Browsing by Author "New, Mark"

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    A pluralistic, socio-ecological approach to understand the long-term impact of mountain conservation: a counterfactual and place-based assessment of social, ecological and hydrological change in the Groot Winterhoek Mountains of the Cape Floristic Region
    (2018) Holden, Petra Brigitte; Hoffman, Timm; Eckardt, Frank; New, Mark; Smit, Julian; Visser, Martine; Ziervogel, Gina
    The problem: For protected areas to remain relevant, we need to understand their impact on a wide set of conservation objectives and environmental outcomes. We also need to evaluate how this influence relates to the socio-ecological environment within which they occur. This is a complex endeavour requiring a pluralistic approach, which draws on a wide range of interdisciplinary fields. Research question: This thesis addresses the following question: What effects do mountain protected areas have on ecosystem services over time and how does this influence relate to broader socio-economic and ecological drivers of landscape change? Aim and objectives: I use a pluralistic, socio-ecological framing to assess the impact of ~40 years of mountain protection, drawing on comparisons of ~30 and ~40 years before and after protection respectively, with an adjacent area of similar terrain informing scenarios of counterfactual conditions. I also investigate what types of values (economic and intrinsic) are important when determining the impact of mountain protected areas. Thesis approach and methods: I operationalise the concepts of socio-ecological systems, ecosystem services, land use transitions and counterfactuals to investigate socio-ecological change and how it relates to protected area impact in the Groot Winterhoek, a mountain catchment in the south-western Cape of South Africa. This mountain catchment is important for regional water supplies for agricultural and domestic uses and falls in the Cape Floristic Region, a global biodiversity hotspot. It is comprised of privately owned mountain wildlands and a wilderness-protected area, known as the Groot Winterhoek Wilderness Area, established in 1978 (gazetted in 1985) which forms part of the Cape Floristic Region World Heritage Site. I combine methods from social science, ecology, environmental geography, geomatics and hydrology to understand the history of land use and cover (land use/cover) and associated ecosystem service trade-offs, how they are perceived by landowners as well as their wider impact on the region. Specifically, I assess the impact of protection on land use/cover, vegetation, fire and water flows over the last ~50 years, by comparing and contextualising results of change within the protected area to alternative scenarios of “no protection” (the counterfactual conditions). Vegetation and land use/cover change inside the protected area were determined respectively using 72 repeat terrestrial photographs and vegetation surveys, and an analysis of orthorectified aerial imagery. Methods used to construct the counterfactual scenarios of mechanisms (e.g. changes in land use/cover) that would likely drive vegetation changes inside the protected area included: i) 60 repeat surveys and in-depth interviews with landowners adjacent or proximal to the protected area owning unprotected land of similar terrain to the protected area; and ii) land use/cover change analysis of orthorectified aerial imagery of adjacent unprotected land of similar terrain before and after protected area establishment. 4 This latter information was used to understand the role of the protected area in driving vegetation changes inside the protected area. Social, biophysical and remote sensing results were directly used to parameterise land use/cover components of a hydrological model to determine the influence of protection on water flows. Specifically, water flows were simulated for the current state of the environment inside the protected area as well as for several counterfactual scenarios i.e. the alternative land use/cover scenarios of “no protection”. These counterfactual scenarios included land use/cover at two-time steps of ~30 and ~8 years before protection and one-time step ~40 years after protection both inside and outside the protected area. Results: Long-term change in ecosystem service use outside the protected area on privately owned land of similar terrain to inside the protected area (Section 3): Over the last ~50 years, outside the protected area, there was a shift from livestock-based, subsistence agriculture and small-scale farming to a diversified set of ecosystem service uses. The combined area of grazing and wildflower harvesting declined by 39%, while the number of landowners using the mountains for personal nature-based recreation and ecotourism increased by 61% and 23% respectively. Agriculture intensified in suitable areas of mountain land with the number of landowners cultivating land increasing by 20%. Exogenous socioeconomic drivers associated with globalisation and economic growth were important causal mechanisms of land use change. Landowners valued mountain protection for intrinsic and non-use reasons (73-80% of landowners), including existence, bequest and option values, as well as for the indirect use of water supply (72% of landowners) in comparison with direct use reasons such as spiritual/cultural experiences and nature-based recreation inside the protected area (18 and 50% of landowners respectively). Personal, nature-based recreation outside the wilderness-protected area was associated with valuing the protection of mountain land for intrinsic and non-use reasons. Long-term vegetation change inside the protected area and plausible mechanisms driving vegetation