According, to the (Department of Environment Affairs,2013) climate change impacts on human health are very complex and are embodied by many cause and effective pathways, interactions and linkages. Furthermore, South Africa is facing difficult public health challenges which are intensified by negative socio-economic conditions such as packed informal settlements with very little or poor service delivery. In addition, climate change in South Africa is bringing about aggravated health risks for example; heat stress, vector-borne diseases (such as malaria, dengue fever and yellow fever), extreme weather events, air pollution and communicable diseases (such as HIV/AIDS, TB and cholera) as well as non-communicable diseases (such as cardio-vascular and respiratory diseases). Moreover, climate change could also have impacts on mental and occupational health thus; all these adverse impacts could be worsened by food insecurity, hunger and malnutrition usually from the agricultural sector bad due to unseasonal drought as well as changes in ecosystems (Department of Environment Affairs, 2013).
Therefore, these health impacts that arise from climate change could result from direct exposures, such as extreme temperature and precipitation, storms, cyclones and other extreme weather events and indirect exposures from worsening air pollution and increasing pollen production. In addition, the changing climate could also lead to a change in the distribution vectors of diseases (Department of Environment Affairs, 2016). Moreover the impacts that climate change will have on human health in South Africa are currently not well quantified however; indications show that the Southern African region of the World will be the most impacted by it (Department of Environment Affairs, 2016). Hence, a study by the World Health Organisation (WHO) has quantified the impact that climate change has on human health by modelling the health impact that four climate-sensitive health risks (diarrhoea, malaria, inland and coastal flooding, and malnutrition) had in the year 2000 compared it with the impact of 1990. Although, this model looked at only a few of the climate change impacts it showed that Southern Africa is a region with the largest mortality rates due to climate change. Thus, it is crucial for South Africa to understand the potential size of the health impacts of climate change, look at which areas and communities may be most vulnerable to these impacts and what adaptation measures are needed to mitigate an increase in these negative health impacts. In addition, would be wise to look at these health impacts individually and understand them (Department of Environment Affairs, 2016).
Firstly, there is little known information about the health impacts of high temperatures on the South African population although; there is unscientifically evidence of direct health impacts due to extreme heat. Thus, the increase in average temperatures and extreme events such as heat waves are seen to bring about heat stress, increase morbidity, and cause respiratory and cardiovascular diseases. In addition, susceptibility to heat stress depends on existing health status as well as socio-economic and environmental factors (Department of Environment Affairs, 2016).
Secondly, Mosquitos and Ticks are vectors for many diseases in South Africa and their numbers are usually affected by climatic and non-climatic factors for example; the increase in mosquito populations which is proportionally to rainfall. Thus, climate change induced changes in rainfall could also change the distribution of these vectors and may change the distribution of diseases like malaria and Lyme disease. In addition, there is little knowledge about which vectors will be more responsive to climate change impacts. For example, climate is known to affect malaria transmission but the impacts have not been fully understood as yet. Thus, Malaria is expected to impact areas where it is assumed to be too cold for transmission (Department of Environment Affairs, 2016).
Thirdly, climate change is predicted to increase the frequency, duration and intensity of droughts and high temperatures as well as perception variations in many areas. This is going to affect food systems, compromising food availability, access and utilisation, leading to food insecurity. This is all due, to the unknown rainfall projections from climate change and could result in area such as the Western and Northern Cape becoming drier and the central and eastern plateau and the Drakensberg area of South Africa get unusual and unexpected precipitation. Moreover, a change in precipitation distribution like this could reduce crop yields more especially when temperatures become hotter furthermore; leading to food shortages and potential increases in food prices thus; hindering food accessibility for some households and lead to malnutrition (Department of Environment Affairs, 2016).
Fourthly, the occurrence and strength of extreme weather events are likely to increase in some parts of South Africa due to climate change. The increased extreme weather event will cause floods and storms, droughts and fires since, theses impacts are hard to predict and compute due to secondary effects and delayed outcomes the have a number of possible health impacts. For example, the spread of water related diseases that are more prevalent in communities with limited social services and support mechanisms (Department of Environment Affairs, 2016).
Fifthly, air pollutants, particulate matter, sulphur dioxide, ozone, carbon monoxide, benzene, lead and nitrogen dioxide, are concerning to public health, and their concentration in the atmosphere is regulated in South Africa. Furthermore, climate change will influence the concentration of air pollutants by affecting weather patterns which is due to meteorological factors such as temperature, precipitation, clouds, atmospheric water vapour, wind speed, and wind direction influencing atmospheric chemical processes. Therefore, South Africa will experience health impacts from pollutants that will result in eye irritation, acute respiratory infection, chronic respiratory diseases and TB, and sometimes death (Department of Environment Affairs, 2016).
Sixthly, climate change will impact non-communicable diseases directly for example; by increasing temperatures and air pollution concentrations and indirectly by adversely impacting agricultural yields resulting in food insecurity. Moreover, it is know that Non-communicable diseases like cardiovascular and respiratory diseases such as asthma and bronchitis are the leading cause of death in South Africa (Department of Environment Affairs, 2016).
Seventhly, Communicable diseases, such as TB and cholera, result from infecting a host and usually transmission is due to direct contact with an infectious person, contaminated foods, beverages or body fluids, or being bitten by an infected animal host. Thus, climate plays a major part in the size and age composition of host populations and the distribution of these diseases. In addition, common climatic factors related to the spread of communicable diseases are rainfall, temperature and wind (Department of Environment Affairs, 2016).
Eighthly, climate change could disrupt social and biophysical support systems by, for example, displacing communities, destroying homes and resulting in loss of life and result in serious implications for mental health and human well-being. Hence, acute climate events such as high temperatures and heat waves have been associated with diminishing mental capacity and increased hospital admissions for mental disorders, mood disorders, somatoform disorders which are mental symptoms suggesting physical illness or injury, senility and psychological development disorders. Furthermore, due to extreme weather events some areas may be render temporarily uninhabitable and unproductive and cause environmental distress and a disturbed sense of place. In addition, this could worsen mental health through increased anxiety, apathy, helplessness, depression and chronic psychological distress. Finally, occupational health impacts like heat stress, dehydration and injuries sustained while at the workplace could be increased by climate change. For example, temperature a common climatic factor that affects occupational health could slow down an agricultural labourer’s productivity by causing heat stress and dehydration (Department of Environment Affairs, 2016).