Urban nexus and transformative pathways towards resilient cities: A case of the Gauteng City-Region, South Africa.

Challenges emanating from rapid urbanisation require innovative strategies to transform cities into global climate action and adaptation centres. We provide an analysis of the impacts of rapid urbanisation in the Gauteng City-Region, South Africa, highlighting major challenges related to (i) land use management, (ii) service delivery (water, energy, food, and waste and sanitation), and (iii) social cohesion. Geospatial techniques were used to assess spatio-temporal changes in the urban landscapes, including variations in land surface temperatures. Massive impervious surfaces, rising temperatures, flooding and heatwaves are exacerbating the challenges associated with rapid urbanisation. An outline of the response pathways towards sustainable and resilient cities is given as a lens to formulate informed and coherent adaptation urban planning strategies. The assessment facilitated developing a contextualised conceptual framework, focusing on demographic, climatic, and environmental changes, and the risks associated with rapid urbanisation. If not well managed in an integrated manner, rapid urbanisation poses a huge environmental and human health risk and could retard progress towards sustainable cities by 2030. Nexus planning provides the lens and basis to achieve urban resilience, by integrating complex, but interlinked sectors, by considering both ecological and built infrastructures, in a balanced manner, as key to resilience and adaptation strategies.

Informing Equitable Water and Food Policies through Accurate Spatial Information on Irrigated Areas in Smallholder Farming Systems.

Accurate information on irrigated areas' spatial distribution and extent are crucial in enhancing agricultural water productivity, water resources management, and formulating strategic policies that enhance water and food security and ecologically sustainable development. However, data are typically limited for smallholder irrigated areas, which is key to achieving social equity and equal distribution of financial resources. This study addressed this gap by delineating disaggregated smallholder and commercial irrigated areas through the random forest algorithm, a non-parametric machine learning classifier. Location within or outside former apartheid "homelands" was taken as a proxy for smallholder, and commercial irrigation. Being in a medium rainfall area, the huge irrigation potential of the Inkomati-Usuthu Water Management Area (UWMA) is already well developed for commercial crop production outside former homelands. However, information about the spatial distribution and extent of irrigated areas within former homelands, which is largely informal, was missing. Therefore, we first classified cultivated lands in 2019 and 2020 as a baseline, from where the Normalised Difference Vegetation Index (NDVI) was used to distinguish irrigated from rainfed, focusing on the dry winter period when crops are predominately irrigated. The mapping accuracy of 84.9% improved the efficacy in defining the actual spatial extent of current irrigated areas at both smallholder and commercial spatial scales. The proportion of irrigated areas was high for both commercial (92.5%) and smallholder (96.2%) irrigation. Moreover, smallholder irrigation increased by over 19% between 2019 and 2020, compared to slightly over 7% in the commercial sector. Such information is critical for policy formulation regarding equitable and inclusive water allocation, irrigation expansion, land reform, and food and water security in smallholder farming systems.

Operationalising the water-energy-food nexus through the theory of change.

The water-energy-food (WEF) nexus facilitates understanding of the intricate and dynamic interlinkages among the three resources. Its implementation can enhance resource securities and sustainable development. Despite its potential, full adoption of the approach has been hindered by a lack of actionable strategies to guide its practical application. This is attributed to (i) poor data (ii) lack of empirical evidence, (iii) inadequate analytical tools, and (iv) lack of clarity on applicable spatial scale. This study undertook a literature review, coupled with systemic analyses of a WEF nexus analytical model, whose outputs were used as a basis to develop a Theory of Change, an iterative outline for operationalising the approach in the context of southern Africa. The consultative and iterative Theory of Change culminated with the formulation of pathways to (i) overcome the barriers impeding WEF nexus operationalisation, (ii) mitigation of trade-offs while enhancing synergies towards attaining simultaneous resource securities, (iii) poverty alleviation and reduction of inequalities, and (iv) reconciling policy with implementation scale. The WEF nexus operationalisation outcomes are linked to Sustainable Development Goals 2 (zero hunger), 6 (clean water and sanitation), and 7 (affordable and clean energy), with synergies to SDGs 1 (no poverty), 5 (gender equality), 8 (decent work and economic growth), 12 (responsible consumption and production), 13 (climate action), 14 (life below water), and 15 (life on land). Operationalising the WEF nexus through an interactive process can inform sustainable pathways towards resource security, job and wealth creation, improved livelihoods and well-being, and regional integration.

