Introduction

Unfortunately, when most cities in the Global North are embracing greening of cities as the way to go, Africa seems to be taking a piecemeal and generally a wait-and-see approach to the whole debate and practice (MO [11, 16]). Some cities (like Kigali in Rwanda) have done very well while many seem lost in endeavours to serve as successful green cities by the obsession to deal with the brown agenda issues. Nevertheless, there are also limits to the endeavours. Absent in the assessment of the situation on the ground and possible scenarios for an African city systems analysis, at theoretical, policy and action research level. Most urban centres in Africa have disintegrated into nothing but places of misery and hopelessness and, with climate change impacts, the situation can get worse by each day. There are unaccounted prospects that are available in endeavours to green the African cities. This article identifies the complexity of environmental issues that cities of Africa face and are likely to face beyond 2050 [11]. It draws some lessons learnt from city greening initiatives implemented beyond Africa as well as those some of the cities are trying to implement. Thus, basing on evidence and experience from selected five cities in the region, this article provides a holistic view of the complex urban environmental systems and how they relate to the efforts by the cities to address environmental challenges. Conventional wisdom has it that the expected growth of the African cities in fifty years will lead to severe urban environmental problems as the challenges are reaching colossal magnitudes ever imagined – for example increasing slum conditions, pollution of water bodies, poor solid waste management practices, to mention but a few. Greening offers a panacea to some of these problems [14, 20] and yet this is not as straightforward and simple as the word implies. Systems dynamics offers some platform on which one can comprehend the urban environmental challenges that urban systems can be encountering and, in this case, the African city. An analysis of various city greening efforts which follows in this article illustrates the complexity of the environmental system. The major thrust of the article is to provide a possible future of Africa beyond 50 years from now (cf. [11]).

Framing the concepts

Accurate projections for Africa in 50 years’ time are very difficult because of dynamic social and economic conditions [1]. The African Development Bank estimates suggest that Africa’s GDP could increase representing a major leap forward in standard of living and the resultant economic and population growth will be associated with rapid rural to urban migration and urbanisation. The rates of urbanisation in Africa will advance quickly with the proportion of urban dwellers likely to reach 65 % by 2060 [1] with most of these urban dwellers being youth below 25 years [11]. This implies larger cities characterised by a young population which is the most productive group hence most likely to strain the urban environments. Overall, cities are human artefacts, developed and modified over time according to perceived needs and values [18, 19]. They play major role concentrating human activities to confined geographical spaces. Cities are not only providers of better employment, shelter and services but also as centres of culture, learning and technological development, and industrial centres for the processing of agricultural produce and manufacturing, and places to generate income [2]. In Africa, the rapid expansion and commercial development, along with population pressure in the region’s urban space, has ushered in deterioration to the urban environment as growth is unmatched with supply of the much needed services [12]. In most parts of the region, cities have become synonymous with decomposition of the urban fabric. Despite this negative set-in, the concept of greening seems to offer some of the much needed solutions to Africa.

Urban greening refers to an integrated method in the development and management of vegetation in cities, towns, urban and peri-urban areas. It has the components of urban forestry, urban agriculture or permaculture and agro-forestry [13]. Greening cities is not only about increasing the vegetation cover, rather it involves all those environmentally friendly initiatives that help to maintain the natural environment in a state of equilibrium while enhancing human well-being. The main objective is to reduce energy consumption, promote conservation and preservation of natural ecosystems in urban areas, reducing environmental degradation and harm while developing infrastructure that helps to sustain the environment. For this article greening cities will thus include efforts undertaken by various stakeholders in cities with the objective of conserving green spaces and establishing infrastructure that co-exists with the natural environment. In simple terms green cities are characterised by green buildings, green transportation, zero waste, clean air, green economy as well as access to nature. Copenhagen is one city that has made great strides in the greening pursuit. For the city 90 % of building waste is reused (zero litter), 36 % of commuters and 50 % of the citizens cycle to work or to school (green transport), 96 % of the residents live within 15 min walk from a recreational area (access to nature), 24 % was cut in carbon emission between 2005 and 2012 (clean air) [7]. Efforts to green Copenhagen city have not only been the responsibility of the local authorities, rather the successful story has been narrated because the city has managed to place public-private partnerships at the centre of its greening approach.

