Cape Town — Climate change has a profound effect on food security in Africa, as increasing temperatures and shifting rain patterns reduce access to food across the continent.
This transpired at a conference on global warming and climate change that started in Cape Town, South Africa, on July 21 and ends today.
The discussion was organised by South Africa's Fynbos Foundation, which aims to realise investment in the media, publishing, arts and culture sectors, and the Nieman Foundation for Journalism at Harvard University in the United States.
The relationship between climate change and food security is complex. Many factors influence food security, which means that often "the link is not even made between failed crops and changing weather patterns," Dr Gina Ziervogel, senior researcher at the Climate Systems Analysis Group at the University of Cape Town, told the conference.
Over the past decade Ziervogel has conducted extensive research on people and the environment in southern Africa.
Climate change affects African food systems in the broadest sense of the word: "It affects the availability of, access to and utilisation of food," she explained.
"Changing weather patterns or extreme weather events, such as floods or droughts, can have negative consequences for agricultural production. As a result people have less access to food, which forces them to buy food products. This affects their financial situation.
"It also influences their health as people often buy cheaper food which is frequently less nutritious. Especially for those who need a nutritious diet -- the chronically ill, for instance -- this poses a problem," Ziervogel indicated.
Increasing temperatures and the change in precipitation and frequency of extreme weather spells also threaten African food systems, Ziervogel continued.
Changes in precipitation "are not merely about increasing or decreasing rainfall. Rainy seasons that begin later or earlier than normal or sudden rain spells hitting a region when it is supposed to be dry, have a greater impact on crops failing than a wetter rainy season that starts on time".
Another scenario where the effects of climate change on the vulnerability of food systems become visible is where arable land is lost. This happens as a result of declining ground water levels and rising sea levels. It can lead to aridity of the soil or increasing levels of saline.
"It reduces the suitability of land for cultivation of crops," Ziervogel argued.
Such changes require farmers to alter their agricultural practices. Sorghum, for instance, is more heat resistant and therefore does better than maize in places where rainfall decreases.
"However, the question is whether communities that are used to and have a preference for maize will switch to sorghum or another more suitable staple crop," Ziervogel pointed out.
Another consequence of climate change that affects food security in Africa is the increasing frequency of extreme weather events such as floods, droughts, hail and heat waves. These can be fatal to crops.
"A couple of years ago, I was in Lesotho during December. A sudden spell of frost destroyed much of the country's maize harvest," Ziervogel told delegates. "This is unusual for summer."
Apart from damaging crops directly, extreme climatological events may damage infrastructure such as roads: "This may prevent people from buying and selling food on the markets and therefore also undermines food security."
Climate change also leads to pest outbreaks that further weaken food systems. "Climate change induces outbreaks of pests such as the desert locust," Professor Onesmo ole-MoiYoi of the International Centre of Insect Physiology and Ecology told the conference.
The centre, which has its headquarters in Nairobi, Kenya, aims to alleviate poverty, ensure food security and improve health in the tropics by developing management tools against harmful insects.
"In case of an outbreak, locusts are capable of destroying crops. I have seen a locust outbreak. They eat everything they can find, within days."
Despite the disastrous effect of locusts on food security in Africa, the world has yet to take action. "That is because outbreaks only occur every seven or so years. But the frequency could change in the future."
Climate change not only impinges on the cultivation of crops, Ziervogel stressed. The fishing industry is being threatened as well. "Fish stocks in large lakes across Africa are declining -- not only because of over-fishing but because of declining water levels due to evaporation as a result of rising temperatures."