Climate Change and Human Habitat - Batch 5

Evaluation of Climate and Environment-Induced Migration in Nigeria

2023-03-01T00:00:00Z

Evaluation of Climate and Environment-Induced Migration in Nigeria Aweda, Emmanuel Damilola Migration has been recognised as a coping mechanism in response to escalating climate change and environmental degradation globally, particularly in Sub-Saharan Africa, where Nigeria is located. The search for livelihood opportunities and improved living conditions, among other underlying factors, makes migration complex and multifaceted. Employing a mixed-methods approach, this study integrates remote sensing and climate data (1993 to 2022) with household surveys (n = 1080) and focus group discussions across selected hotspots in Nigeria. This study revealed a significant increase in temperature at the migration origins in Kano Municipal, Kwali; and sea level rise in coastal communities of Warri South-West and Brass (p < 0.05). The study provided empirical evidence of a paradox: despite the established environmental and climatic changes, there was a notable reluctance to migrate. While perceptions of migration drivers were consistent across the communities (H = 8.108, p = 0.423), socioeconomic factors, particularly the pursuit of job opportunities (35 percent) and business/trading prospects (29 percent), were identified as the major drivers of migration. Climate and environmental factors were cited by 11 percent of the migrants, with persistent drought (32 percent) and inadequate rainfall (27 percent) being the major climatic drivers. Destination communities in Fagge, Kano Municipal, Gwagwalada, and Kwali faced significant variations in challenges due to migration (H = 41.729, p < 0.05). These challenges were competition for jobs (43.7 percent), insecurity (23.2 percent), pressure on agricultural lands (11.7 percent), pressure on environmental resources (10.7 percent), land degradation (7.6 percent), and pressure on land for development (3.4 percent). Furthermore, there was a significant variation among communities regarding who should be responsible for leading interventions related to climate and environment-induced migration (H = 37.327, p < 0.05). The findings imply that while socioeconomic factors are the major drivers, environmental and climatic changes were critical in influencing migration decisions. This study thus advocates for multi-stakeholder partnerships to develop tailored strategies to address climate and environment-induced migration in Nigeria. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Federal University of Technology, Minna, Nigeria, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Climate Change and Human Habitat

Role of Urban Plant Phylogenetic Diversity on Urban Heat Island Effects and reducing Carbon Dioxide in West African Coastal and Savannah Cities

2025-05-01T00:00:00Z

Role of Urban Plant Phylogenetic Diversity on Urban Heat Island Effects and reducing Carbon Dioxide in West African Coastal and Savannah Cities Ahouandjinou, Enagnon Benoit Olivier Urbanisation poses significant challenges to biodiversity, climate resilience, and sustainable city planning, especially in the global south. Rapid urbanisation and industrial growth intensify the Urban Heat Island (UHI) effect, driving temperature disparities between urban and rural areas. At the same time, urbanisation reduces carbon stocks and alters urban plant diversity, contributing to biodiversity loss. A common framework for understanding biodiversity in cities is the luxury effect, which suggests that wealthier neighbourhoods support greater biodiversity due to resources and landscaping. However, the applicability of this hypothesis in the global south, where socio-economic and environmental dynamics differ, remains unclear. This thesis examines the relationships between urban climate, residential plant diversity, and socioeconomic factors across two coastal and mainland cities in West Africa. A survey of 1,902 randomly selected households recorded socioeconomic characteristics and catalogued urban plant species in household gardens. These data were used to estimate household-level diversity metrics, including taxonomic and phylogenetic diversity. The study further investigated how residential plant species with varying phylogenetic diversity optimise cooling in urban areas with different levels of greening. Relationships between phylogenetic diversity, alien species, and urban development indices were analysed using linear mixed-effect models and structural equation modelling. Findings show no general support for the luxury effect on phylogenetic diversity. However, rented properties displayed lower taxonomic (β = -0.197, p = 0.003) and phylogenetic diversity (β = -0.176, p = 0.009) than privately owned houses. Results also reveal that wealth alone does not dictate biodiversity distribution; rather, complex interactions between socioeconomic traits and urban plant diversity shape outcomes. Phylogenetic diversity reduced Land Surface Temperature (LST) regionally (βs = -0.002, p < 0.048), though this effect diminished at the city scale due to landscape homogeneity and urban features (βs = 0.069, p = 0.036). Greenery strongly increased neighbourhood phylogenetic diversity (βs = 0.847, p < 0.0001). Alien species decreased taxonomic diversity while increasing lineage diversity (βs = 0, p = 0.009). Longer residence time increased taxonomic diversity (βs = 0.051, p = 0.042) and reduced ambient temperature in greener areas of Benin (βs = -0.043, p = 0.045). This study underscores the need for integrated urban planning that considers the drivers of plant diversity and their role in mitigating the UHI effect and reducing CO₂ emissions. Strategic approaches should prioritise not only phylogenetic diversity but also functional traits essential for heat regulation, potentially through targeted species introduction. Findings offer guidance for biodiversity conservation and climate resilience in rapidly urbanising regions. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Federal University of Technology, Minna, Nigeria, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Climate Change and Human Habitat

Evaluation of the Impact of Urban Sprawl Dynamics on Ecosystem Services in Selected Metropolitan Areas in Togo and Ghana

