Draft Document: Climate Change Risk and Vulnerability Assessment for Rural Human Settlements

Transcription

1 Draft Document: Climate Change Risk and Vulnerability Assessment for Rural Human Settlements Prepared by Linkd Environment Services for the Department of Rural Development and Land Reform: Spatial Planning and Facilitation Directorate April 2013 Linkd Environmental Services t: f: e: w:

2 Status of this document Our approach to the climate change risk and vulnerability assessment for rural human settlements has been ambitious and has gone somewhat beyond our initial proposal in that it amounts to original research, as opposed to simply collating existing research findings. In undertaking the risk and vulnerability assessment, we have developed a conceptual model of climate change risks and vulnerability based on a complex set of climate change projections from existing models, composite indicators, and raw data from sources such as Stats SA. These have been translated into spatial maps using GIS tools. This document provides a detailed description of the conceptual basis for the risk and vulnerability assessment using explanations and maps of the indicators used to build the model, as well as a description of the overall methodology. In translating our conceptual model into a spatial model, we have inevitably had to make some compromises based on the availability of data, and at this point there are some indicators for which we are still trying to source spatial data. Further progress may be made in this regard prior to engaging stakeholders at the regional workshop. In particular, the comparison of a mapping of risk and vulnerability in relation to a typology of human settlements is still underway, but we expect to present these results at the PSC meeting on the 17 th and update this document at the same time. However, we are already confident that we have useful outcomes in terms of the mapping of climate change risk and vulnerability with which to engage stakeholders. Further progress will amount to a refinement of the model and its spatial mapping, but is not likely to dramatically alter the findings presented in this document. 2

3 Table of ContentsList of Abbreviations... 5 List of Figures Introduction Methodology Time scale Resolution Weighting Outcomes Hazard Exposure Mean annual temperature change Annual precipitation change Extreme Weather Sea-level rise Ocean acidification Aridity Composite Mapping of Hazard Exposure Sensitivity Physical water scarcity Irrigated cultivated land Terrain slope Growing period Net Primary Production (rain fed) Net Primary Production (irrigated) Perennial rivers Ground water availability Land degradation Crop diversification Ecological resilience

4 4.12. Composite Mapping of Sensitivity Adaptive Capacity Population age profile Income Employment Gender Access to basic services Land Tenure status Type of dwelling HIV prevalence Dependence on Agriculture Composite Map of Adaptive Capacity Vulnerability Composite Mapping of Vulnerability Typology of Rural Human Settlements References

5 List of Abbreviations CO² Carbon Dioxide C degrees Centigrade Cm centimetres DRDLR Department of Rural Development and Land Reform DIRCO Department of International Relations and Cooperation DWA Department of Water Affairs FAO Food and Agriculture Organization GIS Geographical Information Systems GAEZ Global Agro-Ecological Zones IIASA Institute for Applied Systems Analysis IPCC International Panel on Climate Change LGP Length of Growing Period mm Millimetres NPP Net Primary Production RDI Radiative Dryness Index SANBI South African National Biodiversity Institute SCOR Scientific Committee on Oceanic Research UNDP United Nations Development Programme List of Figures Figure 1: The components of climate change vulnerability 5