The green agenda in cities is about ensuring the natural ecosystems of land, water and air are part of the city and its management with the aim of improving the sustainability of ecosystems [14]. Yet, to achieve this, systems’ dynamics seems to be a promising tool. Traditionally a “silo approach” has been considered wherein urban development issues have been considered as independent components that are detached from other systems. For example, the transport issues are considered in isolation from the waste management and energy sector yet there is a relationship between all these. Systems dynamics becomes a panacea to solve the complex environmental problems in such a context because the approach views reality from a holistic point of view where the complex web of interrelated components that influence each other and also themselves are treated as causal closed chains or loops. Systems dynamic is a concept that considers the behaviour of a system together with the understanding of the system in terms of the underlying flows that relate to other systems. This way, system dynamics modelling can be a tool for understanding system behaviour over extended periods since no one system can be treated in isolation due to the way systems interlock just like the links of a chain. System dynamics, in short, highlights that, if one wants to fix an issue he is obliged to first understand the whole system. This understanding is made possible because the identification of integrating flows in all systems helps in understanding the interactions that will ultimately contribute to the formulation of policies that affect the whole urban setting. Although the literature on system dynamics modelling is very rich with applications in many fields [8, 15], not many papers on developing system dynamics models were published so far. As urban environment models in system dynamics are extremely complex if an area is subdivided in many dynamic and interacting areas, managing complexity of the environmental network interactions is essential [16]. Environmental problems can be understood through system dynamics simulation. Systems approach to quantification of environmental problems allows better understanding of factors contributing to environmental degradation and more systematic assessment of various measures to solve the problem. No doubt, the urban environmental challenge facing African cities right now is the increasing stress on the environment and little time and resources to rectify the emerging problems [12]. With the heavily populated urban centres, natural bioremediation becomes increasingly fractious. Investment to limit the environmental footprint of the urban processes is required. Unfortunately most African governments are focussing on so many pressing and urgent challenges (health, unemployment and inequality). This is a daunting task in improving urban environments given the opportunity cost.

African cities and the green agenda: a review

As things stand, the expansion of African cities will be difficult to manage even with the best urban governance. Urban poverty is the most critical issue facing African cities at the moment. It is also often understated statistically and thus not likely to be addressed in its full dimensions [2]. One of the major consequences of the rapid urbanisation process has been the burgeoning supply of job seekers in both the modern (formal) and traditional (informal) sectors of the urban economy [17]. In most African countries, the supply of workers far outstrips the demand and the result is awfully high rates of unemployment and underemployment in African cities. Urban areas have become pools of squalid, sordid and morbid eyesores for majority of the people who live in absolute poverty. South Africa and Malawi for example use national-level poverty lines which indicate that poverty is lower within cities due to the overall level of amenities. National poverty lines are often defined as household consumption under $1 or $2 a day and yet these thresholds do not take into account a wide range of costs and hazards that urban residents face. For example, while rural residents can typically collect fuels, building materials, some foods, water, and a host of other basic needs from their surroundings, urban residents must pay to access all these.

In most African cities the poor are marginalised and are left with little option but to operate in the administrative or illegal margins in what has been referred to by UN Habitat as ‘self-help’ urbanisation. Too often African cities suffer from unplanned sprawl [6]. The region has the highest proportion of city dwellers in informal settlements and living in dire poverty in the world. The magnitude and severity of slum and informal settlements are significant indicators for the troubled African urban environment. The living standards in slum areas are agonisingly below the acceptable level. Overall, the water, soil and air qualities are greatly depreciated. Unlike other already developed and developing countries in the Asia region, in Africa, city growth has been through consistent underinvestment in agriculture leading to low productivity gains and low standards of living in rural areas forcing rural–urban migration hence city growth not credited to economic growth and prosperity. Most urban municipalities lack the financial autonomy and capacity to bankroll any initiatives they deem fit for implementation in their jurisdictions. This is also in light of the fact highlighted by [2] that unlike all other regions of the world, urbanisation in Africa has not contributed, through economies of scale and value-adding production chains, to overall growth in GDP. Finance and lack thereof has played a part in the limited success of the green agenda in African cities. Little research hence has been done and some of the mitigatory measures taken are those which are ‘readily available’. This is more pronounced because of inappropriate, unrealistic planning and building regulations, impractical planning theory and imported notions of urban aesthetics which do not reflect the needs of public authorities and the population, as well as current institutional capacities. Many local governments lack the capacity to fulfil their mandate in terms of human resources. This dire lack of skills and qualified personnel coupled with limited manpower can be attributed to Addis Ababa’s and Harare’s failed urban forestation in which the exotic trees which were planted without any professional advice are facing several problems detrimental to their survival (cf. [4, 9]). The lack of municipality’s capacity means that even when better policies are designed, they are difficult to implement at the scale necessary.

