Climate change poses a significant threat to human health and well-being. The direct drivers of climate change can affect all Californians, but some Californians are more most likely to experience adverse health outcomes. Those most vulnerable to the impacts of climate change are the same that have historically experienced health inequities, so climate change has the potential to exacerbate a wide array of pre-existing inequities and conditions of vulnerability for already-disadvantaged people. For additional background information and discussion of climate impacts and vulnerabilities of the Public Health Sector, visit the Background & Climate Impacts information excerpted from the Adaptation Planning Guide and explore the Topic search below.

Addressing climate change presents an opportunity to improve public health, both through climate mitigation activities such as transitioning to renewable energy and promoting low-carbon transportation and diet, and through taking steps to plan for and adapt to climate risks. Examples of adaptation strategies are provided on the Adaptation Strategies page and can be found in many of the resources available by search below.

The following is excerpted from the 2020 Adaptation Planning Guide, Appendix A.

Defining the Sector

The Public Health sector aims to promote and protect the health of people where they live, work, and play.1 This sector focuses on preventing people from becoming sick or injured due to climate change-related effects that impact human life support systems such as water, air, food, shelter, and security. Public health includes healthcare facilities and programs and encompasses health equity issues, because climate change effects do not affect everyone equally. The goal of this sector is to ensure all community members, including those with fewer resources or capacities, can prepare, respond, and recover from short-term and long-term health effects worsened by climate change.

Major Vulnerabilities

There are several diseases and illnesses linked to climate change that have the potential to appear throughout California. Some illnesses, such as Lyme disease, West Nile Virus, Zika, dengue, and chikungunya, are carried by animals such as mice and rats, ticks, and mosquitoes. Some of these vectors have already become more numerous in California due to climate change. Outdoor workers, people experiencing homelessness, children, seniors, persons with chronic health conditions, and pregnant or nursing women are among those who are highly vulnerable to these illnesses because they are either more exposed or have weakened immune systems that may not be able to overcome vector-borne illnesses. People experiencing homelessness are particularly vulnerable because they lack permanent, and often temporary, shelter, leaving them more exposed to extreme events such as extreme heat or flooding. Economically disadvantaged persons may also be unable to afford medical insurance, which would make treatment for these illnesses expensive and difficult. Education, outreach, and emergency alert systems may already exist to help combat these illnesses; however, linguistically isolated persons might not receive adequate emergency warnings or attend educational events due to communication barriers.

Public health infrastructure, such as hospitals, clinics, and public health departments, may not be prepared for an influx of patients from climate-related effects. This leaves the entire health system vulnerable, not only to disease outbreaks, but to health impacts created by wildfires, poor air quality, and extreme heat. Mortality accounts for the greatest share of economic impacts of climate change, resulting in billions of dollars of losses each year in California.2

Climate change effects can also produce secondary health impacts, such as asthma from wildfire smoke and poor air quality, heat-related illnesses from extreme heat, and cardio-pulmonary diseases from mold and mildew growth after flooding. Worsening air quality (ozone, particulate matter, criteria air pollutants, and allergens) and heat stress can cause cardio-respiratory health problems such asthma, chronic obstructive pulmonary disease, and allergies in those who do not have adequate shelter or living conditions, such as persons working outdoors, people experiencing homelessness, children, and households in poverty. Smoke from local or regional wildfires can force outdoor workers to choose between their health and financial stability if they cannot afford to stop work for a day or two. Additionally, low-income households and renters are more likely to live in areas subject to flooding, poor air quality, extreme heat, or landslides, which can create hazardous living conditions or destroy housing, increasing individuals’ susceptibility to human health hazards. Moreover, experiencing extreme weather events can lead to mental health challenges.

The Adaptation Strategies tab of this topic, excerpted from Appendix D of the 2020 APG, provides examples of ways that communities can support a more resilient public health sector as part of adaptation planning efforts. These strategies include preventing people from becoming sick or injured due to climate change–related effects and addressing underlying causes, such as living conditions, that make people more vulnerable to climate-related threats. In addition to traditional public health services and approaches, the strategies address systemic causes of inequity to improve living conditions, to ultimately lead to long-term health improvements and resilience. These strategies are generalized approaches that can be refined for the specific public health programs in a community.


1. California Natural Resource Agency, Safeguarding California Plan: 2018 Update: California’s Climate Adaptation Strategy, 2018.

2. US Government Accountability Office, “Information on Potential Economic Effects Could Help Guide Federal Efforts to Reduce Fiscal Exposure,” Publication No. GAO-17-720, September 2017,

Climate hazards
Adaptation Strategy
Factors to Consider
Sector overlap
Responsible Agencies
Examples & Sources
Air quality, extreme heat, wildfire, flooding, sea level rise

Strategy PH-1: Establish resilience hub locations in neighborhoods throughout the community.

