scholarly journals Mapping 20 Years of Urban Expansion in 45 Urban Areas of Sub-Saharan Africa

2021 ◽  
Vol 13 (3) ◽  
pp. 525
Author(s):  
Yann Forget ◽  
Michal Shimoni ◽  
Marius Gilbert ◽  
Catherine Linard
Keyword(s):  
Case Studies ◽  
Urban Areas ◽  
Urban Expansion ◽  
Local Population ◽  
Sub Saharan Africa ◽  
Annual Growth Rate ◽  
Urban Dynamics ◽  
Mapping Approach ◽  
Sub Saharan ◽  
The Impact

By 2050, half of the net increase in the world’s population is expected to reside in sub-Saharan Africa (SSA), driving high urbanization rates and drastic land cover changes. However, the data-scarce environment of SSA limits our understanding of the urban dynamics in the region. In this context, Earth Observation (EO) is an opportunity to gather accurate and up-to-date spatial information on urban extents. During the last decade, the adoption of open-access policies by major EO programs (CBERS, Landsat, Sentinel) has allowed the production of several global high resolution (10–30 m) maps of human settlements. However, mapping accuracies in SSA are usually lower, limited by the lack of reference datasets to support the training and the validation of the classification models. Here we propose a mapping approach based on multi-sensor satellite imagery (Landsat, Sentinel-1, Envisat, ERS) and volunteered geographic information (OpenStreetMap) to solve the challenges of urban remote sensing in SSA. The proposed mapping approach is assessed in 17 case studies for an average F1-score of 0.93, and applied in 45 urban areas of SSA to produce a dataset of urban expansion from 1995 to 2015. Across the case studies, built-up areas averaged a compound annual growth rate of 5.5% between 1995 and 2015. The comparison with local population dynamics reveals the heterogeneity of urban dynamics in SSA. Overall, population densities in built-up areas are decreasing. However, the impact of population growth on urban expansion differs depending on the size of the urban area and its income class.

scholarly journals Exploring Annual Urban Expansions in the Guangdong-Hong Kong-Macau Greater Bay Area: Spatiotemporal Features and Driving Factors in 1986–2017

2020 ◽  
Vol 12 (16) ◽  
pp. 2615
Author(s):  
Jie Zhang ◽  
Le Yu ◽  
Xuecao Li ◽  
Chenchen Zhang ◽  
Tiezhu Shi ◽  
...  
Keyword(s):  
Growth Rate ◽  
Hong Kong ◽  
Urban Areas ◽  
Urban Expansion ◽  
Driving Factors ◽  
Annual Growth ◽  
Annual Growth Rate ◽  
Spatial And Temporal Scales ◽  
Urban Dynamics ◽  
Bay Area

The Guangdong–Hong Kong–Macau Greater Bay Area (GBA) of China is one of the largest bay areas in the world. However, the spatiotemporal characteristics and driving mechanisms of urban expansions in this region are poorly understood. Here we used the annual remote sensing images, Geographic Information System (GIS) techniques, and geographical detector method to characterize the spatiotemporal patterns of urban expansion in the GBA and investigate their driving factors during 1986–2017 on regional and city scales. The results showed that: the GBA experienced an unprecedented urban expansion over the past 32 years. The total urban area expanded from 652.74 km2 to 8137.09 km2 from 1986 to 2017 (approximately 13 times). The annual growth rate during 1986–2017 was 8.20% and the annual growth rate from 1986 to 1990 was the highest (16.89%). Guangzhou, Foshan, Dongguan, and Shenzhen experienced the highest urban expansion rate, with the annual increase of urban areas in 51.51, 45.54, 36.76, and 23.26 km2 y−1, respectively, during 1986–2017. Gross Domestic Product (GDP), income, road length, and population were the most important driving factors of the urban expansions in the GBA. We also found the driving factors of the urban expansions varied with spatial and temporal scales, suggesting the general understanding from the regional level may not reveal detailed urban dynamics. Detailed urban management and planning policies should be made considering the spatial and internal heterogeneity. These findings can enhance the comprehensive understanding of this bay area and help policymakers to promote sustainable development in the future.