change (Section 4): Inside the mountain protected area, fynbos vegetation cover increased on average between 11 and 30% and there were significant declines in bare ground and rock cover. In 5 accumulation and fire intensities. However, these latter changes in land use/cover also occurred outside the protected area (see results summarised for Section 3 above and Section 4 below) and therefore cannot be attributed to protected area establishment. Land use/cover and the influence on water flows inside the protected area compared to counterfactual scenarios of no protection (Section 5): Declines in grazing and changes to the fire regimes occurred regardless of the protected area boundaries. In the past, there was a high frequency of small, low intensity fires across the landscape, both inside and outside the protected area. More recently, fires have been actively suppressed and this resultsin the build-up of biomass and the development of extensive, high intensity fires which, under suitable conditions, burn large expanses of the mountain catchment. Hydrological modelling showed that a high intensity burning regime negatively affected streamflow regardless of protected area boundaries. Streamflow increased by more than 80% under high flow conditions and decreased by more than 40% under low flow conditions relative to an unburnt ‘natural’ scenario. Over the last 50 years there has also been a substantial increase in dams, buildings and roads and minor increases in cultivation outside the protected area. This has been avoided inside the protected area where these land use/cover classes declined. If the increase in these land use/cover types observed outside the protected area occurred inside the protected area this would have resulted in reductions in daily streamflow leaving the protected portion of the catchment. For example, outside the protected area reductions of 8% to 25% of streamflow were observed during mid and low flow conditions respectively, particularly during dry years, in comparison to a ‘natural’ scenario. In contrast, inside the protected area streamflow recovered from past conditions to more closely resemble the natural flow conditions of the catchment. Therefore, had the protected area not been established there would have been losses in streamflow from the catchment as well as an increase in the degree of fragmentation within this mountain area. However, with increased water storage and fragmentation outside the protected area has also come increased socio-economic opportunities such as employment and local opportunities for ecotourism and sustainable agriculture e.g. indigenous cut flows. This highlights the importance of maintaining various forms of land management systems (multifunctional landscapes) within mountain ecosystems but also the need to understand the sustainability of different land management system types. Determining appropriate land management systems for mountain areas should be based on a full understanding of the impacts on ecosystem service benefits and costs at local and regional levels between social groups both spatially and temporally. Broader significance: This thesis contributes to the conservation literature on two main fronts. Firstly, it contributes conceptually and theoretically to understanding the dynamics of ecosystem services in relation to mountain protection. Secondly, it contributes methodologically by using an inclusive, trans- and interdisciplinary research approach for evidence-based conservation at a place-based and landscape level. The study provides a case 6 study example of the positive impact that mountain protection has on water-related ecosystem services, notably by maintaining streamflow throughout high to low flow periods and during dry years. It also provides clear evidence that ecosystem service trade-offs do not remain constant over time and shows that intrinsic and non-use values are required when describing the importance of mountain protected areas. In terms of understanding the impact that protected areas have in mountain regions, the research shows that complex processes are at play that extend beyond the boundaries of a specific protected area in both time and space. Interactions between global and local drivers were found to be prominent causal mechanisms of socio-ecological change and ultimately determined the influence of mountain-protection on land use/cover, fire, vegetation and water-related ecosystem services. The thesis emphasises that counterfactual framings are necessary to understand and attribute the impacts of protected areas on environmental outcomes, however pluralism and socio-ecological approaches are critical to determine plausible counterfactual conditions. This thesis focused only on landowners adjacent and proximal to the protected area owning the majority of mountain catchment land of similar terrain. It is likely that multiple socioeconomic trade-offs have occurred between different social groups and generations at both local and regional levels. Understanding how the disadvantages and benefits of the impacts of protected areas are apportioned across the landscape and temporally is an aspect that requires future research. Central to this would be to fully consider how human well-being is influenced both upstream and downstream, including at regional levels, and between social groups and across generations. Considering the impact of protected areas on the full range of ecosystem services and linking this to societal preferences and perceptions should be incorporated into the overall goal of developing an evidence base for conservation. This is because it is both scientific evidence and societal change that can determine protected area persistence and thus long-term protected area impact.