Resiliency hubs consist of well-used, existing community-serving facilities that are upgraded to provide local communities with shelter and electricity during extreme heat events, poor air quality, and disasters. These hubs should have other essential resources such as food, ice and refrigeration, charging stations, basic medical supplies, and other emergency supplies. They should have their own renewable energy and energy storage systems that should be able to operate up to 72 hours if a power outage occurs. Resiliency hubs should also act as education centers, where community members can go to learn about climate-related hazards and other effects, how to prepare and respond to them, and enhance community connections to increase adaptive capacity. Local and regional General Plan Safety Elements, Local Hazard Mitigation Plans, and Emergency Operations Plans should integrate site planning and establishment of resiliency hubs, and their importance to emergency preparation and response.

When establishing resilience hubs, local governments should focus on existing community facilities that can be upgraded, instead of new facilities that are unfamiliar to the community. These facilities should be located outside of hazard-prone areas. Jurisdictions should consider ease of access to the site, as those with limited mobility or without access to transportation may be unable to travel to a resilience hub during a disaster. Resilience hubs should be located in or near residential areas to ensure that they are easily accessible. People experiencing homelessness are often overlooked as a population that requires the assistance provided by resilience centers, so local governments should consider this population when planning for resilience hubs. Local governments can work with community-based organizations and neighborhood leaders to identify resilience hub locations and establish neighborhood outreach programs to disseminate information to older adults and linguistically isolated populations. 1 Capital Improvement & Infrastructure Projects Programmatic Education, Outreach, Coordination Emergency Management Land Use and Community Development Climate Justice Cities and Counties Council and Association of Governments Transformative Climate Communities Grant
All hazards

Strategy PH-2: Integrate climate change and health equity into traditional public health programs and core functions.

Traditional public health programs primarily focus on treating individuals who are sick based on their symptoms. Integrating climate change and health equity into this traditional public health system can allow doctors to understand underlying conditions that create illnesses and whether climate change effects could exacerbate those illnesses. Public health officials could use hazard data, such as areas vulnerable to extreme heat or poor air quality, to reach vulnerable populations that may not otherwise have access to healthcare services.

When integrating climate change and health equity into public health programs, local governments should consider where the most vulnerable populations are located and if there are existing community centers or resilience hubs to focus resources. Part of health equity incorporation will be to provide care and educational programs in languages that match the demographics of the local community. This should encourage community members to participate in public health programs. Operational Education, Outreach, Coordination Land Use and Community Development Emergency Management Climate Justice Cities and Counties Council and Association of Governments  
Extreme Heat, Air Quality, Flooding

Strategy PH-3: Collaborate with community-based organizations to develop or expand urban greening and urban agriculture programs.

Community-based organizations have direct ties to the communities they are from or work in, and therefore are optimal partners to identify areas for urban greening and urban agriculture, and then develop and implement these programs. Urban greening can include adding trees, parks, green infrastructure, and other green elements to a neighborhood. This program can help reduce temperatures on the ground by providing shade, clean the air to improve air quality, and provide natural drainage areas that prevent flooding. Urban agriculture includes community gardens or small farms within urban areas of a community. This program can replace paved areas and reduce the urban heat island effect, while also providing additional food and educational opportunities for the community.

The first factor to consider is where urban greening and urban agriculture is most needed, which is typically in areas with few trees, parks, or healthy food options. Local governments should also consider gentrification and displacement that could occur because of these programs. To prevent this, local governments can protect affordable rentals and the ability of residents to remain in their homes, while also hiring local youth or young adults to install green infrastructure or other plants as part of workforce development jobs program. This effort could also include on-site capture of rainwater on private properties. Programmatic Education, Outreach, Coordination Land Use and Community Development Cities and Counties CBOs Transformative Climate Communities Grant General Fund
All hazards

Strategy PH-4: Develop a climate preparedness outreach program focused on vulnerable populations that provide information on staying healthy and safe during hazardous events.

Community members, especially those within a vulnerable population group, may be unaware of the climate-related effects that may be harmful to their community, or how to stay safe during hazardous events. Vulnerable populations may be the least prepared for the impacts of climate effects. Local governments can develop climate preparedness outreach programs to work with community members to increase resiliency to hazardous events. Programming can include educational events, workshops for school aged children, and providing emergency kits to community members. Jurisdictions should prioritize resources for vulnerable populations, provide them in multiple languages, and design them to communicate effectively with all groups to reduce health inequities in communities. 2

Local governments should consider the populations they are trying to reach in these outreach programs, and the effects most likely to impact those communities. Some communities may be at high risk of flooding, while others could be in the high wildfire hazard severity zones. It can be difficult for jurisdictions to reach some populations, especially those that are isolated, with these outreach efforts. Local governments can work with established neighborhood outreach programs or collaborate with community-based organizations to improve trust and communication to reach as many people as possible. Education, Outreach, Coordination Programmatic Emergency Management Cities and Counties  
Air Quality, Extreme Heat, Wildfire, Human Health Hazards

Strategy PH-5: Expand employer and worker training in industries with outdoor work, including assurance or adequate water, shade, rest breaks, protection from poor air quality, training of heat impacts, and vector borne diseases.

