How rivers will behave

IRIN: Soaring temperatures and erratic rains brought on by a changing climate may radically alter water flows in the world’s major river basins, including the Limpopo in southern Africa, forcing people to give up farming in some areas, says a new study.

The study - part of a five-year research project on four continents, the first to take a close look at 10 river basins - is based on data from 17 climate models used by the Intergovernmental Panel on Climate Change (IPCC) to examine the potential effect of changing temperatures and rainfall patterns on the water flows in rivers from now until 2050.

Climate models cannot predict how rainfall patterns will behave in future with a high degree of certainty, said Mark Mulligan, a climate change scientist at King’s College, London, and lead author of the study.

“What we do know is that we cannot be confident about hydrological stability. Some rivers could become wetter and then drier, or vice versa. The key message to countries is: ‘Become more adaptable’.”

There are problems with the science when it comes to making projections of climate change impact on rivers, but the study expects that all African river basins will be water-stressed by increased rates of evapo-transpiration as temperatures rise, but is uncertain about how gains in rainfall may offset that impact....

The Lotsane River, a seasonal tributary of the Limpopo, by the village of Palapye, Botswana. This picture of the riverbed was taken during the rainy season 1994/5 by JackyR, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license