Tshwane, South Africa - Climate change could significantly alter water flows in major river basins in Africa, presenting a new barrier to efforts to better manage water for food production and to resolve potential cross-border water conflicts all over southern Africa, according to research findings presented at this week’s Third International Forum on Water and Food in Tshwane, South Africa.
As part of a five-year global research project, scientists from the Consultative Group on Iternational Agricultural Research’s Challenge Programme on Water and Food (CPWF) examined the potential effect from now through 2050 of higher temperatures and shifting rainfall patterns, caused by climate change, on river basins around the world.

In the process, they say, some unsettling scenarios have emerged for parts of Africa, CGIAR said in a statement made available to PANA here Monday. “Climate change introduces a new element of uncertainty precisely when governments and donors are starting to have more open discussions about sharing water resources and to consider long-term investments in boosting food production,” the statement quoted Alain Vidal, director of the CPWF, as saying. “To prevent this uncertainty from undermining key agreements and commitments, researchers must build a reliable basis for decisions, which takes into account the variable impacts of climate change on river basins,” Vidal said.

Particularly alarming are the projected changes in southern Africa’s Limpopo Basin, which is home to 14 million people and includes parts of Botswana, South Africa, Mozambique and Zimbabwe. Using data averages from climate models by the Intergovernmental Panel on Climate Change, CPWF experts found that rising temperatures and declining rainfall in the Limpopo over the next few decades could deliver a one-two punch to the already marginal environment - depressing food production and intensifying poverty.

“We need to ask whether current agriculture development strategies in the Limpopo, which are predicated on current levels of water availability, are in fact realistic for a climate future that may present new challenges and different opportunities,” the statement quoted Dr. Simon Cook, a scientist with the International Centre for Tropical Agriculture (CIAT) and head of CPWF’s Basin Focal Projects (BFP), as saying.

“In some parts of the Limpopo, even widespread adoption of innovations like drip irrigation may not be enough to overcome the negative effects of climate change on water availability,” Cook added. “But in other parts, investments in rain-fed agriculture such as rainwater harvesting, zai pits and small reservoirs might be better placed, as there could be sufficient rainfall for innovative strategies to boost production. The key is to obtain the data needed to make an informed decision.”

Climate change could also introduce uncertainties into the water politics of the Nile Basin, with the CPWF analysis showing that higher temperatures - a rise by 2050 of two to five degrees Celsius - have the potential to increase water evaporation to the point that it would “reduce the water balance of the upper Blue Nile Basin.”

Today, Egypt and Ethiopia appear to be making meaningful progress after years of tensions over Ethiopia’s plans to build dams upstream that would disrupt Egypt’s water supplies.

Recently, the Egyptian government has also indicated a willingness to consider a comprehensive treaty for governing water resources on the Nile River Basin that would involve a pact among several other countries in the region. In addition to the implications for the Nile and Limpopo, Cook said data also indicate climate change could affect water availability in Africa’s Volta River Basin. And as with the other basins, these shifts would need to be factored into an agriculture revitalisation strategy for the region.

Overall, the analysis of the effect of climate change on water availability found higher temperatures are likely in all of the ten river basins studied globally, which include large areas in Asia and South America. But while the higher temperatures could increase evaporation, most water losses are likely to be offset by increases in annual rainfall, as the energised climate system turbo-charges the amount of water in the atmosphere.

But according to CPWF, the impacts of climate change on water availability will vary in magnitude and direction within and between basins and could flip-flop weather patterns from wet to dry that were once more or less stable. Even where more rain falls on an annual basis, minor shifts in its timing may present challenges in basins that have been “organised” over centuries to manage somewhat consistent patterns of seasonality. “Such changes will create a management nightmare and require a much greater focus on adaptive approaches and long-term climate projections than historically have been necessary,” said Vidal.

In Africa, rainwater management is widely viewed as the key to improving both crop and livestock farming. Innovative ways to make productive use of rainwater are also being touted as a new “climate smart” approach to agriculture. Today, agriculture uses up to 70 percent of the world’s freshwater resources. The CPWF research highlights the increasingly important role of effective water management to allocate and utilise available water resources to ensure food production stays abreast of population growth, even in times of climate uncertainty.

Pana 15/11/2011