Editing IPCC:AR6/WGII/Chapter-9 (section)

===== Observed Impacts and Projected Risks =====

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Climate

'''Increasing mean and extreme temperature trends across Africa are attributable to human-caused climate change (''' '''''high confidence''''' ''').''' {9.5.1, 9.5.2}

'''Climate change has increased heat waves (''' '''''high confidence''''' ''') and drought (''' '''''medium confidence''''' ''') on land, and doubled the probability of marine heatwaves around most of Africa (''' '''''high confidence''''' ''').''' Multi-year droughts have become more frequent in west Africa, and the 2015–2017 Cape Town drought was three times more ''likely'' [[#footnote-001|2]] due to human-caused climate change. {9.5.3–7, 9.5.10}

'''Increases in drought frequency and duration are projected over large parts of southern Africa above 1.5°C global warming (high confidence), with decreased precipitation in North Africa at 2°C global warming (''' '''''high confidence''''' '''), and above 3°C global warming, meteorological drought frequency will increase, and duration will double from approximately 2 months to 4 months in parts of North Africa, the western Sahel and southern Africa (''' '''''medium confidence''''' ''').''' {9.5.2, 9.5.3, 9.5.6.}

'''Frequency and intensity of heavy rainfall events will increase at all levels of global warming (except in north and southwestern Africa), increasing exposure to pluvial and riverine flooding (''' '''''high confidence''''' ''')''' '''''.''''' {9.5.3–7, 9.7}

'''Glaciers on the Rwenzoris and Mt Kenya are projected to disappear by 2030, and by 2040 on Kilimanjaro (''' '''''medium confidence''''' ''').''' {9.5.8}

'''In east and southern Africa, tropical cyclones making landfall are projected to become less frequent but have more intense rainfall and higher wind speeds at increasing global warming (''' '''''medium confidence''''' ''').''' {9.5.7}

'''Heat waves on land, in lakes and in the ocean will increase considerably in magnitude and duration with increasing global warming (''' '''''very high confidence''''' ''').''' Under a 1.5°C-compatible scenario, children born in Africa in 2020 are ''likely'' to be exposed to 4–8 times more heat waves compared to people born in 1960, increasing to 5–10 times for 2.4°C global warming. The annual number of days above potentially lethal heat thresholds reaches 50–150 in west Africa at 1.6°C global warming, 100–150 in central Africa at 2.5°C, and 200–300 over tropical Africa for &gt;4°C. {9.5.2, 9.5.3, 9.5.4, 9.5.5, 9.5.6, 9.7.2.1}

'''Most African countries will enter unprecedented high temperature climates earlier in this century than generally wealthier, higher latitude countries, emphasising the urgency of adaptation measures in Africa (''' '''''high confidence''''' ). {9.5.1}

Compound risks

'''Multiple African countries are projected to face compounding risks from reduced food production across crops, livestock and fisheries, increased heat-related mortality, heat-related loss of labour productivity and flooding from sea level rise, especially in west Africa (''' '''''high confidence''''' ''').''' {9.8.2, 9.8.5, 9.9.4, 9.10.2, 9.11.2}

Water

'''Recent extreme variability in rainfall and river discharge (around −50% to +50% relative to long-term historical means) across Africa have had largely negative and multi-sector impacts across water-dependent sectors (''' '''''high confidence''''' ''').''' {9.7.2, 9.10.2} Hydrological variability and water scarcity have induced cascading impacts from water supply provision and/or hydroelectric power production to health, economies, tourism, food, disaster risk response capacity and increased inequality of water access. {Box 9.4}

'''Extreme hydrological variability is projected to progressively amplify under all future climate change scenarios relative to the current baseline, depending on region (''' '''''high confidence''''' ''').''' Projections of numbers of people exposed to water stress by the 2050s vary widely—decreases/increases by hundreds of millions, with higher numbers for increases—with disagreement among global climate models on the major factor driving these large ranges. Populations in drylands are projected to double by 2050. Projected changes present heightened cross-cutting risks to water-dependent sectors, and require planning under deep uncertainty for the wide range of extremes expected in future. {9.7.1, 9.7.2, 9.9.4}

Economy and livelihoods

'''Climate change has reduced economic growth across Africa, increasing income inequality between African countries and those in temperate northern hemisphere climates (''' '''''high confidence''''' ''').''' One estimate suggests gross domestic product (GDP) per capita for 1991–2010 in Africa was on average 13.6% lower than if climate change had not occurred. Impacts manifest largely through losses in agriculture, as well as tourism, manufacturing and infrastructure. {9.6.3, 9.11.1}

'''Climate variability and change undermine educational attainment (''' '''''high agreement, medium evidence''''' ''').''' High temperatures, low rainfall and flooding, especially in the growing season, may mean children are removed from school to assist income generation. Early life undernutrition associated with low harvests or weather-related food supply interruptions can impair cognitive development. {9.11.1.2}