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    An analysis of local perceptions of the role of drought in exacerbating contemporary pastoral conflict in northern Kenya: a case study of Marsabit County
    (2018) Mohamed, Bishar; Lamb, Guy; New, Mark
    Pastoralists’ communities in Kenya have been co-existed since their migration and settlement in the region. However, frequent conflicts have been experienced among these communities due to scarcity of natural resources and drought. Pastoralists in Kenya are concern with raising their livestock, moving the herds in search of scarce resources such as water and pasture. The root cause of pastoralist conflict in Kenya is scarcity of natural resources and drought. This has often been suggested to trigger conflict flare-ups and that there was a recent flare up in the year 2016. Many descriptions of the conflict suggest that drought is an underlying driver, however other factors have also been suggested, i.e., politics, availability of arms, cultural values, population, governance, and lack of income (Adano et al., 201. Hence this research project explores the local perceptions of the main drivers of conflict. While studies have been conducted on the effects of droughts on pastoral communities and their coping strategies in the County, little is known of the perceptions of the locals on the role of drought in exacerbating inter-ethnic violence among three main pastoral communities in the region i.e. Borana, Gabra and Rendille. The main objective of this study was to establish the local perceptions of drought in exacerbating contemporary pastoral conflict in Marsabit County. Though there have been several studies on vulnerability to drought conducted in the area, all of them tend to neglect the conflict between the three main clans in Marsabit County. Moreover, the pastoralist communities in the region have experienced conflict flare-ups for many years despite availability of institutions that ought to have solved it. Therefore, the study specifically aims to analyze the different causes of conflict in Northern Kenya with an eye to determine the perceptions of Borana, Burji and Rendille clans and government and non-governmental on role of drought in increasing conflict in the Marsabit County. The study also examines different interventions used by government and non-governmental organizations in dealing with conflict in the area. The population of the study comprised 100 randomly selected community members from nine villages in Marsabit County and 15 government and non-governmental employees in Marsabit County. The study draws on data gathered through a questionnaire designed to meet the objectives of the study. The quantitative data was coded, processed and summarized into frequencies, percentages and graphs. The qualitative information from the interview is narrated as a report. In the questionnaire presented to participants, the extent to which each factor contributes to the conflict in the region is given in numerical categories i.e. (4-5) meaning agreed to a very high extent, (3) moderate extent or unsure and (1-2) agree to a very low extent or not at all. The study found that both locals and NGOs in the region perceive scarcity of resources which leads to drought as the main factor that influences the conflict in the region as compared to other factors i.e. cultural values, politics, population increase and cultural values. According to respondents, the drought caused a deficiency in natural resources i.e. water and pasture, which contributed to the conflict to a great extent. The study also found that locals in Marsabit County perceived different factors such as poverty, politics and cultural resources as influencing interethnic conflict in the region. The study recommends the following-: - There is need for the government and other non-governmental organizations to come up with more strategic ideas for climate change adaptation, ideas that could go hand in hand with the changing environment. - There is also a need to broaden and spread the livelihood and entrepreneurship projects to all the sub-counties where the climate change impact is harsh. - The county government needs to increase its budget allocation for pastoralist communities. This will promote sustainable development and create more jobs for the youths in the county. - County government, politicians and community elders should come up with a clear approach to tackle conflict in the region and prosecute the perpetrators of inter-ethnic conflict in the region.
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    Attribution-based parametric insurance: towards affordable premiums
    (2020) Dorbor, Sylvia Saygbay Diamond; New, Mark; Odoulami, Romaric C.
