Editorial

This special issue of Environment and Urbanization ASIA on ‘Changes in Land Use and Land Cover in Cities of the Global South—Patterns and Driving Forces’ comes at an important time in the transition of cities in the global south around the world. Within Asia, emerging urban centres have fundamentally changed the regional landscape and it is an appropriate time to both visualize this dramatic transformation and to take stock of the drivers and forces that have shaped it. This special issue departs from Environment and Urbanization ASIA’s usual focus on Asia to consider the potential for knowledge transfer between urbanizing cities in Asia and Africa. The UN’s World Urbanization Prospects (United Nations, Department of Economic and Social Affairs & Population Division, 2019, p. 1) projects that between 2018 and 2050 the global urban population will grow by 2.5 billion urban dwellers, with almost 90% of this increase located in Asia and Africa.

Africa is at a different stage of its urbanization transformation. According to UN estimates, it is set to reach its tipping point, whereby the majority of its population live in cities, by 2035. Although urban rural distributions are a contentious topic, the scale of the challenge for Asia and Africa is well accepted in academic circles. More than scale, however, it is about the quality and framing of responses to urbanization. How should cities in Africa and Asia manage and design policy for the massive levels of migration to come? Currently, negative views towards urbanizing populations and the urbanization process limit the effectiveness of policies (United Nations Human Settlements Programme, ICLEI-Local Governments for Sustainability & United Cities and Local Governments of Africa, 2014). There is a need to design approaches that manage driving forces in positive and inclusive ways.

Another reason many cities are not well prepared to accommodate urbanizing populations is policies which are built on insufficient data. Asia and Africa have significant data gaps and special issues like the one presented here can help contribute to meeting this need. The special issue is, therefore, framed as an opportunity to reflect and to assess what lessons and knowledge on the urban transition can be transferred from Asia to Africa and vice versa. It is also necessary to compare and recognize the distinctive patterns of urbanization of each region, and to consider what is particular to Asia and, therefore, not relevant to the African experience.

Remote sensing, which all of the eight articles in this special issue touch on and apply to different effect, is one of the most powerful and revealing techniques for understanding this land use and land cover transformation. Actual urban footprints are revealed through remote sensed data, in contrast to bureaucratic boundaries which often disguise the true extent of cities. Some of the most effective technologies are not necessarily that new, yet still offer up startling insights when interrogated and analysed at different scales and using different methods. Remarkable new datasets produced in recent years include the Global Urban Footprint (Esch et al., 2017). Many of these datasets are available in Google Earth Engine and some authors from this special issue have made good use of this aggregator to assemble and analyse these across time to better understand changing spatial patterns of urban land use and land cover.

Such data are frequently global in extent, share common spatial and time periods, and are open access in nature. This makes such resources accessible to all and provides a powerful asset for global comparative analysis. Satellite data especially provide a consistent dataset, making urban comparative research much more accessible and powerful and transforming empirical research on land cover, land use and urban development patterns. The articles in this special issue generally focus on using satellite imagery and other datasets such as census data, to discern developed from undeveloped land. From such classifications a variety of metrics can then be derived to describe the pattern, extent and transformation of urban areas over time. Of particular interest is the shape and fragmentation of spatial growth and its connectivity. Equally important are the land cover types being lost to urban development, such as agricultural and ecological lands. Recent work by d’Amour et al. (2017) has described the extent of this and some of the case studies in this special issue provide focused investigation for the cities at hand.

Today’s urban landscape has been shaped by the emergence of new constellations of cities, often linked in extensive urban regions. Some cities have grown beyond recognition, many new ones have appeared, and others have diminished in size. However, when looked at in aggregate the world’s urban areas are expanding and their densities are decreasing. Generally, the global trend has been for a dramatic decentralization with a reduction of urban density. In the west and east alike this has caused much consternation. However, as scholars such as Angel (2011) attest, the response must be measured and space must be made for urban newcomers. The burgeoning populations of Africa and Asia must be encouraged to urbanize to meet a range of sustainability targets. This means Asian and African cities must make space for migrating populations either through innovative urban extensions, or sensitive increases in urban density.

The eight cities considered in this special issue, moving geographically from east to west are Chongqing, China; Batangas City, Philippines; Dhaka, Bangladesh; Delhi, India; Dar es Salaam, Tanzania; Kigali, Rwanda; Johannesburg, and Cape Town, South Africa. The eight city case studies capture an extraordinary swathe of urban experience and geographic reach, taking in East Asia, Southeast Asia, South Asia, East Africa, Central Africa and Southern Africa. The mapping by the special issue authors reveals a range of patterns, all of them polycentric. Each of these case studies demonstrate a remarkable diversity and the importance of approaches that integrate a more granular urban design scaled analysis that takes into consideration the diversity within the urban footprint and within the broad classes identified by remote sensing approaches.