6 1. Introduction There is a natural amount of carbon dioxide (CO²) in the atmosphere, and this natural amount of carbon dioxide, together with other greenhouse gases, helps keeps the Earth at an average heat of 15 C and ensures a stable global climate in which any change tends to happen over very long time spans. However due to human activity, and particularly the combustion of fossil fuels, the natural balance of CO² in the atmosphere is being exceeded, causing the Earth to rapidly warm. This warming is resulting in changes to the earth s climate that include rising sea levels, changes in precipitation patterns, and an increase in the frequency and intensity of extreme weather events. These global changes are known as climate change and threaten the way in which societies across the world relate to and live within the natural environment. Across the world societies are preparing for the changes that climate change will bring and South Africa is no exception. Climate change presents a particular challenge to developing countries such as South Africa that already experience development problems such as poverty and lack of access to basic services. Changes in the climate will make already existing development challenges harder to resolve because resources will become scarcer as the demand for them from people who are at risk grows. There is therefore an urgent need to put appropriate plans in place now that will make people more resilient to climate change and enable them to not only survive climate change, but also to keep their livelihoods intact. The changes which people must make to survive climate change and protect their livelihoods are commonly known as adaptation. In South Africa, the social and economic costs of climate change are already being incurred and are a growing threat to the achievement of South Africa s sustainable development goals. Across the globe, due to the fact that they tend to rely more on natural systems, rural communities are the first to experience the effects of climate change and are likely to be the most severely affected. This is particularly true of developing countries such as South Africa. It is therefore critical to identify the rural human settlements most at risk from climate change, and to develop plans to reduce their vulnerability. The central purpose of this report is to identify and understand the factors that increase climate change risks, and spatially map these risk factors in order to inform planning and assist in the development of relevant adaptation strategies at a regional and local level. The impacts of climate change are not evenly borne across countries, communities and households. For a few, the net effects of climate change may be positive over certain time frames. For instance, growing periods for crops in some areas, particularly those in the large northern hemisphere land-masses bordering the arctic circle, are likely to increase. For most of Africa including South Africa, the net effect of climate change on growing periods is likely to be negative, however. Furthermore, the ability to respond effectively to climate change is sharply differentiated, with poor rural communities often being the least equipped to respond. Modelling the impacts of climate change presents complex challenges and happens at different levels: The physical impacts of climate change consist of changes such as increased temperature and changes to evaporation rates, precipitation patterns, ocean currents and prevailing winds. The bio-physical impacts of climate change concern the interaction of the physical impacts of climate change with the bio-sphere i.e. living systems. The social impacts of climate change are determined by the human consequences of changes to the environment due to climate change, as well as the socio-economic consequences of climate change mitigation actions. It is commonly maintained by experts and endorsed by the United Nations Development Programme that climate change vulnerability is best understood as an outcome of the interrelationships between three related but different characteristics of a particular geographical location. These characteristics are hazard exposure, sensitivity and adaptive capacity. This relationship can best be understood in the following equation: Hazard exposure x Sensitivity Adaptive Capacity = Climate Vulnerability (UNDP 2010). Hazard exposure can be defined as the physical impacts of climate change such as an incremental rise in temperature, an increase in violent storms or changes in precipitation patterns. This exposure to the hazards of climate change can result in both gradual impacts such as declining crop yields and sudden impacts resulting from an increased exposure to extreme weather events such as floods, droughts and storms. 6

7 Sensitivity can also be referred to as biophysical vulnerability and consists of the reactions of living systems to hazard exposure. Sensitivity is measured by the reactions of a unit of analysis to the impacts of climate change. For instance, a 1 C incr ease in temperature may result in a quantifiable increase or decrease in the incidence of a particular plants species in a particular ecosystem. Equally, it may affect the geographical extent of a particular ecosystem (such as savannah). Adaptive Capacity refers to the financial, physical, cultural and political ability of societies to make the required changes needed to survive the adverse effects of climate change. Adaptive capacity is defined by how people experience and survive the the exposure to hazards. Further adaptive capacity is measured at the unit of analysis (the individual, household or community) and reflects the multi-stressors which these units experience; such as poverty, ill-health or unemployment. An adaptive capacity which is deemed high is usually experience by those with a low social vulnerability and vice versa. The interaction between hazard exposure, based on climate change projections, and sensitivity, based on an analysis of bio-physical characteristics, can be understood as encompassing the risks posed by climate change. Vulnerability is therefore a product of the extent to which these risks are mitigated or exacerbated by the presence or absence of adaptive capacity. The approach used in this study to modelling the interactions between hazard exposure, sensitivity and adaptive capacity in contributing towards vulnerability is illustrated in Figure 1. The figure introduces the indicators that were used to express the three interrelated components of climate vulnerability. Source: Authors own Figure 1: Climate change vulnerability 7

8 2. Methodology In this assessment the climate change vulnerability of rural human settlements is modelled using a Geographical Information System (GIS) to capture the spatial variability of the impacts of climate change in terms of hazard exposure and sensitivity, and the capacity of rural human settlements to respond to these Time scale In terms of planning horizons, future values for the 2020s were used for indicators that include projected future values (primarily those relating to hazard exposure) because these are the earliest values available and are more realistic as a time horizon in planning for the DRDLR than the 2050s or the 2080s. For indicators that have future values, the Hadley CM3 model with the A2 climate change scenario was used. The United Kingdom s Meteorological Office developed this model and it is one of the models that is widely used by the international community, including the Intergovernmental Panel on Climate Change (IPCC). The A2 scenario was developed by the IPCC and describes a very heterogeneous world in the future, with an underlying theme of self-reliance and preservation of local identities. In this scenario, fertility patterns across regions converge very slowly, which results in continuously increasing global population. Economic development is primarily regionally oriented and per capita economic growth and technological change is more fragmented and slower than in other storylines Resolution In principle, the GIS model determines the spatial distribution of communities vulnerability to climate change at ward level. Because many of the data sets used in this study are not compiled at ward level, this has meant in many cases that data has been averaged at the ward level (where the data is at a finer resolution than ward level) or downscaled to ward level. Map 1: The municipal wards of South Africa Source: Statistics South Africa Census