    To deal with the adverse impacts of climate change, index-based or parametric insurance has been recognized as an adaptation technique to compensate farmers for economic losses from extreme weather events. The insurance can be either private or sovereign. African Risk Capacity Insurance (ARC Ltd) offers the latter to African countries against drought events through contingency planning, risk pooling and transfer facilities. While the ARC insurance initiative seems promising, the current approaches used to estimate risk and determine premiums do not consider the change in risk from anthropogenic climate change. As the frequency of extreme weather events changes, the price of insurance premiums is likely to rise. Representing a cutting-edge science from weather to impact attribution, this study links attribution modelling with parametric insurance modelling to quantify how the probability of drought events has changed due to human influence on the climate system and translates the impacts into actual costs. To quantify this change, global climate models consisting of both factual and counterfactual world (with and without human forcing of climate, respectively) experiments were post-processed and used as rainfall inputs into an insurance risk modelling software, Africa RiskView. Estimated response costs needed for drought assistance in a world with and without climate change were calculated in Malawi, Zimbabwe, Senegal and Mauritania for the last 30 years. The empirical cumulative distribution function plots show that the distributions of models that represent the counterfactual natural world estimate lesser drought-affected population and lower response costs for assistance than those of the factual world distributions. The results suggest that climate change is likely to increase the price of insurance premiums. Therefore, there is a need for blended financing models that integrate international climate funds generated on a responsibility-based approach to cater for the added cost brought in by climate change.
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    Climate change impacts and adaptation in South Africa
    (2014) Ziervogel, Gina; New, Mark; Archer van Garderen, Emma; Midgley, Guy; Taylor, Anna; Hamann, Ralph; Stuart-Hill, Sabine; Myers, Jonny; Warburton, Michele
    In this paper we review current approaches and recent advances in research on climate impacts and adaptation in South Africa. South Africa has a well-developed earth system science research program that underpins the climate change scenarios developed for the southern African region. Established research on the biophysical impacts of climate change on key sectors (water, agriculture, and biodiversity) integrates the climate change scenarios but further research is needed in a number of areas, such as the climate impacts on cities and the built environment. National government has developed a National Climate Change Response White Paper, but this has yet to translate into policy that mainstreams adaptation in everyday practice and longer-term planning in all spheres and levels of government. A national process to scope long-term adaptation scenarios is underway, focusing on cross-sectoral linkages in adaptation responses at a national level. Adaptation responses are emerging in certain sectors. Some notable city-scale and project-based adaptation responses have been implemented, but institutional challenges persist. In addition, a number of knowledge gaps remain in relation to the biophysical and socio-economic impacts of climate change. A particular need is to develop South Africa's capacity to undertake integrated assessments of climate change that can support climate-resilient development planning.
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    Contribution of anthropogenic climate change to the magnitude of extreme rainfall events and associated synoptic conditions during recent flooding in Kenya
    (2023) Kimutai, Joyce; New, Mark; Wolski Piotr
    The changing probabilities of extreme climate and weather events, in terms of frequency, intensity, spatial extent, duration and timing, are one of the most noticeable and damaging manifestations of human-induced climate change. The Greater Horn of Africa has experienced a number of extreme weather and seasonal climate events over the past two decades. While droughts have predominated, several heavy precipitation events with devastating impacts have also been recorded. During the MarchApril-May (MAM) rainfall seasons of 2012, 2016 and 2018, Kenya experienced high rainfall that caused both widespread and localised flooding, resulting in human and livestock deaths, destruction of infrastructure and property, bursting of riverbanks, submerging of farmlands and emergence of isolated cases of water-borne diseases. This research aimed to assess whether human influence on climate played a role in modifying the rainfall intensity and associated synoptic conditions of extreme rainfall in these years. The work had three specific objectives: (i) Characterise the rainfall magnitude and associated synoptic conditions at the time of the flooding events; (ii) Evaluate the role of human influence on the magnitude of heavy rainfall; (iii) Evaluate the role of human influence on the synoptic conditions associated with heavy rainfall. By using three different attribution approaches, and utilising two observational datasets, one reanalysis data and two independent climate model experiment setups, the study was able to quantify how the local thermodynamic and regional dynamic conditions driving the flood-inducing rainfall in these seasons may have been altered by human-induced climate change. The rainfall magnitudes and associated atmospheric states were first characterised and then differences in the rainfall magnitudes and frequency of the atmospheric states in MAM 2012, 2016 and 2018 were compared to those in preindustrial climate. Three different seasonal heavy rainfall indices were analysed; seasonal maximum consecutive 5-day, 10-day, and 20-day rainfall. The atmospheric states were based on Self Organizing Maps analysis of specific humidity, air temperature, and zonal and meridional wind at 850hPa on surface level pressure and zonal moisture flux.
