Pathways for resilience to climate change in African cities

Climate change and rapid urbanization are twin global challenges as articulated by Agenda 2030 of the 17 Sustainable Development Goals (SDGs). Climatic threats, including floods, drought, water stress, seal level rise, heat waves and storms, are highest on the list of exposure to economic and social risks in cities (World Bank 2019). Although a weaker intensified rainfall trend has been projected for Africa (Kendon et al 2019), slum settlements in cities like Dhaka and Maputo are some of the most vulnerable during cyclones and heavy rainfall (Zehra et al 2019). Cyclone Kenneth, which landed in the Cabo Delgado province in northern Mozambique on 25 April 2019, led to 45 fatalities and left 374 000 people at risk of waterborne diseases (Cambaza et al 2019). Cholera, diarrheal and rodent-bone diseases may increase as a result of more frequent and severe floods and drought, thus affecting urban populations in high-risk areas (World Health Organization WHO (2018), Fombe 2019, Siegel 2020). For the inland mountainous cities like Addis Ababa, extreme rainfall and droughts have intensified hazards disease outbreaks and food insecurity. In August 2006, for example, floods killed more than 100 people in the Ethiopian capital. In Kampala (Uganda), an inland city, flash floods usually destroy backyard gardens, make roads impassable, accelerate contamination of air and water sources and contribute to the intensive spread of diseases like cholera and malaria (Lwasa et al 2018).

In terms of regional differences in exposure, projections show increased precipitation in areas of Western Africa and Eastern Africa (Endris et al 2019, Odoulami et al 2019), and this has been linked to changes in the characteristics of the El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) for the case of northern and equatorial part of East Africa. Coastal areas are especially subject to flooding as a result of both precipitation events and sea level rise. An estimated 54 million Africans live in vulnerable Low Elevation Coastal Zones (LECZ)—defined as areas 10 meters or less above sea level—and this figure is projected to rise to over 100 million by 2030 (Becker et al 2019). As shown in figure 1, cities around rivers and creeks are susceptible to riverine flooding, though localized flooding occurs outside these areas as well, especially in more heavily developed settings (Abiodun et al 2019, Ponte et al 2019, Soares et al 2019, Ziervogel 2019). In Bamenda (Cameroon), approximately 20% of the 250 000 residents live on floodplains and roughly 7% live in informal settlements on steep slopes. Land clearance for settlement and for quarrying and sand mining, along with other land-use changes caused by urban expansion, have further created serious problems of soil erosion. Soil that is washed down the hills blocks drainage channels and changes peak water flows. Degradation of the land has exacerbated problems with floods (Tume et al 2019). An estimated 17% of Mombasa's area (4600 hectares) could be submerged by a sea-level rise of 0 3 meters, with a larger area rendered uninhabitable or unusable for agriculture because of waterlogging and salt stress Sandy beaches, historic and cultural monuments, and several hotels, industries and port facilities would also be negatively affected. Mombasa already has a history of disasters related to climate extremes, including floods that have caused serious damage and loss of life nearly every year (Okaka and Odhiambo 2019).

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An assessment of the vulnerability in the cities of Alexandria, Rosetta and Port Said (Egypt), suggests that with a sea-level rise of 50 cm, more than 2 million people would have to abandon their homes, 214 000 jobs would be lost, and the cost in lost property value and tourism income would be over US $35 billion, which does not include the immeasurable loss of world famous historic, cultural and archaeological sites (Elshazly et al 2019). In Banjul (Gambia), the city is less than 1 meter above sea level and flooding is common after heavy rains in settlements established on reclaimed land in dried-up valleys, and in settlements close to mangrove swamps and wetlands. Problems with flooding are likely to intensify under a warmer climate with an increase in the strength and frequency of tropical storms, coupled with a negative influence on fish assemblage in the Central River Region (CRR) (Gomez et al 2020). Although some important areas of Abidjan (Côte d'Ivoire) lie on a plateau and may escape the direct effects of sea-level rise, major economic centers, including the nation's largest port and much of the international airport, are on land less than 1 meter above sea level. A sea-level rise in Abidjan is likely to inundate 562 square kilometers along the coastline of the Abidjan region, as lowland Marshes and lagoons dominate the coastal zone. Average retreat will vary from 36 to 62 m (Anouman et al 2019).

