Introduction
Global climate change is a worldwide concern which receives much
attention in scientific and political circles. The measured
atmospheric concentrations of several important gases in terms of
their contribution to the enhanced greenhouse effect, are
increasing. Although the possible consequences of these
increased concentrations are not yet all known or proven, it is
accepted world wide that human activities are the probable cause of
the observed changes in the atmosphere and climate (IPCC),
1995).
South Africa is a climatically
sensitive country. Most crop agriculture in South Africa takes place
where it is only just climatically viable, particularly with respect to
rainfall. Water is the resource most limiting to national
development. Its availability now and in the future is closely
linked to rainfall, temperature, management of water resources and land use practices
(see Freshwater Systems).
A warmer world will cause the sea level to rise, mainly due to
expansion of the water in the oceans. This will negatively impact
coastal ecosystems, water supplies and infrastructure in coastal
regions, via salt contamination of fresh ground and surface water,
and erosion and corrosion of buildings and other infrastructures.
South Africa has a coastline of nearly 3000 km; however most of
this is fairly steep and will not be significantly affected by
small sea level rises (for example the current rise of 1.2 mm per year).
South Africa has a climate which is highly variable, both across the country and over time. In general it is a dry country especially in the west
(the mean annual rainfall is 496 mm, approximately half the world
average). Rainfall is mainly received
in summer, except in the southwest, which is a winter rainfall
region, and a small area in the southern Cape, where rain can occur
at any time of the year. Summer temperatures are generally
warm and the maxima can frequently be very hot (above 35° C).
While winters are not extremely cold, nighttime minimum temperatures
drop below freezing for at least 30 days a year over the entire
high-lying interior, about 50% of the country (Tyson, 1986). For
more information on climate statistics, see the South African Weather Bureau
website (http://www.sawb.gov.za)
South Africa shares its atmosphere with the
rest of the world when it comes to long-lived gases such as carbon
dioxide, methane, nitrous oxide and chlorofluorocarbons. For
short-lived gases such as nitric oxide, sulphur dioxide and for dust
particles, we share our atmosphere with the neighbouring countries
in southern Africa. There are numerous ‘natural’ sources
of atmospheric pollutants, such as veld fires, in addition to the
industrial sources. Outdoor air quality is generally worst in urban,
industrialised areas, but the poorest air quality is to be found
indoors, frequently in rural areas, in badly-ventilated housing
where coal, dung or wood is burned in open hearths without chimneys.
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There is also information about Climatic and Atmospheric Change in the following reports:
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Metropolitan reports:
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Copyright © 1999 Department of Environmental
Affairs and Tourism. All Rights Reserved.
Site maintained by the Directorate Environmental Information and Reporting
Last update: October 1999
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