Box 92 Climate water availability and agriculture in Egypt

Egypt is one of the African countries that could be vulnerable to water stress under climate change. The water used in 2000 was estimated at about 70 km3 which is already far in excess of the available resources (Gueye et al., 2005). A major challenge is to close the rapidly increasing gap between the limited water availability and the escalating demand for water from various economic sectors. The rate of water utilisation has already reached its maximum for Egypt, and climate change will exacerbate this vulnerability.

Agriculture consumes about 85% of the annual total water resource and plays a significant role in the Egyptian national economy, contributing about 20% of GDP. More than 70% of the cultivated area depends on low-efficiency surface irrigation systems, which cause high water losses, a decline in land productivity, waterlogging and salinity problems (El-Gindy et al., 2001. Moreover, unsustainable agricultural practices and improper irrigation management affect the quality of the country's water resources. Reductions in irrigation water quality have, in their turn, harmful effects on irrigated soils and crops.

Institutional water bodies in Egypt are working to achieve the following targets by 2017 through the National Improvement Plan (EPIQ, 2002; ICID, 2005):

• improving water sanitation coverage for urban and rural areas;

• wastewater management;

• optimising use of water resources by improving irrigation efficiency and agriculture drainage-water reuse.

However, with climate change, an array of serious threats is apparent.

• Sea-level rise could impact on the Nile Delta and on people living in the delta and other coastal areas (Wahab, 2005).

• Temperature rises will be likely to reduce the productivity of major crops and increase their water requirements, thereby directly decreasing crop water-use efficiency (Abou-Hadid, 2006; Eid et al., 2006).

• There will probably be a general increase in irrigation demand (Attaher et al., 2006).

• There will also be a high degree of uncertainty about the flow of the Nile.

• Based on SRES scenarios, Egypt will be likely to experience an increase in water stress, with a projected decline in precipitation and a projected population of between 115 and 179 million by 2050. This will increase water stress in all sectors.

• Ongoing expansion of irrigated areas will reduce the capacity of Egypt to cope with future fluctuation in flow (Conway, 2005).

Using ten scenarios derived by using five climate models (CSIRO2, HadCM3, CGCM2, ECHAM and PCM) in conjunction with two different emissions scenarios, Strzepek and McCluskey (2006) arrived at the following conclusions regarding impacts of climate change on streamflow in Africa. First, the possible range of Africa-wide climate-change impacts on streamflow increases significantly between 2050 and 2100. The range in 2050 is from a decrease of 15% in streamflow to an increase of 5% above the 1961-1990 baseline. For 2100, the range is from a decrease of 19% to an increase of 14%. Second, for southern Africa, almost all countries except South Africa will probably experience a significant reduction in streamflow. Even for South Africa, the increases under the high emissions scenarios are modest at under 10% (Strzepek and McCluskey, 2006).

Additional assessments of climate change impacts on hydrology, based on six GCMs and a composite ensemble of African precipitation models for the period 2070-2099 derived from 21 fully coupled ocean-atmosphere GCMs, show various drainage impacts across Africa (de Wit and Stankiewicz, 2006). A critical 'unstable' area is identified for some parts, for example, the east-west band from Senegal to Sudan, separating the dry Sahara from wet Central Africa. Parts of southern Africa are projected to experience significant losses of runoff, with some areas being particularly impacted (e.g., parts of South Africa) (New, 2002; de Wit and Stankiewicz, 2006). Other regional assessments report emerging changes in the hydrology of some of the major water systems (e.g., the Okavango River basin) which could be negatively impacted by changes in climate; impacts that could possibly be greater than those associated with human activity (Biggs et al., 2004; Anderssen et al., 2006).

Assessments of impacts on water resources, as already indicated, currently do not fully capture multiple future water uses and water stress and must be approached with caution (see, e.g., Agoumi, 2003; Conway, 2005). Conway (2005) argues that there is no clear indication of how Nile flow will be affected by climate change because of the uncertainty about rainfall patterns in the basin and the influence of complex water management and water governance structures. Clearly, more detailed research on water hydrology, drainage and climate change is required. Future access to water in rural areas, drawn from low-order surface water streams, also needs to be addressed by countries sharing river basins (see de Wit and Stankiewicz, 2006). Climate change should therefore be considered among a range of other water governance issues in any future negotiations to share Nile water (Conway, 2005; Stern, 2007).

