Johannesburg: Without global cuts in carbon emissions, average temperatures in southern Africa could increase as much as 10°C as early as 2060, according to a study released by the UK’s Meteorological Office last week. The study is based on a range of models, and predicts an average global temperature increase of 4°C by 2060.
But 4°C is just the global average increase — and while some areas will warm by less than 4°C, others will warm by more. For southern Africa, a 10 °C rise is likely in inland areas.
According to Michael Sanderson, co-author of the Met Office report, “The exact impacts of such a large temperature rise on SA were not addressed in this study. However, food production will be adversely affected. The temperature rise will decrease crop productivity and increase the risk of hunger. Some plants and animal species will become extinct. Freshwater supplies will be reduced, and water quality is likely to be adversely affected. There may be a forced migration of people to more habitable areas. As well as the increase in temperature, precipitation over SA is projected to decrease. With continuing increases in emissions we may be likely to exceed 4° of warming. To remain below 2°, emissions will need to be reduced considerably below present day levels.”
So far, average global temperatures have increased 0,7 °C since pre-industrial times. Since it takes decades for the full effects of rises in atmospheric carbon dioxide to be felt, at least another degree of warming is unavoidable, even if emissions are significantly reduced — which appears unlikely given the failure of efforts to cut emissions so far.
Already, there have been consensus predictions under some scenarios that in the next 20 years , SA will lose up to 30% of its maize production and 15% of its wheat production, which has critical implications for food security. If the scenario of 10°C of warming is correct, production could fall further.
“( This prediction ) has always been a possibility, but not thought to be the most likely outcome. It is within the uncertainty bands on the high end, which people don’t like to talk about,” says Bob Scholes of the Council for Scientific and Industrial Research’s Natural Resources and the Environment Programme. Scholes is also an Intergovernmental Panel on Climate Change (IPCC) co-author.
Sanderson says the projection is based on the results from a large number of climate models using a high-emissions scenario. “Current measurements indicate that actual emissions of greenhouse gases are similar to those in the high-emissions scenario we used.
“However, it should be noted that a few models project a high degree of climate change even under a medium-emissions scenario. All of the climate models used in this study are state-of-the- art and have been rigorously validated using observation of the Earth's climate in the past. Many of the climate projections are discussed in detail in the IPCC Fourth Assessment Report. The other results have been published in peer-reviewed journals. Carbon cycle feedbacks amplify the warming, suggesting even larger cuts in emissions will be needed.”
Carbon cycle feedbacks are releases of carbon dioxide into the atmosphere via phenomena such as increased deforestation and release of carbon dioxide from melting permafrost.
World governments meet in Copenhagen in December to decide on new agreements to cut emissions under the United Nations (UN) Framework Convention on Climate Change. The meeting will base many of their discussions on the 2007 Fourth Assessment Report of the IPCC. However, later studies have shown that the IPCC under estimated economic growth, and thus carbon emissions. The result is that observed carbon emissions over the past few years have exceeded some of the IPCC’s most pessimistic predictions.
Guy Midgley, chief director of the Climate Change and Bioadaptation Division of the Kirstenbosch Research Centre at the South African National Biodiversity Institute, says the Met Office scenarios should be considered by policy makers. “If there is enough concern that these high-end changes are possible, I think it would be important to consider them to fully inform policy options and adaptation planning responses. It would seem that investment in effective adaptation would have to be of a far higher level, and possibly involve a different mix of strategies, relative to that suggested by our current understanding, given this level of climate change in such a short time period.”
The hope for the UN Framework Convention on Climate Change negotiations in Copenhagen is that the world will agree on sharp cuts in emissions, with dramatic implications for SA’s carbon-intensive economy. In 2006, SA produced 10,04 tons of carbon dioxide per capita per year, more than the UK (9,66). Following Copenhagen, South African business may face increased tariffs on exports if other countries begin taxing “embedded” carbon dioxide.
Former environmental affairs and tourism minister Marthinus van Schalkwyk announced only last year that SA would need to stabilise emissions by 2025, and then begin reducing them. After some signs of wavering, this position was reiterated last week by Cabinet spokesman Themba Maseko.
While developing countries such as India and China have in the past few months announced massive commitments to developing renewable energy technologies such as wind and solar, SA’s plans for renewable energy development are modest — just 2% by 2025. The Department of Water and Environmental Affairs declined to comment on the Met Office report.
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