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    Drought Response Mechanisms and Adaptation: An Analysis of Strategies Adopted by Wine Grape Farmers in the Western Cape
    (2019) Riedo, Giulia; New, Mark
    This thesis examines the response mechanisms and adaptation strategies adopted by grapevine farmers to counteract the effects of the 2015-2018 Western Cape drought, which was characterised as particularly rare and severe. The challenges that emerged during the drought within the study area were exacerbated by the increasing competition over water resources between urban and agriculture users, as investment to supply water to urban users are expected to bring more economic and social value than investments in water supply for agriculture. The study responds to the dearth of literature on climate change adaptation strategies by grapevine farmers in South Africa. Using information from 27 open-ended, face to face interviews conducted with grapevine farmers operating in the Berg River catchment area, as well as an analysis of existing economic and weather data, the research sought to understand the effects of the water stress on grapevine production, the main cause of yield loss and the key drivers of farmers’ behaviour shifts. Analysis of industry production performance from 2015 to 2018 and observed rainfall from 2015 to 2017 suggests that water stress remains the key factor influencing grapevine yields. The water stress was also found to have catalysed later ripening of red varieties, higher pH levels in the wine and the introduction of emergency pruning methods to reduce water use, which in turn led to uneven budding budding due to pruning methods, later ripening of red varieties, higher pH levels in the wine. It was also found that the depleting quality of the Berg River water led to reduced yield, as well as heightened financial and psychological stress. The research identifies a portfolio of long-term and short-term adaptation options pursued by farmers in the study area, entailing reduced water consumption and increased water efficiency. The research identified that the drought induced farmers to suspend or reduce plant replacement. However, this behavior cannot be explained simply as responses to climate change, but that this is linked to the low profitability of the local wine grape industry. Most farmers adopted incremental measures rather than transformative strategies, where the major barriers to transformative adaptation included uncertainty regarding climate trends, limited financial capacity for large investments, the belief in grapevine drought resilience and the cultural attachment to viticulture.
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    Evaluating temperature and precipitation extremes under 1.5°C and 2.0°C warming above pre-industrial levels: Botswana case study
    (2018) Nkemelang, Tiro; New, Mark; Batisani, Nnyaladzi; Zaroug, Modathir
    The United Nations Framework Convention on Climate Change (UNFCCC) noted the need and therefore requested further quantitative research to better inform policy on the potential impacts of further warming to 1.5 and 2.0 °C above preindustrial levels. Climate extremes are expected to become more severe as the global climate continues to warm due to anthropogenic greenhouse gas emissions. The extent to which extremes and their impacts are to change due to additional 0.5 °C warming increments at regional level as the global climate systems warms from current levels to 1.5 and then 2.0 °C above preindustrial levels need to be understood to allow for better preparedness and informed policy formulation. Having realized the lack of research on this front in Botswana, this study investigates the differentiated impacts of climate change on climate extremes under the current, 1.5 and 2.0 °C warmer climates. The dissertation analysed the projected changes in extremes using Expert Team on Climate Change Detection and Indices (ETCCDI), derived from fifth version of Coupled Model Intercomparison Project (CMIP5) projections over Botswana, a country highly vulnerable to the impacts of climate change. Results indicate that (i) projected changes in temperature extremes are significantly different at the three levels of global warming, with hot day and night extremes expected to realise the greatest increases; (ii) drought related indices are also significantly different, and suggest progressively increasing drought risk with shortened rainfall seasons especially in northern Botswana; and (iii) heavy rainfall indices are likely to increase, but are not statistically different at the different global warming levels. The implications of these changes for key socio-economic sectors are explored, and reveal progressively severe impacts, and consequent adaptation challenges for Botswana as the global climate warms from its present temperature to 1.5 and then 2.0 °C.
