Farmer's Weekly (South Africa)
SA water crisis: Climate change not the only culprit
According to Mike Muller, a visiting adjunct professor at the University of the Witwatersrand’s Graduate School of Governance, low and unpredictable rainfall is not the only cause for South Africa’s water crisis. As a result, no single solution can addre
A serious, multi-year drought in the Northern Cape and Eastern Cape has seen a number of small towns threatened by total water supply failures and livestock farmers facing financial ruin. In other parts of South Africa, heatwave conditions and the late onset of rain have caused local supply failures. Although the dams that supply most of the main urban areas are still at reasonable levels, there are growing fears that the country may be witnessing the start of a major drought. Cape Town’s experience of extreme ‘Day Zero’ supply restrictions has added to these fears. Weather forecasters seem unable to make reliable predictions more than a few weeks in advance, and there are nagging concerns about government’s ability to identify and address emerging problems. Unhelpfully, there is no single water problem, and issues vary from place to place. In Cape Town, water managers thought they could avoid building new infrastructure to supply a growing population by encouraging everyone to use less water; a major drought proved them wrong. During October’s heatwaves in Gauteng, water ran dry as local reservoirs were emptied by residents using extra water for their gardens, and municipalities failed to enforce restrictions.
In Adelaide in the Eastern Cape, where there has been a critical supply failure, one local councillor was reported ( Farmer’s Weekly, 11 October 2019) to have commented that “the Adelaide Dam was at 1% before local authorities woke up”. Even then, there was little they could do because funding was unavailable. Adelaide’s problems are repeated daily in towns countrywide as municipalities expand the distribution of water without first ensuring there is enough supply, or putting in place measures to control excessive use. Too often, poor planning and management are revealed when drought strikes, as is now happening.
Weather predictions
If there was more certainty about future weather, there might be less concern.
But this is not the case. At the end of September, the South African Weather Service (SAWS) said that while summer rains would be late and October very dry, November would almost definitely see good rain. So far, so good; the rain in Gauteng started on schedule on 1 November.
But South Africans should not expect this successful forecasting to continue. It is unusual for a seasonal forecast to be so confident.
For each three-month period, SAWS produces two rainfall maps. The first shows the ‘raw’ predictions from the computer models and is therefore not statistically significant. The second map is important, as it shows only the areas where forecasters are reasonably confident that the predictions are significant. As a result, the second map is often almost blank. Moving into 2020, predictions are becoming more uncertain again. Indeed, at the end of September, SAWS warned that some international forecast models suggest that South Africa may be moving into an El Niño rainfall phase, which would be dry, saying that opposite forecasts for most of the summer period were increasing the uncertainty for the coming summer season.
The combination of forecast uncertainties and problems on the ground offers politicians an easy opportunity to blame climate change and uncertainty to explain failures in their areas of responsibility.
Former Western Cape premier Helen Zille, expanding on Cape Town’s Day Zero debacle, was accused of blaming the country’s weather service, suggesting that the province found itself facing a crisis because SAWS got their predictions all wrong.
Zille would just have been echoing the excuses of then Cape Town mayor Patricia de Lille and water affairs minister Nomvula Mokonyane, who had happily associated
themselves with the notion that the city’s crisis was due to drought becoming “the new normal”.
UNPREDICTABLE RAINFALL
Africa’s rainfall has always been variable and unpredictable. This remains one of the larger risks to rain-fed agriculture, as Karoo farmers in the Northern Cape are experiencing.
Reliable supplies can be provided to urban and industrial water users and irrigation farmers if storage infrastructure is built with enough capacity to cope with regular dry periods. But that infrastructure has to be managed with a watchful eye on the ever-changing climate.
If the necessary infrastructure required is not developed when needed, problems will arise. And if water is drawn without restraint during a dry period, shortages will be the likely outcome.
IS CLIMATE CHANGE THE PROBLEM?
As Zille, De Lille and Mokonyane have demonstrated, it is easy to blame climate change for water problems. Yet it is by no means certain that climate change will dramatically reduce water supplies. Rising temperatures is one trend that forecasters confidently and correctly predict. But it’s not certain what that temperature increase will do to water availability.
Recent research has shown that African groundwater supplies have not yet been negatively affected. Higher temperatures will see more evaporation from the land surface, but it is also expected that storms will become more intense. More rain will fall in a shorter time, and this produces more recharge than slow, gentle rain.
The same effect could see river flows increase. At the moment, South Africa uses only around 30% of the water in its rivers and underground. Using more would rapidly become more expensive. But climate change may help. At present, only 8% of rainfall actually runs into the rivers and is then available to be used or stored in dams. If rainfall becomes more intense, that proportion will be greater.
Environmentalists warn that intense rainfall will cause floods; they want to slow down and spread out the water, although that will help it to evaporate. On the other hand, many hydrologists and water managers would quietly welcome the extra water flowing into their systems and would like to help it get there.
The different challenges faced in different places may look like a single crisis. But the fact is that the underlying problems are often not the same. There is no single prescription, and each locality must understand and address its own particular circumstances.
What is clear is that South Africa is not yet confronting an absolute water shortage. But the extent of public panic suggests a disturbing level of ignorance about how water is made available, and what needs to be done to ensure adequate and reliable supplies.
The key to achieving water security is for government and citizens to understand and manage the country’s water resources.