scholarly journals Seroprevalence of SARS-CoV-2 in urban settings in three sub-Saharan African countries (SeroCoV): a study protocol for a household-based cross-sectional prevalence study using two-stage cluster sampling

BMJ Open ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. e056853
Author(s):  
Eva Lorenz ◽  
Aurélia Souares ◽  
John Amuasi ◽  
Wibke Loag ◽  
Christina Deschermeier ◽  
...  
Keyword(s):  
Study Protocol ◽  
Urban Areas ◽  
Control Measures ◽  
Sub Saharan Africa ◽  
Cluster Sampling ◽  
Two Stage ◽  
Cross Sectional ◽  
Sub Saharan ◽  
The Impact ◽  
Age And Sex

IntroductionThe current COVID-19 pandemic has impacted the entire world with increasing morbidity and mortality and has resulted in serious economic and social consequences. Assessing the burden of COVID-19 is essential for developing efficient pandemic preparedness and response strategies and for determining the impact of implemented control measures. Population-based seroprevalence surveys are critical to estimate infection rates, monitor the progression of the epidemic and to allow for the identification of persons exposed to the infection who may either have been asymptomatic or were never tested. This is especially important for countries where effective testing and tracking systems could not be established and where non-severe cases or under-reported deaths might have blurred the true burden of COVID-19. Most seroprevalence surveys performed in sub-Saharan Africa have targeted specific high risk or more easily accessible populations such as healthcare workers or blood donors, and household-based estimates are rarely available. Here, we present the study protocol for a SARS-CoV-2 seroprevalence estimation in the general population of Burkina Faso, Ghana and Madagascar in 2021.Methods and analysisThe SeroCoV study is a household-based cross-sectional prevalence investigation in persons aged 10 years and older living in urban areas in six cities using a two-stage geographical cluster sampling method stratified by age and sex. The presence of anti-SARS-CoV-2 IgG antibodies will be determined using a sensitive and specific SARS-CoV-2 IgG ELISA. In addition, questionnaires will cover sociodemographic information, episodes of diseases and history of testing and treatment for COVID-like symptoms, travel history and safety measures. We will estimate the seroprevalence of SARS-CoV-2, taking into account test performance and adjusting for the age and sex of the respective populations.Ethics and disseminationEthical approval was received for all participating countries. Results will be disseminated through reports and presentations at the country level as well as peer-reviewed publications and international scientific conferences presentations.

scholarly journals Urbanization and Floods in Sub-Saharan Africa: Spatiotemporal Study and Analysis of Vulnerability Factors—Case of Antananarivo Agglomeration (Madagascar)

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 149
Author(s):  
Fenosoa Nantenaina Ramiaramanana ◽  
Jacques Teller
Keyword(s):  
Urban Areas ◽  
Urban Expansion ◽  
Spatiotemporal Analysis ◽  
Natural Increase ◽  
Economic Resources ◽  
Sub Saharan Africa ◽  
High Rate ◽  
Vulnerable Groups ◽  
Drainage Networks ◽  
Sub Saharan

Flooding is currently one of the major threats to cities in Sub-Saharan Africa (SSA). The demographic change caused by the high rate of natural increase, combined with the migration toward cities, leads to a strong demand for housing and promotes urbanization. Given the insufficiency or absence of adequate planning, many constructions are installed in flood-prone zones, often without adequate infrastructure, especially drainage systems. This makes them very vulnerable. Our research consists of carrying out a spatiotemporal analysis of the agglomeration of Antananarivo (Madagascar). It shows that urbanization leads to increased exposure of populations and constructions to floods. There is a pressure on land in flood-prone zones due to the exponential growth of the population at the agglomeration level. Some 32% of the population of the Antananarivo agglomeration lived in flood-prone zones in 2018. An analysis of the evolution of built spaces from 1953 to 2017 highlights that urban expansion was intense over those years (6.1% yearly increase of built areas). This expansion triggered the construction of built areas in flood-prone zones, which evolved from 399 ha in 1953 to 3675 ha in 2017. In 2017, 23% of the buildings in the agglomeration, i.e., almost one out of every four buildings, were in flood-prone zones. A share of the urban expansion in flood-prone zones is related to informal developments that gather highly vulnerable groups with very little in terms of economic resources. Better integration of flood risk management in spatial planning policies thus appears to be an essential step to guide decisions so as to coordinate the development of urban areas and drainage networks in a sustainable way, considering the vulnerability of the population living in the most exposed areas.