Politics of the day is perhaps the most critical of the above issues in understanding the state of African cities especially looking at urban environmental greening which has not been prioritised by politicians. According to the Economist Intelligence Unit [6] one reason why environmental issues are often not prioritised by political elites is that, by definition, sustainability is a long-term issue, requiring investment now for a longer-term benefit in a resource constrained environment. With people struggling to meet basic needs of food, shelter, and water, those sorts of immediate priorities trump longer-term ones. In cases where politicians have been saved from this dilemma for example through external aid, the African governments have shown commitment to greening programmes for example Egypt’s Clean Technology Fund (CTF) investment plan. On the whole, the state of African cities is defined by its rapid urbanisation and corollary outcomes. A systems approach in city greening efforts helps in holistically handling a multiplicity of factors that can determine the success or failure of efforts like city greening. A number of greening initiatives have been done by some Africa cities.

Case of five cities in Africa

In this section we assess the greening efforts of the cities of Harare, Johannesburg, Nairobi, Addis Ababa and Cairo. These are megacities in Africa whose settings and contexts may proffer comparable evidence of contrasts and comparison.

Harare

Harare is the capital city of Zimbabwe with an estimated population of 2.8 million in its metropolitan area [9]. Water, waste and sanitation standards are generally dropping in Harare. The low consumption of electricity and water is probably due to their erratic supply. The city’s water source is located downstream of the populated area which makes it prone to water pollution. In recent years especially after the economic meltdown (from 1997 to 2008), there has been an increase in the problem of solid waste disposal where most open spaces in the urban area are now dump sites. The local authorities could not provide this facility which they did in the past and had to outsource three companies to carry out the waste removal [9]. Just like in Copenhagen, the communities have engaged in waste management in their respect areas due to awareness efforts made by the local authorities. The government through Environmental Management Agency (EMA) has also made a stance on plastic bags which were once for free and are now being sold to minimize their littering the environment. Environmental bodies like EMA have also come up with a ‘follow your waste’ strategy requiring local companies that produce goods and services which generate litter to follow up and make efforts to clean the waste generated by their products. The private sector (ABC bank, Goldtech electronics, First Pack among others) have also come in and provided bins to be placed in public places. Volunteer cleaners have also helped address this issue through a number of clean up campaigns in many of Zimbabwe’s urban centres.

Efforts to green the city through tree planting, maintaining open spaces and other natural ecosystems have been conspicuous with Harare with efforts being spearheaded by the local authorities and the private sector as well. The government of Zimbabwe has emphasised on the plantation of trees through a national tree planting day held the first week of every December and several organisations (NGOs, local authorities as well as individuals) participate in this annual event. Attempts have been made by Harare City Council since the 1970s to plant more trees in the central areas of the city and to boulevard the main highways out of town. A number of roads leading into the central business district of Harare are tree lined with Jacarandas and Australian bottlebrush trees with the north eastern part of the city centre having the densest concentration of trees. In 2010 Harare embarked on a programme to re-green the city. This was after a realisation on the part of the local authorities that the bulk of the city greenline was ageing and required urgent replacing. Trees were planted on parking bays along street pavements. The government both at central and local level have promoted the conservation of green spaces through statutory plans. An example is the Kopje Market Square Local Priority Plan No. 17 that emphasis the need to preserve the Harare Kopje in its natural state with all the trees and vegetation being undisturbed. Urban greening has not only been a responsibility of the local authorities in Harare but some initiatives have been taken by some property owners who have developed a culture of planting trees on their sites. Moreover, some NGOs such as COSMO have spearheaded the conservation of wetlands in te city of noteworthy Monavale vlei and Marlborough vlei, though there have been some conflicts with some locals who would rather have the wetlands converted into residential areas. The Sunday Mail notes that there is increasing greening culture by individuals in Harare which shows the increase in awareness towards green cities.