Given the location in hot regions, African cities are likely to face increased exposure to excessive heat over the coming decades. Projections show that aggregate exposure in African cities will increase by a multiple of 20–52, reaching 86–217 billion persons per day by 2090, depending on the scenario. The most exposed cities are located in Western and Central Africa, although several East African cities indicate an increase of more than 2000 times the current level by 2090 (Rohat et al 2019). Average temperatures in North African cities are expected to rise between 1.5° and 3° Celsius by 2060, with a risk of increased desertification. The ElNiño-Southern Oscillation (ENSO) events that ran from October 2014 to June 2016, followed by a La Niña from July 2016 to January 2017, are responsible for heightening the drought conditions in the cities of Djibouti, Mogadishu and Addis Ababa, since the year 2017 (Qu et al (2019)). Coral reefs that have the potential of protecting human and marine life in Djibouti, are also vulnerable to rising sea surface temperatures (SSTs), wind and heat waves along the Gulf of Aden, which leads to coral bleaching and anthropogenic impacts (Cowburn et al 2019). High rates of urbanization coupled to drought and high demand for water in Tripoli-Libya, has made groundwater levels decline and exceed 12 m in the Southern area while in the Northern area near the coastal line, depletion is continuous and more than 70 wells will be confronted by saline water intrusion by the year 2100. The salinity levels in these wells will make the groundwater unfit for human consumption (Aswad et al 2019). An almost similar situation has occurred in Niamey-Niger, where ponds have exhibited a change in groundwater discharge behavior due to consecutive dry days and changes in the spatial pattern of rainfall (Boko et al 2020). Drought impacts on water availability and security have also been witnessed in Harare-Zimbabwe, where severe drought episodes have been observed in 1991–1992, 1994–1995, 2002–2003, 2015–2016, and 2018–2019 (Frischen et al 2020, Tanyanyiwa 2020). The studies presented indicate that although rapid onset disasters like cyclones often have devastating effects on informal settlement and African urban ecologies, slow onset climate events, such as drought and flush floods are also negatively impacting lives and infrastructures, which warrants responses from different disciplines and communities of policy and practice.

Building resilience to climatic change in cities is closely linked to how the world will resolve the twin challenges of rapid urbanization and accelerated change in global temperature (Parnell 2016, Simon et al 2016, Holmstedt et al 2017, Patel et al 2017, Rybski et al 2017). The unpacking of pathways to climate resilience in cities, however, is usually dualistic in nature, viewing the resourcefulness of local community actors as a downstream approach that is parallel to, and sometimes conflicting with upstream interventions, which are influenced by municipal regulations, economic trends, technological advancements, geopolitics, and other global forces. The upstream lays emphasis on the role of multi-lateral and government agencies in brokering and facilitating leadership coalitions, through reforming urban policies across sectors, to enhance collaboration amongst municipalities, and deliver on sector-wide plans for recovery from hazardous weather events. For instance a number of city global alliances have been created to confront the specter of a warming planet, and lead the transformative path to limiting the global mean temperature to 1.5 degrees (McGushin et al 2018, Pelling et al 2018). The World Mayors Council on Climate Change (WMCCC) was founded by Kyoto's mayor in December 2005, following the entry into force of the Kyoto Protocol. The C40 Cities Climate Leadership Group of large cities, launched in October 2005, now has 40 participating and 19 affiliate city government agencies (Rosenzweig et al 2010, Viguié and Hallegatte 2012). Of recent, the European Commission launched the 'Covenant of Mayors in Sub-Saharan Africa' (CoM SSA) to work with African cities on the climate challenge.