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    Evaluating the Effectiveness and Efficiency of Climate Information Communication in the African Agricultural Sector: A Systematic Analysis of Climate Services
    (2022-01-24) Ofoegbu, Chidiebere; New, Mark
    The use of climate services (CS) for the provisioning of climate information for informed decision-making on adaptation action has gained momentum. However, a comprehensive review of the literature to evaluate the lessons and experiences of CS implementation in the African agriculture sector is still lacking. Here, we present a systematic review (mapping) of 50 pieces of literature documenting lessons and experiences of CS adoption in the agriculture sector of 20 African countries. The qualitative analysis of the reviewed literature revealed: (1) CS implementation overwhelmingly relied on a participatory process through workshops and participatory scenario planning meetings to connect users with actors along the CS value chain of forecast production, translation, integration, and application. Additionally, innovations such as mobile phones and internet service are increasingly being integrated with CS to strengthen the relationship between CS providers and users. They are, however, mostly at the trial stage and tend to have a varying impact depending on available facilities and infrastructure in the community. (2) Although there is a growing recognition of the need for the integration of indigenous and scientific knowledge systems in the production of climate information, such integration is currently not happening. Rather, indigenous knowledge holders are engaged in a participatory process for insight on modalities of making scientific climate information locally relevant and acceptable. Given the aforementioned findings, we recommend further research on modalities for facilitating indigenous knowledge mainstreaming in climate information production, and investigation of options for using innovations (e.g., mobile) to enhance the interactions between CS users and CS providers. Such research will play a great role in scaling up the adoption of CS in the African agricultural sector.
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    The food-energy-water-land-biodiversity (FEWLB) nexus through the lens of the local level : an agricultural case study
    (2015) Hulley, Sarah May; Ziervogel, Gina; New, Mark
    There is a recognised need to turn the abstract concept of resilience thinking into practical action for resource management. This is often difficult as resource management is complex and multifaceted. Nexus thinking attempts to address this by promoting a framework that integrates and coordinates resource management across many different but interlinked resource pillars and sectors. This research focuses on the local level implementation of the food, energy, water, land and biodiversity (FEWLB) nexus framework, and assesses farmers' understanding and implementation of nexus thinking in relation to the support of the Bergrivier Municipality. Agriculturalists (farmers) have been described as significant custodians of natural resources, as they sit in a key position when it comes to implementing and practising sustainable development. There has been little research into the relationship between farmers and local municipalities, or into the role that local government can play in supporting holistic resource management through agriculture. While there are many different actors contributing towards resource management, this research focuses on the agricultural sector within the municipality. Qualitative research methods, including semi-structured interviews, participant observation and surveys, were used to undertake a case study of the agricultural sector within the Bergrivier Municipality. In a context where local government struggles to find its role in supporting socio-ecological resilience, the FEWLB nexus framework offers an opportunity to implement effective planning and policies that could enable more efficient resource use.
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    Is sustainable intensification possible in smallholder crop production systems in semi-arid West Africa? The case of the Red Volta and Black Volta basins in Northern Ghana
    (2023) Ansah, Prince; New, Mark; Norton, Marieke
    Food systems experts consider Sustainable Intensification (SI) a key concept to tackle the increasing global and regional food demand, particularly in semi-arid West Africa, which is prone to socioeconomic and biophysical challenges. In Ghana, crop production varies across semi-arid systems, particularly between the Red Volta and Black Volta basins. Given this context, the study assessed and compared the factors contributing to crop productivity differences between and within the RVB and the BVB and explored how these factors contribute to achieving SI goals of productivity, resilience, efficiency, and equity. This study applies an integrated SI framework and case study approach in these basins, using mixed methods: 200 household surveys, six in-depth interviews, three focus group discussions, five key informant interviews, and two workshops, with both random and purposive sampling. The results identified several important determinants of crop productivity that are relevant to SI. These included water/soil-related risks and strategies, access to agricultural resources, demographic characteristics, institutional collaboration, and household production needs. These determinants, which differ in importance within each basin, impact the achievement of SI goals. Farmers' perceptions of water/soil-related risks have a direct bearing on crop productivity across basins. Access to consistent resources was found to enhance yields, though an over-reliance on sporadic government support posed challenges especially in RVB. Demographic factors, notably age, gender, and education, emerged as significant determinants of farming practices and outcomes. Furthermore, the research emphasized the importance of robust inter-institutional collaboration in bolstering agricultural innovation and productivity. Notably, the choice of crops cultivated was influenced by a delicate balance between household consumption needs and market demands. The study underscores the need for local institutions to mitigate weak policies, limited resources, and poor knowledge transfer that could inhibit SI strategies implementation. The thesis concludes by recommending that national and local agriculture stakeholder should promote the SI concept as a guiding principle for improving existing farming systems through strengthening agriculture policies and facilitating innovations within smallholder crop production systems to enhance sustainable productivity in semi-arid Northern Ghana.