Application of the Random Forest Classifier to Map Irrigated Areas Using Google Earth Engine.

Improvements in irrigated areas' classification accuracy are critical to enhance agricultural water management and inform policy and decision-making on irrigation expansion and land use planning. This is particularly relevant in water-scarce regions where there are plans to increase the land under irrigation to enhance food security, yet the actual spatial extent of current irrigation areas is unknown. This study applied a non-parametric machine learning algorithm, the random forest, to process and classify irrigated areas using images acquired by the Landsat and Sentinel satellites, for Mpumalanga Province in Africa. The classification process was automated on a big-data management platform, the Google Earth Engine (GEE), and the R-programming was used for post-processing. The normalised difference vegetation index (NDVI) was subsequently used to distinguish between irrigated and rainfed areas during 2018/19 and 2019/20 winter growing seasons. High NDVI values on cultivated land during the dry season are an indication of irrigation. The classification of cultivated areas was for 2020, but 2019 irrigated areas were also classified to assess the impact of the Covid-19 pandemic on agriculture. The comparison in irrigated areas between 2019 and 2020 facilitated an assessment of changes in irrigated areas in smallholder farming areas. The approach enhanced the classification accuracy of irrigated areas using ground-based training samples and very high-resolution images (VHRI) and fusion with existing datasets and the use of expert and local knowledge of the study area. The overall classification accuracy was 88%.

Spatiotemporal Analysis of Land-use and Land-cover Dynamics of Adama District, Ethiopia and Its Implication to Greenhouse Gas Emissions.

Uncontrolled change in land use and land cover (LULC) enhances the concentrations of greenhouse gases in the atmosphere. This study, therefore, is aimed at the spatiotemporal analysis of LULC dynamics and their implications for the greenhouse gas emissions of the Adama district of Ethiopia. The dry season Landsat image Thematic Mapper (TM) of 1986, Enhanced Thematic Mapper (ETM) of 2000, and Enhanced Thematic Mapper Plus (ETM+ ) of 2014 were downloaded from the United States Geological Survey Global Visualization Viewer Website and employed. The hybrid classification approach was performed after the preprocessing of the image. Moreover, observations, key informant interviews, and focus group discussions were used. The analysis was carried out using the image data and survey data. The result indicates that agricultural land and shrub and bush lands covered 80.98%, 76.75%, and 74.42% of the study area during 1986, 2000, and 2014, respectively. Although there were differences in the magnitudes and rates of change during the considered years, the LULC classification results of this study indicated that most natural environments are converted to human-dominated environments, which can be attributed to human-induced activities. Due to this conversion, environmental degradation is aggravated, which again paves the way for the increased concentration of greenhouse gases in the atmosphere. The study concludes that, largely as a result of interventions from the communities living in the area, the study area is being transformed from the natural ecosystem to a managed environment. Hence, the practices of smallholder farmers with respect to protected areas, afforestation, and reforestation must be strengthened and supported by an integrated policy framework. Integr Environ Assess Manag 2019;00:1-13. © 2019 SETAC.

An integrative analytical model for the water-energy-food nexus: South Africa case study.

The missing link between cross-sectoral resource management and full-scale adoption of the water-energy-food (WEF) nexus has been the lack of analytical tools that provide evidence for policy and decision-making. This study defined WEF nexus sustainability indicators, from where an analytical model was developed to manage WEF resources in an integrated manner using the Analytic Hierarchy Process (AHP). The model established quantitative relationships among WEF sectors, simplifying the intricate interlinkages among resources, using South Africa as a case study. A spider graph was used to illustrate sector performance as related to others, whose management is viewed either as sustainable or unsustainable. The model was then applied to assess progress towards the Sustainable Development Goals in South Africa. The estimated integrated indices of 0.155 and 0.203 for 2015 and 2018, respectively, classify South Africa's management of resources as marginally sustainable. The model is a decision support tool that highlights priority areas for intervention.

Migration under Climate Change in Southern Africa: A Nexus Planning Perspective.

