We’ve heard a lot about climate change and its effect of rising CO2 levels on the environment, but what about the impact of the resulting climate change on human health? It is not surprising that climate change has already significantly impacted our health, with both direct and indirect effects. Without a concerted effort to slow and eventually reverse climate change, these impacts will only worsen. Let’s look at these health implications, focusing on the various pathways through which climate change affects our overall well-being.
The extreme temperatures that we are experiencing can trigger a variety of heat stress conditions, including dehydration and potentially fatal heat stroke. Many hospitals are reporting increased numbers of patients with heat related illnesses as well as cardiovascular and respiratory disorders due to the high temperatures that contribute to the build up of harmful air pollutants. This includes an increase in allergenic pollen production that triggers respiratory diseases such as asthma, allergies and other pulmonary diseases.
Vector-borne diseases are another example of a direct health effect. Vectors are living organisms that transmit infectious pathogens. Changes in temperature and rainfall patterns impact the distribution, behavior, and survival of disease carrying vectors like mosquitoes, ticks, and rodents. In turn, vector-borne diseases such as malaria, dengue fever, Lyme Disease, encephalitis and West Nile Virus are more widespread. Warmer summers and shorter winters extend the vector transmission season. Christopher Braden, M.D., the Acting Director of the Centers for Disease Control and Prevention (CDC) Center for Emerging and Infectious Zoonotic Diseases stated, “More Americans are at risk than ever before as mosquitoes and ticks are moving into new areas of the country, increasing cases and geographic ranges of vector-borne diseases”
Waterborne diseases are also increasing because of climate change. Extreme weather events (storms, droughts, precipitation, floods and wildfires), increases in local temperatures, and rising water temperatures, are variables that most influence waterborne diseases. High temperatures accelerate the growth and proliferation of pathogens in their habitats (like raw food or water). For example, a 1°C rise in temperature was associated with a two-fold increase in cholera cases in Zanzibar. Increased precipitation and flooding can cause clean water contamination from wastewater while droughts can increase the concentration of pathogens in water. A study in Bangladesh found that the number of cholera cases increased by 14% when rainfall increased by 10mm above the rainfall threshold.
Wildfires are an extreme weather event that not only affect our air quality but can also affect the quantity and quality of our water supply. During active burning, ash and contaminants settle on streams, lakes and water reservoirs. They disrupt the vegetation that prevent erosion. In the aftermath of wildfires this will cause flooding which will bring vast quantities of ash, sediment, nutrients and contaminants into streams, rivers, and downstream reservoirs.
Climate change negatively influences agricultural productivity, altering crop yields, nutritional content, and food availability. Changes in precipitation patterns, extreme weather events, and shifting pest and disease dynamics can lead to food shortages and malnutrition. This is especially true in vulnerable populations, such as in poorer socioeconomic regions. Low income communities and socioeconomically disadvantaged communities often lack the resources and infrastructure to adapt to and cope with climate change impacts. They face higher risks of exposure to extreme heat, air pollution, and inadequate housing conditions, exacerbating existing health disparities. Indigenous communities deeply connected to their local environments face unique health challenges as climate change disrupts their traditional ways of life, food systems, and cultural practices.
One example are communities that rely on fishing. Since fish need a specific habitat to thrive, rising water temperatures will significantly disrupt fresh water and ocean based fishing. As oceans warm, fish are moving elsewhere in search of suitable locations. These fish migrations are already having a negative effect on the fishing industry and costal communities.
It is well established that mental health can be impacted by climate change. This includes eco-anxiety (anxiety caused by the fear of environmental doom), depression, Post Traumatic Stress Disorder (PTSD), and increased social and economic stressors, which contribute to a decline in mental well-being and an increase in mental health disorders. Hospitalizations for psychiatric disorders and emergency psychiatric visits tend to increase during heatwaves. Rates of suicides have also been shown to be higher during heatwaves and are expected to increase with rising temperatures, although evidence on the link between heat and suicide remains mixed.
Rising sea levels, extreme weather events and environmental degradation can result in forced displacement and migration. Each year, natural disasters force an average of 21.5 million people from their homes around the world, according to the U.N. High Commissioner for Refugees. These population movements often lead to overcrowding, inadequate access to healthcare, increased exposure to infectious disease and mental health challenges.
Those most vulnerable to the negative health impacts of climate change are children and the elderly because their physiological and immune systems are less robust. They have limited adaptive capacity and they have a dependency on others for care. In addition to these factors, The National Council on Aging lists the unique circumstances that may make it more difficult for adults 60 and older to prepare for, respond to, or survive a climate change event. These include complex medical conditions, dependence on caregivers, agility and mobility limitations, cognitive impairments, dependence on medications and “social determinants of health” like economic security or substandard housing.
For children the adverse health implications of climate change are even more significant. Air pollution can harm a person’s health at any age, but children are particularly vulnerable because their organs are still developing, says Ruth Etzel, MD, PhD, a pediatrician, expert on children’s environmental health, and the editor of Pediatric Environmental Health. The American Academy of Pediatrics (AAP) affirms the association between air pollution and many pediatric diseases and advises healthcare providers to educate parents and communities about prevention and mitigation, as well as to advocate for policy change that will improve air quality.
The link between climate change and health is undeniable. The consequences of a warming planet are manifested through direct and indirect pathways affecting physical, mental, and social well-being. Tackling climate change is not only crucial for environmental sustainability but also a necessary step towards protecting human health. Urgent global action, including mitigation efforts to reduce greenhouse gas emissions and adaptation strategies to enhance resilience, is imperative to minimize the health impacts of climate change and create a healthier future for all.