Pressures affecting the climate and atmosphere

The energy sector, which includes electricity generation, emissions resulting from oil and coal refining to produce petroleum products, coal mining and gas extraction, wood burning and the burning of coal and oil to produce heat for industrial and other purposes, is the single largest source of Carbon dioxide (CO₂)and sulphur dioxide (SO₂) emissions in South Africa as it is in most countries (Table 1.1). This is mainly due to the combustion of coal and oil or its products for the country’s energy purposes [see Economics].

The transport sector, (including aeroplanes, ships, trains and road vehicles) contribute 44% of the total national nitric oxide emissions and 45% of the total national volatile organic carbon emissions (VOC). Volatile organic carbon emissions (VOC). is not toxic itself, but combines with nitric oxide and carbon monoxide, in the presence of sunlight, to form "photochemical smog", which contains ozone and other gases toxic to plants and animals. This is particularly a problem in urban areas. Road vehicles, rather than trains or aircraft, contribute the most to the total carbon dioxide, nitric oxide and volatile organic carbon emissions (VOC). emissions from the transport sector (94%, 53% and 89% respectively). Road vehicles also contributes to lead emissions, especially in urban areas.

Agricultural activities contribute the most to methane emissions (48% of the national total) and nitrous oxide emissions (78% of the national total). The main sources of methane emissions are cattle and sheep. Livestock numbers are driven by agricultural economics and population changes (for instance, the meat consumption per capita in a wealthy, urban area is larger than in a poor or rural area), but have been fairly stable for several decades, at what is thought to be close to the grazing carrying capacity of the veld. Livestock raising technology is also changing, towards the greater use of feedlots for animal fattening. The methane emissions from manure handling of animals in feedlots are larger than from manure deposited on a rangeland, due to the anaerobic conditions typically associated with the former. The main source of nitrous oxide emissions is the use of nitrogen fertilisers [see Terrestrial].

The total emissions of sulphur dioxide from the energy sector were fairly stable during the 1990s and remained at about 1.7 kilotons from 1989 to 1993 (latest figures available: Pretorius et al 1998), despite the overall increase in energy production. This is due to management of coal quality and a small degree of sulphur dioxide removal from the stack emissions. Greater efficiences have also been achieved in primary industrial combustion processes, particularly the power sector.

Table 1.1. Main sources and the amounts of air pollutants emitted in 1990 in kilotons (10⁹g) (Source: Country study report on greenhouse gas emissions from South Africa, unpublished report.) Countries which have already submitted their national greenhouse gas emissions inventories used 1990 as the base year. In the Country Study Report, emissions for 1990 were calculated in order to compare South Africa on an equal basis with the other countries. Empty blocks in the table represent that according to current knowledge, these specific greenhouse gases are not emitted from the mentioned sources.

As shown in Table 1.2, South African usage of ozone-depleting substances (CFC-11,12,113, 114 and 115) has decreased substantially following the signing of the Montreal Protocol in 1987.

>     Climatic and Atmospheric Change: State

There is also information about Climatic and Atmospheric Change in the following reports:
Metropolitan reports:
	Cape Metropolitan Council (1998 edition)		Durban Pilot Study
	Greater Johannesburg Metropolitan Council (1999 edition)		Greater Pretoria Metropolitan Council (1999 edition)