Climate Change Mitigation Perspectives from Sub-Saharan Africa: The Technical Pathways to Deep Decarbonization at the City Level

Abstract

The complex and multidimensional effect of climate change, coupled with low socioeconomic development, in Sub-Saharan Africa (SSA) makes the region vulnerable to the changing climate and threatens its inhabitants’ survival, livelihood, and health. Subnational actions have been widely acclaimed as effective in combatting climate change. Local governments in SSA have been developing and implementing climate action plans to reduce greenhouse gas (GHG) emissions. In this article, we qualitatively assessed climate change mitigation technical pathways at the city level by studying four major African megacities’ climate plans and actions. The cities studied are Accra, Ghana; Addis Ababa, Ethiopia; Lagos, Nigeria; and Nairobi, Kenya. This study provides insight into the novel and innovative policy design and instrumentation options to sustainably address climate change mitigation in SSA. With the past literature focusing on climate adaptation for the Global South, this study shows leading context-specific efforts in climate change mitigation that simultaneously address local sustainable development needs. Our assessment identified the prioritized technical pathways for climate change mitigation in the selected cities, as well as innovative techniques and areas for improvement. Given that it also identifies emerging best practices, this study’s findings can be helpful to local governments and practitioners pursuing local deep decarbonization and international organizations supporting these programs.

1. Introduction

Due to climate change, greenhouse gas (GHG) emissions are presently at the center of political, environmental, technical, and cultural debates [1,2]. The dynamic effect of climate change on socio-economic welfare and sustainable development is profound and its impact is seen in the form of a rise in temperature called global warming and extreme weather events [3]. Extremely steep cuts in global GHG emissions coupled with an urgent transition to a low-carbon economic system are required to avert the impending global environmental catastrophe [2,4]. The Paris Agreement stipulates that emission reduction strategies must be implemented in the context of sustainable development, considering individual national and geographical peculiarities [5].

GHG mitigation has always been met with a global approach, with many also highlighting the significance of the private and public sector activities at the local level [6]. It is germane to complement the global strategy with local efforts by putting cities and local governments at the forefront of climate change mitigation and sustainable development, as the majority of the world population now lives in cities [7,8,9]. This trend is also corroborated by 70% of GHG emissions originating from urban areas [7].

Many Sub-Saharan African (SSA) countries are on an upward trajectory in their socioeconomic development, which is complemented by improved socioeconomic standards, relative peace, and favorable commodity prices [10,11,12]. These countries are experiencing a population boom, rural–urban migration, and a growing youthful workforce [13]. Global climate change poses a significant challenge to SSA’s marginal socioeconomic progress [3]. The effect of climate change in Africa is distinctive, and Africa’s vulnerability to the impacts of past and present climate change is visible [3,14,15]. The vulnerability of agriculture, the leading employer in Africa, food supply chain vulnerability, a limited resilience framework, and a lack of capacity for adaptation and mitigation make the effect of climate change in SSA very unique [3,16,17,18,19].

Climate change is affecting every facet of life and exacerbating physical climate risks—the risks arising from the physical impact of a changing climate [20]. Numerous studies have documented the impact of climate change in Africa, including impacts on income [21,22,23], precipitation [18,21,24,25], agriculture and food security [26,27,28,29,30,31], poultry production [31], biodiversity and endangered species [32,33], tourism [34], water resources [35,36,37], healthcare [38,39], social unrest [40], and investments [20,41,42]. Understanding deep decarbonization technical pathways for climate change mitigation is key to informing environmental policies to lessen the physical climate risks.

Anthropogenic climate change in Africa, particularly since 1980, has escalated the risk of conflict by approximately 11% [43]. Industries such as agriculture, mining, and manufacturing, which are resource-intensive, are especially susceptible to chronic climate risks. The economic implications are stark, with climate change-induced losses potentially reaching up to 15 percent of the GDP per capita growth in Sub-Saharan Africa, thereby posing a significant threat to cities and municipalities [44]. This jeopardizes the very foundation of these countries’ GDP per capita growth [20]. Li and Gallagher [20] found that foreign direct investment (FDI) in Africa is significantly more exposed to heat stress, water stress, floods, hurricanes, and typhoon risks, all of which are induced by climate change. Manufacturing facilities face significant heat stress risks [20]. Kling et al. [44] confirmed that climate vulnerability drives up the cost of debt and equity, thereby constraining firms investing in countries with a high climate risk exposure. Climate change increased the cost of sovereign debt by 0.63% between 1999 and 2017 [44], thereby affecting public budgets and investment in climate change mitigation programs.

Climate change also affects human health and well-being, affecting individuals through environmental exposures and influencing the social determinants of health, such as health-related behaviors and socio-economic factors [43,45]. Environmental exposures may manifest via direct exposures such as during flash floods or as indirect exposures which may occur because of harmful changes in water, food, and air quality [46,47]. These events have drastically reduced the agricultural productivity and household incomes across cities in the region [30,48]. By reducing households’ agricultural incomes, climatic variability also leads to a decrease in the demand for goods and services in the affected communities. This threatens the livelihoods of people who indirectly depend on agriculture, such as traders [48], intensifying the prevalent poverty in SSA.

A crucial point of note in discussing climate change is the ambiguity in the distribution of climate events, complicating the process of risk management [47,49]. As the climate changes, in addition to causing extreme environmental conditions, it is erratically altering the patterns and frequency of these extreme events, creating a two-way shock [24,30,49] which is making the use of historical data for forecasting less reliable. The increasing unpredictability of climate change-induced weather events is creating new challenges in risk management, which is impacting the insurance market [47] and further creating uncertainty for many economic agents, many of which are sources of loans, FDI, grants, and investment in SSA. The influence of the changing climate on the historical evolution of the global economy, and the current efforts to shift to low-carbon economies, necessitates an understanding of climate change mitigation technical pathways, associated policies, and governance strategies which will help inform the response [49] without jeopardizing the sustainable development of the cities in the region.