Conversely, the downstream approach usually centers on actions and networks that pervade the realm of government and municipal interventions. Such actors operate through neighborhood groups, citizen coalitions, associations of informal urban service delivery operators, and federations of city traders, who seek to coalesce their efforts towards re-building local communities in face of flooding and other consequences of extreme weather events. Examples include green roofing and rain water harvesting movements in urban informal settlements of cities in the global south, which are targeted at improved storm-water management, better regulation of building temperatures, reduced urban heat-island effects, while promoting the conservation of green spaces for reduced pollution and intensity of surface run-off (Oberndorfer et al 2007). The downstream approach has also been researched widely in the global north with concepts such as a 'first-responder city', which stem from studies that illuminate the opportunities associated with increasing the capacity of local communities to avoid, prepare for, and effectively respond to extreme weather events (Ebi 2011, Schmeltz et al 2013, Rosenzweig and Solecki 2014). The other component of studies on the downstream approach are on-ground volunteers and local nonprofits that influence urban development dynamics for enhanced community resilience, by for example disseminating early warning information to low-income urban residents, which is framed as the 'civic infrastructure' for resilient neigbourhoods by Graham et al (2016) and Elkin and Keenan (2018). Quantitative studies on downstream interventions have provided metrics for measuring the effectiveness of community-led efforts, by factoring in the extent of community engagement, emergency supplies, communication with neighbors, civic engagement, and collective efficacy (Eisenman et al 2016, Kwok et al 2018).

What is common across the framing and operationalization of downstream and upstream approaches, is the notion that climate resilience in cities is an incremental, multi-actor and cross-scalar process. The incrementalists like Abdoumaliq (2016) and Dovey (2016), argue that resilience starts in what is gradual and integral for people with regard to the natural and built landscapes in which they live, the talents and skills of stakeholders chosen to represent them, rather than emphasis on what is lacking in terms of opportunities and resources. The interdependence amongst actors and their multiple decisions for climate resilience is key from a multi-actor perspective, where for example communities and inter-municipal collaborations take lead to build networks that catalyze efforts towards confronting extreme weather events (Giest and Howlett 2013, Fünfgeld 2015, Bansard et al (2017)). Both incremental and multi-actor processes are characterized by interlocking and dynamic political, social, economic and spatial factors, which means that the hindrances to and enablers for climate resilience are cross-scalar in nature (Bahadur et al 2013, Bahadur and Tanner 2014, Tanner et al 2015). But advances in framing climate resilience in cities have not taken on a broader perspective when it comes to the contextual diversity and local priorities of urban regions in Africa. Cities of Africa are not only shaped by informality, which is the opposite of centralized planning systems in China and much of the global north (Bai et al 2014, Shatkin 2016), but are also characterized by multiple ecologies and infrastructures that perhaps require unique pathways to resilience in the face of climatic hazards (Schäffler and Swilling 2012, Fraser et al 2017). However, our understanding of African urban pathways to climate resilience has remained patchy and minimally represented, even in global assessments such as those by the Intergovernmental Panel on Climate Change (IPCC). This paper addressed this gap through a systematic review of evidence, from both science and policy, on the interventions that are emerging at neigbourhood to city scale, to enhance resilience to climate change in Africa.

Approach

The key terms used in the search for material were: Climate Change (CC), Climate Resilience (CR) and African Cities (AC) (see supplementary file 1 available online at stacks.iop.org/ERL/15/073002/mmedia for String of Search Terms). The initial search result was 1051, covering the period of 2006–2019. But when subjected to the inclusion and exclusion criteria (figure 2), 95 academic articles appeared from Scopus for selection, 72 were excluded and 25 articles were included, based on their tittles, abstracts, texts, methodology and results. Papers were also included if they contained climate-related terms such as: flooding, storm surges, drought, landslides, heat waves, wind storms and wild fires. We also considered papers with abstracts, texts and results on West, East, South, Central, and North Africa, as a way of representing different geographical locations in the continent. The search further considered papers with ecological terms namely; in-land, coastal, semi-arid or arid and mountainous cities. For pathways to CR, we included papers with abstracts, texts and results on: (i) local community interventions; (ii) interfaces amongst different actors, (iii) climate change policies and climate change plans; and (iv) local and technological innovations. Papers with terms such as adaptation, mitigation, environmental change, sustainability, risk reduction, urban transitions and community resilience were also included the review (see supplementary data S1 of the search string table).

Titles, abstracts and texts were extracted and screened independently against the inclusion criteria by three reviewers, namely: Buyana Kareem (BK), Shuaib Lwasa (SL) and Jaqueline Walubwa (JW). The abstracts, texts, methodology and results of the included papers were reviewed using three complimentary strands: (1) identification of titles and abstracts on interventions for CR in AC; (2) internal validity of the material with regard to how well the methodology and results answered the research question(s) set in the paper being reviewed; and (3) external validity of material which refers to how well the methodology and results answered the review question. Each paper was reviewed independently twice, with disagreements resolved through discussion and consensus with the rest of the co-authors as third party reviewers. Full text articles were reviewed by Paul Mukwaya (PM) and Samuel Owuor (SO) for final decisions regarding inclusion, with disagreement resolved by consulting the other reviewers, that is; Denis Tugume (DT), Peter Kasaija (PK), Hakimu Sseviiri (HS), Gloria Nsangi (GN), and Disan Byarugaba (DB).