2025-07-01T00:00:00Z

Evaluation of the Impact of Urban Sprawl Dynamics on Ecosystem Services in Selected Metropolitan Areas in Togo and Ghana and population growth in West Africa have led to significant changes in land use and land cover (LULC), raising environmental concerns. In view of this, the study evaluated the impact of urban sprawl on ecosystem services in the District Autonome du Grand Lome (DAGL) and Greater Accra Metropolitan Area (GAMA) from 1986 to 2023 and from 1991 to 2023 respectively, using geospatial techniques; the Google Earth Engine platform and InVEST model. The findings indicate a decline in the verdant landscape, with forested areas in DAGL declined from 24 % in 1986 to 3 % by 2023, and from 34 % in 1991 to 2 % in 2023 in GAMA. Grasslands also saw significant reductions, while built up areas expanded dramatically rising from 18 % to 62 % in DAGL and from 10 % to 70 % in GAMA. The Urban Expansion Intensity Index (UEII) reflects rapid urban growth, with DAGL at 1.19 % and GAMA at 1.88 %. Directional analyses revealed that urban expansion predominantly occurs towards the north-west in DAGL and both north-east and north-west in GAMA. In DAGL the total carbon storage significantly declined from 3,604,852 Mg of C in 1986 to 1,367,113 Mg of C by 2023. The most substantial loss in carbon storage was between 2001 and 2015. Similarly, in the GAMA, carbon storage dropped from 16,574,522 Mg of C in 1991 to 4,120,702 Mg of C by 2023, with major decrease between 2002 and 2017. More so, in DAGL, the runoff retention index has remained low, fluctuating between 2.00 % in 1986 and 2.43 % in 2001, before dropping to 2.01 % by 2023 with total runoff retention decreasing from 29,098,483 m³ in 1986 to 17,908,270 m³ in 2023. In contrast, in GAMA region had a higher runoff retention index of 14.75 % in 1991, and decreased to 9.66 % by 2023. Despite this initial advantage, total runoff retention also declined significantly from 85,027,128 m³ in 1991 to 57,500,096 m³ in 2023. The study also revealed a decrease in cooling capacity from 0.60 % in 2001 to 0.30 % in 2023 in DAGL with direct correlation with the average temperature increase from 26°C in 2001 to 29.5°C in 2023. In the same vein, cooling capacity declined from 0.65 % in 2002 to 0.25 % in 2023 in GAMA with average temperatures rising from 25.5°C in 2002 to 29.0°C in 2023. Going by all these negative impacts of urban sprawl in both cities, it is therefore recommended that vertical and mixed land use development with integrated ecological preservation approaches, should take pre-eminence over horizontal development to achieve eco-development and more resilient urban future. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Federal University of Technology, Minna, Nigeria, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Climate Change and Human Habitat

Dynamics of Green Spaces and their Impacts on Urban Ecosystem Services in a Climate Change Context in Dakar Region, Senegal

2025-05-01T00:00:00Z

Dynamics of Green Spaces and their Impacts on Urban Ecosystem Services in a Climate Change Context in Dakar Region, Senegal Cisse, Mariama Senegalese cities have undergone rapid urbanisation, resulting in significant landscape transformations. Dakar, one of Senegal’s fastest-growing cities, is experiencing rapid urban expansion, leading to a substantial reduction in green spaces. These green spaces, essential for urban sustainability and resilience, are becoming increasingly scarce, negatively impacting the city’s environment and the quality of life for its inhabitants. In this context of climate change, this study aims to assess the impacts of changes in the region’s public green spaces on urban ecosystem services. To collect the data, several approaches were employed. These included a combination of methods, such as an itinerant inventory of public green spaces, surveys with questionnaires, and semi-structured interviews. Secondary data, such as Landsat satellite images, were also collected. Data analysis involved approaches such as geographic information systems, remote sensing, descriptive statistical analysis, and content analysis. This study also utilised new methods for evaluating ecosystem services, such as the InVEST model. The results obtained in this study revealed an interesting typology of public green spaces, characterised by low diversity, with Shannon and Evenness indices equal to 1.44 and 0.56, respectively. Furthermore, green spaces are unevenly distributed in the region, as revealed by the Gini coefficient of 0.59. In terms of quantity, the green spaces showed low density, with only 2 green spaces per square kilometre, a low coverage rate of 3.5 %, and a low ratio of 4.69 square metres per inhabitant. Qualitatively, the NDVI values are also relatively low for most green spaces. The spatiotemporal analysis from 1990 to 2022 showed a downward trend, with the total green space coverage decreasing from 13.36 % in 1990 to 9.54 % in 2022. This study also examined the three major green spaces in Dakar, revealing substantial changes in vegetation cover, accompanied by significant losses despite some observed gains. The primary factors contributing to these changes were anthropogenic, primarily due to the city’s rapid urban expansion. The dynamics of green spaces directly impacted the selected regulatory services, particularly in the forest. The reduction in vegetation cover led to a decrease in carbon stocks, urban cooling capacity, and flood control. However, in the park and the reserve, the correlation was negative, suggesting that other factors influence ecosystem services. In light of this, this study conducted a suitability analysis to identify areas suitable for green space development. The results revealed significant potential for green space development in the Dakar region, with over 90% of the area being suitable, and moderately suitable being the most prevalent type. Consequently, this study highlights a critical issue with the integration of public green spaces in urban planning in Dakar, which has resulted in substantial loss of these spaces and the services they provide. To address this issue, this study recommends the expansion of green spaces and the implementation of a robust management policy for their proper conservation. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Federal University of Technology, Minna, Nigeria, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Climate Change and Human Habitat