The study of climate change in Africa has been particularly focused on climate change adaptation, while mitigation is considered the Global North’s domain [5,50]. Therefore an inherent knowledge gap exists on the climate change mitigation framework at the local level in developing countries [8], and filling this gap is the goal which this paper sets out to achieve. Understanding of deep decarbonization in SSA cities provides a new and inclusive perspective on the efforts of reducing and mitigating GHG emissions. The similarity between economies and levels of development allows for the transferability of learnings across cities in developed nations [8]. This will not be so for developing countries due to massive disparities in key human and economic indicators, making a focused study on the Global South’s local decarbonization strategy germane. Bataille et al. [5] asserts that there are varied options for deep decarbonization, which is evident in the diversity of regional strategies. Climate change mitigation efforts have the potential to support socio-economic growth in SSA countries by both reducing the future economic consequences of disasters and by fostering sustainable development.

Climate change mitigation is defined as the process of reducing the production of GHGs and enhancing of carbon sinks, both to combat further anthropogenic climate change [51]. It uses social and technological solutions to combat climate change [51]. This sociotechnical paradigm investigates the interconnected social and technological processes through which sustainability ideas develop and become established through the adoption of low-carbon technology and the lowering of GHG-intensive consumption and waste [52]. While GHGs comprise different types of gases—namely carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons, and sulfur hexafluoride (SF₆)—this paper focuses on carbon dioxide (CO₂) and methane (CH₄), the most prevalent GHG emissions from cities.

Deep decarbonization is a complex societal, economic, and political reengineering program aimed at achieving net-zero carbon systems in the various sectors and procedures within the study boundary while emphasizing development and the climate [50,53]. It involves overcoming carbon lock-ins to eliminate the carbon intensity in systems and reducing GHG emissions to net-zero [8]. Decarbonization pathways are connected to fulfilling local development priorities, political structures, global trade, prices, financial flows, and international agreements [54]. Deep decarbonization strategies must consider governmental priorities, socio-cultural norms, and economic factors in achieving the desired environmental and social sustainability [55]. Climate change mitigation actions, including deep decarbonization, must be specific, be localized, and consider the local opportunities and challenges.

Transitions to a low-carbon way of life can give ‘win-win-win’ solutions [56]. There is evidence that mitigation strategies are a stimulant for economic growth and development, which have various sound side effects: human health, ecological functioning, and other macroeconomic, social, and equitable side effects which may exceed the value of climate change mitigation advantages in certain circumstances [57,58]. Climate action strategies can directly impact lives by creating green jobs, healthier lifestyles, happier lives, and cleaner environments [59,60,61]. The achievement of decarbonization targets in developing nations is strongly dependent on the crucial eradication of inequality—social, economic, technological, and fiscal inequality [62].

The goal of this study is to determine the technical pathways for deep decarbonization and their peculiarities in selected cities in developing nations. Using qualitative methods, this research examines deep decarbonization activities and plans, and low-carbon transition efforts, using Sub-Saharan African cities as case studies. Key findings from the existing literature are compared with deep decarbonization actions and plans of leading local governments and cities in developing nations to characterize pathways toward implementing climate actions at the local level.

This research will achieve its goal by answering the following questions:

What are the technical and strategic pathways being implemented and planned for GHG emission reduction for deep decarbonization in cities in developing nations?

What are the systemic similarities and differences between the case cities in their plans toward deep decarbonization?

This research aims to demystify the peculiar features and characteristics of deep decarbonization in SSA, thereby presenting needed pathways and technical mechanisms for achieving GHG emission reduction targets and solving climate change issues with consideration of the realities of the diversity of urban systems, culture, and political frameworks in developing economies.

2. Technical Pathways to Deep Decarbonization at the City Level

Critical sectors of the socioeconomic system at the local level need to be prioritized to achieve deep decarbonization, and many cities increasingly recognize their potential contribution to climate change and have committed to achieving net-zero [63]. As of August, 2024, more than 800 cities have committed to achieving net-zero GHG emissions [64]. The areas of priority for decarbonization at the local level in developing nations are electricity, buildings (cooling, heating, and cooking), transportation, waste, industry, and agriculture, forestry, and other land use (AFOLU) [54,65]. The details of these areas are discussed below. The categories are not always mutually exclusive.

A predominant energy source for most sub-Saharan African countries is biomass—the burning of charcoal, fuelwood, and animal dung primarily for cooking, cooling, and heating—which emits a significant amount of GHGs, causes serious health concerns, and leads to poor indoor air quality [66]. Significant progress can also be made in decarbonization efforts and the reduction of GHG emissions through the transformation of electricity systems [55,67]. The pathways for deep decarbonization involve adopting social system-enabled net-zero electricity grids [68]. They also build on the more typical efficiency and renewable actions; thus, cities have pursued low-carbon development in transformative ways to achieve reduction goals [68]. At the local level, the deep decarbonization of energy systems combines three main ideas: (1) reducing energy and material demand, (2) switching energy supply to net-zero carbon sources, and (3) enhancing carbon sequestration [68]. The greatest challenge to decarbonization is the necessary changes in energy use and lifestyle [69].

Building energy use accounts for 17.5% of total GHG emissions [70], making it a good and efficient target for global decarbonization efforts [53]. In developing nations, the increase in electricity demand is driven by increased cooling due to climate change, rapid urbanization, population growth, and general social development [71]. The energy needed for building cooling and heating presents an environmental and economic burden [7]. Efforts are also needed to reduce the extent of carbon emissions from construction activities and building operations [72]. Efficiency improvement in energy-intensive building activities and progress in building envelopes are required [70]. Decarbonizing buildings entails factors beyond operational energy resources. The embodied carbon emissions associated with materials such as steel and cement are substantial [7]. The environmental sustainability of buildings can be improved through energy conservation and retrofits, which can also result in improved well-being and comfort [73]. Retrofitting includes upgrades to building envelopes and shifts to zero-carbon heating and cooling technologies [73].