9 2.3. Weighting Vulnerability to climate change is not directly measurable, so the approach adopted here is to express it as the net outcome of a weighting of composite indicators for hazard exposure, sensitivity and adaptive capacity. The indicators within each composite indicator were scored according to individual criteria and the scores were summed to arrive at final scores for hazard exposure, sensitivity and adaptive capacity per ward. A municipal ward s final score for vulnerability was calculated using the following weighting (based on the uncertainties in the data) for the composite indicators: hazard exposure 20% sensitivity 30% adaptive capacity 50% The sections that follow describe each group and its indicators in more detail. The reasoning behind selecting these indicators and using wards as the final spatial unit is based on the main findings of the literature review of this study Outcomes The primary outcome of this study is a spatial mapping of vulnerability in terms of areas of relatively high, medium, and low vulnerability to climate change. As such it provides a useful guide in terms of prioritising rural human settlements for resource allocation and planning for climate change adaptation. The implication is not, of course, that areas that have a relatively low risk do not need to plan for adaptation. Vulnerability is location specific phenomenon, and simply knowing that a particular area is highly vulnerable to the impacts of climate change is only a starting point in terms of planning. For this reason, the spatial mapping of particular risk vectors and adaptive capabilities (or absence thereof) is an important part of the outcomes of this study. To this end this assessment includes: Maps of the composite indices for hazard exposure, sensitivity and adaptive capability Maps of the component indicators for each of these indices. These resources can be used to obtain some level of insight into the particular threats and challenges facing specific communities. While beyond the immediate scope of this work, the approach adopted here could be potentially used to develop a ward-level adaptation planning tool for local government that exposes not just the overall vulnerability of settlements at ward level, but also the component factors that constitute vulnerability. The sections that follow describe each composite index and its component indicators in more detail. The reasoning behind selecting these indicators and using wards as the final spatial unit is based on the main findings of the literature review of this study. 3. Hazard Exposure In this assessment hazard exposure is defined as the physical impacts of climate change which can either happen over a prolonged period of time or through weather variability and weather related events. The indicators selected to measure the hazard exposure are: mean annual temperature change, annual precipitation change, climate extremes index, sea-level rise, ocean acidification and change in the aridity index. These indicators are further explained in the following sections Mean annual temperature change Mean annual temperature can be described as the average temperature at any given location for the entire year. In South Africa, temperatures are largely affected by the elevation of any given location and its distance from the sea. The inland areas are highly elevated and they experience a warm summer with daily 9

10 temperatures reaching C. These high areas al so experience cool winters with mean daily temperatures of around 0-2 C which also may be acco mpanied by frost. The temperature of the east coast is determined by the warm Mozambique current and the areas between East London and Mozambique are therefore warmer throughout the year. The northern parts of the coast are sub-tropical and experience a warm winter with daily minimums of around 9-10 C an d a hot summer with a maximum of 32 C. The interior which hold the Nam-karoo biome has more of an extreme climate than the rest of the country with daily maximum highs in the summer reaching 34 C and mini mums in the winter sitting at around 6 C. The temperatures of the West Coast are influenced by the Benguela current and therefore the area experiences daily highs in the summer of around 32 C and daily winter minimum temperatures of around 6 C with no frost. Under and A2 scenario there is a general consensus that South Africa s coastal regions will warm by around 1-2 C by about 2050 and around 3-4 C by about Also, South Africa s interior regions will warm by around 3-4 C by about 2050 and around 6-7 C by abou t Rising temperature is understood to be one of South Africa s major impacts of climate change and therefore the change in mean annual temperature Is included in this study (Department of International Relations and Cooperation 2011). Changes in the modelled mean annual temperature in the 2020s and the baseline values were scored by assigning marks using the absolute value of the percentage change. This is because adaptation is needed in all areas where the temperature changes, not only where it increases. Map 2 shows the differences between the mean annual temperature in the 2020s and the baseline from 1961 to Map 2 : Mean annual temperature changes ( C) in Sou th Africa between the baseline of the 2020s Source: calculated from GAEZ data (Hadley CM3 model and A2 climate change scenario) 3.2. Annual precipitation change Annual precipitation is the average amount of water, which is measured in mm, and falls from the clouds in a solid or liquid form at any given location during the course of the year. Currently South Africa has a mean annual rainfall of around 450mm and is therefore regarded as semi-arid. The country does however 10