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    Observed and modelled trends in rainfall and temperature for South Africa: 1960-2010
    (2014) MacKellar, Neil; New, Mark; Jack, Chris
    Observed trends in seasonal and annual total rainfall, number of rain days and daily maximum and minimum temperature were calculated for a number of stations in South Africa for the period 1960-2010. Statistically significant decreases in rainfall and the number of rain days are shown over the central and northeastern parts of the country in the autumn months and significant increases in the number of rain days around the southern Drakensberg are evident in spring and summer. Maximum temperatures have increased significantly throughout the country for all seasons and increases in minimum temperatures are shown for most of the country. A notable exception is the central interior, where minimum temperatures have decreased significantly. Regionally aggregated trends for six water management zones covering the entire country are not evident for total rainfall, but there are some significant trends for the number of rain days. Temperature in these zones has increased significantly for most seasons, with the exception of the central interior. Comparison of the observed trends with statistically downscaled global climate model simulations reveals that the models do not represent the observed rainfall changes nor the cooling trend of minimum temperature in the central interior. Although this result does not rule out the possibility of attributing observed local changes in rainfall to anthropogenically forced global change, it does have major implications for attribution studies. It also raises the question of whether an alternative statistical downscaling method or dynamical downscaling through the use of a regional climate model might better represent regional and local climatic processes and their links to global change.
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    The Influence of Anthropogenic Climate Change on the 2015-2017 Hydrological Drought in the South-Western Cape, South Africa
    (2021) Hall, Andrew; New, Mark; Wolski, Piotr
    The Western Cape Province in South Africa recently experienced below-average rainfall during the period 2015−2017, this resulted in a three-year compound hydro-meteorological drought event in the Province. The 2015−2017 Western Cape hydro-meteorological drought was the worst drought event since 1904 and caused severe unprecedented water shortages throughout the Western Cape region, with many municipal water supply systems close to failure by the first quarter of 2018; most especially the Western Cape Water Supply System that serves Cape Town. The drought gained a lot of interest from the public, media and climate scientists alike. The main aim of this study was to assess the extent to which human influence on climate from fossil fuel emissions has changed the likelihood of a hydrometeorological drought event with the magnitude of that experienced in 2015−2017 in the SouthWestern Cape. The Pitman hydrological model was set up for the Berg River catchment in a way that enabled multiple simulations with different rainfall inputs so that attribution experiments could be undertaken. The key differences to the standard Pitman model set up included: (i) constant abstractions, return flows, and land use conditions; (ii) reservoir and dam storages were set to reflect current storage volumes; and (iii) extending the observed rainfall inputs to include the drought period. A hydrological model evaluation was then undertaken, using updated streamflow gauging station data, to assess the ability of the Pitman model to realistically simulate runoff in the Berg River catchment. The model was deemed suitable for the purposes of this study in simulating runoff. To generate the climate attribution experiments, Coupled Model Intercomparison Project Phase 5 historical simulations (1861−2010) were merged with the Representative Concentration Pathway 8.5 greenhouse gas scenario simulations (2011−2100) of rainfall from 77 simulations From 42 models to create a long-term (150 years) time series. Attribution experiments were constructed by considering the average conditions in the 31 year period centred on the years of the event, i.e. 2002−2031 to represent current climate conditions and the period 1861−1890 to represent pre-industrial climate conditions. Five 150-year long stochastic time series of rainfall for each individual simulation were then generated conditioned on observed rainfall characteristics this was done to increase the sample size of the models available. These stochastic rainfall time series were then used as input to the Pitman model to generate outputs/realisations of runoff for a pre-industrial and current world; thus generating impact attribution experiments. To determine the role of anthropogenic climate change on the 2015−2017 hydro-meteorological drought in the South-Western Cape the risk-based approach was applied to the rainfall and runoff attribution outputs. The 2015−2017 