The present climate of East Africa varies considerable between the cool, moist conditions of the western highlands, to the warm, arid and semi-arid conditions of northern Kenya, southeast Ethiopia, Djibouti and Somalia. These climatic conditions are influenced by the region’s diverse topography and three prominent climatic process: the Inter-Tropical Convergence Zone (ITCZ), the Indian Monsoon and the El Niño Southern Oscillation (ENSO). These processes affect temperatures and, in particular, the timing, duration, quantity and quality of rainfall throughout the region. Changes in climatic conditions have been witnessed in recent years in the region, due either to natural climate variability or, possibly, climatic change. Temperatures in the region have risen by approximately 1.3°C since 1960 (an average rate of 0.28°C per decade). Seasonal shifts in precipitation as well as increased incidence of droughts and floods have also been observed in various countries (AF, 2010; McSweeney et al., 2009a; McSweeney et al., 2009b; DMHUEAT, 2006; Naess et al., 2010).
In the decades ahead, projections suggest that East Africa will see annual temperatures rise by 1.8oC to 4.3oC (with a mean of 3.2oC) by the period 2080 through 2099. Warming is likely to be greatest during the period of June to August (Christensen et al., 2007). Projected changes in precipitation patterns are less clear, due in large measure to uncertainty regarding how the inter-related processes of the ICTZ, tropical monsoon and ENSO patterns will be altered in a warmer world. Available reports, however (as synthesized in the 2007 Assessment Report of the Intergovernmental Panel on Climate Change), suggest that the region will likely experience an increase in average precipitation over the region. However, this increase will be accompanied by greater seasonal variation in rainfall patterns, a possible increase in the occurrence of intense precipitation events, and increased frequency of drought.
These changes in temperature and precipitation patterns will affect the economies of East Africa, primarily through their impacts on agriculture production, as well as pastoralism, hydropower production, biodiversity, coastal zones and human health. Future climate changes may affect East African socioeconomic sectors in the following ways (Boko et al., 2007; Christensen et al., 2007; Seitz and Nyangena, 2009; van de Steeg et al., 2009; Thornton et al., 2008):
- Water resources: Increased incidence of drought; increased rainfall during rainy seasons combined with prolonged and/or intensified dry seasons; decreased and/or increased runoff in river basins and disturbances in stream ecosystems may disrupt water supplies.
- Agriculture: Greater rainfall variability within and between seasons may have a considerable impact on crop productivity; one study projects declines in the yield from maize and certain bean varieties in over 50 to 70 per cent of East Africa. Depending on location and the crop in question, productivity may also increase (such as coffee production in higher altitude regions; CIAT, 2010). Climate change is also anticipated to have an effect on the livestock and fisheries sectors—significant sources of employment in East African countries such as Eritrea, Ethiopia and Kenya.
- Pastoralism: More precipitation may lead to enhance grass production, while heat stress caused by rising temperatures could lead to lower productivity and loss of livestock. Other concerns include a possible increased frequency of flooding during rainy periods and a potential increase in the livestock diseases that spread during the wet seasons.
- Hydropower: Many East African countries rely on hydropower for their electricity, a source that is vulnerable to changes in precipitation patterns.
- Biodiversity: Estimates suggest that 10 to 15 per cent of species within Africa may become critically endangered or extinct by 2050 due to warmer temperatures and changing precipitation patterns. This projection has consequent implications for the tourism sector of many East African countries.
- Human health: Higher temperatures combined with intense rainfall are projected to lead to more suitable conditions for malaria transmission in the highlands of Burundi, Ethiopia, Kenya and Rwanda.
- Coastal zones: Sea level rise and resulting coastal erosion are also of particular concern for certain East African countries, particularly Kenya and Tanzania (Seitz and Nyangena, 2009). Sea level rise is expected to lead to coastal flooding and the intrusion of saltwater into lagoons, coastal lakes and coastal aquifers, with impacts on local fisheries, aquaculture and drinking water sources.
Identified Adaptation Needs and Priorities
Adaptation priorities for East African countries have been identified through National Communications to the United Nations Framework Convention on Climate Change (UNFCCC), National Adaptation Programmes of Action (NAPAs) and studies conducted by regional experts. These documents reveal that East African countries share many of the same concerns, including impacts on: agriculture, pastoralism and food security; freshwater resources; forestry and sustainable land management; human health; and the need for improved weather forecasting, early warning and climate risk reduction. East African countries and experts have identified a number of priority adaptation options that would allow these countries to respond to climate change within these areas, including the following measures (GOT, 2007; KMENR, 2002; RMLEFWM, 2006; EMWR & NMA, 2007; UNEP et al., 2010):
- Agriculture, pastoralism and food security: promoting crop insurance systems, crop switching, enhanced rangeland management practices, sustainable land-use management, improved weather forecasting for farmers, and the adoption of climate resilient agricultural practices.
- Freshwater resources: integrated water resources management, conservation measures, the creation of water reservoirs, and the development of water recycling facilities.
- Forestry and sustainable land management: promotion of forestry and agro-forestry practice on farms and homesteads in arid and semi-arid areas; engaging in activities aimed at combatting desertification; the development of energy source alternatives to firewood; and the creation of community forest fire prevention plans.
- Human health: enhancement of public health campaigns and malaria containment programs; ensuring the availability of trained health staff; and surveillance of diseases and data collection.
Source: Review of Current and Planned Adaptation Action: East Africa. Contributing Authors: Hilary Hove, Daniella Echeverría, Jo-Ellen Parry (International Institute for Sustainable Development), 2011.