11 experience regional differences in rainfall patterns. Areas which border Namibia (the Richtersveld) may only receive less than 50 mm of rainfall while the mountains of the south west Cape can receive more than 600 mm of rainfall. Furthermore, South Africa experiences more below average rainfall years than above average and the annual potential evapo-transpiration may exceed annual precipitation by ratios of up to 20:1 (Palmer & Ainslee 2013).There are three major rainfall zones in South Africa: the winter rainfall region of the western, south western and southern Cape; the bimodal rainfall region of the Eastern Cape, and the summer rainfall region of the highveld and KwaZulu Natal (ibid). Oncoming climate change will entail significant changes in rainfall patterns and this, coupled with increased evaporation, will result in significant changes in respect of water availability. Examining changes in annual precipitation averages therefore prove as useful indications as to which areas will experience the most environmental change in the future and overall vulnerability to climate change (DIRCO 2011). Changes in the precipitation mean baseline and modelled mean annual precipitation in the 2020s and values were scored by assigning marks using the absolute value of the percentage change. This is because adaptation is needed in all areas where the rainfall changes, not only where it increases. Map 3 shows the absolute percentage change in precipitation between the 2020s and the baseline. Map 3: Absolute percentage change in precipitation between the 2020s and the baseline Source: calculated from GAEZ data (Hadley CM3 model and A2 climate change scenario) 3.3. Extreme Weather A climate extremes index or incidence of extreme weather events has been selected in order to determine locations that are currently prone to and will be more prone to weather events in the future. In simple terms extreme climate is extremely bad or devastating weather. In South Africa this often takes the form of drought, flooding, frost and hail storms. 11

12 3.4. Sea-level rise Sea-level rise refers to the rising levels of the ocean which is contributed to by the expansion of the waters as the temperatures of the ocean rise and the melting of glaciers and ice sheets. Sea level rise therefore provides evidence that the temperature of the atmosphere is indeed increasing. The extent to which the waters of the sea will increase is unclear; however, the IPCCC estimates that over the course of the 21st Century, the seas could rise between 18 to 59 cm (IPCCC, 2007). The rising up of the oceans waters will have a detrimental effect on human populations that live in coastal areas as well as to marine ecosystems, and it is for this reason that sea level rise has been selected as a hazard exposure indicator because it will point towards wards where populations are at risk or may even have to be relocated. Sea level rise scores were assigned to coastal municipal wards only, according to the length of its coast line and its population density. Map 5 displays this analysis. The reason for not using low lying land areas as an indication of areas that are vulnerable to sea level rise is because of data constraints. Map 4: Population per length of coastline (displayed by ward) Source: calculated from Statistics SA Census Ocean acidification Ocean acidification refers to the continuous decrease in the ph levels of the Earth s oceans which is caused by the dissolving of carbon dioxide into the waters of the oceans. It is estimated that up to 40% of carbon dioxide in the atmosphere is absorbed by the oceans and other large water bodies, and as this happens the acidity of the water increases as the water reacts with the carbon dioxide to form carbonic acid. It is estimated the oceans waters may have become up to 30% more acidic over the past 200 years and that this increasing acidity has negative effects for ocean eco-systems and for food chains (SCOR). Because of this detrimental effect of ocean acidification on marine food chains, ocean acidification has been selected as an indication of hazard exposure because it points out where communities which are reliant on the productivity of the ocean for their livelihoods are vulnerable to climate change. 12

13 Scores for ocean acidification were assigned based on the relative importance of fishing in the GDP of the ward. (See Section 5.8 for a map of the relative contribution of agriculture, fisheries and forestry to the economy.) For this indicator only the coastal municipal wards were considered Aridity The aridity index is the ratio between the annual precipitation and the potential evapotranspiration. This gives an indication of the dryness of the climate; that is whether the water balance is positive or negative at a given location. South Africa is already largely a dry country and in the process of climate change it is expected that some regions will become drier. As these regions become drier, agriculture and livestock farming will be impacted on negatively. This indicator therefore takes account of areas where rain fed agriculture and livestock agriculture will become more difficult in future as water deficit increases. Changes in the modelled aridity index in the 2020s and the baseline values were scored by assigning marks to places where the index decreased in the future. Since a higher aridity index indicates more moisture compared to evapotranspiration, areas with a reduced future aridity index in the future (compared to the baseline) scored on this indicator. Therefore the areas in 7 below with negative values were assigned scores for this indicator. Map 5: Aridity index changes in South Africa between the baseline of the 2020s Source: calculated from GAEZ data (Hadley CM3 model and A2 climate change scenario) 3.7. Composite Mapping of Hazard Exposure When the analysis of all of the selected indicators for hazard exposure (mean annual temperature change, annual precipitation change, climate extremes index, sea-level rise, ocean acidification and changes in the aridity index) is combined into a single composite map of hazard exposure, the map below is generated. In this map areas that have a high hazard exposure are clearly distinguished from areas that have a low hazard exposure. The map below shows that municipal wards along the coast will experience a high exposure to climate hazards, especially in the western coastal regions of the Northern Cape. Coastal municipal wards between the Western Cape and Eastern Cape also receive a high score in terms of the combined hazards. Municipal wards in the North West, Mpumulanga and Limpopo province receive a medium score in terms of climate hazard exposure. 13

