Climate change drives erratic water cycles, not scarcity alone – experts

As the agricultural sector comes under increasing pressure from global warming, Prof Mike Muller of the University of the Witwatersrand’s School of Governance says the issue is not a simple shortage of water, but increasingly erratic water cycles.

“I think it is interesting because when we first started talking about climate change 20 or 30 years ago, people were saying there’s going to be water scarcity, there’s going to be drought. What they were missing is that as the atmosphere and the Earth warms, more and more water is held in the atmosphere, which means there is potential for more rain. What they did not tell us is that if we have more rain, it might fall all at once,” Muller said at Nation in Conversation during the annual NAMPO Harvest Day.

Despite average rainfall figures in parts of the region showing increases, Muller said the pattern and intensity of rainfall present the real challenge for water management. “That’s actually one of the real threats that we are seeing. We don’t have to worry quite so much about average rainfall – it’s probably going to go up. What we do have to worry about is how it comes and what happens afterwards,” he said.

He warned that heavier downpours, followed by longer dry spells, are becoming more common globally. “As temperatures get hotter, we are probably going to evaporate more. Unless we think very carefully about how we capture water and then use it, we might find that although there is more water coming when it rains on those two days, in the two years when it does not rain we lose a huge amount through evaporation,” he said.

Apply science

Muller said commercial agriculture is beginning to adapt by applying science and investment to manage greater variability in weather patterns.

“I think organised commercial agriculture can apply the science and the capital to try and manage this increased variability and intensity of events. Climate change is happening, and we are beginning to manage it, but unfortunately we tend to look at events after they happen and say we’ve got to do it better,” he said.

Infrastructure management was also highlighted as a key concern.

Greg Smith, chief executive of the South African Association for Water User Associations (SAAFWUA), said decentralised management is essential for effective water resource governance.

“If you don’t manage it and ensure the right amounts are flowing in the right place, it could cause quite significant damage,” he said. “If you don’t operate and maintain infrastructure, you are simply deferring costs because you will pay more later when you have to replace entire systems.”

Janse Rabie, head of the Natural Resources Centre of Excellence and Legal and Policy Executive at Agri SA, called for greater collaboration between government and the private sector.

“We need to think creatively. If one party comes with data and another with solutions, you can sit around a table with government,” he said. “You cannot only complain or destroy relationships. We are entering phases of transformation in the water sector and need both government and the private sector to play their part.”