9.4.2 Energy

There are remarkably few studies available that examine the impacts of climate change on energy use in Africa (but see a recent regional assessment by Warren et al., 2006). However, even in the absence of climate change, a number of changes are expected in the energy sector. Africa's recent and rapid urban growth (UNEP, 2005) will lead to increases in aggregate commercial energy demand and emissions levels (Davidson et al., 2003), as well as extensive land-use and land-cover changes, especially from largely uncontrolled urban, peri-urban and rural settlements (UNEP/GRID-Arendal, 2002; du Plessis et al., 2003). These changes will alter existing surface microclimates and hydrology and will possibly exacerbate the scope and scale of climate-change impacts.

9.4.3 Health

Vigorous debate among those working in the health sector has improved our understanding of the links between climate variability (including extreme weather events) and infectious diseases (van Lieshout et al., 2004; Epstein and Mills, 2005; McMichael et al., 2006; Pascual et al., 2006; Patz and Olson, 2006). Despite various contentious issues (see Section, new assessments of the role of climate change impacts on health have emerged since the TAR. Results from the "Mapping Malaria Risk in Africa" project (MARA/ARMA) show a possible expansion and contraction, depending on location, of climatically suitable areas for malaria by 2020, 2050 and 2080 (Thomas et al., 2004). By 2050 and continuing into 2080, for example, a large part of the western Sahel and much of southern central Africa is shown to be likely to become unsuitable for malaria transmission. Other assessments (e.g., Hartmann et al., 2002), using 16 climate-change scenarios, show that by 2100, changes in temperature and precipitation could alter the geographical distribution of malaria in Zimbabwe, with previously unsuitable areas of dense human population becoming suitable for transmission. Strong southward expansion of the transmission zone will probably continue into South Africa.

Using parasite survey data in conjunction with results from the HadCM3 GCM, projected scenarios estimate a 5-7% potential increase (mainly altitudinal) in malaria distribution, with little increase in the latitudinal extent of the disease by 2100 (Tanser et al., 2003). Previously malaria-free highland areas in Ethiopia, Kenya, Rwanda and Burundi could also experience modest incursions of malaria by the 2050s, with conditions for transmission becoming highly suitable by the 2080s. By this period, areas currently with low rates of malaria transmission in central Somalia and the Angolan highlands could also become highly suitable. Among all scenarios, the highlands of eastern Africa and areas of southern Africa are likely to become more suitable for transmission (Hartmann et al., 2002).

As the rate of malaria transmission increases in the highlands, the likelihood of epidemics may increase due to the lack of protective genetic modifications in the newly-affected populations. Severe malaria-associated disease is more common in areas of low to moderate transmission, such as the highlands of East Africa and other areas of seasonal transmission. An epidemic in Rwanda, for example, led to a four-fold increase in malaria admissions among pregnant women and a five-fold increase in maternal deaths due to malaria (Hammerich et al., 2002). The social and economic costs of malaria are also huge and include considerable costs to individuals and households as well as high costs at community and national levels (Holding and Snow, 2001; Utzinger et al., 2001; Malaney et al., 2004).

Climate variability may also interact with other background stresses and additional vulnerabilities such as immuno-

compromised populations (HIV/AIDS) and conflict and war (Harrus and Baneth, 2005) in the future, resulting in increased susceptibility and risk of other infectious diseases (e.g., cholera) and malnutrition. The potential for climate change to intensify or alter flood patterns may become a major additional driver of future health risks from flooding (Few et al., 2004). The probability that sea-level rise could increase flooding, particularly on the coasts of eastern Africa (Nicholls, 2004), may also have implications for health (McMichael et al., 2006).

Relatively fewer assessments of possible future changes in animal health arising from climate variability and change have been undertaken. The demographic impacts on trypanosomiasis, for example, can arise through modification of the habitats suitable for the tsetse fly. These modifications can be further exacerbated by climate variability and climate change. Climate change is also expected to affect both pathogen and vector habitat suitability through changes in moisture and temperature (Baylis and Githeko, 2006). Changes in disease distribution, range, prevalence, incidence and seasonality can all be expected. However, there is low certainty about the degree of change. Rift Valley Fever epidemics, evident during the 1997/98 El Niño event in East Africa and associated with flooding, could increase with a higher frequency of El Niño events. Finally, heat stress and drought are likely to have further negative impacts on animal health and production of dairy products, as already observed in the USA (St-Pierre et al., 2003; see also Warren et al., 2006).