Case Studies on Energy Subsidy Reform—Lessons and Implications - Supplement

Policy Papers ◽  
2013 ◽  
Vol 13 (5) ◽  
Author(s):  
Keyword(s):  
Case Studies ◽  
Public Support ◽  
Sub Saharan Africa ◽  
Energy Prices ◽  
Energy Product ◽  
Sub Saharan ◽  
The Impact ◽  
Energy Subsidy ◽  
Subsidy Reform

This supplement presents country case studies reviewing energy subsidy reform experiences, which are the basis for the reform lessons identified in the main paper. The selection of countries for the case studies reflects the availability of data and of previously documented evidence on country-specific reforms. The 22 country case studies were also chosen to provide cases from all regions and a mix of outcomes from reform. The studies cover 19 countries, including seven from sub-Saharan Africa, two in developing Asia, three in the Middle East and North Africa, four in Latin America and the Caribbean, and three in Central and Eastern Europe and the CIS. The case studies are organized by energy product, with 14 studies of the reform of petroleum product subsidies, seven studies of the reform of electricity subsidies, and a case study of subsidy reform for coal. The larger number of studies on fuel subsidies reflects the wider availability of data and past studies for these reforms. The structure of each case study is similar, with each one providing the context of the reform and a description of the reforms; discussion of the impact of the reform on energy prices or subsidies and its success or failure; mitigating measures that were implemented in an attempt to generate public support for the reform and offset adverse effects on the poor; and, finally, identification of lessons for designing reforms.

scholarly journals Access to electricity and digital inclusion: evidence from mobile call detail records

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Georges V. Houngbonon ◽  
Erwan Le Quentrec ◽  
Stefania Rubrichi
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Original Data ◽  
Text Messages ◽  
Sub Saharan Africa ◽  
Digital Inclusion ◽  
Data Set ◽  
Sub Saharan ◽  
The Impact ◽  
Call Detail Records

AbstractDespite significant progress in mobile connectivity, a large number of individuals in Sub-Saharan Africa are at risk of being left behind, especially those living in rural areas and women. In this paper, we use an original data set of mobile call detail records from Senegal and exploit variations across plausibly similar rural municipalities to assess the impact of access to electricity on mobile connectivity. We find that access to mobile connectivity for rural users, measured by mobile telephony subscriptions or smartphone ownership, increases with access to electricity, with a stronger impact for women. The impact on usage is also positive, but stems from the increased volume of incoming communications: rural mobile users with access to electricity do not place more calls than those with limited access; rather, they receive more calls and text messages from urban areas, especially those with higher living standards. These findings suggest that access to electricity can be a significant driver of digital inclusion in Sub-Saharan Africa.

scholarly journals Classifying and Mapping Periurban Areas of Rapidly Growing Medium-Sized Sub-Saharan African Cities: A Multi-Method Approach Applied to Tamale, Ghana

Land ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 40 ◽  
Author(s):  
Hanna Karg ◽  
Rafael Hologa ◽  
Johannes Schlesinger ◽  
Axel Drescher ◽  
Gordana Kranjac-Berisavljevic ◽  
...  
Keyword(s):  
Land Use ◽  
Rural Areas ◽  
Urban Areas ◽  
Spatial Scales ◽  
Urban Expansion ◽  
Urban Land Use ◽  
The Body ◽  
Sub Saharan Africa ◽  
Urban Rural ◽  
Sub Saharan