The article by Sun et al. emphasizes the scale of China’s urban transformation, noting that Chongqing has expanded by almost 500% in the last 20 years in a polycentric pattern. So much so that it is sometimes regarded as the largest city in China, although that depends how its urban area and connectivity is defined. Chongqing’s urbanization is generally admired within China and has come about through a combination of good management and opportunistic use of circumstance. For example, its strategic location on the Yangtze and geopolitical location in relation to the Belt and Road initiative and its ability to keep housing prices relatively stable through good management of property auctions and land development, amongst other factors, has allowed rapid and more inclusive growth than many other Chinese cities. Significantly, Chongqing has not blindly followed the eastern seaboard cities in some regards and has instead focused on its competitive advantage and, therefore, benefited from its own distinctive developmental path (Bao et al., 2019).

In Southeast Asia, the path to urbanization has been challenging and dominated by large metropolitan areas and supporting peripheral cities. This is the case for Manila and its extended urban region (Kelly, 1999, 2003), which has stimulated the industrialization of a cluster of surrounding settlements such as Cavite, Laguna, Batangas, Rizal and Quezon. Daguio, et al investigate Batangas, one of these peripheral cities to the south of Manila, seeking to chart the patterns of land value dispersed throughout this formerly agricultural area.

South Asian urbanization has taken a very different turn from that in East and Southeast Asia. There is a remarkable diversity of urban patterns emerging in this region, with urban areas experiencing unprecedented rates of growth over the past three decades. This economic growth has come at great cost, placing extreme pressure on India’s social and environmental systems. Roy et al., map the sprawling peri-urban area of Dhaka, describing the driving factors that have stimulated growth in the urban periphery. Further, they highlight that socio-economic sustainability is a major challenge with inadequate service provisioning creating inequalities and segregated communities surrounding the denser city centre. These new areas are emerging without policies and measures for safeguarding the interests of urbanizing citizens in the sprawling periphery of the city. They note that these forces could lead to future social unrest in the city region. In such contexts, better management of bottom up and informal resource development and capacity building need to be a high priority. Mondal et al., focus more on the green resources of Delhi and assess the landscape and ecological risk zones considering both landscape fragmentation and land use land cover vulnerability. Their findings suggest the urgency of understanding more about the ecological security patterns within Indian cities and their associated mega-urban regions.

Within the different regions of Africa, a range of complementary but also new pressures are evident. Amongst these new pressures, the extreme rate of urbanization in cities such as Dar es Salaam is described by the special issue authors Msuya et al., From 2000 to 2015, Dar es Salaam’s population grew from 2,272,483 to 5,115,698—a growth rate of 5.74%, whilst the built-up area expanded by 23.16%. The need for new housing has driven both informal and formal housing development. Populations who had lived in informal inner city developments have been resettled in formal schemes on the periphery. This has, however, come at the expense of ecological resources that the city relies upon.

The article on Kigali, Rwanda by Nduwayezu et al., presents another case of the distinctive rapid urbanization taking place in Africa. Within Kigali the average annual growth rate was almost 10.24% from 1999 to 2018. Informal urban expansion has characterized the city since independence, with formal developments lacking the scale, resources and ambition to provide for urbanizing populations on the periphery. Of note is the special economic zone that sits as a formal development in the midst of more informal urbanization. One interesting aspect of Kigali’s urbanization has been an increase in afforestation despite the massive new urban development taking place.

The final two articles considered, and those farthest west in the city sample, focus on Johannesburg and Cape Town in South Africa. Both cities are immensely complex and, in many ways, unique within global discussions of urbanization. The authors attempt to lay bare several decades of urbanization drivers and trends in relation to urban land cover and census data analyses. Katumbe and Everatt explain that the question of urbanization, land cover and ‘sprawl’ are inherently political in South Africa, where the post-apartheid constitutional settlement negotiation gave the state the right to expropriate land but effectively left the property status quo in place. Cities and urbanization were not effectively considered a national priority by the new ruling party, the African National Congress (ANC), until 2014, when a new national urban policy came into effect. Nevertheless, this has come as too little too late, with the structural inequalities of apartheid proving both formidable and lasting.

Extending on from the article by Katumba and Everatt, the excellent article by Scheba et al., describes how policy that does not interface well with underlying driving forces will often produce unintended outcomes. In Cape Town this means a densification of already incredibly dense poorer townships located well beyond easy access to services, whilst the wealthy inner urban residential areas, well placed in relation to urban amenity, have generally resisted densification. The result is an increase in the already severe inequalities that plague the city. This has not been helped by the sidelining of urban design as a city shaping approach in recent years. More than any other article in the special issue, Scheba and co-authors consider the importance of the fine grain and how it can transform the broad and high-level impressions and findings provided by remote sensing and census data. Further urban design approaches are necessary to translate high-level remote sensing analyses in a way that is meaningful and effective to the lives of local people. This affirms the importance of multidisciplinary research between remote sensing specialists and planners and those working on the ground shaping cities at the level of the street.

I am delighted to be given the opportunity to introduce this special issue, my first as a member of the editorial board for Environment and Urbanization ASIA, which offers an important range of insights on cities that are generally beyond the purvey of mainstream urban studies. It is so important because they are emblematic of the challenges throughout Asia and Africa, where the most critical new urban growth of the next two decades will take place.