Greening efforts have also been observed in infrastructure development in Harare, which is mostly done by the private sector. Since most of the energy is consumed in built environment, efforts have been made to construct buildings that minimise environmental degradation. Eastgate Centre in Harare constructed by Old Mutual is a green building that mimics an anthill that makes use of natural ventilation and lighting thus reducing carbon emission and overall cutting costs of air conditioning and lighting. The building also has overhangs where vegetation is grown. The other building is one housing Ernst and Young offices (Angwa city) which incorporated rooftop gardening. Street and traffic lights are increasingly being replaced with solar powered lights in Harare which is an indication of a city that is transforming and adopting green initiatives through use of environmentally friendly solar energy.

Green tourism, despite all the statistics and research to support it, is still being carried out at lower levels in Zimbabwe and also there is still yet to be a documented framework on green hospitality by the Zimbabwe Tourism Authority (ZTA) [21]. In addition, because of human disturbances, rivers like Manyame which used to have perennial flow have changed since now most of the water is now sewage as evidenced by the proliferation of water hyacinth. There have been efforts by the African Development Bank (AfDB) and a recent US$144 million loan from China to improve water inflows into businesses and homes. There have also been efforts to refurbish the cities major sewage treatment plants, Prince Edward and Morton Jeffrey waterworks where US$78 million has been secured for the project.

A lot has also been done in the transport sector in efforts to green the city of Harare. In Harare, commuter omnibuses (popularly referred to as kombis) have been blamed for traffic congestion and the city in an attempt to address this problem created a holding bay a kilometre from the city which is to hold the kombis currently driving into the city centre. This will be complemented by a mass transit system which will bring forth shuttle buses ferrying people into the city centre. They have also changed roads which used to be two way (R Mugabe, Chinhoyi street, Innez terrace and Leopold Takawira) into one ways to increase traffic flow. Also in a move to increase smooth flow of traffic they have installed ‘intelligent’ robots (King George and Baines avenue) which adjust time with differing traffic flows to ensure smooth traffic movement. With the aid of Old mutual a private company, the city of Harare has also constructed Harare drive as a ring road to limit traffic passing through the already congested city centre. Shopping centre like Westgate, Gleneagles and Avondale and office parks (Arundel Business Park, Mt Pleasant Business Park) have also been put in place to limit the pressure on the central business district. From the colonial days, industrial clustering has been used to improve the impact of green manufacturing practices in industry by enabling reduced energy and water consumption levels, solid waste and wastewater minimisation strategies and enabling increased participation in corporate social responsibility activities. For instance, the plan for industrial clustering was implemented in Old Ardbennie Industrial area in Waterfalls.

Discussion and policy options

Cities in Africa are vulnerable to systemic shocks which are strong impacts affecting substantial parts or all of an urban system (nationally or internationally), rather than having just isolated (e.g., sector-based or merely local) impacts. These shocks have the potential to threaten the sustainability and survival of the urban system as a whole. The rate and extent of technological advancements and globalization have substantially increased their likelihood, geographic scope and potential magnitudes for example the global economic recession of 2008/09, while others have longer gestation periods, like climate change, the effects of which may be no less severe and will be much longer lasting. System dynamics can be used to solve these systematic shocks in African cities and avoid after effects which in the African context often leads to more challenges and problems.

