9 Africa Coordinating Lead Authors: Michel Boko (Benin), Isabelle Niang (Senegal), Anthony Nyong (Nigeria), Coleen Vogel (South Africa) Lead Authors: Andrew Githeko (Kenya), Mahmoud Medany (Egypt), Balgis Osman-Elasha (Sudan), Ramadjita Tabo (Chad), Pius Yanda (Tanzania) Contributing Authors: Francis Adesina (Nigeria), Micheline Agoli-Agbo (Benin), Samar Attaher (Egypt), Lahouari Bounoua (USA), Nick Brooks (UK), Ghislain Dubois (France), Mukiri wa Githendu (Kenya), Karim Hilmi (Morocco), Alison Misselhorn (South Africa), John Morton (UK), Imoh Obioh (Nigeria), Anthony Ogbonna (UK), Hubert N’Djafa Ouaga (Chad), Katharine Vincent (UK), Richard Washington (South Africa), Gina Ziervogel (South Africa) Review Editors: Frederick Semmazzi (USA), Mohamed Senouci (Algeria) This chapter should be cited as: Boko, M., I. Niang, A. Nyong, C. Vogel, A. Githeko, M. Medany, B. Osman-Elasha, R. Tabo and P. Yanda, 2007: Africa. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge UK, 433-467. Africa Chapter 9 Table of Contents .....................................................435 9.4.4 Agriculture ............................................................447 Executive summary 9.4.5 Ecosystems ...........................................................449 ........................................................435 9.1 Introduction 9.4.6 Coastal zones........................................................450 9.1.1 Summary of knowledge assessed in the Third Assessment Report ...............................................435 9.4.7 Tourism ..................................................................450 9.1.2 New advances and approaches used in the 9.4.8 Settlements, industry and infrastructure................451 Fourth Assessment Report....................................436 ..452 9.5 Adaptation constraints and opportunities ...................436 9.2 Current sensitivity/vulnerability 9.5.1 Adaptation practices .............................................452 9.2.1 Current sensitivity to climate and weather.............436 9.5.2 Adaptation costs, constraints and opportunities....453 Box 9.1 Environmental changes on Mt. Kilimanjaro .........438 .........................................................454 9.2.2 Current sensitivity and vulnerability to other 9.6 Case studies stresses .................................................................440 9.6.1 Food insecurity: the role of climate variability, change and other stressors ...................................454 ..................443 9.3 Assumptions about future trends 9.6.2 Indigenous knowledge systems ............................456 9.3.1 Climate-change scenarios.....................................443 9.3.2 Socio-economic scenarios ....................................444 9.7 Conclusions: links between climate ...........457 change and sustainable development 9.4 Expected key future impacts and ...444 9.8 Key uncertainties, confidence levels, ......457 vulnerabilities, and their spatial variation unknowns, research gaps and priorities 9.4.1 Water .....................................................................444 9.8.1 Uncertainties, confidence levels and unknowns....457 Box 9.2. Climate, water availability and agriculture 9.8.2 Research gaps and priorities.................................458 in Egypt .................................................................445 9.4.2 Energy....................................................................446 ......................................................................460 References 9.4.3 Health ....................................................................446 434 Chapter 9 Africa Executive summary 350-600 million people by the 2020s and 2050s, respectively. [9.2.1, 9.2.2, 9.4.1] Africa is one of the most vulnerable continents to climate Changes in a variety of ecosystems are already being change and climate variability, a situation aggravated by detected, particularly in southern African ecosystems, at a the interaction of ‘multiple stresses’, occurring at various faster rate than anticipated (very high confidence). levels, and low adaptive capacity (high confidence). Climate change, interacting with human drivers such as Africa’s major economic sectors are vulnerable to current climate deforestation and forest fires, are a threat to Africa’s forest sensitivity, with huge economic impacts, and this vulnerability ecosystems. Changes in grasslands and marine ecosystems are is exacerbated by existing developmental challenges such as also noticeable. It is estimated that, by the 2080s, the endemic poverty, complex governance and institutional proportion of arid and semi-arid lands in Africa is likely to dimensions; limited access to capital, including markets, increase by 5-8%. Climate change impacts on Africa’s infrastructure and technology; ecosystem degradation; and ecosystems will probably have a negative effect on tourism as, complex disasters and conflicts. These in turn have contributed according to one study, between 25 and 40% of mammal to Africa’s weak adaptive capacity, increasing the continent’s species in national parks in sub-Saharan Africa will become vulnerability to projected climate change. [9.2.2, 9.5, 9.6.1] endangered. [9.2.2, 9.4.4, 9.4.5] African farmers have developed several adaptation Climate variability and change could result in low-lying options to cope with current climate variability, but such lands being inundated, with resultant impacts on coastal adaptations may not be sufficient for future changes of settlements (high confidence). climate (high confidence). Climate variability and change, coupled with human-induced Human or societal adaptive capacity, identified as being low changes, may also affect ecosystems e.g., mangroves and coral for Africa in the Third Assessment Report, is now better reefs, with additional consequences for fisheries and tourism. understood and this understanding is supported by several case The projection that sea-level rise could increase flooding, studies of both current and future adaptation options. particularly on the coasts of eastern Africa, will have However, such advances in the science of adaptation to climate implications for health. Sea-level rise will probably increase change and variability, including both contextual and outcome the high socio-economic and physical vulnerability of coastal vulnerabilities to climate variability and climate change, show cities. The cost of adaptation to sea-level rise could amount to that these adaptations may be insufficient to cope with future at least 5-10% of gross domestic product. [9.4.3, 9.4.6, 9.5.2] changes of climate. [9.2, 9.4, 9.5, 9.6.2, Table 9.2] Human health, already compromised by a range of factors, Agricultural production and food security (including could be further negatively impacted by climate change access to food) in many African countries and regions are and climate variability, e.g., malaria in southern Africa and likely to be severely compromised by climate change and the East African highlands (high confidence). climate variability (high confidence). It is likely that climate change will alter the ecology of some A number of countries in Africa already face semi-arid disease vectors in Africa, and consequently the spatial and conditions that make agriculture challenging, and climate temporal transmission of such diseases. Most assessments of change will be likely to reduce the length of growing season health have concentrated on malaria and there are still debates as well as force large regions of marginal agriculture out of on the attribution of malaria resurgence in someAfrican areas. production. Projected reductions in yield in some countries The need exists to examine the vulnerabilities and impacts of could be as much as 50% by 2020, and crop net revenues could future climate change on other infectious diseases such as fall by as much as 90% by 2100, with small-scale farmers dengue fever, meningitis and cholera, among others. [9.2.1.2, being the most affected. This would adversely affect food 9.4.3 9.5.1] security in the continent. [9.2.1, 9.4.4, 9.6.1] Climate change will aggravate the water stress currently faced by some countries, while some countries that 9.1 Introduction currently do not experience water stress will become at risk of water stress (very high confidence). 9.1.1 Summary of knowledge assessed in the Third Climate change and variability are likely to impose additional Assessment Report pressures on water availability, water accessibility and water demand in Africa. Even without climate change, several The ThirdAssessment Report (TAR) of the IPCC identified countries in Africa, particularly in northern Africa, will a range of impacts associated with climate change and exceed the limits of their economically usable land-based variability, including decreases in grain yields; changes in water resources before 2025. About 25% of Africa’s runoff and water availability in the Mediterranean and southern population (about 200 million people) currently experience countries of Africa; increased stresses resulting from increased high water stress. The population at risk of increased water droughts and floods; and significant plant and animal species stress inAfrica is projected to be between 75-250 million and extinctions and