Population increase is exacerbating resource insecurities due to increased demand for already depleted resources. Coupled with climate change, they are the main drivers of both intra-(rural-urban and urban-urban) and inter-migration (from one country to the other). We carried out a systematic review of literature, focusing on available options to ensure water and food security, as well as improve the socio-economic environment, highlighting the drivers of migration in southern Africa. The aim was to develop informed adaptation strategies and build resilience in the advent of accelerated migration. We developed a migration conceptual framework based on the nexus between water, food and socio-economic interlinkages. Urban areas in southern Africa are under immense pressure to accommodate climate refugees from resource stressed rural areas, a situation that is impacting on agricultural production. Most urban areas are exceeding their ecological thresholds to support the built environment, causing some socio-ecological challenges. Nexus planning can inform adaptation planning on permissible migration that are aligned with regional goals such as regional integration, poverty reduction and improved livelihoods. This would also contribute to the region's achievements of the Sustainable Development Goals. Furthermore, through the identification of synergies and trade-offs, nexus planning can inform regional adaptation strategies for positively managing migration leading to sustainable outcomes.

The Water-Energy-Food Nexus as a Tool to Transform Rural Livelihoods and Well-Being in Southern Africa.

About 60% of southern Africa's population lives in rural areas with limited access to basic services and amenities such as clean and safe water, affordable and clean energy, and balanced and nutritious diets. Resource scarcity has direct and indirect impacts on nutrition, human health, and well-being of mostly poor rural communities. Climate change impacts in the region are manifesting through low crop yields, upsurge of vector borne diseases (malaria and dengue fever), and water and food-borne diseases (cholera and diarrhoea). This study applied a water-energy-food (WEF) nexus analytical livelihoods model with complex systems understanding to assess rural livelihoods, health, and well-being in southern Africa, recommending tailor-made adaptation strategies for the region aimed at building resilient rural communities. The WEF nexus is a decision support tool that improves rural livelihoods through integrated resource distribution, planning, and management, and ensures inclusive socio-economic transformation and development, and addresses related sustainable development goals, particularly goals 2, 3, 6 and 7. The integrated WEF nexus index for the region was calculated at 0.145, which is marginally sustainable, and indicating the region's exposure to vulnerabilities, and reveals a major reason why the region fails to meet its developmental targets. The integrated relationship among WEF resources in southern Africa shows an imbalance and uneven resource allocation, utilisation and distribution, which normally results from a 'siloed' approach in resource management. The WEF nexus provides better adaptation options, as it guides decision making processes by identifying priority areas needing intervention, enhancing synergies, and minimising trade-offs necessary for resilient rural communities. Our results identified (i) the trade-offs and unintended negative consequences for poor rural households' livelihoods of current silo approaches, (ii) mechanisms for sustainably enhancing household water, energy and food security, whilst (iii) providing direction for achieving SDGs 2, 3, 6 and 7.

Climate Change Adaptation through the Water-Energy-Food Nexus in Southern Africa.

Climate change is a complex and cross-cutting problem that needs an integrated and transformative systems approach to respond to the challenge. Current sectoral approaches to climate change adaptation initiatives often create imbalances and retard sustainable development. Regional and international literature on climate change adaptation opportunities and challenges applicable to southern Africa from a water-energy-food (WEF) nexus perspective was reviewed. Specifically, this review highlights climate change impacts on water, energy, and food resources in southern Africa, while exploring mitigation and adaptation opportunities. The review further recommends strategies to develop cross-sectoral sustainable measures aimed at building resilient communities. Regional WEF nexus related institutions and legal frameworks were also reviewed to relate the WEF nexus to policy. Southern Africa is witnessing an increased frequency and intensity in climate change-associated extreme weather events, causing water, food, and energy insecurity. A projected reduction of 20% in annual rainfall by 2080 in southern Africa will only increase the regional socio-economic challenges. This is exacerbating regional resource scarcities and vulnerabilities. It will also have direct and indirect impacts on nutrition, human well-being, and health. Reduced agricultural production, lack of access to clean water, sanitation, and clean, sustainable energy are the major areas of concern. The region is already experiencing an upsurge of vector borne diseases (malaria and dengue fever), and water and food-borne diseases (cholera and diarrhoea). What is clear is that climate change impacts are cross-sectoral and multidimensional, and therefore require cross-sectoral mitigation and adaptation approaches. In this regard, a well-coordinated and integrated WEF nexus approach offers opportunities to build resilient systems, harmonise interventions, and mitigate trade-offs and hence improve sustainability. This would be achieved through greater resource mobilisation and coordination, policy convergence across sectors, and targeting nexus points in the landscape. The WEF nexus approach has potential to increase the resilience of marginalised communities in southern Africa by contributing towards attaining the Sustainable Development Goals (SDGs 1, 2, 3, 6, 7, and 13).