The climate of southern Africa is generally subtropical, but is characterized by a varied latitudinal rainfall distribution. The southernmost countries of Botswana, Lesotho, Namibia, South Africa and Swaziland experience a low rainfall index and high variability, while the northernmost countries of Malawi, Mozambique, Zambia and Zimbabwe experience higher annual rainfall and lower variability (UNEP and ICRAF, 2006). This diversity of climatic conditions is reflected in southern Africa’s wide array of agro-ecological zones (UNEP and ICRAF, 2006). Studies suggest that the climate of southern Africa changed during the 20th century: mean annual temperature rose by approximately 0.5°C; inter-annual rainfall variability increased since the 1970s; the extent and intensity of drought events grew over the past several decades; and the occurrence of heavy rainfall events escalated in a number of countries (UNEP and ICRAF, 2006; Boko et al, 2007, and citations therein; SEI, 2008).
Determination of whether these observed changes are indicators of how southern Africa’s climate will change in the future is challenging due to limited understanding of two of the key processes that drive the region’s climate—the El Nino-Southern Oscillation and the Inter-Tropical Convergence Zone. Development of climate projections is also hampered by deficiencies in Africa’s meteorological data and the limited capacity of current Global Circulation Models to replicate African conditions. Within these limitations, available projections suggest that southern Africa may experience a mean annual temperature rise of between 1.9 and 4.8°C (with a mean of 3.4°C) by the period of 2080 to 2099 (Christensen et al, 2007). Greater uncertainty remains regarding how precipitation patterns may shift in southern Africa. Existing studies, though, suggest that mean annual rainfall in the region as a whole will decline by the period of 2080–2099, with the greatest decline occurring during June to August. An increase in the intensity of high-rainfall events is also projected to occur (Christensen et al, 2007). Rising air and sea surface temperatures have the potential to lead to more frequent and intense tropical storms in the southern Indian Ocean (Christensen et al., 2007) and to more frequent droughts (NCAR, 2005).
These projected climatic trends are anticipated to adversely affect a variety of socioeconomic sectors in southern Africa. Of particular concern to countries in the region are the projected impacts of climate change on agricultural systems, the quantity and quality of freshwater resources, coastal zones, fisheries, forests, biodiversity and tourism. These concerns include:
- Agriculture—As rain-fed agriculture is a significant source of employment and a large proportion of many countries’ economies, concerns include: potential decreases in the extent of land suitable for rain-fed agriculture; possible impacts on the production potential of certain crops, including maize; projected shifts in growing seasons; increased rates of evapotranspiration; enhanced vulnerability of the livestock and pastoralism sectors to heat stress and drought; and negative impacts on food security.
- Freshwater resources—Particularly in countries that are already water stressed and in island states that have limited access to ground and surface water, concerns include: decreased water quality and availability; saline intrusion in coastal areas; potentially significant decreases in stream flow and runoff; and negative impacts on hydropower production.
- Coastal zones and fisheries—As coastal areas are home to large populations and the site of critical economic activities, concerns include: enhanced coastal erosion due to sea level rise; damage to coastal infrastructure; shifts or declines of fish populations due to coral reef bleaching and changes in ocean upwelling and currents, with consequent implications for food security and local economies; loss of marine resources and biodiversity; and associated negative impacts on tourism.
- Human health—As human health is already compromised in the region due to factors such as underdeveloped health infrastructure, high levels of poverty and a high incidence of HIV/AIDS, concerns include: increased food insecurity; malnutrition and water scarcity; diarrheal sicknesses; and the possibility of greater spatial and temporal transmission of malaria, cholera and schistosomiasis.
- Biodiversity and tourism—The region’s diverse array of agroecological zones and large tourism sector has raised concerns regarding: greater movement of the sand dune fields of the Southern Kalahari basin; an increase in the number of species identified as critically endangered or extinct; changes in ecosystems; and possible negative impacts on tourism.
Identified Adaptation Needs and Priorities
A number of common adaptation priorities have been identified by southern African countries through expert studies, National Communications to the United Nations Framework Convention on Climate Change (UNFCCC), National Adaptation Programmes of Action (NAPAs), national strategies and other sources. These shared concerns stem in part from the high dependence of many countries on climate-sensitive sectors, such as agriculture (crop and livestock), tourism, fisheries and forestry (Madzwamuse, 2010). All countries have identified agriculture as a priority area for adaptation action, with other common priorities including freshwater resources, coastal zones and fisheries, disaster risk management, forestry and human health. A wide range of adaptation priorities in these socioeconomic sectors have been identified, including the following (UNEP and ICRAF, 2006; BMWTC, 2001; WWF, 2011; NMET, 2008; CMRDFHE, 2006; ZMTENR, 2007; MICOA, 2007; MMNRE, 2006; SNCCC, 2009):
- Agriculture: crop switching; planting new seed varieties; improving water forecasting systems; raising awareness of the effects of climate change within farming communities; enhancing water efficiency and irrigation measures; instituting rainwater storage systems; agroforestry; and drought early warning systems.
- Freshwater resources: water conservation, recycling and efficiency measures; inter-basin water transfer; improved water resource planning; regional water partnerships; short-term contingency planning; and drought relief measures, as well as better drought monitoring and forecasting.
- Disaster risk reduction and meteorological research: the establishment or expansion of weather monitoring stations; meteorological training; the creation of early warning systems for different climate-related threats; and the improvement of channels of communication between weather monitoring stations and remote communities.
- Coastal zones and fisheries: formulation of integrated coastal zone management strategies; enhanced climate change research and data collection and the possibility of sea level rise in the region; improved public awareness of the potential impacts of climate change and implications for fishery yields; and economic diversification.
- Forestry: reforestation and agroforestry; identification of species that are better adapted to higher temperatures and lower precipitation; development of alternative energy sources; and promotion of natural regeneration of indigenous forests.
- Human health: integration of climate change into prevention and monitoring programs for disease prevention; extension of treatment facilities; and improvement of monitoring and forecasting systems.