Climate change has become a global environmental issue. Although natural trends of global warming and cooling have always occurred on Earth, the current overall global warming trend is attributed to human activity and is not just part of the natural cycle of climate change. The current warming trend is mostly attributed by the increase in human activities that emit greenhouse gases, in particular carbon dioxide (CO2) into the atmosphere. Although there is some uncertainty as to the exact consequences of the anthropogenic global warming, it will have cause negative impacts on us and the ecosystems we depend on. While no one will be able to escape from climate change, it is the poorer people and countries, such as South Africa, who are most vulnerable to its negative impacts. (1)
Greenhouse gases help keep heat from escaping from the earth’s atmosphere and into space. The more greenhouse gases present in the atmosphere the less heat that escapes into space. Without any greenhouse gases in our atmosphere the earth’s average temperature would be -17 degrees Celsius instead of an average of 14 degrees Celsius. (2) Humans already have increased the levels of CO2 in the atmosphere by more than 30 percent since the beginning of the industrial revolution and the large-scale use of fossil fuels. (3) The increase in greenhouse gases, such as CO2, has caused the earth to warm by over half a degree Celsius. The climate is projected to warm another one to three and a half degrees Celsius over the next century due to projected increases in atmospheric concentrations of greenhouse gases becoming the fastest rate of global warming in over 10,000 years. (4)
Two of the interrelated threats caused by just a few degrees of global warming are an increased rate of ice melting and a rise in sea level. The global warming trend may eventually cause the ice sheets in Greenland and the West Antarctic to melt each causing up to an 18 feet increase in global sea level. (5) The melting ice will add freshwater into the ocean potentially weakening or stopping ocean currents that help warm areas such as Europe, thus causing regions of cooling within an overall warming globe. The rise in sea level will also result in whole island nations being submerged and coastlines being significantly altered.
In South Africa one of the concerns of climate change is the change in rainfall patterns and the effect it will have on farming and land degradation, especially in poor areas. Global warming is predicted to cause an increase in precipitation in some areas, while a decrease is predicted for other areas. In South Africa there already exists several economically poor areas with severe land degradation that were once part of the apartheid era ‘homelands.’ (6) Many of these past ‘homelands’ are predicted to have further land degradation, as they are located in areas most susceptible to climate change induced changes in rainfall patterns. In this case climate change will also likely have economic impacts, as well as environmental impacts.
Models have been used to predict how rainfall distribution and quantity will change for different regions in South Africa based on the predictions of climate change, primarily warming, in those areas. In the eastern parts of South Africa rainfall values are expected to increase by as much as 1.2mm per day. (7) The KwaZulu-Natal, an eastern former ‘homeland’ state, is likely to have drier springs and wetter summers with one dry summer month. (8) This change in rainfall is expected to threaten both the crop and pasture activities for the farming communities like those in KwaZulu-Natal and thus have an economic impact on their agriculturally based economy.
The field crop sector of the agricultural economy is expected to be more affected by the increasing temperatures rather than by the change in rainfall patterns. The Ricardian model of climate change impacts on the economy predicts up to what seasonal average temperature net revenue will increase. If the average temperature goes above the maximum or below the minimum net revenue is predicted to decrease. The optimal maximum temperature point in relation to maximum net revenue for South Africa in the winter is predicted to be 14 degrees Celsius. South Africa’s current winter average is 15 degrees Celsius, which is already above the maximums and thus any further increase in winter temperature is expected to cause further decline in crop revenue. The model also shows that there is an increase in net revenue when summer temperatures are above the minimum optimal temperature of 22 degrees Celsius, thus warming could be beneficial to summer crops. However, the decrease in summer rainfall may negate the positive effects of a rise in summer temperatures.
Estimates of total economic damage from a two to three degree Celsius warming trend tend to be a few percent of world GDP, with considerably higher levels of damage to developing countries. (10) The changes in temperature and rainfall are relatively the same across the country of South Africa, but different areas are predicted to have different economic effects. In the already arid Northern Cape Province a two degree Celsius rise and temperature and five percent decrease in rainfall is expected to result in approximately a forty percent increase in net revenue per hectare. In contrast the same changes in climate will cause approximately a 15% decrease in new revenue per hectare in the typically wetter Kwazulu Natal Province. This difference in net revenue is attributed to the fact that farmers in the Northern Cape Province have already adapted to more arid conditions through the implementation of irrigation and thus are less sensitive to climate adversities. (11) Overall there will not be a significant change in the agricultural net revenue, but the areas with decreasing net revenues will greatly suffer if they are not able to adapt to the changes. Their ability to is a significant challenge, as these areas are already dominated by the poorer farming communities associated with the former apartheid ‘homelands.’
Climate change is a global problem largely caused by CO2 emissions from the developed countries, although developing countries are increasingly contributing. Both those in developed countries and developing countries will feel the effects of climate change, but the developing countries and poorer areas within countries will likely have a harder time adapting. In South Africa there rainfall patterns are expected to change and temperatures are predicted to get warmer. The agriculture industry is one of the sectors of South Africa’s economy that will be affected by climate change. Some areas of South Africa will benefit from the increased summer temperatures, as they tend to be the richer farming communities and have already adapted to a warmer and drier climate. Other areas will be negatively affected by the changes in climate, as they have not adopted irrigation. These areas are also mostly poorer farming communities, which may not be able to adapt fast enough to face the problems climate change poses for them.
1. Climate Change Secretariat, UNFCCC, A Guide to Climate Change and its Kyoto Protocol (2002), 6.
2. John Carey and Sarah R. Shapiro, “Global Warming,” Business Week, 16 August 2004, 60-69.
3. Robert T. Watson and others, United Nations Environment Programme, Protecting Our Planet Securing Our Future: Linkages Among Global Environmental Issues and Human Needs (1998), 13.
4. Ibid., 13-14.
6. Michael E. Meadows and Timm M. Hoffman, “Land degradation and climate change in South Africa,” The Geographical Journal 169 no.2 (2003): 170-171.
7. Ibid., 172.
8. Ibid., 176.
9. G.A. Gibetibouo and R.M. Hassan, “Measuring the economic impact of climate change on major South African field crops: a Ricardian approach,” Global and Planetary Change 47 (2005): 147-148.
10. Watson, 14.
11. Ibid., 149.