Climate Change and Human Health

## **Temperature-related impacts on human health** Changes in global temperatures significantly impact human health, leading to a rise in climate-related health effects. Both extreme heat and severe cold have direct and measurable effects on our bodies, and some communities are feeling it more than others. ### **Heat-related and cold-related deaths** Extreme heat has led to a growing number of hospitalizations and deaths, especially among older adults, children, and those with chronic illnesses. In 2021, for instance, an extreme heat wave in the Pacific Northwest led to hundreds of heat-related deaths across the US and Canada. Many victims were older adults, low-income individuals, or people living alone, underscoring how climate change amplifies existing health inequities (Mass et al., 2024). Prolonged heat exposure can trigger dehydration, heat stroke, and cardiovascular strain. At the same time, extreme cold continues to claim lives in regions that lack proper insulation, heating systems, or emergency support, especially during sudden cold snaps. ### **Air quality and respiratory health** Higher greenhouse gas emissions and rising carbon dioxide concentrations worsen air pollution, increasing respiratory diseases like asthma and chronic obstructive pulmonary disease (COPD). The World Health Organization warns that these health effects harm children and the elderly. ### **Mental health consequences** Extreme heatwaves, wildfires, and floods don't just damage homes; they take a toll on mental health, too. People exposed to these events often experience anxiety, depression, and posttraumatic stress disorder (PTSD). After Hurricane Katrina, for instance, serious psychological distress among survivors was noted, especially those displaced from their homes. ### **Water and food safety risks** Temperature changes affect food safety by increasing the spread of foodborne pathogens. Additionally, water-related illnesses rise due to contaminated water sources, threatening public health care.

## **Air quality impacts on human health** Poor air quality is one of the clearest signs of our changing climate, and one of the most dangerous. As we face more extreme weather events, rising temperatures, and higher emissions, the air we breathe becomes a vehicle for illness and long-term damage. ### **Respiratory diseases** Smog, wildfire smoke, and pollution from fossil fuels expose people to harmful particles that worsen asthma, COPD, and other respiratory illnesses. Children and older adults are especially vulnerable. During the record-breaking Canadian wildfires in 2023, cities across North America experienced air quality alerts that triggered spikes in ER visits due to breathing difficulties (Government of Canada, 2023). ### **Cardiovascular issues** Exposure to fine particulate matter harms the lungs, and it's also linked to high blood pressure, strokes, and heart attacks. Long-term exposure to air pollution increases the risk of cardiovascular events, especially during extreme heat events when pollution levels rise and blood vessels are already under strain. ### **Allergies and infectious diseases** Warmer temperatures and rising carbon dioxide concentrations contribute to longer pollen seasons, worsening allergy symptoms. Shifting climate change patterns also influence the spread of infectious diseases, such as vector-borne illnesses carried by mosquitoes and ticks. This increases the risk of infectious diseases like Lyme disease and West Nile virus, especially in areas previously unexposed and unprepared. ### **Mental health consequences** >When air pollution is driven by disasters like wildfires, it can even trigger PTSD in affected communities. Air pollution contributes to mental health conditions like anxiety and depression. Combined with the constant stress of climate risks, worsening air quality adds to a sense of unease, commonly referred to as climate anxiety. When air pollution is driven by disasters like wildfires, it can even trigger PTSD in affected communities. To manage these risks, public health systems are investing in early warning systems and education campaigns to help people respond more effectively to poor air quality days. The Fourth National Climate Assessment calls for action to reduce greenhouse gas emissions and protect public health from unanticipated health problems caused by climate change (USGCRP, 2018).

## **Extreme weather events and human health** Extreme weather events are among the most visible and destructive signs of climate change, and their toll on human health is growing. - Hurricanes, wildfires, floods, and heat waves, fueled by global warming, are causing more physical injuries and fatalities. Vulnerable groups, like older adults or individuals with mobility issues, are at higher risk during evacuations or prolonged exposure. - Rising sea levels and frequent disasters force communities to relocate, often cutting off access to hospitals, medications, and ongoing treatments. This disruption strains public health systems and delays urgent care. - Heat stress and polluted air during events like wildfires worsen chronic conditions such as asthma, diabetes, and heart disease. Prolonged exposure to heat can overwhelm the body's cooling system, leading to severe complications. - Droughts, floods, and storms affect crops and livestock, reducing food availability and quality. Malnutrition risks grow in lower-income regions and among children, adding long-term developmental consequences to the list of climate considerations. - After floods and hurricanes, water sources often become contaminated, driving outbreaks of cholera, E. coli, and other infectious diseases. Standing water and poor sanitation also support the spread of mosquito and rodent-borne illnesses. - Survivors of extreme events often experience long-term psychological impacts, including anxiety, depression, and PTSD. Communities repeatedly hit by disasters may suffer a collective erosion of safety and stability.

