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The damage caused by climate change doesn’t just stop with damage to the environment. Climate change also can cause significant damage to human health. Climate change directly and indirectly affects our health in several major ways. This includes, but is not limited to, illness and disease, mental health, resource disruption, and other conditions from natural hazards and extreme weather. The extent to which climate change affects human health varies widely across different communities, as some communities are more severely impacted due to socioeconomic factors.
The impacts of climate change on public health are expected to significantly increase in the coming decades. According to the World Health Organization, climate change is expected to cause approximately 250,000 additional deaths worldwide per year between 2030 and 2050 due to malnutrition, malaria, diarrhea, and heat stress. Most of these deaths are expected to happen in the Global South, but even prosperous northern hemisphere nations, such as the United States, will not be spared. Climate change-related deaths in the United States have largely been a result of extreme weather. According to the CDC, more than 11,000 Americans have died from exposure to heat since 1979. Overall, the damage caused by climate change will have fatal and costly impacts across the world.
Climate change results in more frequent extreme weather events, including extreme heat. Illness and death caused by extreme heat can occur after the body loses its ability to regulate its internal temperature or by worsening the effects of pre-existing health conditions. According to the Centers for Disease Control and Prevention, St. Louis, Philadelphia, Chicago, and Cincinnati are major U.S. cities in which heat wave death rates have significantly increased.
According to the 6th National Climate Risk Assessment: Hazardous Heat, which was published by the First Street Foundation in August 2022, the number of Health Caution Days — which is defined as feeling like a temperature of 90°F or higher, based on National Weather Service standards — in Philadelphia County, Pennsylvania is expected to increase by 18 days in 30 years. 51 Health Caution Days are expected in 2023 and 69 Health Caution Days are expected in 2053.
The 6th National Climate Risk Assessment: Hazardous Heat also states that the number of Health Caution Days in Hamilton County, in which Cincinnati, Ohio is located, is expected to increase by 21 days in 30 years. 56 Health Caution Days are expected in 2023 and 77 Health Caution Days are expected in 2053.
Climate change impacts the abundance and quality of resources that are necessary for survival, such as air, food, and water. Increased concentrations of ground-level ozone, an air pollutant found in smog, is harmful to respiratory health. Ground-level ozone is formed by chemical reactions between oxides of nitrogen and volatile organic compounds, and these reactions occur when pollutants mix with sunlight. Climate change also contributes to malnutrition because extreme weather conditions affect crop quality. This then makes it difficult for nutritious food to be evenly distributed, resulting in increased food insecurity.
According to a November 2021 NASA study published in Nature Food, high greenhouse gas emissions may result in a decline in maize crop yields and an increase in wheat crop yields by 2030. Lastly, climate change affects access to fresh water due to contamination from pathogens, harmful algae, cyanobacteria, and human-introduced chemicals, which can then result in water-related illnesses. According to a March 2022 University of California, Irvine research study that analyzed the 91 contaminants regulated by the Safe Drinking Water Act (SDWA), an average of 1.0 million people per year in the U.S. between 2000 and 2018 received water from systems that were noncompliant with health and safety regulations.
Higher temperatures and changes in precipitation patterns contribute to increased transmission of diarrheal diseases and waterborne illnesses. Diarrheal diseases, which include salmonellosis and campylobacteriosis, are prevalent in developing countries. Waterborne illnesses may pose a greater threat in the United States: for example, the Centers for Disease Control and Prevention predicts that the risks of waterborne illness will increase in the Great Lakes region. Climate change also increases the transmission of vector-borne diseases, such as Lyme, dengue fever, and West Nile virus.
For example, most Lyme Disease cases occur in the Northeast US, according to the Centers for Disease Control and Prevention. The Centers for Disease Control and Prevention also explained that climate change is helping Lyme Disease spread because the changes in temperature, precipitation, and humidity allow for greater survival rates of disease-carrying ticks. Specifically, more ticks are “overwintering” and not dying during milder winter months.
Extreme weather events and disasters can negatively affect mental health. According to the Centers for Disease Control and Prevention, floods, heat waves, and wildfires can significantly increase levels of anxiety and stress, including post-traumatic stress disorder. Heat waves are also a health risk to those with depression, dementia, and schizophrenia. Medication for schizophrenia and other severe mental illnesses can affect temperature regulation. Lastly, awareness of the harmful impacts of environmental degradation can cause distress and despair, regardless of previous mental health history.
Although it’s evident that climate change has numerous effects on physical and mental health, these effects are much more prevalent in certain populations. According to the Centers for Disease Control and Prevention, the following groups are at a higher risk of climate vulnerability: low-income individuals, some communities of color, immigrant groups, Indigenous peoples, children and pregnant women, older adults, vulnerable occupation groups, persons with disabilities, and persons with preexisting or chronic medical conditions.
AreaHub’s Knowledge Center is updated regularly and provides information drawing upon scientific studies and sources.
The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment
CDC: Justice, Equity, Diversity, and Inclusion in Climate Adaptation Planning
Global Climate Change Impact on Crops Expected Within 10 Years, NASA Study Finds
Climate impacts on global agriculture emerge earlier in new generation of climate and crop models
Climate Change Increases the Number and Geographic Range of Disease-Carrying Insects and Ticks