Climate change refers to significant long-term shifts in Earth’s average temperatures and weather patterns. These include warming, altered precipitation, rising sea levels, and shrinking glaciers. While natural factors cause some shifts, human activities, primarily burning fossil fuels, have been the main driver since the 1800s. These actions release greenhouse gases that trap heat, leading to a warmer planet.
Direct Physical Health Impacts
Rising global temperatures directly contribute to heat-related illnesses. Heat exhaustion and heatstroke become more common and severe during heatwaves. Prolonged exposure to high temperatures can also worsen existing conditions like cardiovascular, respiratory, and kidney diseases. For instance, a 2003 heatwave in Europe was linked to over 40,000 deaths.
Extreme weather events result in injuries and fatalities. Floods, severe storms, droughts, and wildfires cause immediate harm, including drownings and physical trauma. Wildfires, for example, can also lead to carbon monoxide poisoning. Vulnerable populations, such as the elderly, often face higher risks during these events.
Changes in air quality also affect respiratory health. Increased temperatures and altered weather patterns can worsen air pollution, including ground-level ozone and particulate matter from wildfires and dust storms, exacerbating conditions like asthma and chronic obstructive pulmonary disease (COPD). Warmer temperatures can also shift pollen seasons, prolonging and intensifying allergy symptoms. Poor air quality is associated with risks such as heart and lung diseases, and even some cancers.
Changing Patterns of Infectious Diseases
Climate change alters the spread and prevalence of infectious diseases by influencing their environments. Warmer temperatures and changing precipitation patterns create more favorable conditions for disease vectors like mosquitoes and ticks. This leads to an expansion of their geographic range and increased activity, abundance, and longevity. Consequently, vector-borne diseases such as malaria, dengue fever, Zika virus, and Lyme disease are emerging or re-emerging in regions where they were previously uncommon.
Mosquito-borne diseases like malaria and dengue are highly affected by climate change. Higher temperatures can accelerate mosquito life cycles, such as Anopheles (malaria) and Aedes (dengue, Zika), and pathogen development within them. Increased rainfall creates more mosquito breeding sites, further spreading diseases. For example, malaria transmission has increased in highland areas previously too cold for the Anopheles mosquito.
Water-borne diseases are also affected. Increased flooding and extreme rainfall events can contaminate drinking water sources with sewage and other waste products, even in areas with treated water systems. This contamination can lead to outbreaks of diarrheal diseases caused by pathogens like Vibrio cholerae (cholera), Giardia lamblia (giardiasis), and Cryptosporidium species (cryptosporidiosis). Both heavy rainfall and dry periods have been linked to diarrheal disease outbreaks, as dry periods can concentrate pathogens and precipitation can mobilize them into water supplies.
Food-borne diseases are also influenced by rising temperatures. Warmer conditions can accelerate the growth of bacteria such as Salmonella, Campylobacter, and Escherichia coli in perishable foods like meat, dairy, and produce. For example, studies show Salmonella multiplies faster between 35°C and 37°C. Increased humidity can also promote Salmonella growth on raw produce like lettuce. This increases the risk of food spoilage and outbreaks of foodborne illnesses.
Climate Change’s Influence on Nutrition and Mental Well-being
Climate change significantly impacts food and water security, leading to consequences for nutrition. Erratic weather patterns, including prolonged droughts, intense heatwaves, and severe floods, directly affect agricultural yields and livestock productivity. These disruptions contribute to lower food availability, reduced nutritional quality of staple crops like wheat and rice, and increased food prices, making healthy diets less affordable for vulnerable populations. Water scarcity further compromises hygiene and health, increasing susceptibility to various illnesses.
The mental well-being of individuals and communities is also significantly affected. Exposure to extreme weather events can lead to direct psychological trauma, resulting in conditions such as post-traumatic stress disorder (PTSD). The ongoing threat of environmental degradation, including loss of biodiversity and changes to familiar landscapes, can evoke feelings of sadness, anxiety, and helplessness, often termed eco-grief or climate anxiety. Young people, in particular, may experience heightened levels of climate anxiety due to concerns about their future.
Beyond acute events, broader impacts, such as displacement from homes due to sea-level rise or repeated natural disasters, contribute to chronic stress, depression, and a loss of personal and community identity. These stressors can strain social relationships and lead to feelings of powerlessness or fatalism. The interconnectedness of physical and mental health means that compromised physical well-being can further exacerbate psychological distress.