The transport sector has been identified as the fastest-growing source of GHGs and the hardest to decarbonize [74]. Agarana et al. [75] articulate the pathway to minimize road transport emissions in Sub-Saharan Africa as (1) the development of mass transit systems; (2) the proper maintenance of road transports; (3) encouragement of the use of non-fossil fuel-powered road transportations; (4) improving the quality of fuel; (5) the use of hybrid and electric vehicles; (6) reducing the need to travel, and road traffic and congestion; and (7) the promotion of non-motorized forms of transportation. A significant portion of transport management is within local governments’ circle of authority, which is critical to the scope of this research work [76,77]. Cities in Sub-Saharan Africa can also promote non-motorized forms of transportation as part of a decarbonization strategy by developing a dense cycle network, reducing traffic levels, and better streets for cycling and walking [54].

The deep decarbonization of industries, especially energy-intensive industries, is essential to limit global warming [78]. The energy-intensive industries—manufacturing and construction—contribute over 20% of GHG emissions without considering the indirect emission from purchased heat and electricity [4]. Most local climate plans do not account for industrial emissions, as these are better addressed by higher levels of government and the private sector [79]. In developing nations, international collaboration on R&D will be necessary [60,61], and the great potential of collaboration for systemic cost-reduction improvements is important [4]. Focusing on a specific set of industries and processes can generate tremendous results because 90% of GHG emissions from industrial processes are from the top 10 industries [80].

Sub-Saharan Africa has the lowest average waste generation per capita globally but has the highest growth rate in solid waste [81]. Organic waste decomposition is a significant source of methane, a potent GHG [82,83,84]. Some ways to mitigate the GHG emissions from waste in Sub-Saharan Africa include the efficient management and operation of most landfills and dumpsites, as well as waste reduction, recovery, and recycling. Capturing and burning landfill gas, with energy recovery when possible, is the most common method for lowering carbon emissions from waste management [85]. To reduce carbon emissions from waste in developing nations, cities can ensure the segregation and sorting of waste at the collection point [86]. A social reorientation, campaign, and human behavioral change would need to occur for this to happen [81,83].

The agriculture, forestry, and other land use (AFOLU) sectors are responsible for 57% of the anthropogenic GHG emissions in SSA [87]. A continual surge in GHG emissions related to AFOLU is anticipated in developing nations because of the forecasted increase in food production and land development attributed to growing populations and rapid urbanization [88,89]. The opportunities for GHG emission reduction on the supply side in agriculture include (1) land management; (2) pastoral improvement; (3) the management of organic soils; (4) the restoration of degraded lands; (5) livestock management; (6) manure management; and (7) bioenergy use [90,91]. Using sustainable cooking stoves and an off-grid energy supply will reduce the pressure on biofuels such as firewood and charcoal [92]. There exist several options for reducing emissions from the forest sector, including (1) forest conservation through afforestation and reforestation; (2) sustainment of the stand-level carbon density; (3) maintaining or increasing the landscape-level carbon density using forest conservation, longer forest rotations, fire management, and protection against insects; and (4) increasing off-site carbon stocks in wood products, enhancing product and fuel substitution using forest-derived biomass to substitute products with high fossil fuel requirements and increasing the use of biomass-derived energy to substitute fossil fuels [90,91].

Climate change mitigation at the city level will require transforming urban infrastructure, particularly implementing nature-based solutions for carbon sinks [53]. Due to the ability of vegetation to capture and store carbon, urban green infrastructure in the form of parks, greenways, gardens, green roofs, woodlands, wetlands, and forests can be an efficient approach even at the microscale [8,87,90,93]. Planting and nurturing trees in urban areas is beneficial to decarbonization by providing carbon bio-storage [93,94]. For example, cities in Sahel have areas of vegetation which are significant carbon sinks, as evidenced by the Sudano-Sahelian woodlands in Burkina-Faso, the miombo forests in southern Africa, and the urban forests of Ghana [95].

Table 1. Key variables for technical pathways to decarbonization.

Sectorial Pathways	Contribution to Africa’s GHG [87]	Findings	References
Agriculture, Forestry, and other land use (AFOLU)	57%	AFOLU is the central area of focus for deep decarbonization in developing nations. Implementing sustainable agricultural practices like farm management and agroforestry will help reduce GHG emissions from agriculture. Reducing overdependence on forests for energy sources, land restoration, and spatial planning is also crucial for climate change mitigation. There has been a significant focus on reforestation and forest management as a climate change mitigation pathway.	[91,93,96]
Energy—Electricity	17.5%	Energy accessibility for over 500 million Africans with energy poverty through renewable sources like hydro, wind and solar and energy efficiency will support the decarbonization of the electricity sector. Decarbonizing electricity involves reducing energy consumption (efficiency) and switching the energy supply to net-zero carbon sources. Socioeconomic factors constrain the penetration of low-carbon electricity sources.	[55,67,71,97]
Building and building services	9.4%	The sustainable building sector involves the reduction of emissions related to residential and corporate building construction, operation, and maintenance. Using sustainable materials in the building sector will also aid decarbonization. The sustainability of buildings can be improved through energy conservation and retrofits.	[72,73,98]
Industry	4.0%	Collaboration on research and development will aid decarbonization efforts. Transitioning to a low-energy source for industrial processes is crucial for reducing GHG emissions. Most local climate plans do not account for industrial emissions.	[6,79,80]
Transportation	8.1%	High GHG emission is recorded from the use of imported secondhand cars. Poor road infrastructure and networks in cities contribute significantly to GHG emissions. Electricity access and socioeconomic limitations are affecting the use of electric vehicles. The development of a non-motorized mode of transportation is critical to decarbonization.	[54,74,75]
Waste	4%	Major challenges are the collection, sorting, and segregation of waste. Social reorientation is needed for sustainable waste management and remediating the poor construction of landfills. There is a lack of market for recyclables due to low manufacturing and economy. Cities in SSA are exploring waste-to-gas projects for power generation.	[83,86,99]

shows the key variables for technical pathways to decarbonization, their contribution to GHG emissions, and the applicable references.

