Mandela Washington Fellow and Public Health Specialist
Article made in submission of the Green Week and Climate Online Campaign
Climate change, also called global warming, refers to the rise in average surface temperatures on Earth. The gases trap heat within the atmosphere, which can have a range of effects on ecosystems, including rising sea levels, severe weather events, and droughts that render landscapes more susceptible to wildfires.1 Climate change affects the social and environmental determinants of health – clean air, safe drinking water, sufficient food and secure shelter. Between 2030 and 2050, climate change is expected to cause approximately 250 000 additional deaths per year, from malnutrition, malaria, diarrhea and heat stress.2 According to World Health Organization (WHO), the direct damage costs to health (i.e. excluding costs in health-determining sectors such as agriculture and water and sanitation), is estimated to be between US$ 2-4 billion/year by 2030. 2 Addressing the effects of climate change on human health is especially challenging because both the surrounding environment and the decisions that people make influence health. 3 Categories of human health consequences of climate change
- Asthma, Respiratory Allergies, and Airway Diseases
- Cardiovascular Disease and Stroke
- Foodborne Diseases and Nutrition
- Heat-Related Morbidity and Mortality
- Human Developmental Effects
- Mental Health and Stress-Related Disorders
- Neurological Diseases and Disorders
- Vector borne and Zoonotic Diseases
- Waterborne Diseases
- Weather-Related Morbidity and Mortality
Climate change has the potential to impact airway diseases by increasing ground level ozone and possibly fine particle concentrations. Breathing ozone can trigger a variety of reactions including chest pain, coughing, throat irritation, and congestion; and can worsen bronchitis, emphysema, and asthma. Exposure to ground-level ozone can also reduce lung function and inflame the linings of the lungs; repeated exposure may permanently scar lung tissue. Cancer refers to a group of diseases in which abnormal cells divide without control and are able to invade other tissues.
One possible direct impact of climate change on cancer may be through increases in exposure to toxic chemicals that are known or suspected to cause cancer following heavy rainfall and by increased volatilization of chemicals under conditions of increased temperature. In the case of heavy rainfall or flooding, there may be an increase in leaching of toxic chemicals and heavy metals from storage sites and increased contamination of water with runoff containing persistent chemicals that are already in the environment. Another direct effect of climate change, depletion of stratospheric ozone, will result in increased ultraviolet (UV) radiation exposure.
UV radiation exposure increases the risk of skin cancers and cataracts. Cardiovascular disease refers to a class of diseases that pertain to the heart or blood vessels. There is evidence of climate sensitivity for several cardiovascular diseases, with both extreme cold and extreme heat directly affecting the incidence of hospital admissions for chest pain, acute coronary syndrome, stroke, and variations in cardiac dysrhythmias, though the reported magnitude of the exposure-outcome associations is variable.
Indirect impacts of weather, weather variability, and climate changes on cardiovascular disease are many and varied. Associations between air quality, especially ozone and particulate burdens, and cardiovascular disease appear to be modified by weather and climate. Nutrition is the sum of the processes by which humans and other living organisms take in food and use it for growth and nourishment. Along with clean air, water, and shelter, nutritious food is a basic necessity of life. Failure to obtain sufficient calories and an adequate mixture of macronutrients (calories, fat, proteins, and carbohydrates), micronutrients (vitamins, minerals) and other bioactive components of food can result in illness and death.
Indirectly, there is potential for harm from undernutrition or even famine resulting from damage to agricultural crops and related trade, economic, and social instability; diversion of staple crops for use in biofuels (corn for ethanol or other biofuels); changes in agricultural practices including those intended to mitigate or adapt to climate change; impaired ability to grow crops due to changing environmental conditions and water availability; and reduced availability and nutritional quality of protein from fisheries, aquaculture, and other marine-based foods.
Drought has been shown to encourage crop pests such as aphids, locusts, and whiteflies, as well as the spread of the mold Aspergillus flavus that produces aflatoxin, a substance that may contribute to the development of liver cancer in people who eat contaminated corn and nuts. The health outcomes of prolonged heat exposure include heat exhaustion, heat cramps, heat stroke, and death. Vectorborne and zoonotic diseases (VBZD) are infectious diseases whose transmission cycles involve animal hosts or vectors.
Climate is one of several factors that influence the distribution of vectorborne and zoonotic diseases (VBZD) such as Lyme disease, Hantavirus, West Nile virus, and malaria. There is substantial concern that climate change will make certain environments more suitable for some VBZD, worsening their already significant global burden and potentially reintroducing some diseases into geographic areas where they had been previously eradicated. Waterborne diseases are caused by a wide variety of pathogenic microorganisms, bio-toxins, and toxic contaminants found in the water we drink, clean with, play in, and are exposed to through other less direct pathways such as cooling systems. Climate change is expected to raise overall temperature distribution and contribute to an increase in the frequency of extreme heat events, or heat waves. Temperature, particularly temperature extremes, is associated with a wide range of health impacts.
It is essential that people should invest in their own health to mitigate the health impacts and consequences of climate change by taking the following actions:
- Endeavour to plant a tree around your vicinity to improve afforestation
- Avoid use of substances that produce bio-fuels and gasses as much as possible like charcoals, fire wood etc.
- Avoid indiscriminate burning of materials (e.g. old used tyres) that releases toxic gases to the atmosphere to preserve the ozone layer
- Avoid indiscriminate and unauthorized bush burning which usually releases toxic gases that damages the ozone layer.
- Avoid unauthorized tree cutting (deforestation)
- Avoid illegal mining of petroleum products and other resources that causes chemical spillage and poisoning
There is abundant evidence that human activities are altering the earth’s climate and that climate change will have significant health impacts both domestically and globally. Some degree of climate change is unavoidable, and we must adapt to its associated health effects; however, aggressive mitigation actions can significantly blunt the worst of the expected exposures.