Periurban areas of growing cities in developing countries have been conceptualised as highly dynamic landscapes characterised by a mixture of socioeconomic structures, land uses and functions. While the body of conceptual literature on periurban areas has significantly increased over the past two decades, methods for operationalising these multi-dimensional concepts are rather limited. Yet, information about the location and areal extent of periurban areas is needed for integrated planning in the urban–rural interface. This article presents the results of a study aiming at classifying and mapping periurban areas along the urban–rural gradient of Tamale, a medium-sized city in Ghana. The study used a quantitative, multi-dimensional methodology involving the following as core elements: (1) a relative measure of how urban a place and its people are in terms of services, infrastructure and livelihoods (urbanicity index); (2) the diversity of households regarding their livelihoods and access to urban services; and (3) land use dynamics. Therefore, data from a household survey, as well as land use and other secondary geospatial data were collected and analysed at different spatial scales. The findings suggested that the periurban space consists of two main zones. Inner periurban areas are driven by urban expansion and the conversion of non-urban into urban land use is most visible here. These areas exhibit higher levels of socioeconomic diversity, compared to both rural and urban areas. Outer periurban areas are less dynamic in terms of land use change and exhibit lower building densities, and compared with rural areas, hold stronger links to the city related to the movement of people and goods. The spatial analysis revealed that periurban areas develop mainly along major transport corridors across administrative divisions, as well as in the form of periurban islands in the rural zone. This study set out to extend existing methodologies to map urban and periurban development in medium-sized cities in sub-Saharan Africa, useful for urban and regional planning beyond administrative boundaries.

Conflicts in Biafra, Katanga and Cabinda as a result of the geopolitical legacy of colonialism

2020 ◽  
Vol 2020 (10-3) ◽  
pp. 238-246
Author(s):  
Olga Dzhenchakova
Keyword(s):  
Democratic Republic ◽  
Economic Factor ◽  
Colonial Period ◽  
Sub Saharan Africa ◽  
Negative Consequences ◽  
Post Colonial ◽  
Republic Of The Congo ◽  
Sub Saharan ◽  
The Republic ◽  
The Impact

The article considers the impact of the colonial past of some countries in sub-Saharan Africa and its effect on their development during the post-colonial period. The negative consequences of the geopolitical legacy of colonialism are shown on the example of three countries: Nigeria, the Democratic Republic of the Congo and the Republic of Angola, expressed in the emergence of conflicts in these countries based on ethno-cultural, religious and socio-economic contradictions. At the same time, the focus is made on the economic factor and the consequences of the consumer policy of the former metropolises pursuing their mercantile interests were mixed.

Managing African Urbanization in the Context of Environmental Change

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Shuaib Lwasa
Keyword(s):  
Climate Change ◽  
Economic Growth ◽  
Social Services ◽  
Urban Areas ◽  
Urban Governance ◽  
Sub Saharan Africa ◽  
African Countries ◽  
Sub Saharan ◽  
Urbanization Rate ◽  
Development And Management

Africa’s urbanization rate has increased steadily over the past three decades and is reported to be faster than in any other region in the world . It is estimated that by 2030, over half of the African population will be living in urban areas . But the nature of Africa’s urbanization and subsequent form of cities is yet to be critically analyzed in the context of city authorities’ readiness to address the challenges . Evidence is also suggesting that urbanization in African countries is increasingly associated with the high economic growth that has been observed in the last two decades . Both underlying and proximate drivers are responsible for the urbanization, and these include population dynamics, economic growth, legislative designation, increasing densities in rural centers, as well as the growth of mega cities such as Lagos, Cairo and Kinshasa, that are extending to form urban corridors . With the opportunities of urbanization in Sub–Saharan Africa, there are also challenges in the development and management of these cities . Those challenges include provision of social services, sustainable economic development, housing development, urban governance, spatial development guidance and environmental management, climate change adaptation, mitigation and disaster risk reduction . The challenge involves dealing with the development and infrastructure deficit, in addition to required adaption to and mitigation of climate change . This paper examines the current state of urban management in Africa .

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