3. Materials and Methods

3.1. Research Design

This research utilized a qualitative case study methodology based on the combination of primary and secondary data to evaluate technical pathways and strategies of leading cities of SSA towards a sustainable and carbon-neutral future. The case studies apply descriptive and qualitative methods to synthesize information from various sources, notably document analysis, a verifiable database, and semi-structured interviews [100]. By utilizing a multi-case study design, the adopted qualitative methodology enables the analysis, assessment, and individualism of cases to identify trends and divergences that are transferable and replicable within the same context [101].

This research studied deep decarbonization in developing nations utilizing selected leading cities in Sub-Saharan Africa as case studies. The Sub-Saharan African cities considered for this study have leading socioeconomic indices in the sub-region in terms of population, economic development, governance, gross domestic product (GDP), and social advancements. Cities are defined as human settlements that are generally big, dense, and diversified, with a complex social framework and governance, resulting in cultural creation that extends beyond their borders [102]. In this project, cities are an integration of the urban plus suburban areas that are part of the city boundaries under a single jurisdiction, municipality, and administrative control [102].

3.2. Case Selection and Case Cities

In determining the case cities for this project, some attributes which align with the goals of this study were identified. For this study, the criteria to be met by the case cities were: (1) have an ambitious climate action commitment with targets, (2) are reporting to the CDP database, (3) have a written climate action plan document, (4) have a completed emission inventory, (5) have ongoing implementation of their climate action plan, (6) the climate action document must be in English, and (7) be in a SSA country with relatively robust socioeconomic development.

Case cities were identified using data from the Carbon Disclosure Project (CDP), downloaded from the CDP online portal. The portal contains datasets on climate-related risks and opportunities, emissions, mitigation, adaptation, energy, water, and other topics in cities throughout the world including cities in the geographical area of interest in this study. The CDP database provides a globally unified reporting system based on a simple questionnaire that allows city governments to publicly disclose their greenhouse gas emissions data [64]. The platform data were assessed for the latest updates on climate change mitigation actions for the case cities of this study. Using a combination of filters based on the case cities selection criteria, the following cities were chosen for this case study: Accra (Ghana), Addis Ababa (Ethiopia), Lagos (Nigeria), and Nairobi (Kenya) (as shown in

Table 2. Selected case cities for research.

City	Country	Population	Sub-Region	Role
Accra	Ghana	1,999,810	West Africa	Capital city and commercial hub
Addis Ababa	Ethiopia	3,353,000	North Africa	Capital city and commercial hub
Lagos	Nigeria	20,341,000	West Africa	Commercial hub
Nairobi	Kenya	3,916,000	East Africa	Capital city and commercial hub

).

The city level GHG emissions inventory for all the case cities was compiled following the Global Protocol for Community-scale GHG Emission Inventories standard (GPC), a protocol developed by C40, the World Resource Institute (WRI), and ICLEI—Local Governments for Sustainability [77,103,104]. Where GHG emission data were not readily available, benchmarking against other cities, downscaled national data, and international estimates were utilized as needed in accordance with best practices [76]. The GHG emission data presented for each case city and their sectoral breakdown are directly from the secondary data mentioned in the reviewed climate policy-related documents.

Ghana’s capital city, Accra, is the country’s largest population center and the country’s economic hub. Accra generated a total of nearly 2.4 million tons of carbon dioxide equivalent (tCO₂e) in the year 2015 [76]. On average, a person residing in Accra would emit about 1.2 tCO₂e per year [76]. Most emissions in Accra (44%) are from solid waste and wastewater treatment, followed by transportation (30%) and, finally, stationary energy (26%) [76]. The Accra Metropolitan Assembly (AMA) has developed a Climate Action Plan (CAP), the first to be prepared at a sub-national level in the country. Accra’s first city-level GHG inventory for the baseline year of 2015 was developed and published in 2019 [76].

Addis Ababa is Ethiopia’s most prominent commercial, educational, and administrative center. The capital city, located in the geographical center of the country, is of historical, diplomatic, and political importance to the African continent [105]. With a booming population of 3.3 million inhabitants, Addis Ababa is expected to have a population of 9.8 million by 2037, with an annual growth rate of 3.8 percent [106]. The city has set climate targets of achieving transformational change by 2030, 2040, and 2050 [106]. The 2016 GHG inventory estimates the emissions from Addis Ababa as 9.85 MtCO₂e, representing 2.9 tCO₂e per capita, with the most extensive sectoral emissions emanating from the transport sector and waste [103].

Lagos, Nigeria, is one of the major economic hubs of West Africa and one of the fastest-growing cities in the world [107]. The city is situated on a low-lying coastal plain, and water bodies and wetlands cover over 40% of its area. Lagos is expected to become Africa’s most populated metropolis over the next 50 years, with a current population of 15 million inhabitants [108]. A GHG inventory for 2015, based on the GPC Protocol for Cities, showed that Lagos generated emissions of 1.3 tCO₂e per capita and a total of 26 MtCO₂e [104]. The figures show that the highest sectorial emissions are stationary energy (energy use in buildings and industry), transportation, and waste. Guided by climate change scenarios, the city has set up an ambitious target of achieving net-zero carbon emissions by 2050 [104].

Nairobi is Kenya’s capital, and is the largest city and among the fastest-growing cities in East and Central Africa [77]. The distribution of the population, infrastructure, and socioeconomic activities in Nairobi is characterized by intricate variation, temporal distribution, and spatial complexities [77]. Currently encompassing 704 km² of land, Nairobi is situated in South-Central Kenya, 140 Kilometers south of the Equator [77]. It is surrounded by 113 km² of plains, cliffs, and forest that make up the city’s Nairobi National Park [109]. Nairobi has developed its most recent GHG inventory based on 2016 data and following global best practices. Results from the inventory showed that, in 2016, the total GHG emissions in the city of Nairobi amounted to 4.7 MtCO₂e, equivalent to 1.2 tCO₂e per person [110]. The largest source of GHG emissions in the selected city is the transportation sector.