'''Limiting global warming to 1.5°C is''' '''''very likely''''' '''to positively impact GDP per capita across Africa.''' Increasing economic damage forecasts under high emissions diverge from low emission pathways by 2030. Inequalities between African countries are projected to widen with increased warming. Across nearly all African countries, GDP per capita is projected to be at least 5% higher by 2050 and 10–20% higher by 2100 if global warming is held to 1.5°C compared with 2°C. {9.11.2}

Food systems

'''In Africa, climate change is reducing crop yields and productivity (''' '''''high confidence''''' ''').''' Agricultural productivity growth has been reduced by 34% since 1961 due to climate change, more than any other region. Maize and wheat yields decreased on average 5.8% and 2.3%, respectively in sub-Saharan Africa due to climate change in the period 1974–2008. Farmers and pastoralists perceive the climate to have changed and over two-thirds of Africans perceive climate conditions for agricultural production have worsened over the past 10 years. Woody plant encroachment has reduced fodder availability. {9.4.5, 9.6.1, 9.8.2}

'''Future warming will negatively affect food systems in Africa by shortening growing seasons and increasing water stress (''' '''''high confidence''''' ''').''' By 1.5°C global warming, yields are projected to decline for olives (north Africa) and sorghum (west Africa) with a decline in suitable areas for coffee and tea (east Africa). Although yield declines for some crops may be partially compensated by increasing atmospheric CO 2 concentrations, global warming above 2°C will result in yield reductions for staple crops across most of Africa compared to 2005 yields (e.g., 20–40% decline in west African maize yields), even when considering adaptation options and increasing CO 2 ( ''medium confidence'' ). Relative to 1986–2005, global warming of 3°C is projected to reduce labour capacity in agriculture by 30–50% in sub-Saharan Africa. {9.8.2, 9.8.3, 9.11.2}

'''Climate change threatens livestock production across Africa (''' '''''high agreement, low evidence''''' ''').''' Rangeland net primary productivity is projected to decline 42% for west Africa by 2050 at 2°C global warming. Vector-borne livestock diseases and the duration of severe heat stress are both projected to become more prevalent under warming. {9.8.2}

'''Climate change poses a significant threat to African marine and freshwater fisheries (''' '''''high confidence''''' ''').''' Fisheries provide the main source of protein for approximately 200 million people in Africa and support the livelihoods of 12.3 million people. At 1.5°C global warming, marine fish catch potential decreases 3–41%, and decreases by 12–69% at 4.3°C by 2081–2100 relative to 1986–2005 levels, with the highest declines for tropical countries. Under 1.7°C global warming, reduced fish harvests could leave 1.2–70 million people in Africa vulnerable to iron deficiencies, up to 188 million for vitamin A deficiencies, and 285 million for vitamin B 12 and omega-3 fatty acids by mid-century. For inland fisheries, 55–68% of commercially harvested fish species are vulnerable to extinction under 2.5°C global warming by 2071–2100. {9.8.5}

Health

'''Climate variability and change already negatively impacts the health of tens of millions of Africans through exposure to non-optimal temperatures and extreme weather, and increased range and transmission of infectious diseases (''' '''''high confidence''''' ''').''' {9.10.1}

'''Mortality and morbidity will escalate with further global warming, placing additional strain on health and economic systems (''' '''''high confidence''''' ''').''' Above 2°C of global warming, distribution and seasonal transmission of vector-borne diseases is expected to increase, exposing tens of millions more people, mostly in west, east and southern Africa ( ''high confidence'' ). Above 1.5°C risk of heat-related deaths rises sharply ( ''medium confidence'' ), with at least 15 additional deaths per 100,000 annually across large parts of Africa, reaching 50–180 additional deaths per 100,000 people annually in regions of North, West, and East Africa for 2.5°C, and increasing to 200–600 per 100,000 people annually for 4.4°C. Above 2°C global warming, thousands to tens of thousands of additional cases of diarrhoeal disease are projected, mainly in west, central and east Africa ( ''medium confidence'' ). These changes risk undermining improvements in health from future socioeconomic development ( ''high agreement, medium evidence'' ). {9.10.2, Fig. 9.35}

Human settlements

'''Exposure of people, assets and infrastructure to climate hazards is increasing in Africa compounded by rapid urbanisation, infrastructure deficit, and growing population in informal settlements (''' '''''high confidence''''' ''').'''

