‘Southern Africa in for 10°C temperature rise’

Published in The Weekender, 3 Oct 2009Southern Africa, seen from Apollo 17

Without global cuts in carbon emissions, Southern Africa could see average temperature increases as high as 10 degrees centigrade as soon as 2060, according to a study released by the UK’s Meteorological Office last week.

The study is a based on a range of models, and predicts an average global temperature increase of four degrees centigrade by 2060. But four degrees 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 likely 10 degrees 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 South Africa 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 South Africa is projected to decrease.”

“With continuing increases in emissions we may be likely to exceed four degrees of warming. To remain below two degrees, emissions will need to be reduced considerably below present day levels.”

So far, average global temperatures have increased 0.7 degrees 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 were 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 just 20 years time, South Africa will lose up to 30% of its maize production and 15% of its wheat production, which has critical implications for food security. If the 10 degrees of warming scenario is correct, production could fall even further.

Bob Scholes, of the CSIR’s Natural Resources and the Environment Programme, who is an IPCC co-author, said, “[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.”

Sanderson told the Weekender that, “this 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 observations of past climate. 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.

The world’s governments meet in Copenhagen in December to decide on new agreements to cut emissions under the UN Framework Convention on Climate Change, and will be basing many of their discussions on the 2007 Fourth Assessment Report of the Intergovernmental Panels on Climate Change. 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 last few years have in fact exceeded some of the IPCC’s most pessimistic predictions.

Guy Midgeley, chief director of the Climate Change and Bioadaptation Division of the Kirstenbosch Research Centre in the South African National Biodiversity Institute, said the Met Office scenarios should be considered by policymakers. “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 UNFCCC negotiations in Copenhagen is that the world will agree on sharp cuts, with dramatic implications for South Africa’s carbon intensive economy. In 2006, South Africa produced 10.04 metric tons of carbon dioxide per capita annually, more than the UK (9.66). Following Copenhagen, South African business may face increased tariffs on its exports if, as is considered likely, other countries beginning taxing “embedded” carbon dioxide.

Former environmental affairs and tourism minister Marthinus van Schalkwyk first said last year the country would need to stabilize emissions by 2025, and then begin reducing them. After some signs of wavering, this position was reiterated last week by cabinet spokesman Themba Maseko.

But how this will be done remains unclear. While developing countries like India and China have in the last few months announced massive commitments to developing renewable energy technologies such as wind and solar, South Africa’s current plans for renewable energy development are modest – just 2% by 2025.

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David

I am an environmental writer, journalist and speaker living in Cape Town, South Africa.

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