The South African agricultural sector is highly diverse in terms of its activities and socio-economic context. The agriculture sector employs approximately 860 000 people and is critical in terms of national food security as well as supporting thousands of urban and rural households in terms of subsistence agriculture and small scale production.

The sector is considered to be one of the most critical economic sectors in terms of potential impacts of climate change in South Africa. Agriculture is impacted directly by changes in precipitation, temperature and evaporation and through secondary impacts including disaster risk and health issues. The most significant climate change risks and vulnerabilities to agriculture in South Africa include increasing temperatures and more variable precipitation that are likely to have significant impact on a wide variety of crops and forestry products.

The yields of rain-fed crops such as maize, wheat and sorghum are likely to be affected most drastically, whilst irrigation demands projected to increase due to increased temperatures. Moreover, more extreme temperature events will directly impact farm labour through enhanced heat stress conditions. Livestock production will also be negatively affected under oppressive temperatures. Adaptation strategies in agriculture include the implantation of Climate Smart Agriculture, improved water management, improved monitoring and early warning, the development of knowledge and decision support systems, and the development of new crop varieties and technologies to support farming.

The interaction between climate change stressors, estuarine processes and features and biotic responses are complex, with multiple interactions which can both amplify and moderate responses. Analysis shows that KwaZulu-Natal and West Coast estuaries will be the most influenced by climate change from a structural and functional perspective.

This is contrary to the current monitoring programmes which are focusing on biotic responses in the biogeographic transition zones (e.g. the Transkei and western Southern Cape). In the case of KwaZulu-Natal the major driver of change is increased runoff into the numerous small, perched temporarily open/closed estuaries, which may result in more open mouth conditions, a decrease in retention time and a related decrease in primary productivity and nursery function. In contrast, west coast estuaries may be negatively impacted as a result of reduction in runoff, related decrease in nutrient supply and an increase in sea level rise.

This in turn may increase salinity penetration in permanently open estuaries and increase mouth closure in temporarily open ones. Similar to KwaZulu-Natal, west coast estuaries will experience a decline in primary production and loss of nursery function. Although Wild Coast, Eastern and southern Cape estuaries may show some shifts in mouth states, nutrient supply, salinity distribution and ultimately production (e.g. fisheries), the most likely impacts of climate change along these coastal regions will be the change in temperature (nearshore and land), associated species range expansions or contractions and changes in community structure.

South Africa exhibits multiple risks that contribute to the overall burden of disease (i.e. the quadruple burden of disease), which currently puts stress on the health sector. This stress may make the sector as a whole more vulnerable to climate change due to additional stress a changing climate may put on the system.

The challenging burden of disease in South Africa may make people more vulnerable to the health impacts from climate change (e.g. through pre-existing conditions). However, the impact of pre-existing conditions on the resultant health impact from climate change in South Africa is not quantified. There is a lack of understanding on the linkages between climate and health in South Africa (e.g. quantitative link between high temperatures and mortality). Thus, the current impact of climate-related diseases is not quantified, nor is the vulnerability of communities to such risks. Without a better understanding of the current health burden, it is not possible to understand how climate-sensitive health risks will change in a changing climate.

A quantitative vulnerability and risk assessment for the health sector should be performed; this would help to identify the most important health risks, as well as begin to identify the most vulnerable populations or communities. Adaptation strategies can then be tailored to region or communities based upon their risks and vulnerability. The South African health system is also vulnerable to the health status and disease burden of people from neighbouring countries. For example, a majority of malaria in South Africa is not from local transmission.

CLIMATE CHANGE IMPACTS ON HEALTH IN SOUTH AFRICA

The climate variability and change threats to terrestrial ecosystems include rising average temperatures, more temperature extremes, changes in rainfall intensity and magnitude, a higher likelihood of extreme events (such as droughts, floods, heat waves, etc.) throughout South Africa, shifting rainfall season, sea level rise and rising atmospheric concentrations of carbon dioxide (CO2).

In addition, non-climatic conditions such as changes in the occurrence, seasonality and severity of fire and land use change resulting from climate variability and change are also presented in this report. These threats vary in their importance between the biomes, increase over time through the 21st century, and increase with the level of greenhouse gas emissions globally.

Each of the settlement types (urban, informal settlements, rural and coastal) have variable vulnerability and exposure to the projected impacts of future climate changes. These variabilities are as a result of Apartheid legacy, spatial variabilities, planned and unplanned growth and dispersion patterns, topography and numerous socioeconomic factors.

Higher vulnerability and lower coping capacity areas will have increased risk exposure to climate related hazards; informal settlements and their population being the most exposed. A deficit in infrastructure and provision of services in some areas acts as barriers to adaptation and increases vulnerability to climate change.

This can be compounded by a lack of resources, unclear regulations and unexpected consequences resulting from previous mal-adaptation or poor development practices. Reducing capacity for necessary operation and maintenance is also contributing to the failure of critical infrastructure needed to mitigate the potential impacts and development risks associated with climate change.

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South Africa already suffers from high-risk hydrology, with high levels of variability in rainfall from year to year, resulting in frequent floods and droughts. As a water scarce country, the river systems and aquifers are highly used and developed, and many are already highly degraded. In addition to this scenario, there is extreme inequality in access to water for productive purposes, arising out of the apartheid legacy.

Under an unconstrained greenhouse gas emissions scenario, modelling results suggest a change in runoff that lies between a 20% reduction to a 60% increase. If global emissions are constrained the risk of extreme increases and reductions in runoff are sharply reduced, and the impacts lie between a 5% decrease and a 20% increase in annual runoff.

Climate change will affect water quality but in many areas the impacts may be masked by changes in land use, or compliance to effluent standards. Some of the impacts can be foreseen and can be mitigated by careful planning to include potential climate change in water quality management strategies.