9.4.4 Agriculture

Results from various assessments of impacts of climate change on agriculture based on various climate models and SRES emissions scenarios indicate certain agricultural areas that may undergo negative changes. It is estimated that, by 2100, parts of the Sahara are likely to emerge as the most vulnerable, showing likely agricultural losses of between 2 and 7% of GDP. Western and central Africa are also vulnerable, with impacts ranging from 2 to 4%. Northern and southern Africa, however, are expected to have losses of 0.4 to 1.3% (Mendelsohn et al., 2000b).

More recent assessments combining global- and regional-scale analysis, impacts of climate change on growing periods and agricultural systems, and possible livelihood implications, have also been examined (Jones and Thornton, 2003; Huntingford et al., 2005; Thornton et al., 2006). Based on the A1FI scenario, both the HadCM3 and ECHAM4 GCMs agree on areas of change in the coastal systems of southern and eastern Africa (Figure 9.4). Under both the A1 and B1 scenarios, mixed rain-fed semi-arid systems are shown to be affected in the Sahel, as well as mixed rain-fed and highland perennial systems in the Great Lakes region and in other parts of East Africa. In the B1 world, marginal areas (e.g., semi-arid lands) become more marginal, with moderate impacts on coastal systems (Thornton et al., 2006; see Chapter 5, Section 5.4.2). Such changes in the growing period are important, especially when viewed against

Kilo met era 0 670 13J0 2.010 2 68(5

Figure 9.4. Agricultural areas within the livestock-only systems (LGA) in arid and semi-arid areas, and rain-fed mixed crop/livestock systems (MRA) in semi-arid areas, are projected by the HadCM3 GCM to undergo >20% reduction in length of growing period to 2050, SRES A1 (left) and B1 (right) emissions scenarios, after Thornton et al. (2006).

Kilo met era 0 670 13J0 2.010 2 68(5

Figure 9.4. Agricultural areas within the livestock-only systems (LGA) in arid and semi-arid areas, and rain-fed mixed crop/livestock systems (MRA) in semi-arid areas, are projected by the HadCM3 GCM to undergo >20% reduction in length of growing period to 2050, SRES A1 (left) and B1 (right) emissions scenarios, after Thornton et al. (2006).

possible changes in seasonality of rainfall, onset of rain days and intensity of rainfall, as indicated in Sections 9.2.1 and 9.3.1.

Other recent assessments using the FAO/IIASA Agro-Ecological Zones model (AEZ) in conjunction with IIASA's world food system or Basic Linked System (BSL), as well as climate variables from five different GCMs under four SRES emissions scenarios, show further agricultural impacts such as changes in agricultural potential by the 2080s (Fischer et al.,

2005). By the 2080s, a significant decrease in suitable rain-fed land extent and production potential for cereals is estimated under climate change. Furthermore, for the same projections, for the same time horizon the area of arid and semi-arid land in Africa could increase by 5-8% (60-90 million hectares). The study shows that wheat production is likely to disappear from Africa by the 2080s. On a more local scale, assessments have shown a range of impacts. Southern Africa would be likely to experience notable reductions in maize production under possible increased ENSO conditions (Stige et al., 2006).

In other countries, additional risks that could be exacerbated by climate change include greater erosion, deficiencies in yields from rain-fed agriculture of up to 50% during the 2000-2020 period, and reductions in crop growth period (Agoumi, 2003). A recent study on South African agricultural impacts, based on three scenarios, indicates that crop net revenues will be likely to fall by as much as 90% by 2100, with small-scale farmers being the most severely affected. However, there is the possibility that adaptation could reduce these negative effects (Benhin, 2006). In Egypt, for example, climate change could decrease national production of many crops (ranging from -11% for rice to -28% for soybeans) by 2050 compared with their production under current climate conditions (Eid et al., 2006). Other agricultural activities could also be affected by climate change and variability, including changes in the onset of rain days and the variability of dry spells (e.g., Reason et al., 2005; see also Chapter 5).

