Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
08 April 2025 | Story Andre Damons | Photo Andre Damons
DrSophie-Biskop_ProfFrancois-Engelbrecht
Dr Sophie Biskop from the Department of Geography at the Schiller University Jena, Germany, and Prof Francois Engelbrecht, a Professor of Climatology at the Global Change Institute (GCI), University of the Witwatersrand, at the Southern African Mountain Conference (SAMC).

The severe El Niño drought of 2015/16, which culminated in the Vaal dam reaching an alarming low water level (~25%), prompted scientists to try and predict whether climate change could bring a drought so severe and long lasting that Gauteng could run out of water. 

Prof Francois Engelbrecht, a Professor of Climatology at the Global Change Institute (GCI), University of the Witwatersrand, is one of the scientists working on this project and says though they cannot predict a Day Zero drought with certainty, he thinks it is possible that Gauteng might run out of water in the 2030s or 2040s.

 “This is the biggest climate change risk South Africa faces”, he said.  

Prof Engelbrecht and Dr Sophie Biskop from the Institute of Geography at the Friedrich Schiller University Jena, Germany, together with other scientists are working on a project involving hydrological modelling to predict and prevent a Day Zero from happening. Dr Biskop presented their research paper titled ‘Projected hydrological futures of South Africa's mega-dam region’ at the second Southern African Mountain Conference (SAMC2025) in March, indicating there is a high risk that the water demand in Gauteng will exceed available water resources within the Integrated Vaal River System (IVRS) under future climate change.

 

Gauteng may be severely compromised

The IVRS, a large, complex water system comprising water resources of different river basins, and several mega-dams within, has been constructed to secure the water supply of the Gauteng province, the economic hub in South Africa. 

According to the researchers, Southern Africa is a water-stress hot spot and is projected to become significantly warmer and likely also drier under global climate change, increasing the risk of devastating hydrological droughts. The IVRS, Dr Biskop told the attendees, is vulnerable to the occurrence of multi-year droughts as experienced between 2012 and in 2016. The alarming low water level of the Vaal dam after a period of drought of 2015/16 provided early warning that water security of Gauteng may be directly and severely compromised in a changing climate. Potential evapotranspiration will increase as a consequence of strong regional warming.

 

Answering questions

“There is consequently a high risk that the water demand in the Gauteng province will exceed available water resources within the IVRS under future climate change. This raises the question if under ongoing climate change the natural hydrological system (without considering water transfers between dam catchments) can maintain dam levels in South Africa’s eastern mega-dam region, and particularly within the Lesotho Highlands,” explained Dr Biskop. 

 “To answer this question, the aim of our study is to quantify future water balance changes of several dams under changing climate conditions using the Jena Adaptable Modelling System (JAMS), a software framework for component-based development of environmental models. For this purpose, we build process-based hydrological models for several dam catchments.”

She said an ensemble of high-resolution regional climate change projections is subsequently used as forcing, to generate future hydrological projections. The analysis of projected changes in hydrological system components (precipitation, evapotranspiration, run-off) provides probabilistic estimates of the occurrence of a regional climate change tipping point - when the natural water supply can no longer achieve the full storage capacity of the mega-dams which supply the Gauteng region.

 

Working to prevent Day Zero 

According to Prof Engelbrecht, they are working with the City of Johannesburg, the National Department of Water and Sanitation and Rand Water on this project. Their hope for this research is to create awareness in order to try and prevent Day Zero from happening. They also hope to assist these role players in building resilience and help them prepare for Day Zero. Their work with the City of Johannesburg also includes helping the city to reduce water wastage and change water users’ behaviour as well as formulating a disaster management plan should Day Zero happen. 

The Southern African Mountain Conference (SAMC) series is unique as it seeks to integrate science, policy and practitioner sectors for sustainable interventions in southern African mountains. SAMC events are conceptualised by the Afromontane Research Unit (ARU) of the University of the Free State (UFS), the African Mountain Research Foundation (AMRF) and Global Mountain Safeguard Research (GLOMOS), a joint initiative between Eurac Research and the UNU Institute for Environment and Human Security. These three organisations form the Primary Partners, with the SAMC series being implemented by The Peaks Foundation (a non-profit company). SAMC2025 is being held under the patronage of UNESCO.

News Archive

Inaugural lecture: Prof André Pelser
2004-06-04

Tendencies and changes in the South African population structure in future decades.

Within the next five years South Africa will for the first time in the past century enter a period where the death rate will exceed the birth rate, largely due to the impact of HIV / AIDS.

According to sociologist Prof André Pelser, sociologist at the of the University of the Free State’s (UFS) Department of Sociology, the death rate exceeding the birthrate is only one of three demographic trends which will fundamentally change South Africa’s population structure in the following decades.

He was speaking at the UFS in Bloemfontein during his inaugural lecture as professor this week.

Prof Pelser said that according to some models the South African population will decrease within the next five decades by between 10 and 26 percent.

A second important trend which will impact on the population structure is the progressive ageing of the population.

He said the group above 65 years is the only age category in the South African population which will witness sharp increases in the next few decades.

In the next 50 years, the group younger than 15 years will reflect a decrease of 39% and those older than 65 years in South Africa will increase by approximately 110% in the next two decades.

“The systematic “greying” of the South African population will create the same economic and welfare issues as those with which governments in some more developed countries are already grappling,” said Prof Pelser.

A third trend affecting the South African population structure is the constant decrease in life expectancy.

Life expectancy at birth for the total population is projected to decrease from approximately 62 years at the beginning of the 1990’s to 43 years in 2015-2020, with sharp differences between the various population groups.

These tendencies and changes to the South African population structure have serious implications, he said.

For example, he said, the reduction in life expectancy could compromise national development objectives.

“It is estimated that more than a quarter of the economically active population will be infected with HIV by 2006,” said Prof Pelser.

The increase in the population, in age category 65, will place a financial burden on government and the economically active sector.

“Especially worrying is the fact that ever-increasing proportions of the state budget will be allocated to health and welfare services and this at the expense of other priorities like education, infrastructure, criminal justice system and trade and industry, to name but a few,” he said

“A comprehensive and integrated strategy is thus vitally important in addressing the overarching issues caused by changes in the population structure,” said Prof Pelser.

 

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept