ATMOSPHERE AND CLIMATE

Global climate change is a worldwide concern, which receives much attention in scientific and political circles. South Africa has signed and ratified the United Nations Framework Convention on Climate Change (UNFCCC) and is required to fulfil certain obligations under the Convention. The measured atmospheric concentrations of several important gases in terms of their contribution to the enhanced greenhouse effect are increasing. The possible consequences of these increased concentrations are not yet all known or proven. In addition, South Africa is a climatically sensitive country. Most crop agriculture in South Africa takes place in areas where the climate is only marginally suitable, particularly with respect to rainfall. Water is the most limiting resource to national development. Its availability now and in the future is closely linked to rainfall, temperature, management and land use practices.

Stratospheric ozone depletion is an international issue. However the impacts of stratospheric ozone depletion are of more significance on a local scale. South Africa was a signatory to the Montreal Protocol (controls the use of ozone-depleting substances for the protection of the ozone layer) in 1990 and subsequently ratified the London Amendments (restriction of the use of CFCs and halons) in 1992. Future predictions show that the period of greatest ozone depletion is to be expected in the next two decades. Stratospheric ozone depletion is responsible for a wide range of impacts, including impacts on human health such as cataracts and melanomas.

Trans-boundary air pollution is of national and international concern. The atmosphere is not constrained by anthropogenic or natural boundaries and global atmospheric movements will therefore influence regional, national and local atmospheric movements. The atmosphere throughout South Africa is influenced by regional air movements, which together with local climatic and meteorological conditions, are responsible for the distribution of air pollutants both within the country and between neighbouring countries. Air quality impacts are governed by the distribution of air pollutants, with impacts often being experienced some distance from the pollution source. Long-lived air pollutants such as carbon dioxide, methane, nitrous oxide and chlorofluorocarbons are internationally significant in terms of their distribution and impacts. Short-lived pollutants such as nitric oxide, sulphur dioxide and particulate matter are regionally (and locally) significant in terms of distribution and impacts. Outdoor air quality is generally worse in urban, industrialised areas whereas indoor air quality frequently constitutes a health hazard in poorly ventilated dwellings without chimneys, where coal, wood or paraffin are used as fuel.

Climate change was identified by stakeholders contributing to this project as being a significant issue that requires attention through the identification of relevant indicators. It is known that Africa contributes about 3.5% to global CO2 emissions. In addition, South Africa is the single largest contributor to total CO2 emissions from the African continent (more than 40%) and is ranked as the 15th largest emitter of greenhouse gases in the world (UNEP, 2000). South Africa ratified the United Nations Framework Convention on Climate Change (UNFCCC) in 1997 and is therefore required to fulfil certain obligations under the Convention. South Africa, being a party to this Convention, is required to report to the parties of the UNFCCC (reporting frequency has not yet been determined) its annual emissions of at least carbon dioxide, methane and nitrous oxide. The possible consequences of greenhouse gases vary widely from human health to agricultural impacts.

Stratospheric Ozone

Destruction of the stratospheric ozone layer due to the production and use of ozone-depleting substances is a significant global concern. Based on past emissions of ozone-depleting substances and a projection of the maximum allowances under the Montreal Protocol into the future, the maximum ozone depletion is estimated to lie within the next two decades. Potential future changes in other gases important in ozone chemistry (such as nitrous oxide, methane, and water vapour) and climate change will influence the recovery of the ozone layer (WMO/UNEP, 1998).

Air Quality

South Africa's atmosphere is shared with many other countries around the world, with some compounds transported throughout the globe while others are transported on a regional/local scale only. Many sources of air pollution exist all over South Africa, ranging from veld fires to industrial processes, vehicle use and domestic use of fossil fuels. The driving forces of poor air quality therefore include both human activities and natural processes (DEA&T, 1999; Beaglehole et al, 1998; Godish, 1997). There are two main categories of impacts associated with poor air quality, namely human health impacts and ecosystem impacts (including flora and fauna). These impacts suggest that it is vital that the issue of air quality is addressed in the core set of South African national environmental indicators.