There are many "drivers" of the agricultural sector in South Africa, each of which can have wide -ranging repercussions not only in the production of food, fibre and forests, but also on GDP, employment or foreign exchange earnings. One such "driver" that already varies from year to year, and within any given year, is climate. Climate is vital for the selection of appropriate crops for a given locality or site, irrespective of whether farmers are planning for maximum economic returns or for sustaining their immediate family's livelihood, and the more detailed the knowledge, the more intelligently the land use can be planned on all scales, be they at the macro, farm or plot scales. Climate information is equally important for optimising agricultural practices and for day -to -day operational planning ranging from when and how much to irrigate, to timing of fertiliser application, the selection of cultivars / varieties or to deciding when to plant. The influence exercised by climate on living organisms is, however, exceedingly complex, not only because the individual climatic variables play important roles, but also because of the constant interaction between the variables.
Through direct and indirect human activities which are altering the composition of the global atmosphere, climate drivers such as rainfall, temperature and atmospheric carbon dioxide (CO2) concentrations that affect agricultural activities and output, are projected to change non -uniformly in magnitude, direction and variability over the next few decades, not only on a global scale, but more particularly so regionally and locally within South Africa. Such human - induced climate change is projected to occur in addition to the already ..