This indicator measures the projected number of extreme heat days annually for 2050 and 2085. The term “extreme heat” refers to the weather being  hotter than 98% of historic temperatures at a given location. For more information, see: The California Department of Public Health’s California Building Resilience Against Climate Effects (CalBRACE) Extreme Heat Narrative.

Our homes, neighborhoods and jobs should help protect us from heat-related health impacts. When temperatures are extremely high, especially for extended periods, people can experience heat-related illnesses such as heat stress, heat exhaustion, and heat stroke, which if not promptly and properly treated can be fatal. High heat can also make pre-existing cardiovascular, respiratory and other conditions worse. This is especially true for people like children and older adults. Heat events can be particularly intense in cities where buildings, pavement, and other dark surfaces capture heat in what is known as the “heat-island effect” where temperatures can be up to 22°F higher than in surrounding areas.¹³⁵ Communities of color and low-income communities tend to be disproportionately exposed to the heat-island effect due to historic disinvestment in parks, shade trees, and other cooling elements. High heat can also intensify air pollution like smog and particulate matter.¹³⁶

Addressing the health impacts of Extreme Heat requires a range of measures designed to prepare communities and households for extreme heat and to increase resilience.⁶⁹

Plan for Resilience

Assess Vulnerabilities

Legislation enacted in 2015 (SB 379) requires California jurisdictions to conduct vulnerability assessments and define resiliency goals, policies, and objectives in either the safety element of their General Plan, or by incorporating it in local hazard mitigation planning. Local jurisdictions can reduce the health impacts of extreme heat by using these planning processes to understand likely climate changes and impacts, assess vulnerability, and craft interventions. The State of California has developed the Adaptation Planning Guide, a step-by-step guide for local governments, and the U.S. Centers for Disease Control and Prevention’s Building Resilience Against Climate Effects (BRACE) Framework offers guidance for health agencies and others seeking to address the health effects of climate change.

Assessing vulnerability to climate impacts is a particularly important step in resilience planning. While climate change impacts all Californians, some individuals and families are more impacted, and have fewer resources to draw upon to help them adapt. The health impacts of climate change often deepen existing social inequities—magnifying or layering new risks on top of economic, social, environmental, biological, and health disparities.. Using the BRACE framework, the California Department of Public Health has produced Climate Change and Health Profile Reports, summarizing health risks and vulnerability by county. They have also published Climate Change and Health Vulnerability Indicators to help local jurisdictions understand climate change and health vulnerability. The Healthy Places Index Can also be used to assess underlying social vulnerabilities at the census tract level.

Maximize Health Benefits

Actions designed to improve climate resilience also provide the opportunity to maximize additional health or quality of life benefits that can be achieved in addition to increased resilience. Extreme heat adaptation measures create several opportunities for additional benefits. For instance, weatherization programs can help reduce asthma triggers and improve indoor air quality, protect residents from extreme heat, provide job training opportunities, and save residents money; urban greening and cooling measures can also provide opportunities for healthy recreation and transportation and manage wastewater; and fostering community power and connection can prepare residents to participate and respond to a range of other planning processes and emergency situations. Local governments should prioritize interventions that minimize risk in low-income communities or communities of color, while maximizing benefits that support healthier community conditions.

Ensure Participation

Resilience efforts should prioritize the participation of community members in each step of the process. This will help ensure that community standards, expectations and requirements are effectively addressed, while building buy-in and support for resilience measures, and improving community capacity to envision and address climate impacts. For more information, see: The California Department of Public Health’s Climate Action for Health, and the Urban Sustainability Directors Network’s Equitable, Community Driven Climate Preparedness Planning.

Policy Actions

Local governments have many tools they can use to increase resilience to extreme heat. In the short term, they should make sure they are Getting Ready, by reviewing and improving emergency response plans and systems to warn and protect residents during extreme heat events. When heat events strike, jurisdictions should have effective and targeted Emergency Response systems in place. Jurisdictions can also help their residents become Heat Resilient Households through home weatherization, air conditioning, education and other programs.

In the longer term, governments can create Cool Communities by prioritizing cool infrastructure and recreation facilities, Green Communities that provide shade, mitigate heat-island effects, and manage storm water, and Smart Growth to reduce paved surfaces and vehicle miles traveled. Jurisdictions should help foster Community Power and Connection which has been shown to reduce social vulnerability and the health impacts of climate events.

Although climate resilience actions tend to save money in the long term, some come with a high immediate cost. Several funding sources and technical assistance programs can support local government efforts to improve resilience. For more information, see: The U.S. Climate Resilience Toolkit’s Funding Opportunities Page, and the Federal Emergency Management Agency‘s Hazard Mitigation Grant Program.