Environmental Change Institute, University of Oxford

Sufficient water supply is vital for all aspects of human life, particularly agriculture, industry and thus food supply of the population. Both the absence of rain (with drought as a consequence) and intensive heavy rainfall (leading to flooding) cause major problems in the supply of clean water.

Climate change and variation in water management and consumption change how these events play out with dramatic consequences, particularly in highly vulnerable parts of the world.

The HIASA project aims to identify and understand changes in extreme hydrological events in Southern Africa, in particular catchment areas for large cities (e.g. Cape Town).

Two factors are examined to determine the vulnerability of different areas:

  1. Exposure: What is the impact of human climate change on droughts and floods?
  2. Sensitivity: How do local human activities change vulnerability to climate events?

In answering these questions, we aim to attribute the changing risk of significant droughts and floods. We also hope to estimate economic damage, the benefits of adaptation, and any residual economic damage that remains after adaptation.

At the same time, this research enables us to identify the most effective adaptation measures to decrease vulnerability, set the right priorities and prevent future loss and damage. Above all, the evaluation of the economic and social benefits of adaptation measures (evaluation of the return on investment) is crucial for the most efficient use of resources.

This project aims to assess the effectiveness of different kinds of responses, to reduce the vulnerability of African countries to climate change in the future and to generate effective adaptation programs.

Why is this research important?

For the first time, this project attempts to disentangle drivers of changes in flood and drought from the human influence on the climate and the direct human influence on the affected systems.

This contributes to the emerging debates of the UNFCCC on damage and is one of the first steps towards quantifying damage caused by climate change – separate from natural climate events – thus closing a recognised knowledge gap.

Where does this project take place?

Southern Africa is highly sensitive to the impacts of climate change due to its geography and level of socio-economic development. As a case study, it can represent many other developing countries.

The main focus is on two catchment areas (Berg River Catchment and uMngeni Catchment), as they are particularly important for Cape Town's water supply and are characterised by strong urban and agricultural influence.

Models and methods

For this project, the attribution methods from World Weather Attribution will be used and adapted to the region. Further hydrological and economic models will also be developed.


The project has investigated the drought in West South Africa from 2015 to 2017, which caused major problems with water shortages in Cape Town in 2018 ("Day Zero"), and identified a need for adaptation for the city and the region. This and other detailed results of the project can be found in the following links.


Project details