However, not all changes in climate and climate variability will be negative, as agriculture and the growing seasons in certain areas (for example, parts of the Ethiopian highlands and parts of southern Africa such as Mozambique), may lengthen under climate change, due to a combination of increased temperature and rainfall changes (Thornton et al., 2006). Mild climate scenarios project further benefits across African croplands for irrigated and, especially, dryland farms. However, it is worth noting that, even under these favourable scenarios, populated regions of the Mediterranean coastline, central, western and southern Africa are expected to be adversely affected (Kurukulasuriya and Mendelsohn, 2006a).

Fisheries are another important source of revenue, employment and proteins. They contribute over 6% of Namibia's and Senegal's GDP (Njaya and Howard, 2006). Climate-change impacts on this sector, however, need to be viewed together with other human activities, including impacts that may arise from governance of fresh and marine waters (AMCEN/UNEP, 2002). Fisheries could be affected by different biophysical impacts of climate change, depending on the resources on which they are based (Niang-Diop, 2005; Clark,

2006). With a rise in annual global temperature (e.g. of the order of 1.5 to 2.0°C) fisheries in North West Africa and the East

African lakes are shown to be impacted (see ECF and Potsdam Institute, 2004; Warren et al., 2006). In coastal regions that have major lagoons or lake systems, changes in freshwater flows and a greater intrusion of salt water into lagoons will affect the species that are the basis of inland fisheries or aquaculture (République de Côte d'Ivoire, 2000; République du Congo, 2001; Cury and Shannon, 2004). In South Africa, fisheries could be affected by changes in estuaries, coral reefs and upwelling; with those that are dependent on the first two ecosystems being the most vulnerable (Clark, 2006). Recent simulations based on the NCAR GCM under a doubling of carbon dioxide indicate that extreme wind and turbulence could decrease productivity by 50-60%, while turbulence will probably bring about a 10% decline in productivity in the spawning grounds and an increase of 3% in the main feeding grounds (Clark et al., 2003).

The impact of climate change on livestock farming in Africa was examined by Seo and Mendelsohn (2006a, b). They showed that a warming of 2.5°C could increase the income of small livestock farms by 26% (+US$1.4 billion). This increase is projected to come from stock expansion. Further increases in temperature would then lead to a gradual fall in net revenue per animal. A warming of 5°C would probably increase the income of small livestock farms by about 58% (+US$3.2 billion), largely as a result of stock increases. By contrast, a warming of 2.5°C would be likely to decrease the income of large livestock farms by 22% (-US$13 billion) and a warming of 5°C would probably reduce income by as much as 35% (-US$20 billion). This reduction in income for large livestock farms would probably result both from a decline in the number of stock and a reduction in the net revenue per animal. Increased precipitation of 14% would be likely to reduce the income of small livestock farms by 10% (-US$ 0.6 billion), mostly due to a reduction in the number of animals kept. The same reduction in precipitation would be likely to reduce the income of large livestock farms by about 9% (-US$5 billion), due to a reduction both in stock numbers and in net revenue per animal.

The study by Seo and Mendelsohn (2006a) further shows that higher temperatures are beneficial for small farms that keep goats and sheep because it is easy to substitute animals that are heat-tolerant. By contrast, large farms are more dependent on species such as cattle, which are not heat-tolerant. Increased precipitation is likely to be harmful to grazing animals because it implies a shift from grassland to forests and an increase in harmful disease vectors, and also a shift from livestock to crops.

Assessing future trends in agricultural production in Africa, even without climate change, remains exceedingly difficult (e.g., contributions to GDP and impacts on GDP because of climate variability and other factors - see, for example, Mendelsohn et al., 2000b; Tiffen, 2003; Arrow et al., 2004; Desta and Coppock, 2004; Ferguson, 2006). While agriculture is a key source of livelihood in Africa, there is evidence that off-farm incomes are also increasing in some areas - up to 60 to 80% of total incomes in some cases (Bryceson, 2002). Urbanisation and off-farm increases in income also seem to be contributing to reduced farm sizes. Future scenarios and projections may thus need to include such changes, as well as relevant population estimates, allowing for the impact of HIV/AIDS, especially on farm labour productivity (Thornton et al., 2006).

9.4.5 Ecosystems

A range of impacts on terrestrial and aquatic ecosystems has been suggested under climate change (see, for example, Leemans and Eickhout, 2004), some of which are summarised in Table 9.1 (for further details see Chapter 4; Nkomo et al., 2006; Warren et al., 2006).