'''High population growth and urbanisation in low-elevation coastal zones will be a major driver of exposure to sea level rise in the next 50 years (''' '''''high confidence''''' ''').''' By 2030, 108–116 million people in Africa will be exposed to sea level rise (compared to 54 million in 2000), increasing to 190–245 million by 2060 ( ''medium confidence'' ). {9.9.1, 9.9.4}

'''Africa’s rapidly growing cities will be hotspots of risks from climate change and climate-induced in-migration, which could amplify pre-existing stresses related to poverty, informality, social and economic exclusion, and governance (''' '''''high confidence''''' ''').''' Urban population exposure to extreme heat is projected to increase from 2 billion person-days per year in 1985–2005 to 45 billion person-days by the 2060s (1.7°C global warming with low population growth) and to 95 billion person-days (2.8°C global warming with medium-high population growth), with greatest exposure in west Africa. Under relatively low population growth scenarios, the sensitive populations (people under 5 or over 64 years old) in African cities exposed to heat waves of at least 15 days above 42°C in African cities is projected to increase from around 27 million in 2010 to 360 million by 2100 for 1.8°C global warming (Shared Socioeconomic Pathway 1 (SSP1)) and 440 million (SSP5) for &gt;4°C global warming. Compared to 2000, urbanisation is projected to increase urban land extent exposed to arid conditions by around 700% and exposure to high-frequency flooding by 2600% across west, central and east Africa by 2030. {9.9.1, 9.9.2, 9.9.4, Box 9.8}

Migration

'''Most climate-related migration observed currently is within countries or between neighbouring countries, rather than to distant high-income countries (''' '''''high confidence''''' ''').''' Urbanisation has increased when rural livelihoods were negatively impacted by low rainfall. Over 2.6 million and 3.4 million new weather-related displacements occurred in sub-Saharan Africa in 2018 and 2019. {Box 9.8}

'''Climate change is projected to increase migration, especially internal and rural to urban migration (''' '''''high agreement, medium evidence''''' ''').''' With 1.7°C global warming by 2050, 17–40 million people could migrate internally in sub-Saharan Africa, increasing to 56–86 million for 2.5°C (&gt;60% in west Africa) due to water stress, reduced crop productivity and sea level rise. This is a lower-bound estimate excluding rapid-onset hazards such as floods and tropical cyclones. {Box 9.8}

Infrastructure

'''Climate-related infrastructure damage and repairs will be a financially significant burden to countries (''' '''''high confidence''''' ''').''' Without adaptation, aggregate damages from sea level rise and coastal extremes to 12 major African coastal cities in 2050 under medium and high emissions scenarios will be USD 65 billion and USD 86.5 billion, respectively. Potential costs of up to USD 183.6 billion may be incurred through 2100 to maintain existing road networks damaged from temperature and precipitation changes due to climate change. Increased rainfall variability is expected to affect electricity prices in countries highly dependent on hydropower. {9.9.4, Boxes 9.4, 9.5}

Ecosystems

'''Increasing CO''' 2 '''levels and climate change are destroying marine biodiversity, reducing lake productivity, and changing animal and vegetation distributions (''' '''''high confidence''''' ''').''' Impacts include repeated mass coral bleaching events in east Africa, and uphill (birds) or poleward (marine species) shifts in geographic distributions. For vegetation, the overall observed trend is woody plant expansion, particularly into grasslands and savannas, reducing grazing land and water supplies. {9.6.1, 9.6.2, 9.8.2}

'''The outcome of the effect of the interaction of increasing CO''' 2 '''and aridity that operate in opposing directions on future biome distributions is highly uncertain.''' Further increasing CO 2 concentrations could increase woody plant cover, but increasing aridity could counteract this, destabilising forest and peatland carbon stores in central Africa ( ''low confidence'' ). Changes in vegetation cover could occur rapidly if tipping points are crossed {9.6.1, 9.6.2, 9.8.2}

'''African biodiversity loss is projected to be widespread and escalating with every 0.5°C increase above present-day global warming (''' '''''high confidence''''' ''').''' Above 1.5°C, half of assessed species are projected to lose over 30% of their population or area of suitable habitat. At 2°C, 36% of freshwater fish species are vulnerable to local extinction, 7–18% of terrestrial species assessed are at risk of extinction, and over 90% of east African coral reefs are projected to be destroyed by bleaching. Above 2°C, risk of sudden and severe biodiversity losses becomes widespread in west, central and east Africa. Climate change is also projected to change patterns of invasive species spread. {9.6.2, Figure 9.19}

Climate security

'''There is increasing evidence linking increased temperatures and drought to conflict risk in Africa''' ( '''''high confidence''''' ) '''.''' Agriculturally dependent and politically excluded groups are especially vulnerable to drought-associated conflict risk. However, climate is one of many interacting risk factors, and may explain a small share of total variation in conflict incidence. Ameliorating ethnic tensions, strengthening political institutions and investing in economic diversification could mitigate future impacts of climate change on conflict. {Box 9.9}

Heritage

'''African cultural heritage is already at risk from climate hazards, including sea level rise and coastal erosion. Most African heritage sites are neither prepared for, nor adapted to, future climate change (''' '''''high confidence''''' ''').''' {9.12}

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