## **Infectious diseases and climate change** The climate crisis is reshaping how infectious diseases emerge and spread, creating urgent challenges for the health sector. As rising temperatures, shifting rainfall patterns, and severe weather events change environmental conditions, new regions are becoming hotspots for disease outbreaks. Mosquitoes and ticks are expanding into areas that were previously too cold for them to survive. This climate impact has fueled the spread of vector-borne diseases like Lyme disease, dengue, Zika, and malaria in parts of Europe and North America. These illnesses, once considered tropical, are now affecting communities unprepared to deal with them. Flooding events also increase the risk of waterborne illnesses such as cholera, giardiasis, and hepatitis A. Poor sanitation and contaminated water supplies put already vulnerable populations at greater risk, particularly those facing food insecurity and limited access to healthcare. Meanwhile, prolonged heat-related illnesses can weaken immune systems, making people more susceptible to infection. Health professionals play a crucial role in detecting and managing these risks. Surveillance systems, public education, and early intervention strategies are critical tools for limiting outbreaks. As climate conditions continue to shift, the healthcare system must be equipped to anticipate and respond to these evolving threats.

## **Food safety and nutrition impacts** The climate crisis is putting food security at risk. Changes in temperature, rainfall, and extreme weather events continue to disrupt agricultural systems, leading to reduced crop yields and worsening food insecurity. These disruptions have a direct climate impact on the availability of nutritious food, particularly in vulnerable communities. Warmer, more humid conditions also raise the risk of foodborne illnesses by helping bacteria spread more easily. This puts additional strain on the health sector as health professionals deal with rising cases of illness and undernutrition. Shifts in livestock health and fish populations also impact the quality of protein sources, making balanced diets harder to maintain. In some regions, heat-related illnesses and poor nutrition are already happening side by side.

## **Mental health impacts of climate change** The emotional toll of climate change is becoming harder to ignore. From intense weather events to long-term changes in daily life, people are experiencing stress, anxiety, nd even post-traumatic stress following displacement or disaster. These mental health effects can linger long after the event, especially in communities hit repeatedly by floods, wildfires, or drought. Certain groups, like first responders, farmers, and those working outdoors, face greater exposure and are more likely to deal with ongoing emotional strain. Climate anxiety is also on the rise, especially among younger generations concerned about the future. Research from Cambridge University Press highlights how climate events can increase the burden on health services, leading to greater demand for mental health care (Berry et al., 2010).

## **How can healthcare facilities help address these issues?** Healthcare facilities are on the front lines when it comes to protecting people from the effects of climate change. As temperatures rise, extreme weather and water-related events become more common, and clinics and hospitals need to adapt to keep delivering safe, reliable care. Here's how healthcare institutions can respond to how human health is affected by climate change and improve health outcomes: - **Improve energy efficiency:** Upgrading energy-efficient systems can reduce greenhouse gas emissions and lower operational costs. - **Strengthen emergency preparedness**: Developing response plans for extreme heat, infectious disease outbreaks, and air pollution events ensures continued patient care. - **Support community health programs**: Collaborating with local organizations helps improve climate resilience and access to care. - **Adopt sustainable practices**: Reducing waste, using green building materials, and investing in renewable energy help facilities meet the goals of forward-thinking climate policies while protecting patients.

## **Conclusion** The connection between climate change and human health is impossible to ignore. From respiratory illnesses and mental health conditions to food insecurity and disease outbreaks, the effects are widespread, and they're hitting developing countries and low-resource communities the hardest. As climate hazards grow more intense, healthcare systems must do more than treat symptoms. They must integrate climate planning into long-term care strategies. This means reinforcing social support structures, strengthening infrastructure, and improving preparedness for extreme events that often push communities deeper into extreme poverty. By staying informed, adapting services, and advocating for systemic change, health professionals and organizations can help lead the way in protecting people from the mounting health threats of climate change.

## **References** Berry, H. L., Bowen, K., & Kjellstrom, T. (2010). Climate change and mental health: a causal pathways framework. International Journal of Public Health, 55(2), 123–132. https://doi.org/10.1007/s00038-009-0112-0 Government of Canada (2023). Canada’s record-breaking wildfires in 2023: A fiery wake-up call - Natural Resources Canada. https://natural-resources.canada.ca/stories/simply-science/canada-s-record-breaking-wildfires-2023-fiery-wake-call Mass, C., Ovens, D., Christy, J., & Conrick, R. (2024). The Pacific Northwest Heat Wave of 25–30 June 2021: Synoptic/mesoscale conditions and climate perspective. Weather and Forecasting, 39(2), 275–291. https://doi.org/10.1175/waf-d-23-0154.1 U.S. Global Change Research Program. (2016). The impacts of climate change on human health in the United States: A scientific assessment. 1–312. https://health2016.globalchange.gov/