Human Health Impacts of Climate Change

Human Health Impacts of Climate Change

Climate change can affect our health in many ways, including more intense heat waves and wildfires, and worsening the impacts of air pollution. For over a decade, OEHHA has conducted studies on health impacts of climate change, in collaboration with a wide range of academic, state, and nonprofit partners. This page provides links to these scientific publications. 

 As heat rises, so do the chances of experiencing climate-related health impacts

OEHHA studies have focused on the health impacts of climate change in the general population, and identified high-risk, vulnerable population subgroups, for example, the elderly, children, people with existing health conditions, pregnant individuals, people who live in coastal areas who are less acclimated to heat, and people from disadvantaged communities. Our findings highlight disparities in climate change’s impacts and help California get public health information and other resources to the most vulnerable communities.

OEHHA also investigates the health impacts of wildfires. We identified increased adverse health outcomes, like respiratory and cardiovascular diseases, after wildfire smoke exposure. Some of our studies also indicate that the co-exposure of heat and wildfire smoke could pose an increased risk to human health. Our research indicates a need for improved health mitigation strategies during wildfire events. It also helps inform air pollution guidance recommendations.

Health Effects of Heat Exposure

Heat waves, as well as high ambient temperatures that do not get recorded as heat waves, appear to increase mortality.

Also, increased ambient temperatures have been linked to increased hospitalization and emergency room (ER) admissions for many outcomes, including dehydration and heat illness as well as intestinal infection, acute renal failure, diabetes, hypotension, cardiac dysrhythmia, ischemic heart disease, and even mental health issues.

Further, high ambient temperature is associated with adverse birth outcomes such as preterm delivery, stillbirth, and term low birth weight. Greater risks were observed for mothers who were younger, Black, Hispanic, underweight, smoked, consumed alcohol during pregnancy, or had pre-existing health conditions. These impacts on public health are expected to worsen with projected future increases in temperature.

Pregnant individuals and children can be more vulnerable to health impacts from heat and climate change

OEHHA has other resources that inform actions to protect Californians’ health from the impacts of heat. Learn more about:

  • CalHeatScore, a tool to raise public awareness about dangerous heat waves affecting the state.
  • Children’s Environmental Health Center and Air and Climate Epidemiology section with fact sheets with helpful tips for pregnant people and kids to stay safe when it’s hot out.

OEHHA’s publications on the health effects of heat exposure are listed below.

Heat and Mortality

Heat and Morbidity

Heat and Birth Outcomes

OEHHA studies found relationships between wildfire smoke and various adverse health outcomes

Wildfire Smoke Exposure and Health Effects

Wildfire smoke exposure is associated with not only respiratory disease and asthma but also cardiovascular impacts and mental health impacts, for example, schizophrenia. Pregnant individuals have higher risks of pre-term birth during co-occurring heat and wildfire smoke events.

Additional OEHHA work related to wildfires can be found on the OEHHA Wildfires website.

Climate Change and Infectious Diseases

As the warm season extends and weather patterns shift, viruses become more active and have increased opportunities to spread, leading to a rise in the incidence and prevalence of certain infectious diseases.