Water and Climate Change
Author: Dr Smangele Mnquba - Director of Climate Change at the Department of Water Affairs
( Article Type: Sustainable Development )
Even though there is still much that is not understood about the way climate will respond in the future, globally the overall impacts of climate change on water resources are expected to be negative.
IPPC and Climate Change Forecasts
According to the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), this is no longer a potential threat but a conclusive inevitable reality.
Rainfall is generally expected to become more variable
- Floods are expected to become more common;
- Droughts are expected to be more intense and last longer
- Sea-levels are expected to rise.
Expected Effects of Impacts
The net effect of all these impacts is:
- Reduced availability of water (surface and groundwater)
- Reduced security of water supply.
- It is expected that these impacts will be spatially variable, with the eastern seaboard of South Africa possibly becoming slightly more wet.
- Increased storm intensities will result in flooding becoming more common, which could increase sedimentation and scouring in dams and rivers.
This could potentially impact on water infrastructure assets such as dams and water and wastewater treatment works. These will impact water quantity and quality.
It is clear that the water sector cannot be an exception to the rule (i.e. cannot remain unaffected). Particularly against the background of high evaporation rates and low rainfall under natural conditions as well as increased demands for water to support developments among others, even before climate change is accounted for.
While the link between increased temperatures and changes in rainfall has been modelled in detail for climate change, such science for river flows and studies of underground waters are still lagging behind. Specific challenges posed by the melting of snow and glaciers still need to be understood in greater depths, as do the magnitude of impacts on water quality and water resources as a whole. Understanding the dynamics of current variability and future climate change as they affect water supply and demand across all sectors and enhancing the capacity to respond is crucial.
Adaptation of Water Sector
Because of these important reasons, adaptation in the water sector has become of urgent and of crucial importance. Achieving and sustaining water security provides a clear focus for starting to implement adaptation strategies and a framework for action.
For countries like South Africa, that have not achieved water security, climate change will make it harder. As for countries that have achieved water security, it may prove harder to sustain in the future.
In other words, all countries of the world - whether they are water secured or not - are likely to be faced with new challenges that they have not anticipated before.