Mountain ecosystems appear to be undergoing significant observed changes (see Section, aspects of which are likely to be linked to complex climate-land interactions and which may continue under climate change (e.g., IPCC, 2007a). By 2020, for example, indications are that the ice cap on Mt. Kilimanjaro could disappear for the first time in 11,000 years (Thompson et al., 2002). Changes induced by climate change are also likely to result in species range shifts, as well as in changes in tree productivity, adding further stress to forest ecosystems (UNEP, 2004). Changes in other ecosystems, such as grasslands, are also likely (for more detail, see assessments by Muriuki et al., 2005; Levy, 2006).

Mangroves and coral reefs, the main coastal ecosystems in Africa, will probably be affected by climate change (see Chapter 4, Box 4.4; Chapter 6, Section 6.4.1, Box 6.1). Endangered species associated with these ecosystems, including manatees and marine turtles, could also be at risk, along with migratory birds (Government of Seychelles, 2000; Republic of Ghana, 2000; République Démocratique du Congo, 2000). Mangroves could also colonise coastal lagoons because of sea-level rise (République du Congo, 2001; Rocha et al., 2005).

The coral bleaching following the 1997/1998 extreme El Niño, as mentioned in Section 9.2.1, is an indication of the potential impact of climate change-induced ocean warming on coral reefs (Lough, 2000; Muhando, 2001; Obura, 2001); disappearance of low-lying corals and losses of biodiversity could also be expected (République de Djibouti, 2001; Payet and Obura, 2004). The proliferation of algae and dinoflagellates during these warming events could increase the number of people affected by toxins (such as ciguatera) due to the consumption of marine food sources (Union des Comores, 2002; see also Chapter 16, Section 16.4.5). In the long term, all these impacts will have negative effects on fisheries and tourism (see also Chapter 5, Box 5.4). In South Africa, changes in estuaries are expected mainly as a result of reductions in river runoff and the inundation of salt marshes following sea-level rise (Clark, 2006).

The species sensitivity of African mammals in 141 national parks in sub-Saharan Africa was assessed using two climate-change scenarios (SRES A2 and B2 emissions scenarios with the HadCM3 GCM, for 2050 and 2080), applying a simple IUCN Red List assessment of potential range loss (Thuiller et al., 2006). Assuming no migration of species, 10-15% of the species were projected to fall within the IUCN Critically Endangered or Extinct categories by 2050, increasing to 25-40% of species by 2080. Assuming unlimited species migration, the results were less extreme, with these proportions dropping to approximately 10-20% by 2080. Spatial patterns of loss and gain showed contrasting latitudinal patterns, with a westward range shift of species around the species-rich equatorial transition zone in central Africa, and an eastward shift in southern Africa; shifts which appear to be related mainly to the latitudinal aridity gradients across these ecological transition zones

Table 9.1. Significant ecosystem responses estimated in relation to climate change in Africa. These estimations are based on a variety of scenarios (for further details on models used and impacts see Chapter 4, Section 4.4 and Table 4.1).

Ecosystem impacts

Area affected

Scenario used and source

About 5,000 African plant species impacted: Africa substantial reductions in areas of suitable climate for 81 -97% of the 5,197 African plants examined, 25-42% lose all area by 2085.

Fynbos and succulent Karoo biomes:

losses of between 51 and 61%.

Critically endangered taxa (e.g. Proteaceae):

losses increase, and up to 2% of the 227 taxa become extinct.

Losses of nyala and zebra:

Kruger Park study estimates 66% of species lost.

Loss of bird species ranges: (restriction of movements). An estimated 6 species could lose substantial portions of their range.

Sand-dune mobilisation: enhanced dune activity.