As can been seen in

Table 3. City emissions by sector in tCO₂e.

Case City	Electricity	Building and Building Services	Industry	Transport Mode	Waste	AFOLU	Total Emissions	Emission per Capita
Accra, Ghana	Not available	381,478	238,424	715,272	1,049,066	Not available	2,384,240	1.2
Addis Ababa, Ethiopia	Not available	1,115,659	11,434	6,641,237	1,946,389	141,372	9,856,091	2.9
Lagos, Nigeria	Not available	8,461,970	6,082,041	5,288,731	6,610,914	Not available	26,443,656	1.3
Nairobi, Kenya	Not available	1,052,596	Not Available	2,097,274	1,529,828	Not available	4,679,698	1.2

, which shows city emissions by sector, the GHG inventories of each case city contain different sectors [76,103,104,106], so that the totals are comparable.

3.3. Data Collection Framework

Two synergistic methods of data collection were utilized to answer the research questions. The first is an extensive review and systematic content analysis of official climate change policy documents of each case city, such as laws, special reports, policy documents, plans, and press releases. Climate and sustainability city officials and personnel that were directly involved with the development of their respective city climate action plans were identified and interviewed as a second method of data collection and for triangulation.

The document review involved the analysis of a total of 31 documents across all four case cities of this study. The identification of relevant documents started with searching for the available climate action plan (CAP) document for each case city, which was already a criterion for their selection for the case study. Upon location of the CAP document, the official website of each case city was searched for various municipal policies in the areas of deep decarbonization pathways identified in the literature review: electricity, building, transportation, industry, waste management, and AFOLU. All the documents that are directly related to the technical pathways climate change mitigation objectives were selected for content analysis. The list of documents analyzed is presented in

Table 4. List of documents used for content analysis across all four case cities.

Accra	Addis Ababa	Lagos	Nairobi
Accra Climate Action Plan (2020–2025) [76]	Addis Ababa Climate Action Plan (2021–2025) [106]	Lagos Climate Action Plan (2020–2025) [104]	Nairobi Climate Action Plan (2020–2050) [77]
Accra Resilience Strategy	Addis Ababa Non-motorized Transportation Strategy	Lagos Resilience Strategy	Nairobi Air Quality Action Plan
Pedestrian Safety Action plan for the Accra Metropolitan Assembly	Addis Ababa Air Quality Management Plan	Lagos State Development Plan (2012–2025)	Nairobi City County Budget Review and Outlook Paper
Towards a Carbon Neutrality by 2050	Addis Ababa Scenarios for 2030 Transportation Master plan	Lagos: City Scoping Study	Nairobi City County Youth Policy
Accra: City Scoping Study	Addis Ababa: City Scoping Study	Lagos Urban Transportation Project Report	Nairobi: City Scoping Study
Accra Metropolitan Assembly Annual Action plan	Addis Ababa City Structure Plan (2017–2027)	Lagos Non-Motorized Transport Plan	Nairobi County Annual Development Plan (2022/2023)
CDP data	Addis Ababa Greenhouse Gas Emissions Inventory	CDP Data	Nairobi County Annual Development Plan (2020/2021)
	CDP Data		Nairobi City County Integrated Development Plan (2018–2022)
			CDP Data

. Twelve potential participants were invited for an interview, representing three participants per case city. The total number of interviews conducted was four in two case cities.

4. Results and Analysis

The assessment of deep decarbonization pathways at the local level in the case cities shows the following results. The results for each of the case cities, which are grouped according to the six main pillars prioritized for local deep decarbonization, as identified in the literature review, are: electricity, building, industry, transportation, waste management, and AFOLU. The variables from each section were categorized and inductively coded manually for keywords in a cross-case comparison to identify the emergent patterns, themes, and trends.

Table 5. Cross-case evaluation of technical pathways.

Technical Pathway	Accra	Addis Ababa	Lagos	Nairobi
Electricity	No Target	No Target	49% renewable energy by 2050	30% reduction in GHG
	Solar-powered Street lighting program	Development of a large hydropower project	1GW of installed PV capacity by 2030; Installing renewable energy systems, building scale renewable energy; electricity regulation lobby	Development of energy efficiency standards, solar-powered street lighting program
Building & Building services	50% of buildings are fitted with solar photovoltaic systems	100% solar water heaters by 2030; 90% of residential buildings to electric stoves by 2050	100% electric cook stoves by 2050	Uptake of efficient cookstoves
	Development of green building rating system; building retrofits	Fixing permitting process for new builds	Permitting process for new builds regulation; government building retrofits	Regulation, awareness; building code
Industry	45% of industrial operators to electric	95% of industrial energy to electricity by 2050; 60% industrial efficiency increase by 2050	No Target	No Target
	Industrial energy efficiency guidelines	Large hydropower development	Incentives	Policy; regulation
Transportation mode and fuel shifting	90% of buses will be powered by electricity by 2050, and 40% of trips through Non-Motorized Transportation (NMT) in 2050	10% electric transit by 2050	EV transit, 50% modal shift from motorcycle to bicycle	600,000 tCOe reduction per year by 2050, Electronic motorcycle assembly
	Infrastructure investment, low-emission policies; user-friendly platform, and network; NMT infrastructure development	Low-emission transit infrastructure investment; NMT infrastructure development	Transit infrastructure investment, water transport development, regulation; NMT infrastructure development	Infrastructure development; regulation; NMT infrastructure development
Waste management	100% eradication of open dumping of organic waste; harnessing of 65% of landfill gas by 2030	Diversion of 70% organic waste by 2050	Composting of 50% of organic waste by 2050; 90% waste collection by 2050	No Target
	Regulation, infrastructure investment	Landfill gas capture; waste management facility investment	Policy, regulation, development of waste management infrastructure; landfill gas capture, waste to energy (WTE)	Landfill gas capture; awareness; engagement; infrastructure development; decentralized WTE systems
AFOLU	No Target	No Target	No Target	No Target
	Policy development; restoration of local green spaces	Restoration of local sinks; afforestation and biodiversity enhancement program	Afforestation and tree planting programs	Green space protection; regulation

highlights patterns that emerged across the case studies.