14 Map 6: Combined hazard scores 4. Sensitivity Sensitivity can also be referred to as biophysical vulnerability and is defined as the biological and ecological reactions of ecosystems, biomes, sectors and countries to hazard exposure. Different physical environments will experience climate hazards differently and this difference determines their sensitivity to climate change. The sensitivity of different physical locations to climate hazards impacts the way in which humans use the environment because it indicates how productive and safe the land is. Sensitivity is measured at the unit of analysis which can be either a small ecosystem in a garden or an entire biome. The indicators selected to achieve a high level analysis of the sensitivity for rural human settlements in this assessment are: physical water scarcity by major river basin, irrigated cultivated land, terrain slope index, growing period, Net Primary Production (NPP) (rain fed), NPP (Irrigated), major perennial rivers, ground water availability, land degradation index, crop diversification index and ecological resilience. These indicators are discussed in greater detail throughout the rest of this section. 14

15 4.1. Physical water scarcity Rivers form a part of natural water courses and the hydrological cycle. Rivers are usually made up of fresh water which flows towards the ocean or to another body of water. Sometimes rivers dry before they can reach these other bodies of water. The water within a river is collected from precipitation and from the process of surface runoff, groundwater recharge, springs and the release of stored water such as natural ice. South Africa has several small rivers along the coast line which run into the sea, but none are navigable. There are only two major rivers in South Africa; the Limpopo River which is shared with Zimbabwe and the Orange (including its tributary river the Vaal) which runs across the centre of the country from the east to the west towards the Atlantic Ocean. Because South Africa is a dry country the levels of these rivers and the available amount of water is highly sensitive to climate change and therefore physical water scarcity by river basin is seen as an important indication of sensitivity to climate change especially for rural populations that are dependent on river water as their primary water resource. A river basin constitutes the land area that is drained by a river and its tributaries. Physical water scarcity by major river basins refers to areas where there are negative water balances in the major basins. These values were modelled by the FAO and they expressed this negative balance in terms of the ratio between irrigation water that is consumed by plants through evapotranspiration and renewable fresh water resources. Renewable fresh water resources as well as net irrigation water requirements in the river basin are calculated through a water balance model, with information regarding climate, soils and irrigated agriculture as input data. Scores were assigned according to the classes. Map 7: Physical water scarcity Source: Global Agro-Ecological Zones (FAO and IIASA) 15

16 4.2. Irrigated cultivated land Irrigation can be explained as the artificial application of water to the land or soil in order to assist with the cultivation of crops and the restoring of soils during times of insufficient rainfall. The process of irrigation can also assist in protecting crops from frost, in combating the growth of weeds, suppressing dust, and in preventing soil consolidation. The water source for irrigation can be groundwater, surface water from rivers or lakes, dams, desalinated water, waste water or drainage water. The quality of the water used in the irrigation process has a direct effect on the quality of the cultivated crops and on the productivity of the soil. Given South Africa s dry climate, it is extremely reliant on irrigation for continued agricultural production. Irrigated lands are therefore extremely sensitive to reductions in available water. This indicator was scored according to the percentage of an area that is irrigated the higher the percentage, the higher the score. Map 8: Irrigated, cultivated land in South Africa Source: Global Agro-Ecological Zones (FAO and IIASA) 4.3. Terrain slope The terrain, otherwise known as land relief, is the vertical and horizontal dimension of land surface. It is a common geographical term used to describe how the land is laid out and is usually expressed in terms of elevation, slope and the orientation of features. The terrain is important to consider because it can affect weather and climate patterns and also affects the distribution and quality of water. Furthermore a firm grasp of the terrain is important because it determines the suitability of the earth s surface for human settlements, for example the flat plains have a better soil quality for the production of crops. South Africa s terrain falls into two major physiographic features: The interior plateau and the land between the plateau and the coast. The Great Escarpment forms the boundaries between these two regions. The Great Escarpment is the most prominent relief feature of the country and its height ranges from 1500 m 16

17 above sea level at the Roggeveld scarp in the south-west to 3482 m above sea level in the Drakensburg Mountains. The plateau is characterized by wide plains and the escarpment forms the highest portion of the plateau. The plateau forms a part of the Southern part of the continuation of the great African plateau which stretches all the way to the Sahara Desert. The coastal area between the Great Escarpment and the coast varies in width from 80km to 240km in the east and in the south, and between 60 to 80 km in the west. Three sub-divisions of the coastal areas are recognized; the eastern plateau slopes, the Cape folded belt and the western plateau slopes. Because the lay out of the South African surface area has a direct impact on climate and water distribution, which impacts on rural human settlements and the livelihoods of human settlements it has been selected as an important indication of sensitivity to climate change. Agriculture becomes more difficult as the slope increases and therefore this indicator scores higher for steeper slopes. Map 11 shows how the terrain slope varies across South Africa. Map 9: Terrain slope across South Africa Source: Global Agro-Ecological Zones (FAO and IIASA) 4.4. Growing period The growing period, or the growing season, is a botanical term which refers to the period of the year when certain plants or crops can be grown. The growing period is determined by the climate, the elevation, the crop selection, the location, the temperature, daylight hours and rainfall amongst other features. The rainfall seasonality of South Africa impacts growing periods throughout the country. In the north, east and along the coastal belt, summer seasonality encourages grass production and the main focus is cattle and sheep production. In the semi-arid central and western regions grasses and shrubs predominate, and this favours sheep and goat production (Palmer & Ainslee 2003). As agricultural production is critical for rural livelihoods in the form of food and job security the growing period is critical in maintaining the agricultural production balance and therefore that of rural livelihoods. Here, areas were looked for in which the growing period will shorten between the present and the 2020s. The number of growing period days (LGP) are 17

