Service Contract No 2007 / 147-446 Strategic ... - Swaziland

4.2 Climate and climate changeSwaziland has a sub-tropical climate, with warm wet summers and cool dry winters, althoughclimatic conditions vary from region to region. Mean annual rainfall ranges from 700-1550mm in the Highveld to 400-550 mm in the Lowveld; in the Middleveld and the LubomboPlateau rainfall ranges between 550-850 mm 6 .Mean annual temperatures range from 17°C in the Highveld to 22°C in the Lowveld. Duringthe summer mean temperatures range from 20°C (Highveld) to 27°C (Lowveld) and in thewinter from 12°C (Highveld) to 18°C (Lowveld) (Simelane, 2007).The high vulnerability of Africa to various manifestations of climate change has beenconfirmed by the Inter-Governmental Panel on Climate Change (IPCC) and other reports.According to Swaziland’s first National Communication to the United Nations FrameworkConvention on Climate Change (UNFCCC), the projections from the climatic models point totemperature increases in the future with varying magnitudes, but mixed results with regardsto precipitation projections. The report states that “in general, the models project total annualrainfall amounts by 2075 falling below those received under current climate by single digitpercentages. The monthly situation projects amounts that are higher than those undercurrent climate in the late spring to midsummer period (October to January). For the rest ofthe months of the year projections give future rainfall amounts that are lower than undercurrent climate”.A consequence of the above is that ”as most of the country’s annual rainfall is received overthe summer period, an increase in precipitation over this period is likely to result in floodingconditions. The projections on winter rainfall reduction also pose the problem of higherpossibilities of drought occurrences”.According to the World Bank’s Climate Change Data Portal, the climate change modelsdisagree on whether Swaziland will become wetter or drier (e.g. the Global Climatic Models –GCMs – reviewed by the IPCC indicate reduced mean annual precipitation in the order of 4%by 2050, but a high resolution model indicates an increase of 21% by 2100). Temperaturesare expected to increase in the order of 1°C by 2050 (IPCC GCMs) and 2°C by 2100 (highresolution GCM). A moderate decrease in run-off (>35%) is expected, and a caution is givento that effect: “these areas are quite prone to desertification, so strict water management andsustainable land uses are important issues to consider”.4.3 Ecology and biodiversityThe country is divided into four distinct agro-ecological zones, based on elevation, landforms,geology, soils and vegetation (Van Wavere, and Nhlengetfwa, 1992), as shown in Figure 2below. Each of the three regions, the Highveld, the Middleveld and the Lowveld, occupyabout one-third of the country, whilst the Lubombo Range occupies less than one-tenth ofthe country.The Highveld, which runs along the western border of the country, is the upper part of anoverall escarpment consisting of a complex of steep slopes between low and high levels,dissected plateaus, plateau remnants, and associated hills, valleys and basins. The upperMiddleveld consists of strongly eroded plateau remnants and hills at an intermediate level ofthe overall escarpment with structurally defined basins in relatively protected positions. TheLower Middleveld is basically the piedmont zone of the escarpment, characterised bygenerally strongly eroded foot slopes.6 Water Profile of Swaziland – Encyclopaedia of Earth (http://www.eoearth.org/article/Water_profile_of_Swaziland)RDMU (Strategic Environmental Assessment of the National Adaptation Strategy) - Page 21