5. Discussion

5.1. Electricity

The literature review indicates that reducing GHG emissions from electricity systems at the local level involves transitioning to low-carbon energy sources, reducing the energy demand, and the electrification of other sectors [8,68,69]. This transformation is more achievable locally because of the small scale, direct connection, and impact [69]. However, local governments often do not have direct control over their electricity sources, as this is managed by higher-level governments [8,76]. Due to this lack of control, cities often focus on deploying distributed clean energy solutions for decarbonization [8,111].

The empirical results validate the literature. All case cities significantly leverage renewable energy sources and energy efficiency for capacity improvement and to reduce GHG emissions. The cities of Nairobi and Lagos have set various targets for GHG emission reduction by 2050, while Accra and Addis Ababa do not have clear targets for electricity decarbonization.

The four case cities of Sub-Saharan Africa are utilizing diverse strategies to accomplish the GHG emission target for their electricity sectors, which validates the findings in the literature. The cities of Accra and Nairobi have developed a solar-powered street lighting program, while Lagos is planning 1 GW of installed photovoltaic (PV) capacity by 2030. Due to the socio-economic constraints of these cities, they are also implementing unique and innovative strategies to meet climate action goals through advocacy, partnership, and regulatory influence. The cities of Accra and Addis Ababa are leveraging their respective national government programs for renewable energy to build their renewable energy portfolio for GHG emission reduction, while the government of Lagos is lobbying the federal government of Nigeria to allow local governments to develop grid-connected electricity infrastructures.

5.2. Building and Building Services

The empirical results validate the literature on building energy use efficiency improvements [7,57,70,73]. All the case cities have a form of retrofit or efficiency improvement program in their climate action plan, which acknowledges retrofit and efficiency improvement as important decarbonization strategies. Accra and Lagos are at the forefront of this through retrofitting their municipal building stocks. The GHG emissions reduction strategies in the case cities are characterized by their deploying varied forms of affordable, climate-friendly appliances and targets. Clean cooking using electric cookers is an integral decarbonization strategy for energy use in buildings, as all cities have clean cooking targets. The city of Accra adopted the use of solar power systems in buildings, while the city of Addis Ababa is focused on 100% solar water-heater usage in buildings by 2030.

Cities’ governments will have to be at the forefront of fostering, governance, and accelerating the sustainability of buildings [98]. There is a need to update existing building codes and laws while also building local human capacity in building sustainability [98,112]. A wide range of targeted and customized governance frameworks is required to effectively reduce emissions in the building sector [98,112]. The empirical evidence shows that some cities have ambitious strategies regarding building policy development and bylaws. The city of Accra is developing a green building rating system for auditing, while Nairobi is reviewing building codes for enhanced energy efficiency in buildings. Addis Ababa and Lagos are fixing the permitting process for new buildings to ensure sustainability and compliance.

There is empirical evidence that none of the case cities offer any form of targeted incentive or financial tool for residents and organizations to influence the retrofitting of existing buildings in order to achieve decarbonization. This is consistent with findings from the literature. There are many possible reasons for the lack of incentives: (1) a lack of fiscal capacity to implement such a program, (2) a lack of an adequate database for transparent implementation, and (3) the existence of national subsidy programs in the form of energy prices.

5.3. Industry

Decarbonizing the power sector is critical to the successful deep decarbonization of industries [80]. Significant changes to current industrial processes, the development and use of breakthrough technologies, and efficient consumption are all required to achieve deep decarbonization [4,78]. Empirical evidence corroborates these points. The electrification of the industrial process is Addis Ababa’s and Accra’s choice of decarbonization strategy as a co-benefit of significant improvement inrenewable energy supply from the national grid. The city of Accra has taken on a much more ambitious approach through developing industrial energy audits, capacity development, engaging local banks for industrial energy efficiency investment, and rolling out incentives to support GHG emissions reduction in industries. The city also has an industrial energy efficiency toolkit. The climate action plans of Lagos and Addis Ababa for decarbonization of the industrial sector are centered on the co-benefits from energy decarbonization.

Most local climate plans do not account for industrial emissions, as these are better addressed by higher-level government and the private sector [79]. Empirical result validates this literature finding. Most cities either do not have targets or rely on the actions of the higher levels of government to implement GHG emission programs in the industrial sector.

5.4. Transportation Mode and Fuel Shifting

Agarana et al. [75] and Thambiran and Diab [113] both articulate the pathway to minimizing emissions from the transportation sector in Sub-Saharan Africa as: (1) the development of mass transit systems, (2) the proper maintenance of road transports, (3) the encouragement of the use of non-fossil fuel power road transportations; (4) improving the quality of fuel; (5) the use of hybrid and electric vehicles; (6) reducing the need to travel, road traffic, and congestion. One method for reducing air pollution is to replace older passenger vehicles with newer ones that use sophisticated vehicle technology. Cities in Sub-Saharan Africa will also need to promote a non-motorized form of transportation as part of their decarbonization strategy by developing a dense cycle network, reduced traffic levels, and better streets for cycling and walking [54]. At the local level, targeted initiatives such as efficiency improvements, operational improvements, behavioral change programs, and speed control might be investigated as decarbonization approaches [54,114]. A poor electricity supply has significantly constrained the penetration of electric vehicles and other electric mobility services which could help reduce the carbon footprint of transportation in Sub-Saharan Africa [114].

The empirical results found in this study validate the literature on pathways to minimize emissions from the transportation sector in Sub-Saharan Africa [54,75,113,114]. All case cities have developed a public transit system powered by low-emission engines or electricity which operates on dedicated roads and tracks. Lagos and Addis Ababa have developed a light rail system to aid public transit. All the case cities are promoting zero-emission, non-motorized modes of transportation by developing infrastructure like streetlights, pedestrian walkways, and shades. These improvements and infrastructural changes are geared towards incentivizing and encouraging the adoption of and behavioral changes towards these emission-free forms of transportation.