18 calculated on the basis of average climatic parameters. LGP quantification is based on a water balance model comparing moisture supply from precipitation and soil moisture storage and reference evapotranspiration. Reference LGP assumes available soil moisture capacity of 100 mm per meter soil depth and a reference soil depth of one meter. Changes in the modelled growing period in the 2020s and the baseline values were scored by assigning marks to those areas in which the growing period shortened. Map 10: Difference in number of growing days per year between the baseline of and the 2020s Source: calculated from GAEZ data (Hadley CM3 model and A2 climate change scenario) 4.5. Net Primary Production (rain fed) Primary production is the production of organic compounds from carbon dioxide, this process can occur either through the process of photosynthesis of chemosynthesis. Almost all life on Earth relies on primary production because the process forms the basis of the food chain. The organisms that are responsible for primary production, and which sit at the bottom of the food chain, are primary producers or autotrophs. Primary producers are mainly plants in terrestrial ecosystems. Primary production can be determined in net or gross terms with net primary production accounting for losses such as cellular respiration. The Net primary production (NPP) is the total energy accumulated by an ecological unit. The NPP is the difference between the gross primary production and respiration. The NPP equation looks as follows: The NPP of rain fed agriculture refers to the total production of agriculture which has relied on rainfall as its only water source. It was modelled by GAEZ ad a function of incoming solar radiation and soil moisture at the rhizosphere. Actual crop evapotranspiration (ETa) has a close relationship with NPP of natural vegetation as it is quantitatively related to plant photosynthetic activity which is also driven by radiation and water availability. For NPP estimates under natural, i.e rain-fed conditions, radiative dryness index (RDI) is 18

19 calculated from prevailing net radiation and precipitation of a grid cell and ETa is determined by the GAEZ reference water balance. Locations where the NPP reduced between the modelled 2020s values and the baseline received positive scores in the GIS model. Map 11: Areas of reduced NPP under rainfed conditions between the 2020s and the baseline ( ) Source: calculated from GAEZ data (Hadley CM3 model and A2 climate change scenario) 4.6. Net Primary Production (irrigated) This indicator is similar to the previous one, but is applied to irrigated land. It was modelled by the FAO and the International Institute for Applied Systems Analysis (IIASA) in their GEZ system. For an NPP estimate applicable under irrigation conditions, ETa = ETmax is assumed and a radiative dryness index of is used, which maximises the approximation of the ratio between diffusion conditions of CO 2 and sensible heat. Locations where the NPP reduced between the modelled 2020s values and the baseline received positive scores in the GIS model. 19

20 Map 12: Areas of increased NPP under irrigated conditions between the 2020s and the baseline ( ) 4.7. Perennial rivers A perennial river is one which has a continuous flow in all parts of its bed throughout the year if the year has a normal rainfall. This is in contrast to intermittent rivers which stop flowing or dry up during some months of the year. These definitions and boundaries between different rivers are however, blurred and are often subject to the definitions placed on them by local areas. About two-thirds of South Africa has non-perennial rivers and are therefore more sensitive to the erratic rainfall patterns and water shortages that climate change will bring (Rossouw et al. 2005). In this assessment the availability of perennial rivers is combined with major perennial rivers to find areas that have no alternative to rainfall. Municipal wards with no perennial river within 5 km of them received scores for this indicator. 20