A synthesis of the case studies provided in this discourse shows the greening efforts yet by the cities and there are many determinant factors to trend. To a great extent, South African cities have successful embraced city greening. This can be attributed to the aspect of good governance after building on from the political resources accumulated after the end the apartheid government in 1994. These political resources lead to strong environmental policies which include strategies, codes and plans to monitor and improve the urban environment which have also been a factor in the success of greening in South Africa’s cities. One of the cities with the lowest green ratio, Addis Ababa has no colonial heritage and still maturing governance. Funding is an important factor determining the success or failure of city greening efforts. In a number of cities some well-known successful projects, have effectively received funding from some from external aid by donor agencies and a few from government funding. Financing has been important for the successful greening of cities. For example, Johannesburg received US$5.3 million from The Bill and Melinda Gates Foundation and US$1.2 million from Danish Development Agency; Cairo received US$350 million Clean Technology Fund (CTF) and US$5.3 million from The Bill and Melinda Gates Foundation [6].

For an initiative to be successful in Africa like elsewhere, there is first need to understand the society in which it is to be implemented and incorporate it. Good practices can be taken from Egypt where informal sector is working on facilitating the formalising process [5]. This has made it easier for policies to be implemented especially the brown agenda policies. Addis Ababa has also incorporated the poor along with the rich in dealing with greening issues and this can be credited for the success the greening agenda in the housing sector. The poor make up the majority of populations of the cities, and the quality of the urban economy and environment are shaped by people with middle to low incomes. Given the numbers and needs of the lower income population, it is imperative that they play a central role in planning and implementing urban greening as shown by the initiatives of Addis Ababa Ethiopian and Institute of Architecture, Building Construction and City Development (EiABC) of developing green building codes. Attitudes towards the environment and socio-demographic factors such as age, education determine the success of city greening. These determinants are mainly through the interaction of the households and the environments (i.e. household behaviour and water use, waste generation and recycling and willingness to pay for “environmental” goods). Strengthening people and open space interaction has been a practice that has made the greening a success story in cities of South Africa. To achieve this there are capacity building and empowerment programmes and environmental theme days (Water Week, Wetlands Day, Arbor Week, and Environment Week) [3]. It is critical that a part of any urban greening investment goes toward building local institutional capacity.

Government participation and support is important for the success of city greening initiatives. In Africa, government is largely the financing organ to major projects and programmes. Although national governments are not usually involved in the specifics of urban greening programs, they can greatly facilitate country-wide goal attainment by setting policy objectives and standards, and by providing institutional and network support to regional and local governments that do not have the funds to develop such resources on their own [10]. By also integrating urban greening into national environmental plans and performing evaluations, the central government can monitor progress made in urban greening throughout the country. Required often, is a robust legal framework. Normally, laws and regulations have to be enacted at various levels of government, and designed that they complement each other rather than have overlaps and gaps. Regarding laws and regulations, the more developed cities in South Africa have tend to be more active, while in the generality of most sub-Saharan Africa this has not be the case. South African cities have city departments, often under the direction of a city council, to directly oversee and implement policies at the urban level [6].

Review

Missing in existing literature on African cities is a critical review of the systems approach in solvingthe issues of these all-important locales. Offered in this short paper, is a review of aspects of complexity andsystems approach in the definition of environmental parameters of development in African cities.

Conclusion

Urban environmental challenges in Africa are increasingly becoming the centre of focus of African governments and philanthropist. Conventional greening approaches, by themselves, will prove ineffective in addressing these challenges and will, in fact, just treat the symptoms. If cities are to be sustainable in the next fifty years, there is need for a change in the greening approach. Given the much localised characteristics of countries, cities and settlements, it is worth stressing that in the design of any intervention, a strongly situational approach is essential. Urban environments in African cities should be prepared for the expected substantial growth. For urban authorities to fully deal with the urban environmental challenges, environmental impact assessment procedures should be followed and improved cross-sectoral linkages and joint enforcement of environmental laws and standards should occur. Though this sounds complex, the use of system dynamics in trying to understand all the factors that come into play and how they affect each other will go a long way in ensuring policies fully address issues raised during assessments. Because of the dynamism of African cities, systems dynamics can help solve the African urban environmental problems through system stability. The urban challenges in Africa can be attributed to ignoring (long run) feedback which has led to unintended consequences. System dynamics will help solve this by conceptualising a more stable system whose long run effects can be assessed.