It is anticipated that in the hotter, wetter and drier South Africa of the future, many things will go wrong.

Water sources will evaporate.

Malaria, yellow fever and dengue fever will thrive.

Extreme weather and malnutrition could potentially cripple vulnerable communities.

Some animal and plant species could vanish, possibly forever.

These are the reasons why Dr Belinda Reyers believes preparing for climate change and reducing our vulnerability to its impacts is “possibly the most important societal priority facing us now”.

Reyers, of the natural resources and environment unit at the Council for Scientific and Industrial Research (CSIR), was commenting on this week’s release of the Long-term Adaptation Scenarios (LTAS) Phase One reports by the Department of Environmental Affairs.

These documents sketchthe broad range of impacts that projected changes in temperature, rainfall and extreme events such as floods and storms will unleash on water resources, biodiversity, health and agriculture.

The LTAS has been divided into two phases to build the “fundamental knowledge base” about climate change impacts and adaptation options in key sectors to guide policymakers towards a “climate resilient” future economy and society.

The reports note how climate change projections up to 2050 and beyond project warming as high as 5 to 8º Celsius over the South African interior, and somewhat less over the coastal regions, under an unmitigated global emissions scenario.

“A general pattern of a risk of drier conditions to the west and south of the country, and a risk of wetter conditions over the east of the country has been projected, but many of the protected changes are within the range of historical natural variability.”

Under both climate futures, there are significant consequences.

“These implications would largely be felt through impacts on water resources and a higher frequency of natural disasters, flooding and drought; with… effects on human settlements, disaster risk management and food security.”

The reports outline how potential health impacts may result from direct exposures, such as extreme temperature and precipitation, storms, cyclones, and indirect exposures such as worsening air pollution and increasing production of pollen.

Extreme heat could cause heat waves, while diseases like malaria are projected to spread within regions bordering current malarial areas and the transmission of cholera, linked to rainfall and temperature is likely to be affected by climate change.

More floods could cause the spread of water-related diseases such as cholera and will be “more prevalent in communities with limited social services and support mechanisms”.

Climate change will increase the frequency and intensity of drought, leading to food insecurity. By increasing temperatures and air pollution concentrations it could lead to more asthma and bronchitis, for example, already a leading cause of death in the country.

Less irrigation and drinking water could be available due to increasing water temperatures linked to higher ambient temperatures, which will also cause waterborne diseases to incubate and thrive.