This was according to Prof Bob Scholes, a system ecologist at the Centre of Scientific and Industrial Research (CSIR) and a convening lead author of the 5th IPCC Assessment Report. The report was discussed at the recent Nedbank Sustainability Outlook breakfast in Johannesburg. According to Scholes, the world-wide target was to push global warming down to just under 2°C.
“This is what’s officially on the table at the moment,” he said. “Unofficially, this is not possible, it cannot be done.” The increase was more likely to be in the region of 3°C, with South Africa warming at twice the rate.“I think areas such as Upington and many parts of Namibia will be seriously affected and things would be very difficult, especially for livestock farmers,” said Scholes.
Livestock farming, he explained, cannot occur above certain temperatures, due to the physiology of mammals.
With very high temperatures, animals, and especially those which are lactating, find it difficult to shed heat. “So cows cannot produce milk if the temperature goes very high,” said Scholes. Cereal farms, whether dryland or irrigated, would also be affected, said Scholes. “If the temperatures are very low, you get poor production,” he explained.
But yields improve as it gets warmer. “If, for example, you are growing maize in places like Canada, 2°C warming is actually a good thing,” said Scholes.“But if you go above 28°C you’re on the wrong side of the curve. “Almost all of Africa is already on the wrong side of the curve, except some parts of Lesotho and Ethiopia.”