Lake ecosystems, wetlands


South Africa

HadCM3 for years 2025, 2055, 2085, plus other models -shifts in climate suitability examined (McClean et al., 2005)

Projected losses by 2050, see details of scenarios (Midgley et al., 2002; see Chapter 4, Section 4.4, Table 4.1) 4 land use and 4 climate change scenarios (HadCM2 IS92aGGa) (Bomhard et al., 2005)

Hadley Centre Unified Model, no sulphates (Erasmus et al., 2002; see Chapter 4, Section 4.4.3)

Projected losses of over 50% for some species by 2050 using the HadCM3 GCM with an A2 emissions scenario (Simmons et al., 2004; see Chapter 4, Section 4.4.8)

Southern Kalahari basin - northern Scenarios: HadCM3 GCM, SRES A2, B2 and A1fa, IS92a. South Africa, Angola and Zambia. By 2099 all dune fields shown to be highly dynamic For details in Sahel, see Section (Thomas et al., 2005; see Chapter 4, Section 4.4.2) 9.6.2 and Chapter 4, Section 4.3.

Lake Tanganyika Carbon isotope data show aquatic losses of about 20%

with a 30% decrease in fish yields. It is estimated that climate change may further reduce lake productivity (O'Reilly et al., 2003; see Chapter 4, Section 4.4.8)

Complex impacts on grasslands inc- See detailed discussion Chapter 4, Section 4.4.3 luding the role of fire (southern Africa)

Low-lying coastal areas


South Africa (Kruger Park)

Southern African bird species (Nama-Karoo area)

9.4.6 Coastal zones

In Africa, highly productive ecosystems (mangroves, estuaries, deltas, coral reefs), which form the basis for important economic activities such as tourism and fisheries, are located in the coastal zone. Forty percent of the population of West Africa live in coastal cities, and it is expected that the 500 km of coastline between Accra and the Niger delta will become a continuous urban megalopolis of more than 50 million inhabitants by 2020 (Hewawasam, 2002). By 2015, three coastal megacities of at least 8 million inhabitants will be located in Africa (Klein et al., 2002; Armah et al., 2005; Gommes et al., 2005). The projected rise in sea level will have significant impacts on these coastal megacities because of the concentration of poor populations in potentially hazardous areas that may be especially vulnerable to such changes (Klein et al., 2002; Nicholls, 2004). Cities such as Lagos and Alexandria will probably be impacted. In very recent assessments of the potential flood risks that may arise by 2080 across a range of SRES scenarios and climate change projections, three of the five regions shown to be at risk of flooding in coastal and deltaic areas of the world are those located in Africa: North Africa, West Africa and southern Africa (see Nicholls and Tol, 2006; for more detailed assessments, see Warren et al., 2006).

Other possible direct impacts of sea-level rise have been examined (Niang-Diop et al., 2005). In Cameroon, for example, indications are that a 15% increase in rainfall by 2100 would be likely to decrease the penetration of salt water in the Wouri estuary (République de Côte d'Ivoire, 2000). Alternatively, with an 11% decrease in rainfall, salt water could extend up to about 70 km upstream. In the Gulf of Guinea, sea-level rise could induce overtopping and even destruction of the low barrier beaches that limit the coastal lagoons, while changes in precipitation could affect the discharges of rivers feeding them. These changes could also affect lagoonal fisheries and aquaculture (République de Côte d'Ivoire, 2000). Indian Ocean islands could also be threatened by potential changes in the location, frequency and intensity of cyclones; while East African coasts could be affected by potential changes in the frequency and intensity of ENSO events and coral bleaching (Klein et al., 2002). Coastal agriculture (e.g., plantations of palm oil and coconuts in Benin and Côte d'Ivoire, shallots in Ghana) could be at risk of inundation and soil salinisation. In Kenya, losses for three crops (mangoes, cashew nuts and coconuts) could cost almost US$500 million for a 1 m sea-level rise (Republic of Kenya, 2002). In Guinea, between 130 and 235 km2 of rice fields (17% and 30% of the existing rice field area) could be lost as a result of permanent flooding, depending on the inundation level considered (between 5 and 6 m) by 2050 (République de Guinée, 2002). In Eritrea, a 1 m rise in sea level is estimated to cause damage of over US$250 million as a result of the submergence of infrastructure and other economic installations in Massawa, one of the country's two port cities (State of Eritrea, 2001). These results confirm previous studies stressing the great socio-economic and physical vulnerability of settlements located in marginal areas.

