Climate change could force redesign of SA’s farming regions – ARC

Climate change impacts farming regions

As temperatures rise and rainfall patterns become less predictable, some of South Africa’s established farming areas may become less suitable for the crops they currently support. New research suggests that carefully shifting production towards emerging suitable areas could deliver economic, employment and food-security benefits, but the right decision will differ from crop to crop.

A maize field, wheat farm or citrus orchard cannot simply pack up and move when the climate changes. Yet, over the coming decades, South African agriculture may have to reconsider not only how crops are produced, but also where they are produced.

Rising temperatures, changing rainfall patterns, water stress and more frequent extreme weather events are already increasing uncertainty for farmers. A production area that has supported a crop for generations may not offer the same growing conditions in 2055 or 2080.

This raises a difficult but increasingly urgent question: would it make economic sense to gradually shift some agricultural production towards areas that are expected to remain suitable or become more suitable under a changing climate?

Modelling potential shifts in production

A study by researchers from the Agricultural Research Council examined this question for six important South African commodities: maize, wheat, sorghum, citrus, avocado and macadamia nuts. The study combined climate and crop-suitability modelling with a cost-benefit analysis.

In simple terms, it compared the long-term value that could be created by moving a portion of production with the costs of establishing and operating farms in new areas. The results offer both encouragement and a warning. Shifting production can be a worthwhile climate-adaptation strategy, but its feasibility depends on each crop’s climate requirements, water needs, production cycle, infrastructure requirements and market prospects.

Moving production does not mean abandoning South Africa’s established farming regions overnight. It means planning a gradual transition as climate suitability changes.

The study modelled a hypothetical scenario in which 10% of the current production area for each crop shifts towards newly suitable agroecological zones. The 10% is a modelling assumption used to test the potential economics of adaptation; it is not a recommendation that 10% of national production should be relocated.

Economic returns and crop specifics

The researchers used a measure called the benefit–cost ratio, or BCR. A BCR above 1 means that the estimated benefits are greater than the costs. A ratio of 1.50, for example, means that every R1 invested is expected to generate about R1.50 in wider economic and social benefits.

The study did not look only at income earned by farmers. It also considered broader benefits such as food security, employment and export earnings. Under the study’s central estimates, maize and citrus produced some of the strongest returns, with benefit–cost ratios of about 1.50. Sorghum also performed well, with a ratio of approximately 1.41.

These findings matter because the crops play very different roles in the economy. Maize is central to South African food security, livestock feed and agricultural processing. Citrus is a major export earner and supports many jobs in rural communities. Protecting these industries from future climate risks would therefore have benefits far beyond the farm gate.

However, high-value crops are not automatically the safest adaptation investments.

Avocado and macadamia orchards require substantial establishment expenditure and take several years to reach full production. This creates a long period between the initial investment and the expected return. It also leaves producers exposed to future changes in water availability, temperatures, input costs, export prices and market access.

The lesson is clear: a crop may have a high market value and still carry considerable long-term adaptation risk.

Sorghum is a much smaller industry than maize or wheat, but its ability to tolerate heat, drought and unreliable rainfall gives it strategic value in a changing climate. In the study, sorghum remained comparatively resilient under severe climate conditions, even as the outlook for several other crops weakened.

Planning for future agricultural resilience

The modelling shows that the economic outlook generally becomes more difficult as climate change intensifies towards the middle and end of the century.

Under a high-emissions future, projected yields decline sharply for several crops. Maize, citrus, avocado and macadamia are particularly exposed to combinations of heat and water stress, while long-lived orchards face the additional risk that conditions may change substantially during the productive life of the trees.

This is why adaptation decisions cannot be based only on current growing conditions. An orchard planted today may still be producing decades from now. Infrastructure such as irrigation systems, packhouses, roads and storage facilities also represents a long-term commitment. If these investments are made without considering future climate suitability, producers and government may lock themselves into increasingly risky locations.

South Africa needs a practical crop-suitability monitoring system that is updated regularly as new climate, soil, water and production information becomes available. Such a system could help farmers, financiers and government identify where risks are increasing and where new opportunities may emerge. It could also guide land-use planning, infrastructure investment, agricultural finance, insurance and extension support.

Climate change adds another layer of pressure, but it also strengthens the case for better information and earlier planning. The study shows that moving some production towards more suitable areas could generate meaningful economic and social returns. It could protect food supplies, sustain rural jobs and help important export industries remain competitive.