Lagos and Nairobi are going further by regulating and disincentivizing transportation using market-based instruments through high-paid parking and tolls in commercial business districts. Addis Ababa has implemented car-free days in the city. Accra plans to establish low-emission zones by restricting access to fossil fuel vehicles beyond 2025. As a climate change mitigation plan, all case cities are improving their transportation networks and tightening their vehicular emission standards. Accra, Addis Ababa, and Lagos are also adopting biofuels, especially in freight as a GHG emission reduction strategy in the transportation sector.

All case cities are also developing electric vehicle (EV) infrastructure to promote the purchase and adoption of electric vehicles. Nairobi is developing a local EV motorcycle manufacturing facility. Lagos is partnering with local energy company OANDO to build EV charging facilities across the metropolis. The high cost of electricity, poor electricity infrastructure, and the high upfront cost of electric buses are barriers to EV uptake [76]. The detailed, high level of focus, diversified strategies, and increased investments into the decarbonization of transportation being displayed by these cities are justifiable, as this sector represents the highest source of GHG emissions across the case cities cumulatively. None of the case cities are investing in zero-emission fleets for corporate activities.

5.5. Waste

Empirical findings validates the utilization of advocacy and sensitization mechanisms to elicit behavioral changes towards best practices like waste sorting, recycling, and reuse by local governments [81,83,85,99]. All case cities have an advocacy program for waste management in their climate action plan. Lagos is implementing camps for kids to learn about waste management. Nairobi advocates for waste source separation and segregation through its monthly clean-up program. All case cities have a solid waste plan based on waste diversion from landfills. Most case studies have a clear target for waste emission.

Service delivery and capacity-building improvements are important ways to limit waste. All the case cities are looking to improve their services and build more capacity for waste management. Accra and Lagos are constructing new micro and large waste-transfer stations. Lagos and Nairobi are equipping low-income communities with biodigesters to treat solid and liquid organic waste. The use of decentralized waste-to-energy systems (biodigesters) for gas capture and cooking in low-income communities is a unique and innovative decarbonization strategy. Addis Ababa is building compost facilities, while the city of Nairobi is establishing treatment centers for recycled waste.

All the case cities have built or are planning to develop landfill gas-capture systems to reduce the emission of GHGs from landfills. In addition, the cities of Accra and Lagos are retrofitting existing landfills into engineered landfills. All case cities use waste as energy through different WTE processes. Lagos is also developing a green circular economy through waste by repurposing waste to produce organic manure. To reduce carbon emissions from waste in developing nations, cities could ensure the segregation and sorting of waste at the collection point [86]. This point is validated by our empirical findings which indicate that that all cities are working on efficient waste collection, sorting, and characterization methods.

5.6. AFOLU

Mitigation actions in the AFOLU sector are critical to attaining emission reduction objectives [87,90]. The mitigation of the AFOLU sector’s GHG emissions is crucial to mitigating the impacts of climate change on the ecosystem. Climate change mitigation in the agricultural sector is done through the sequestration and reduction of GHG emissions from agricultural processes on the supply and demand sides [91]. There has been a significant focus on reforestation and forest management as a climate change mitigation pathway [90]. Within AFOLU, the principal mitigating methods include a mix of different strategies [90,91].

The empirical findings of this study validate our literature review and affirm that GHG emission reduction in the AFOLU sector is a key pathway to deep decarbonization. All case cities have climate change actions related to AFOLU. Still, none of the studied cities have set GHG emission reduction targets. Lagos did not consider GHG emissions in the AFOLU sector in designing its current climate action plan. All case cities are developing strategies to increase green spaces in their territory. Accra is focused on policy development and the restoration of local green spaces while Addis Ababa is focused on restoring local sinks and increasing GHG sequestration through the protection and restoration of forests. Lagos and Accra are implementing afforestation and tree-planting programs. Nairobi is implementing green space protection and regulation. The city is also actively protecting public open spaces, greenbelts, forest reserves, water bodies, wetlands, water catchment areas, and other ecologically sensitive areas from physical development and urban encroachment.

Lagos, Accra, and Addis Ababa are incorporating green and nature-based ecosystem services into their urban development. The diversified and mixed strategies used in the AFOLU sector are an empirical finding in line with the literature [32,90,91,92,93,94,96]. Most cities did not include GHG emission data for the AFOLU sector in their climate action plan and GHG emission inventory. As a result of its importance in climate change mitigation and GHG emission reduction strategies, the AFOLU sector requires far more attention than it currently receives.

The relevant empirical findings and literature are presented in

Table 6. Technical pathways discussion.

Pathways	Empirical	Literature	Comments
Energy/electricity	Local governments do not have control over the electricity grid. All case cities have plans to leverage renewable energy and energy efficiency for capacity improvement significantly	The transition to low-carbon energy sources, reducing energy demand and electrification of other sectors	Validate
Buildings and building services	All cases also addressed the need for low-emission building	Retrofit of the existing building, use of energy-efficient appliances, clean cooking, and improvement in building codes	Validate
Industry	Local governments are implementing climate action in industrial energy usage and waste management	Collaboration on research and development. Transitioning to low-energy sources for industrial processes	Validate
Transportation mode and fuel shifting	All case cities are developing EV infrastructure and investing in low-energy transit systems. Local governments are implementing behavioral change strategies for transportation mode shift	Poor road infrastructure and networks in cities contribute significantly to GHG emissions. Electricity access and socioeconomic limitations are affecting the use of electric vehicles. The development of a non-motorized mode of transportation is critical to decarbonization	Validate
Waste management	All cities are improving the waste diversion rate, improving waste service delivery, and developing landfill gas capture and waste-to-energy programs	Waste diversion from landfills is essential for cities to reduce GHG emissions from the sector. Major challenges are the collection, sorting, and segregation of waste. Social reorientation is needed for sustainable waste management	Validate/Extend The use of decentralized waste-to-energy systems (biodigesters) in low-income communities for gas capture and cooking is a unique strategy
AFOLU	All cities are developing tree planting programs and green space improvement, and carbon sink protection	Local Governments focus on reforestation and forest management. Sequestration and GHG emission reduction from agricultural processes	Validate/Extend Cities do not have any action related to the decarbonization of the agricultural process. AFOLU remains a priority sector for deep decarbonization

for technical pathway discussion.