9.4.7 Tourism

Climate change could also place tourism at risk, particularly in coastal zones and mountain regions. Important market changes could also result from climate change (World Tourism Organization, 2003) in such environments. The economic benefits of tourism in Africa, which according to 2004 statistics accounts for 3% of worldwide tourism, may change with climate change (World Tourism Organization, 2005). However, very few assessments of projected impacts on tourism and climate change are available, particularly those using scenarios and GCM outputs. Modelling climate changes as well as human behaviour, including personal preferences, choices and other factors, is exceedingly complex. Although scientific evidence is still lacking, it is probable that flood risks and water-pollution-related diseases in low-lying regions (coastal areas), as well as coral reef bleaching as a result of climate change, could impact negatively on tourism (McLeman and Smit, 2004). African places of interest to tourists, including wildlife areas and parks, may also attract fewer tourists under marked climate changes. Climate change could, for example, lead to a poleward shift of centres of tourist activity and a shift from lowland to highland tourism (Hamilton et al., 2005).

9.4.8 Settlements, industry and infrastructure

Climate variability, including extreme events such as storms, floods and sustained droughts, already has marked impacts on settlements and infrastructure (Freeman and Warner, 2001; Mirza, 2003; Niasse et al., 2004; Reason and Keibel, 2004). Indeed, for urban planners, the biggest threats to localised population concentrations posed by climate variability and change are often expected to be from little-characterised and unpredictable rapid-onset disasters such as storm surges, flash floods and tropical cyclones (Freeman, 2003). Negative impacts of climate change could create a new set of refugees, who may migrate into new settlements, seek new livelihoods and place additional demands on infrastructure (Myers, 2002; McLeman and Smit, 2005). A variety of migration patterns could thus emerge, e.g., repetitive migrants (as part of ongoing adaptation to climate change) and short-term shock migrants (responding to a particular climate event). However, few detailed assessments of such impacts using climate as a driving factor have been undertaken for Africa.

In summary, a range of possible impacts of climate change has been discussed in this section (for other summaries, see Epstein and Mills, 2005; Nkomo et al., 2006). The roles of some other stresses that may compound climate-induced changes have also been considered. Clearly, several areas require much more detailed investigation (particularly in the energy, tourism, settlement and infrastructure sectors). Despite the uncertainty of the science and the huge complexity of the range of issues outlined, initial assessments show that several regions in Africa may be affected by different impacts of climate change (Figure 9.5). Such impacts, it is argued here, may further constrain development and the attainment of the MDGs in Africa. Adaptive capacity and adaptation thus emerge as critical areas for consideration on the continent.

Climate change could decrease mixed rain-fed and semi-arid systems, particularly the length of the growing period, e.g. on the margins of the Sahel. (9.4.4)

Some assessments show increased water stress and possible runoff decreases in parts of North Africa by 2050. While climate change should be considered in any future negotiations to share Nile water, the role of water basin management is also key. (9.4.1)

Rainfall is likely to increase in some parts of East Africa, according to some projections, resulting in various hydrological outcomes. (9.4.1)

Previously malaria-free highland areas in Ethiopia, Kenya, Rwanda and Burundi could experience modest changes to stable malaria by the 2050s, with conditions for transmission becoming highly suitable by the 2080s. (9.4.3)

Ecosystem impacts, including impacts on mountain biodiversity, could occur. Declines in fisheries in some major East African lakes could occur. (9.4.5)

Possible changes in rainfall and storms

Assessments of water availability, including water stress and water drainage, show that parts of southern Africa are highly vulnerable to climate variability and change. Possible heightened water stress in some river basins. (9.4.3)

Southward expansion of the transmission zone of malaria may likely occur. (9.4.3)

By 2099, dune fields may become highly dynamic, from northern South Africa to Angola and Zambia.

Some biomes, for example the Fynbos and Succulent Karoo in southern Africa, are likely to be the most vulnerable ecosystems to projected climate changes, whilst the savanna is argued to be more resilient. (9.4.5)

Food security, already a humanitarian crisis in the region, is likely to be further aggravated by climate variability and change, aggravated by HIV/AIDs, poor governance and poor adaptation. (9.4.4) (9.6.1)

Changes in ecosystem range and species location Changes in water availability coupled to climate change

Possible changes in rainfall and storms

Desert dune shifts

Sea-level rise and possible flooding in megacities

Changes in health possibly linked to climate change

Conflict zones

Figure 9.5. Examples of current and possible future impacts and vulnerabilities associated with climate variability and climate change for Africa (for details see sections highlighted in bold). Note that these are indications of possible change and are based on models that currently have recognised limitations.

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