21 Map 13: Perennial rivers of SA and wards at least 5 km from a perennial river Source: Own map from Statistics South Africa Census 2011 and Department of Water Affairs data 4.8. Ground water availability Ground water refers to the water which is found below the Earth s surface and which is stored in soil and rock and that supplies water to wells and springs. In South Africa 90% of the ground water occurs in hard rock that contains no porous spaces. In this hard rock the ground water is contained within faults and fissures. The ground water supplies that are found in hard rock are called secondary aquifers. In South Africa, the ground water that is not found in secondary aquifers is stored in primary aquifers which are found in spaces between sand grains in soils. Such aquifers are found in locations such as the Kalahari Desert (Ground water Division 2012). Ground water contributes very little to the total water supply of South Africa at around 13%, yet at the same time, is an extremely vital water resource. Because of the dry nature of the country and the lack of perennial stream in the arid areas, ground water is an invaluable water resource. Irrigation for agriculture is the largest user of ground water in South Africa, but ground water also forms the major water supply of over many smaller towns and rural settlements. Because precipitation patterns are expected to change with climate change, many areas of the country will become more dependent on ground water as their primary source of water. Ground water will not only also become under threat then as demand increases, but settlements which are located in rapidly drying areas and which are not near to ground water sources, will be more sensitive to climate change. In this assessment ground water availability is combined with major perennial rivers to find areas that have no alternative to rainfall (Ibid). Ground water availability was approximated through borehole yield, which was obtained from DWA. Areas with smaller yield scored higher on this indicator. The map below shows these scores that resulted from the spatial variation of borehole yield as it varies across South Africa; higher scores indicate less borehole yield. 21

22 Map 14: Borehole yield as a measure of groundwater availability Source: Own map from Department of Water Affairs data 4.9. Land degradation Land degradation can be described as the process by which the quality of the environment is negatively impacted by human behaviour. This can be by one aspect of human behaviour or by multiple human activities. It can also be understood as an undesirable change made to the land caused by human activity. The extent of land degradation has serious impacts for agricultural and for human health. Desertification is also a form of land degradation in that it refers to the degradation of dry land areas also due to human activity. Desertification is commonly understood to mean the extension of desert but it actually means the destruction of productive land which is situated in dry areas. This destruction is mainly caused by overuse (Environmental Monitoring Group 2013). Many features contribute towards land degradation, but the underlying cause is the placing of too much pressure on the land. One such form of this pressure is overgrazing and another is deforestation. It is estimated that up to 25% of South Africa s land is already badly degraded (ibid.), and therefore land degradation constitutes a very big problem for the country of which 90% of the surface area is classified as arid. Much of this land degradation can be contributed to the history of apartheid in which land was unequally distributed. In the former homelands much of the land is degraded beyond repair because of over farming and overgrazing. This land degradation is a major reason behind the massive amounts of urbanization which the country is experiencing, in which people are moving to the cities in search of a better life and more opportunities (ibid). Land which is already degraded is fragile and is therefore more sensitive to climate change. On-going land degradation will be made worse by climate change and will threaten the livelihoods of rural population further. It is for this reason that land degradation has been chosen as an important indicator of sensitivity to climate change. Erodabilty from EnpNat 2002 was used to compile this indicator, since erodability depends largely on the condition of the soil and vegetation. Higher erodability index values obtained higher scores on this indicator. 22

23 Map 15: Erodability index Source: EnpNat Crop diversification Agricultural diversification refers to the cultivation of a multiplicity of different crops on the same land. The reasons for making use of crop diversification include reducing risk, responding to external shocks, increasing the capacity of the land to meet a growing need for cereals, to improve the quality of the soil and the ecosystem, increasing the income of small farms, surviving price fluctuation, mitigating the effects of changing weather, improving the fodder for livestock, to reduce dependence on external inputs, increasing community food security and responding to the impacts of climate change. Crop diversification is not the same as multiple cropping or succession planting in which different crops are grown in successive growing seasons, but rather aims to grow a mix of crops. These crops may also have complementary and higher market values than other crops such as fresh fruits and vegetables. In South Africa crop diversification has the potential to increase the resilience of rain fed subsistence farming to drought and therefore could play an important role in increasing the adaptive capacity and food security of rural human settlements in the country Ecological resilience Ecological resilience refers to the capacity of an ecosystem or natural population to resist of recover from major changes in its structure and function after the negative effects of human activity have disturbed it. Furthermore ecological resilience refers to the ability of a natural ecosystem or population to recover without shifting to a different regime that will be difficult to reverse with human intervention. This indicator is included to find areas where ecological services are compromised and therefore more sensitive to climate change. It was calculated from SANBI s biogeographic nodes and their importance. These were identified as part of the National Biodiversity Assessment in Biogeographical nodes contain many ecological and evolutionary processes and are therefore more likely to be resilient to climate change. Areas with low or medium importance scored on this index. 23