Quality appraisal of the included academic literature was undertaken using the ten-item Critical Appraisal Skills Programme (CASP) checklist for qualitative research (Critical Appraisal Skills Programme 2018). Despite its demerits, the CASP tool is commonly used in qualitative research (Hannes et al 2010). Three evaluators (BK, SL and JW) independently assessed the quality of each study with discrepancies resolved through consensus and discussion with third party evaluators (PM and SO). No studies were excluded on the basis of quality, as per the summary of the results in supplementary data S2.

Academic literature was triangulated with a purposive online search for climate change strategies and action plans mounted by African city authorities of government. The plans were purposively selected to achieve representation across regions of East, West, North and Southern Africa. The plans that were mapped are: (i) the City of Alexandria Energy and Climate Change Action Plan (North Africa); (ii) the Durban Climate Change Strategy (South Africa); (iii) the Kampala Climate Change Action Strategy (East Africa); and (iv) Lagos State Climate Change Adaptation Strategy (West Africa). Review of evidence from policies and plans focused on the objectives, key stakeholders, targets and object(s) to be made resilient as well as implementation programmes under each strategy and action plan. The documents were useful in discerning the notions and pathways to mainstreaming climate resilience in city planning and governance processes. City plans published in languages other than English were not considered in the mapping and therefore the evidence presented may not necessarily speak for Anglophone compared to Francophone cities.

Resilience at neigbourhood scale means harnessing the local resource base and technologies

City planning for resilience targets buildings, mobility, and energy service delivery but without explicit mechanisms on cross-sector collaboration

As noted by Nagendra et al (2018), the ways in which resilience plays out in cities that are less-built with agile informal settlements and multiple ecologies, is different. However, only two studies in the review contained an explicit definition of what resilience means. Chirisa et al (2016) defines resilience as, 'the ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning, the capacity for self-organization, and the capacity to adapt to stress and change.' Ziervogel et al (2017) on the other hand, focuses on rights and justice as the point of departure for resilience to support risk management and inclusive development, as opposed to infrastructures, technical engineering and ecosystem services. However, both studies note that much of the resilience agenda has been shaped by policies and discourses from the global north, and therefore its practicability for cities of the global south, particularly African cities, has not been sufficiently addressed. There is need for theoretical perspectives from Africa that shine light on urban transformations to resilient cities, guided by emerging processes across case studies. In order to bring some structure to the debate on resilience in African cities, we postulate three interlinked streams: (i) social resilience as the lens for understanding interconnected networks of local community actors poised for sustainability-oriented urban experiments and learning; (ii) ecological resilience that means harnessing the positive interactions amongst interventions at neigbourhood to city and inter-regional scales; and (iii) institutional resilience, whose major constitute element is inter-municipal and intra-metropolitan collaborations with flexibility and capacity for coordinated response to climate risks and impacts on systems that make city regions functional (figure 3).

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Inter-regional and ecological comparisons require expansion in scope and coverage

More research is needed on the role played by inter-municipal and inter-metropolitan collaborations in enhancing resilience to climate change in Africa

The colloquiums for conceiving the paper and manuscript review workshops, were funded by the AXA Research Fund, under the Kampala-based project known as a new understanding of urban sustainability pathways in Africa. We also obtained support from the International Science Council (ISC), under a global research programme known as Leading Integrated Research on Agenda 2030 (LIRA)-GRANT NUMBER: LIRA 2030-GR10/18. Training on systematic reviews was supported by the Mercator Research Institute on Global Commons and Climate Change (MCC), Berlin Germany.

Any data that support the findings of this study are included within the article.

BK and SL conceived the paper, framing and drafting, while DT, PM, JW and SO made major reviews to the content and methodological approach. PK, HS, GN and DB led the efforts on data management and developing the map on climate risks in African cities.

The authors have no competing interests to declare.