion into a society in which all can participate, prosper, and reach their full potential
The central equity challenges for climate change policy involve several core issues: addressing the impacts of climate change, which are felt unequally; identifying who is responsible for causing climate change and for actions to limit its effects; and understanding the ways in which climate policy intersects with other dimensions of human development, both globally and domestically.
The process of transferring water through plants by evaporation from the land to the atmosphere.
The presence of people, infrastructure, natural systems, and economic, cultural, and social resources in areas that are subject to harm.
When a weather or climate variable exceeds the upper or lower thresholds of its observed range
An extreme weather event is significantly different from the average or usual weather pattern. This may take place over one day or a period of time. For example, flash floods, wildfires, and heatwaves
Federal Emergency Management Agency
Composed of trees including wood from the trunk of the tree, limbs, tops, roots, and foliage. The principal sources of forest biomass for energy production are: 1) trees killed or damaged by fire, insects, disease, drought or that have no other use; 2) trees grown specifically for energy production; and 3) trees removed to reduce hazardous fuel accumulations or improve forest health.
These communities experience the impacts of issues such as environmental pollution, climate change, and the economic crisis first and most severely. These communities are most often communities of color and low income.
Global Climate Model
Greenhouse Gas Reduction Fund
Geographic Information Systems
Global Warming Potential
An approach to water management that protects, restores, or mimics the natural water cycle. It incorporates both the natural environment and engineered systems to provide clean water and conserve ecosystem values and functions.
Any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere. Greenhouse gases include, carbon dioxide, methane, nitrous oxide, ozone, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride.
Healthy Soils Initiative
Heating Ventilation, Air Conditioning
An event or physical condition that has the potential to cause fatalities, injuries, property damage, infrastructure damage, agricultural losses, damage to the environment, interruption of business, or other types of harm or loss.
Sustained action taken to reduce or eliminate the long-term risk to human life and property through actions that reduce hazard, exposure, and vulnerability. Hazard mitigation can one component of climate change adaptation.
An urban area characterized by temperatures higher than those of the surrounding non-urban area. As urban areas develop, buildings, roads, and other infrastructure replace open land and vegetation. These surfaces absorb more solar energy, which can create higher temperatures in urban areas.
Also referred to as extreme heat events, these are prolonged periods of excessive heat, often combined with excessive humidity.
The cycle representing how drought, as a slow-moving natural disaster, tends to emerge under the radar screen, and then intensifies until people can no longer ignore it or wish it away. The cycle illustrates that when drought ends, people are often glad to forget about it and resume to business as usual; yet, it is also important to learn from these experiences.
California Infrastructure and Economic Development Bank
Integrated Climate Adaptation and Resilience Program
Investor Owned Utility
Intergovernmental Panel on Climate Change
integrated regional water management
integrated regional water management plan
In the context of climate adaptation, the effects (especially the negative effects) of a hazard or other conditions associated with climate change. Impact is often considered the combination of exposure and sensitivity. Impacts are sometimes discussed in terms of direct or indirect impacts. Direct impacts on physical assets or immediate operations can lead to more indirect impacts on the broader system or community.
Observations or calculations that can be used to track conditions and trends. Indicators of climate change can communicate key aspects of the changing environment, point out vulnerabilities, and inform decisions about policy, planning, and resource management. For example, an indicator can be a record of global temperature showing the number of degrees by which the average global temperature for each year differs from the average global temperature during the last century.
A process which promotes the coordinated development and management of water, land and related resources in order to maximize economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems.
The submergence of land by water, particularly in a coastal setting.
An international agreement linked to the United Nations Framework Convention on Climate Change that agrees to reduce emissions of six greenhouse gas emissions that contribute to global warming: carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, HFCs and PFCs. The goal was to collectively reduce emissions of greenhouse gases by 5.2% below the emission levels of 1990 by 2012.
local coastal program
Local Education Authority
Local Government Partnerships
local hazard mitigation plan
Tool for the systematic evaluation of the environmental aspects of a product or service system through all stages of its life cycle.
A natural alternative to bulkheads and seawalls that uses plants, sand, and limited use of rock to provide shoreline protection and maintain valuable habitat.
Municipal Owned Utility
Metropolitan Planning Organization
Adaptation efforts that worsen a situation, or transfer the challenge from one area, sector, or social group to another.
A form of 'soft' engineering. In most cases it involves breaching an existing coastal defense, such as a sea wall or an embankment, and allowing the land behind to be flooded by the incoming tide, thus setting back the line of actively maintained coastline.
Climate change mitigation refers to “a human intervention to reduce the human impact on the climate system; it includes strategies to reduce greenhouse gas sources and emissions and enhancing greenhouse gas sinks.”
National Aeronautics and Space Administration
National Integrated Drought Information System
National Oceanic and Atmospheric Administration
Governor’s Office of Emergency Services
Ocean Protection Council
Governor’s Office of Planning and Research
Office of Science and Technology Policy (White House)
Significant changes to the chemistry of the ocean that occurs when carbon dioxide gas (or CO2) is absorbed by the ocean and reacts with seawater to produce acid.
Publicly Owned Utility
Power Purchase Agreement
Public Purpose Program
Photovoltaic (as in Solar PV)
An agreement within the framework of the United Nations Framework Convention on Climate Change (UNFCCC) dealing with greenhouse gases emissions mitigation, adaptation, and finance starting in the year 2020.
