The climate of the world varies from one decade to another, and a changing climate is natural and expected. However, there is a concern that the human industrial and development activities of the past two centuries have caused changes over and above natural variation... What is climate change? Climate change is the natural cycle through which the earth and its atmosphere are going to accommodate the change in the amount of energy received from the sun. The climate goes through warm and cold periods, taking hundreds of years to complete one cycle. Changes in temperature also influence the rainfall, but the biosphere is able to adapt to a changing climate if these changes take place over centuries. Unfortunately, human intervention is currently causing the climate to change too fast. (Climate models predict that the mean air temperature over South Africa will increase by an estimated 2°C over the next century.) Plants and animals may not be able to adapt as quickly to this rapid climate change as humans can, and therefore the whole ecosystem is in danger. What causes climate change? The global climate system is driven by energy from the sun. Several gases in the atmosphere act to trap the energy from the sun, thus warming the earth. These gases are called greenhouse gases and the process is the greenhouse effect. Without this there would be no life on earth. Human activities over the last 200 years, particularly the burning of fossil fuels (oil, coal, natural gas) and the clearing of forests, have increased the concentration of greenhouse gases in the atmosphere. This is likely to lead to more solar radiation being trapped, which in turn will lead to the earth's surface warming up - called the enhanced greenhouse effect. How does a changing climate influence South Africa? Higher temperatures will influence the rainfall, but it is still uncertain how the annual rainfall will change. It could increase in some parts of the country, and decrease in other parts. Water resources Human and animal health Maize and wheat Grazing livestock Forestry The coastal zone Fisheries Biodiversity What can we do to slow the process down? The enhanced greenhouse effect can be slowed down by following two guidelines: (1) Increase sinks and (2) decrease sources of greenhouse gases. A sink is a process which removes greenhouse gases from the atmosphere. For example: growing a tree where one did not previously exist provides a sink for carbon dioxide, because the tree extracts carbon dioxide for photosynthesis. A source is a place or activity from which greenhouse gases are emitted. This can be a process such as coal burning or a location such as cultivated fields. The Kyoto Protocol The Kyoto Protocol is a legal instrument that is separate from, but related to the Climate Change Convention. Countries ratifying the Protocol have mainly the following obligations: (1) Developed countries are obliged to ensure that their greenhouse gas emissions do not exceed the amounts assigned to them. (2) Climate change policies must be implemented. (3) Energy efficiency must be enhanced. (4) Emissions in the waste and transport sectors must be limited and/or reduced. (5) Sinks for greenhouse gases must be protected. (6) Market instruments that are counter productive to the aims of the Protocol should be phased out. (7) Sustainable forms of agriculture and relevant research must be promoted. All these activities must be undertaken in such a way that potentially adverse effects on developing countries are minimised. The future of climate change issues in South Africa are on the moment mainly in the government's hands.