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17 May 2021
DSI/NRF/CSIR Chair in Waste and Society Webinar Series
DSI/NRF/CSIR Chair in Waste and Society Webinar Series presents South Africa’s economy gauged in Megatonnes: Linear and circular flows including the informal sector's contribution to circularity.

Presenters: Dipl. Ing. Dr. phil. Willi Haas & Dr.-Ing. Harro von Blottnitz (Pr.Eng.)
Host: Dr Takunda Chitaka
Date: Thursday, 20 May 2021 @ 12h00


South Africa’s economy gauged in Megatonnes: 
Linear and circular flows including the informal sector's contribution to circularity

South Africa’s physical economy has a strong linear profile (2017 figures): Its extraction of all food, feed, minerals, metal ores, and fossil energy carriers (coal) is 875 million tonnes heavy (these are Megatonnes, in short Mt). 66% of this extraction is metal ores and coal. Compared to this, imports are relatively small (32 Mt). Exports are large (170 Mt) and consist predominantly of refined metals and coal while leaving the associated extractive waste in South Africa. The material used domestically for building and maintaining stocks like roads, buildings, dams, factories, or artifacts is relatively small (131 Mt) and needs to be critically discussed as to whether it is sufficient to deliver the required services to the South African population. By comparison: In per capita terms the EU’s material consumption is just 10% higher than the South African, but the building and maintenance of stocks is three times higher. Altogether, waste flows are relatively high. Solid and liquid outputs returned to nature are about 310 Mt of which 171 Mt are extractive waste from mining activities. Emissions from technical processes, humans, and livestock accounted as carbon only amount to 175 Mt. If oxygen taken from the air is included, this results roughly in 640 Mt of GHG emissions, of which 36% are roughly of biogenic origin. These estimates are mass balanced on an annual basis, meaning that everything that goes into the South African economy has to be either a net-add to stocks or output to nature. Numbers also include an estimate of informal flows like waste from un-serviced households.
Recycling and reuse: Within the South African economy materials are recycled. Loops are relatively well developed for some metals, mainly lead, copper, aluminium, and steel as well as some other materials such as paper products. Our study includes a first-time estimate of reuse, which is everything but complete yet. We considered the reuse of wood, plastic, and steel products, of bricks, and container glass. However, if put into perspective of the economy’s entire processed materials, the contribution of cascaded and secondary materials is still very moderate with 1,5% by recycling and 0,4% by reuse. This leaves much room for improvement in quantitative terms, hand in hand with an appreciation of informal reuse activities. It is important to note that such activities can only be increased significantly if they receive broader direct support and favourable framework conditions by the government at all levels and if entire provisioning systems are designed to foster reuse, repair, or recycling instead of dumping, burning, or landfill disposal.


Dipl. Ing. Dr. phil. Willi Haas
Senior Scientist and Lecturer at the Institute of Social Ecology, University of Natural Resources and Life Sciences (BOKU), Vienna.

Willi Haas has an interdisciplinary background as he graduated as a mechanical engineer and obtained his doctorate in philosophy, subject sociology.

He investigates society-nature interactions across time and space and draws insights on the transition from agrarian to industrial societies for a better understanding of the option space for the next transition to a post-fossil society.

From a fundamental perspective, he studies the transformation of labour in socio-ecological transitions, as labour plays a key role in societal metabolism. He is the author of several publications discussing the potentials and limits of the circular economy and was commissioned as an expert for the European Commission (JRC) on the topic of material flows in the circular economy. Further, he was co-chair and project leader of the APCC’s Austrian Special Report on Health, Demography, and Climate Change and headed several studies in the interface of health and climate. Previously he was a public official at the Ministry of Social Affairs (Vienna), director of the Institute of Applied Ecology (Vienna), acting director of the Environmental Monitoring Group (Cape Town), and researcher at the International Institute of Applied System Analysis (IIASA, Austria).

Dr.-Ing. Harro von Blottnitz (Pr.Eng.)
Professor, University of Cape Town

Harro von Blottnitz is a professor in the Faculty of Engineering and the Built Environment at the University of Cape Town (UCT). He defines his research and teaching interests by the multiple challenges of sustainable development in developing country settings. 

Professor von Blottnitz holds a BSc in Chemical Engineering from UCT, a BSc Honours in Operations Research from UNISA, an MSc in Engineering from UCT, and a Doctorate in Engineering from the RWTH Aachen in Germany. He leads research in energy and industrial systems analysis and is registered as a professional engineer with the Engineering Council of South Africa. He has published widely in the fields of Life Cycle Assessment, Renewable Energy (biogas, biodiesel, and bio-ethanol), and Waste Management, thanks to extensive supervision of postgraduate students researching these topics. Many of his graduates have gone on to practise as knowledge providers in the emerging green economy.