meteorological/hydrological drought event was defined in terms of three-year mean annual rainfall/runoff received in the Berg River catchment and its individual 12 quaternary catchments. This event definition was used as a rainfall/runoff threshold in the attribution analysis for the 2015−2017 meteorological/hydrological drought in the South-Western Cape. The three-year minimum averages of rainfall/runoff were identified in each of the 150-yearstochastic time series generated from the 77 simulations; resulting in 385 values for both current and pre-industrial climates for rainfall and runoff. A normal distribution was then fitted to the 385 values of the current and pre-industrial rainfall/runoff. From this distribution, the probability of the current rainfall/runoff occurring, based on the defined threshold, was identified and compared to the pre-industrial time series to calculate the risk ratios of the Berg River catchment and its 12 quaternary catchments. Results show that the risk of the meteorological drought event occurring in the Berg River catchment was increased by a factor of 28.5, 95% confidence interval: 26.0−32.4, (but ranged from 11.5−41.0 in the individual quaternary catchments) due to anthropogenic climate change. The occurrence of the hydrological drought event in the Berg River catchment was found to be increased by a factor of 12.9, 95% confidence interval: 11.3−13.5 (2.7−61.0 in the quaternary catchments) due to anthropogenic climate change. The risk ratio for runoff was higher than for rainfall in the wetter southern quaternary catchments, while it was lower than for rainfall in the drier more northern quaternary catchments. Thus, the human influence on meteorological drought appears to have been amplified in those catchments most important to the Western Cape Water Supply System.
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    Vulnerability of horticulture producers to climate variability and change : the case of Chókwe District, Mozambique
    (2016) Vilissa, Delfim Julio; New, Mark
    Climate change is projected to have continued and globally severe environmental, economic and socioeconomic effects. These effects are forecast to be more severe in the agriculture sector, considering that it is one of the most sensitive industries to climate change. Studies from the Mozambican National Institute for Disaster Management (INGC) suggest that Mozambique is among the countries highly vulnerable to climate change due to its geographical location, in the coastal zone. In addition, the majority of its population is entirely dependent on agriculture activities for food and income. For example, in the Chókwe district, tomato production plays a key role in farmers' livelihood; however, this district is prone to weather variability and climate stresses, affecting the region's agricultural performance and making farmers' livelihood even more precarious. There is indeed limited information on this vulnerability, how farmers cope with the risks as well as their need to manage these stresses. The study conducted includes a survey of 43 farmer households in two villages of Chókwe: Massavasse and Muianga. The study then compares farmers' perceived effects of climate variability with actual climate data observed between 1980 and 2012. Meteorological data was analyzed using R software.
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    Open Access
    What drives farmers to make top-down or bottom-up adaptation to climate change and fluctuations? A comparative study on 3 cases of apple farming in Japan and South Africa
    (Public Library of Science, 2015) Fujisawa, Mariko; Kobayashi, Kazuhiko; Johnston, Peter; New, Mark
    Agriculture is one of the most vulnerable sectors to climate change. Farmers have been exposed to multiple stressors including climate change, and they have managed to adapt to those risks. The adaptation actions undertaken by farmers and their decision making are, however, only poorly understood. By studying adaptation practices undertaken by apple farmers in three regions: Nagano and Kazuno in Japan and Elgin in South Africa, we categorize the adaptation actions into two types: farmer initiated bottom-up adaptation and institution led top-down adaptation. We found that the driver which differentiates the type of adaptation likely adopted was strongly related to the farmers' characteristics, particularly their dependence on the institutions, e.g. the farmers' cooperative, in selling their products. The farmers who rely on the farmers' cooperative for their sales are likely to adopt the institution-led adaptation, whereas the farmers who have established their own sales channels tend to start innovative actions by bottom-up. We further argue that even though the two types have contrasting features, the combinations of the both types of adaptations could lead to more successful adaptation particularly in agriculture. This study also emphasizes that more farm-level studies for various crops and regions are warranted to provide substantial feedbacks to adaptation policy.