The likelihood of hazard events occurring. Probabilities have traditionally been determined from the historic frequency of events. With changing climate and the introduction of non-climate stressors, the probability of hazard events also changes.
Resource Conservation District
Regional Energy Networks
Renewables Portfolio Standard
Regional Transportation Plan
"The capacity of any entity—an individual, a community, an organization, or a natural system—to prepare for disruptions, to recover from shocks and stresses, and to adapt and grow from a disruptive experience.” A community’s resilience is determined by its ability to survive, adapt, and thrive no matter what acute shock or chronic stressor it experiences.
Community resilience is the ability of communities to withstand, recover, and to learn from past disasters to strengthen future response and recovery efforts. This can include but is not limited to physical and psychological health of the population, social and economic equity and well-being of the community, effective risk communication, integration of organizations (governmental and nongovernmental) in planning, response, and recovery, and social connectedness for resource exchange, cohesion, response, and recovery.
Risk for the purpose of hazard mitigation planning, is the potential for damage or loss created by the interaction of hazards with assets such as buildings, infrastructure, or natural and cultural resources. For natural hazards, risk tends to be calculated based on evaluation of the probability (likelihood) of a hazard event occurring, vulnerability, and the event’s potential consequences. This method uses data from the past to establish the probability and, in the case of climate change, includes future projections of probability.
Strategic Growth Council
state hazard mitigation plan
Short-Lived Climate Pollutants
Sea Level Rise
Soil Organic Matter
The movement of saline water into freshwater aquifers, which can lead to contamination of drinking water sources and other consequences.
An increase in the mean level of the ocean - a change in global average sea level brought about by an alteration to the volume of the world ocean. Relative sea level rise occurs where there is a net increase in the level of the ocean relative to local land movements.
A wall or embankment erected to prevent the sea from encroaching on or eroding an area of land.
The level to which a species, natural system, or community, government, etc., would be affected by changing climate conditions.
A seasonal accumulation of slow-melting snow.
Social vulnerability is “the susceptibility of a given population to harm from exposure to a hazard, directly affecting its ability to prepare for, respond to, and recover.”
The temporary increase, at a particular locality, in the height of the sea due to extreme meteorological conditions (low atmospheric pressure and/or strong winds). The storm surge is defined as being the excess above the level expected from the tidal variation alone at that time and place.
technical advisory council
The level of magnitude of a system process at which sudden or rapid change occurs. For example, species diversity of a landscape may decline steadily with increasing habitat degradation to a certain point, then fall sharply after a critical threshold of degradation is reached.
Although it is common to refer to "traditional knowledge(s)" as individual pieces of information, this term also refers to traditional “knowledge systems" (TKs) that are deeply embedded in indigenous ways of life. These guidelines use the phrase "traditional knowledges" deliberately in plural form to emphasize that there are diverse forms of traditional knowledge and knowledge systems that must be recognized as unique to each tribe and knowledge holder because knowledges are emergent from the symbiotic relationship of indigenous peoples and places—a nature-culture nexus.
Urban Heat Island
United Nations Framework Convention on Climate Change
United States Department of Agriculture
United States Geological Survey
This is the unpredictability of a system or model. Uncertainty in models can come from many sources; a lack of information, lack of technical ability to model complex processes, a lack of knowledge about a system or uncertainty over human behavior.
The care and management of tree populations in urban settings for the purpose of improving the urban environment.
Vehicle Miles Travelled
Climate vulnerability describes the degree to which natural, built, and human systems are susceptible “…to harm from exposure to stresses associated with environmental and social change and from the absence of capacity to adapt.” In hazard mitigation planning, for buildings and other structures, vulnerability means susceptibility to damage given the inherent characteristics of a particular structure. Its broader meaning is the level of exposure of human life and property to damage from natural and human-made hazards. Vulnerability can increase because of physical (built and environmental), social, political, and/or economic factor(s). In the case of climate change, vulnerability is often defined as the combination of impact and adaptive capacity as affected by the level of exposure to changing climate. Notably, impact is often determined by the combination of exposure and sensitivity, and vulnerability is considered a function of exposure, sensitivity, and adaptive capacity.
For climate change, it is an analysis of how a changing climate may harm a community and which elements—people, buildings and structures, resources, and other assets—are most vulnerable to its effects based on an assessment of exposure, sensitivity, the potential impact(s), and the community’s adaptive capacity.
Vulnerable communities experience heightened risk and increased sensitivity to climate change and have less capacity and fewer resources to cope with, adapt to, or recover from climate impacts. These disproportionate effects are caused by physical (built and environmental), social, political, and/or economic factor(s), which are exacerbated by climate impacts. These factors include, but are not limited to, race, class, sexual orientation and identification, national origin, and income inequality.
Vulnerable populations include, but are not limited to women; racial or ethnic groups; low-income individuals and families; individuals who are incarcerated or have been incarcerated; individuals with disabilities; individuals with mental health conditions; children; youth and young adults; seniors; immigrants and refugees; individuals who are limited English proficient (LEP); and Lesbian, Gay, Bisexual, Transgender, Queer, and Questioning (LGBTQQ) communities, or combinations of these populations (HSC Section 131019.5, CNRA 2018).