6. Conclusions

This study examines and deconstructs technical pathways for deep decarbonization in four leading cities in Sub-Saharan Africa, identifying the best practices that can be helpful to other cities in their deep decarbonization planning. The technical pathways are aimed at identifying the sectors and strategies being implemented and planned for GHG emission reduction in cities in developing nations which have the intended co-benefits of sustainable development. The findings reveal that cities in Sub-Saharan Africa are planning and prioritizing climate actions based on their GHG emission reduction capacity, mainstreaming climate action, and cost-efficiency.

In Sub-Saharan African cities, the pathways to decarbonization and the reduction of GHG emissions are similar across the case cities. The cities had targets and key performance indicators with short-term and long-term objectives. The prioritized technical pathways mainly include six areas (electricity, buildings, transportation, waste, industry, and AFOLU), similar to the cities in developed nations of the world [8]. Despite prioritizing all of the pathways, some cities do not have clear targets for some sectors. For example, none of the case cities have a set GHG emission reduction target for AFOLU. The city of Addis Ababa does not have a GHG emission reduction target for electricity. Each municipality has unique circumstances and priorities, but they all prioritize their highest-emitting sectors for decarbonization.

This research shows that cities in Sub-Saharan Africa are using innovative and affordable methodologies to mitigate GHG emissions. Rather than focusing on large-scale landfill gas waste-to-energy projects, certain cities in Sub-Saharan Africa are also adopting small household and community bio-digesters for waste diversion and producing biogas for cooking, which both contribute to lower emissions. The use of distributed solar photovoltaic power systems is rampant, which is helping to improve the clean and affordable energy supply. The lack of control of the electricity generation and transmission, which is a characteristic of all the case cities, is a challenge to the decarbonization of electricity systems at the local level.

The decarbonization of transportation and fuel shifting must be of the utmost priority in Sub-Saharan African cities due to the sectorial GHG emission prevalence in the cities’ GHG emission inventories. This means that the cities must focus on corporate and community climate action plans towards fuel shifting toward low-emission transportation, as well as focusing on a modal shift toward walking, cycling, and municipal transit systems. Cities can also implement various forms of behavioral intervention tools like incentives, green infrastructure development, and outright restrictions. The absence of a database of effective implementation, inadequate financial resources, and the existence of subsidized energy prices are the possible impediments to the implementation of these behavioral influencing mechanisms.

A key highlight of this study is the need for more climate change mitigation activities in developing nations in the sector of agriculture, forestation, and other land use (AFOLU). The empirical result found by this study indicates that leading cities in Sub-Saharan Africa focus only on city “greening” and beautification programs without clear actions toward reducing GHG emissions through afforestation, agriculture, and improved land use. With anticipated population increases and spatial development, the AFOLU sector must be a focal point for climate actions in these cities.

This paper provides guidance to inform policymakers and practitioners in formulating climate change mitigation policies. This paper provides the areas of focus for deep decarbonization strategies at the city level in SSA: the prioritization of small-scale modular infrastructure development for fast, efficient, and cost-effective deployment, the intensification of corporate action at the city level, the development of city energy and environmental policies, the development of a robust framework for supporting vulnerable populations as a direct incentive system for people experiencing poverty, and the development of effective nature-based solutions for climate change mitigation, starting with natural asset inventory taking, urban forest strategies, and biodiversity strategies. These policies must integrate a human behavioral intervention lens for climate change mitigation.

Finally, as Linton [115] opined, there are few academic research publications on deep decarbonization at the city level, and this is especially true in the Sub-Saharan African context. This research contributes to the knowledge base on decarbonization at the sub-national level. By studying the plans and strategies of four leading cities in Sub-Saharan Africa, this research work was able to identify the actors in, and innovative pathways, strategies, and existing barriers to meeting climate goals by Sub-Saharan African cities. This study and breakdown of the practices of leading cities in Sub-Saharan Africa for deep decarbonization pathways provide a practical model to help other cities develop their climate change mitigation plans irrespective of their varying socioeconomic and political situations.

With C40, a network of mayors working to combat the climate crisis, playing the leadership, coordination, funding, and advocacy roles in the development of the climate action plans for all the case cities, this study also shows the importance of transnational networks like C40 in climate change mitigation programs at the city level. C40 is an umbrella organization of a transnational network of cities working to combat climate change.

Future studies will benefit from more case studies on a more diverse set of cities. Diversity can include the population, language, location, size, and type of government. A similar study with a larger sample size would highlight more emerging patterns, which will help validate findings and establish patterns with more nodes. Future research into the effectiveness of the chosen pathways and strategies used by local governments in Sub-Saharan Africa would be beneficial. This research is designed and implemented with only a qualitative method. Future research in this area would benefit from adopting a quantitative or mixed-methods methodology perspective because greenhouse gas emissions are quantitative.

In addition, further studies could consider the influence of specific policies on local climate pathways and GHG emission reductions. These policies could be regulatory, market-based, or voluntary, and could be at the national or local level. There is no doubt that policies are critical to local climate action [53], so studying this factor in a developing country context would add considerable insights. In addition, further insight into new funding mechanisms, such as how environmental, social, and governance (ESG) efforts by large institutional investors are related to the funding of local social/environmental impact projects, would be a relevant future research direction.

In conclusion, in addition to contributing to the literature on urban climate governance and sustainable development in Sub-Saharan Africa, this study contributes to practical knowledge for developing and implementing deep decarbonization plans at the local level.