How climate change impacts food security in South Africa
South Africa has not been spared the agricultural challenges faced by a growing number of countries. Following a poor harvest in 2024, the country has seen a significant rise in grain prices.
This is just one of many examples of the vulnerability of the agricultural sector to the effects of climate change. Experts predict that it will be one of the hardest hit by these changes.
We spoke to Oliver Wood, a medical entomologist at Envu South Africa, to find out about the tangible effects of climate change on food security and grain protection.
How is climate change impacting food security and grain?
O.W. “In the future, we can expect to see more extreme weather. Regions that have experienced drought are likely to become even drier, while warm and humid areas will become hotter and wetter. This, in turn, will require us to change the geographical locations where we grow different types of grains. Growing areas will move closer to the poles. All this means much greater unpredictability in harvests.
Climate change will affect not only the quantity but also the quality of grain. The composition of grain is also likely to change, resulting in different protein and starch levels in different crops, depending on the weather conditions in each region.
Many things happen in the pre-harvest stage that affect post-harvest results. |
In certain regions, excessive drying can cause grain to crack and become more fragile, making it susceptible to insect infestation. On the other hand, warmer temperatures can increase humidity, meaning more fungi could grow on the grain.”
How does climate change impact pests?
O.W. “High temperatures will increase the metabolic rate of insects, leading to faster growth and an increased number of generations.
Climate change will also affect the distribution of insects in different regions, with some species moving from the equator to the poles. In South Africa, we could get species from Brazil, or we could get some from Australia that would then migrate up. It's uncertain at the moment because there are still gaps in the research that need to be addressed.
However, not all insects will be affected in the same way. For instance, the lesser grain borer and the confused flour beetle have adapted well to different climates around the world. Beetles in general are adept at surviving in dry conditions because their wings allow them to draw moisture from the air.
The challenge will be to be prepared to encounter insects that could come from anywhere in the world. |
Monitoring these changes and industry experts sharing field observations will dramatically improve understanding. Establishing a robust network between facilities would allow data to be collected on insect migration patterns and responses to insecticides.”
What’s the impact on grain storage?
O.W. “As a result of these new conditions, grain is expected to ripen earlier, which will lead to earlier harvests. This will have two important consequences. Firstly, it will be harder to protect grain from farm to fork as it will be stored for longer. Secondly, grain will be brought into silos during warmer periods, creating the ideal conditions for insect infestations to grow quickly.
Even in extreme weather conditions, silos are relatively isolated from the external environment and act as a microclimate buffer, inadvertently creating a refuge for insects. This is obviously a cause for concern.”
What solutions are being explored?
O.W. “Our message remains the same: it is essential for silo owners to have access to a variety of products and modes of action to maintain product efficacy. We already recommend switching to a different insecticide class every few seasons. Monitoring will become increasingly important to ensure products remain effective as insect life cycles accelerate and the risk of resistance grows.
Changing from one brand to another is not, and has never been, an efficient and responsible insecticide rotation strategy. You have to change the mode of action. |
We're also always looking for better ways to use insecticides; there's no magic: the right dose rate and conditions will give you the best control. But insecticides must be part of a broader integrated pest management strategy. We actively communicate with silo owners and people in rural communities to stress the importance of cleanliness. By keeping their facilities clean, people can significantly reduce the risk of infestation.”
Building a sustainable future
As the effects of climate change unfold in our sector, it is becoming increasingly clear that proactive action is essential for our shared future.
Working closely with silo owners and providing training will be key to meeting the challenges and creating a more sustainable future.
Special thanks to Oliver Wood for his invaluable time and expertise!