24 Map 16: Biogeographical nodes and their importance Source: SANBI National Spatial Biodiversity Assessment Composite Mapping of Sensitivity Combining all of the indicators of climate change sensitivity for rural human settlements (physical water scarcity by major river basin, irrigated cultivated land, terrain slope index, growing period, Net Primary Production (NPP) (rain fed), NPP (Irrigated), major perennial rivers, ground water availability, land degradation index, crop diversification index and ecological resilience) results in a composite map for sensitivity which can be seen in the map below. This map clearly shows which areas of the country are highly sensitive to climate change and which areas of the country are the least sensitive to climate change. Highly sensitive municipal wards are found in the western and central parts of the Northern Cape, the North West Province, Limpopo province, Mpumalanga province and dotted in parts of Kwazulu Natal. There are also some highly sensitive areas found in the Western Cape. In comparison with the composite map of hazard exposure, the composite map of climate sensitivity shows a more diverse, location specific picture. This reflects the complexity of the eco-system characteristics that mediate how hazard exposure impacts on the bio-sphere. 24

25 Map 17: Combined sensitivity score (without crop diversification index) 5. Adaptive Capacity Adaptive capacity is defined as the resources, infrastructure and services available to people to respond to climate change and reflects the multiple stressors which they experience; such as poverty, ill-health or unemployment. Adaptive capacity can be thought of as the inverse of social vulnerability a community with high adaptive capacity will have low levels of social vulnerability to climate change and vice versa. The indicators chosen to express the adaptive capacity of rural human settlements in this assessment are as follows: population age profile, annual household income, employment status of household head, gender of head of households, access to basic services, tenure status, type of dwelling, HIV prevalence, % agriculture GDP and dominant crop areas. These indicators are explained and further discussed below. For the purposes of simplicity in building the model of vulnerability, our approach has been to model lack of adaptation capacity, or social vulnerability. This means that areas that we have given high scores to areas that score low in the indicators for adaptive capacity so an area with poor delivery of basic services scores high as being socially vulnerable to climate changes risks. 25

26 5.1. Population age profile The population of South Africa refers to all the inhabitants of the country and the age profile of the country refers to the average ages of the population. In July of 2012 the population of South Africa stood at 48, 810, 427. Census data shows that 28.4% of the population is between the ages of 0 and 14 years and 21% of the population is between the ages of 15 and 24 years; rendering the population of South Africa extremely young. A further 38% of the population is between the ages of 25 and 54 years of age. 7% of the population is between the ages of 55 and 64 years of age and 6% of the population is 65 years or older. The median age of the South African population is 25 years (Indexmundi 2013). It is estimated that climate change will affect individuals within different population groups in different ways. Certain individuals within populations are more vulnerable to climate change as these groups include the sick, the elderly, children, native groups and groups who receive a low income. The reasons for this are that children and the elderly are more susceptible to illness and the stress which climate change will place on already difficult living conditions will make these groups even more so. As the temperatures in South Africa continue to rise, children and elderly populations will become vulnerable to severe heat stress. The expected decline in food security as agricultural productivity drops will lead to increased malnutrition which will have a contributing effect towards other diseases. Climate change and the increase in temperature, lack of water and decreased quality of water may encourage the spread of infectious diseases such as Gastro-enteritis. Areas which will become prone to flooding may attract mosquitoes and therefore the possibility for an increase in malaria cases may arise. Rural populations which live in close proximity with the environment, and often in rudimentary rural dwellings are more vulnerable from the increase in health related risks. These populations also often live far from sources of health care of the health care available in rural areas is substandard (EPA 2013). A population which has a high proportion of individuals that are of a working/adult age therefore shows a stronger adaptive capacity than populations which have high levels of individuals who are children or elderly. Populations that have a high proportion of individuals that are of a working age will also be able to work to increase the resilience of their communities through planting food and climate proofing their dwellings. In this assessment, scores were assigned to municipal wards with high numbers of children and older people, or low numbers of young people compared to the national average and using the following classes: 0-14: child, 15-39: young, 40+: older. These scores are shown in the map below. Map 18: Municipal wards with unfavourable age profiles 26

27 Source: calculated from Statistics South Africa Census 2011 data 5.2. Income The annual household income refers to the total amount of money that each household in South Africa earns per year. This income can be derived from formal or informal employment and constitutes any activity which a member of the household undertakes and that is rewarded in monetary terms. The Income and Expenditure survey of 2010/2011 shows that household income expenditure and expenditure in South Africa is on the rise and according to the survey the average household consumption expenditure increased by 69,5% from the last survey. However, income and expenditure levels remain significantly varied across population groups with black households earning the least (StatsSA 2012). Households with a higher income are less susceptible to poverty and the multiple stressors that contribute to climate change vulnerability. Although poverty is not synonymous with climate change vulnerability, it is a major driver of climate vulnerability. It can therefore be deemed that households with higher annual incomes have a higher adaptive capacity than households with lower annual incomes. In this assessment scores were assigned to wards with high percentages of poor households and low percentages of high-income households compared to the national average. The following classes were used: low: 0 - R38 200, medium: R R , high: >R shows the resultant income scores by municipal ward low scores indicate fewer low-income households and more high-income households. Map 19: Household income scores 27