Health effects from climate change can be more severe for individuals who work outdoors, such as construction workers, landscapers and grounds crews, and agricultural workers. Extreme heat and poor air quality are the primary health effects for these workers, although increased exposure to potential disease vectors such as ticks and mosquitoes can also pose a hazard. The local and regional governments can provide guidance to employers and workers, as well as work with the private sector and community-based organizations, to ensure that outdoor employees are aware of the harm posed by these climate-related effects and how to reduce them.

Many workers in these industries may be difficult to reach and outdoor workers may be fearful of engaging with the government. However, local governments can work with community-based organizations and worker rights advocates to determine the best method to outdoor workers. Information can include protections from climate-related effects, but also information about worker protect laws. Outreach should also be culturally relevant and be in multiple languages that are representative of the outdoor worker population. Programmatic Education, Outreach, Coordination Emergency Management Agriculture Cities and Counties  
All hazards

Strategy PH-6: Coordinate with local homeless services to ensure that emergency shelters are available during extreme heat events, poor air quality, severe weather events, and other highly hazardous conditions. 

Ensure that the local homeless population is made aware of these resources. Local communities should coordinate with agencies and organizations that provide homeless services to provide shelter during hazardous conditions. These emergency shelters should provide information about hazardous events and basic supplies such as insect repellent and hygiene provisions that can increase the adaptive capacity of individuals experiencing homelessness. Outreach and support efforts to homeless individuals is essential to disseminate information on how to stay safe during hazardous conditions and where the nearest emergency shelters are located.

This is a two-pronged adaptation measure that involves both coordination with homeless services and outreach to local homeless individuals or populations. Some communities have existing homeless shelters that can be used during emergencies, and others would have to develop new emergency shelters that can accommodate the homeless population. Recently enacted legislation from 2019 (AB 101, SB 450, SB 744) streamlines the approval process to construct emergency shelters, navigation centers, and supportive housing for vulnerable populations, and it assists local communities with required CEQA review. This can help address a serious shortage of emergency shelters and related facilities in local communities. These locations may not be familiar to homeless individuals, and therefore it is essential to go to the homeless community, homeless shelters, and local soup kitchens to disseminate this information. Education, Outreach, Coordination Emergency Management Land Use and Community Development Cities and Counties Local homeless services organizations (Continuum of Care, homeless partnerships, etc.) Homeless Assistance Grants Emergency Solutions Grants (ESG) Program
All hazards

Strategy PH-7: Work with local medical providers and hospitals to ensure that medical facilities are prepared to meet any increased demand because of hazardous events.

Hazardous events, such as wildfires, floods, poor air quality, and extreme heat, can increase illnesses such as heat stroke, asthma, and cardiovascular diseases. This can increase the demand for medical services at hospitals and local medical providers. This demand can create an unexpected overflow of patients and can strain hospitals and clinics in a community. Local governments can work with the regional public health systems, hospitals, clinics, and private practices to prepare for an influx of patients during hazardous events. This could be stocking up on specific medical supplies for local emergencies or working with emergency management agencies to have medical professionals and supplies at emergency shelter locations.

Local governments can work with medical providers to identify specific health impacts that may occur due to different climate change effects. Medical providers are trained to understand the illnesses of patients, but they may not understand health hazards that are created or worsened by climate change. This adaptation strategy can help community members be treated effectively and efficiently to recover from climate-related effects. Operational Education, Outreach, Coordination Emergency Management Cities and Counties Public Health Departments  
Human Health Hazards

Strategy PH-8: Identify and remedy poor drainage areas to reduce disease risk from stagnant water.

Expand outreach programs to educate communities about potential increases in vector-borne diseases from stagnant water. Stagnant water provides a breeding ground for mosquitoes, which in turn can increase the risk of mosquito-borne pathogens such as West Nile virus. Stagnant water can develop in areas of poor drainage following flood events, creating a health risk in the vicinity. Communities can identify poorly drained areas and complete infrastructure improvements so that they drain properly. If infrastructure improvements are not feasible, communities can categorize these locations as needing mosquito-control efforts following a flood event. Communities can collaborate with local mosquito abatement districts to expand public education programs regarding preventative actions against vector-borne diseases that have the potential to occur in the future.

Local governments can work with local flood control districts and mosquito abatement districts to both identify poor drainage areas, implement abatement measures, and conduct community outreach. Outreach should focus on the most vulnerable populations and be presented in a culturally relevant manor in languages that are representative of the local demographic. Capital Improvement& Infrastructure Projects Education, Outreach, Coordination Programmatic Land Use and Community Development Water Biodiversity and Habitat Cities and Counties Mosquito Abatement Districts Flood Control Districts  

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