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Progress in the area of international climate negotiation has been the site of substantively increased activity of late, yet the task of utilizing appropriate spatial scale climate change projections to understand climate change impacts on sensitive sectors remains challenging. The study described here, undertaken in semi-arid south western South Africa, shows how downscaled climate change projections may be used to characterize climate change impacts in an area that is both valuable from a conservation point of view, yet at the same time serves as host to input intensive commercial agribusiness in the form of potato and rooibos tea production. Such potentially polarized land management objectives have given rise to initiatives to develop better practice guidelines for undertaking intensive commercial agriculture in a sensitive biodiverse environment. The study suggests that climate change may make the achievement of such better practice significantly more challenging. Climate change is here seen as one of a number of critically interacting multiple stressors affecting the area; including the trend to input-intensive farming and competing demands for water.

The KAROO drought assessment model simplifies veld growth responses to rainfall variability by simulation of the growth and dieback of a hypothetical plant species. Soil water content is treated as a simple weighting factor which determines the plant's growth rate as a weighted average of two basic growth rates, viz. those under wellwatered and dry soil conditions. Multiple growth stages of variable extent are postulated on the basis of evolutionary forcing by Karoo rainfall patterns. The model was fitted to growth data of a Karoo dwarf shrub species, assuming three growth stages which are initiated when the annual growth equals 0 (on day 1), 3 and 50% of that of an equivalent, well-watered plant. The averaging of basic growth rates needs further investigation in order to better simulate compensatory growth after drought.

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In order to take advantage of market proximity, intensive livestock-production units are established on the outskirts of cities. Approximately 70 percent of the poultry and pigs in the Republic is kept in the Transvaal and Western Cape. The total amount of wastes produced in intensive animal units in South Africa is estimated at 9,8 million tons per annum. Waste contains large amounts of plant nutrients, and if handling is incorrect, serious pollution will occur. Pollution takes place when plant nutrients and salts infiltrate the soil in excess of the crop requirement and would result in saline soil or pollution of the groundwater. Waste washed away by surface run-off, will render rivers and dams useless. Water contaminated with pathogenes present in animal waste can cause and spread disease. Although the technology for the safe handling of animal waste exists, the number of cases of pollution is annually increasing.