Climate change threatens resilience and sustainability of urban development-environmental gains in the longer run. Even presently, millions of people are sternly feeling the risks of climate change like floods, hunger, energy deficits and heat waves in ‘urban areas of both developed and developing countries’. For Toronto Urban Growers, they ‘see the impacts of climate change every day’. The connectedness of urban living, ecology and climate change arguably theorises ‘urban sustainability’ as the ‘most critical environmental issue facing mankind.’ Associated to this is a complexity that consequentially resurfaces when the number of people living in cities keeps increasing and putting pressure on urban ecology. UN dataset projects that 66 per cent of the world population will live in urban areas by 2050. More urban residents will mean struggle to meet their competing needs, which will probably lead to complex city forms not different from what is depicted in a masterpiece on Making sense of cities.
Universally, the interactions of climate change with the phenomenon of (peri-)urbanisation have complicated concerns for where urban authorities can construct landfills, water treatment plants, school parks, football stadiums, toilets and markets. In the process of providing these public services, the open green spaces are unjustifiably squeezed. Urban lands under agriculture is often underestimated and converted to different courses. The image of urban agriculture is outrageously likened to an industry in sacks, signifying it has no value. Even with this persistent misconception, the activity is enduring and rapidly proliferating in North America, Europe and global South. From Japan, it is found out that ‘85% of Tokyo residents would like their city to have farmland in order to secure access to fresh foods and green space.’ This text re-examines global significance of caring for green urban assets, including producing food sustainably. Why shifting to a new regime of sustainability leadership that recognises that greening urban landscapes will enable cities, and people who live in them, to adapt or mitigate climate change shocks is re-stimulated.
Geotrends and meanings
In cities of Canberra, Shanghai, Singapore or Bogota, the varying effects of climate change on residents and the sustainability of green resources as well as the critical need to reverse the trend through cleaner, greener and sustainable initiatives is not disputed. I happened to visit Budapest, in July of this year amidst other colleagues, where I witnessed how urban natural resources could be expertly reordered to connect people to nature. Urban ecological modernisation is done beautifully. What could I say about the innovative micro-gardens in Dakar city? What about the neatly layout of greenspots in London’s Russell Square and the blossoming biodiversity assets in distant locations such as the Englefield Green? In Ghana’s capital city enclaves, the greenest index score could be found in Dodowa where phytospecies and other countryside assets are better protected and are in natural forms.
At this point, the emphasis is that urban agriculture is not simply the cultivated food crops we see or the uncared for livestock running along railways. The activity has evolved tremendously across geographical spheres, disciplines and cultures. It can be carried out to promote resource use efficiency and productivity; and strategically schemed to combat climate change. Thus, urban agriculture broadly includes hydroponics, permaculture, aquaculture, forestry, rooftop gardening, and mini-stories of several organotivars. The Berkeley Lab excellently elaborates what is meant by ‘precision urban agriculture’.
The undiscovered industry
Innovative practice of urban agriculture fits advancement of the concept of green economy, which is at the ‘forefront of the international sustainable development agenda’. Yet, its value is not something everyone accepts.
The value chain of manufacturing inputs to support output maximisation from urban agricultural activities is in excess of €78.8 billion in cities of global South annually. With rising attempt to introduce solar-driven irrigation technologies to green plots in cities, the potential is certainly higher than I predicted. This is an industry that encompasses selling of pot flowers, ICT messaging to deliver nutrition and extension news to reach growers and consumers, trading and packaging of fruits, creating green jobs, manufacturing of handy cleaner tools, bioinsecticides, organic fertilizers, and light machinery as well as providing expert industrial consultancies so that urban agricultural activities are practised on the basis of greener and sustainable principles, regulations and technical guidelines.
It recycles by-products from biodegradable origin to cultivate and produce pot plants for landscape improvements and, in some instances, feed for livestock or food for human consumption.
In Harare, Hanoi, Havana and Honolulu, thousands of residents are actively working soils to derive multifunctional benefits, including cooling of microclimatic conditions. Havana, in particular, has enviable record in hydroponics and about 90,000 residents are involved in agricultural-related activities. The residents of Windhoek, Lusaka and Cape Town are gaining from agricultural land uses within their cities. In Windhoek, the UN-FAO and local government agencies partnered with private sector institutions, including UPH Consultancy, to encourage residents to translate the science of horticulture into enhancing environments and food production. UPH adopts vermicompost production and application, which greatly contributes to eco-prosperity and limits the rate of evapotranspiration thereby reducing global warming at a micro scale.
Greening to purge climate risks
In Ghana, not less than 60% of local poultry is commercially reared outside of city fringes like Accra. With regards to vegetables, almost 90% of cabbage, lettuce, carrot, and leafy onions consume every day are cultivated within city catchments. These small-scale plots of green biospecies absorb essential proportion of CO2 to perform photosynthetic processes. Also, the vegetable plots are commonly sited along roads or near to markets. Because of the close proximity, there is no need to burn fossil fuel to transport harvested produce to markets. Emitting GHGs is avoided. Similarly, refrigeration is minimised since the fresh produce is sold out at the market immediately without storing in refrigerators. The situation where ‘chlorofluorocarbon (CFC)’ can arise from refrigeration to damage ozone layer is zero or negligible in regards to urban agriculture.
Greening urban agricultural value chain provides climate solutions. Advances in scientific research prove this. The extent it does remain mystery to many, though. As I indicated above, it is evidently documented that urban agriculture ‘taps into a significant part of the photosynthetic resources of the city; thus the green agenda is advanced through the brown agenda of the city synergistically’ (Murphy 1999 cited in UN-Habitat, 2009:121). A more recent research result released by scientists based at the University of California reaffirms that urban agriculture, including the practice of gardening is important in aiding the reduction of GHGs. An aspect of the result, which was shared by ScienceDaily and the Food Climate Research Network based at the University of Oxford is summarised as: ‘In the baseline vegetable garden scenario, the gardens were calculated to be able to contribute 0.5 percent of the city of Santa Barbara’s 2050 greenhouse gas reduction target, 3.3 percent of the 2020 target for unincorporated Santa Barbara County and 7.8 percent of the state of California’s 2020 target.’ Cautiously analysing and drawing insight from this result goes to strongly substantiate the notion that urban agriculture has ‘high potential for improving the urban environment and urban adaptation to climate change’.
Resource efficiency and eco-friendly
The evidence is clear that greening urban lands could lessen climate change risks and boost resource efficiency. Combining the maintenance of wetlands, community gardens and aquaculture with wastewater treatment and its reuse could increase efficient use of urban natural resources for multi-purposes as it is the case in Calcutta, Beijing, Pretoria and Kampala. In Lethbridge city, the adoption of ‘crop management and biodiversity for weed and insect control’ helped to decouple environmental pollution from production system.
Co-engaging all heads and hands
The sustainable formation of cities, including greening of landscapes, to deal with unpredictably surging hazards of climate change will require co-engagements to be successful. Why? Urban sustainability is a multifaceted task. As a result, consulting others and leaving out scientists is not a genuine urban development approach and will not work well as explicitly encapsulated in ‘Scientists must have a say in the future of cities’. Harnessing development-environmental values offered by urban agriculture to resolve crisis of GHGs demand that actors are involved in urban policy formulation and implementation from local to global level along the vision of achieving smart-climate cities. This means, as has been said over and over, that urban agriculture should be integrated into ‘city-level climate change strategies’ – an integration that does not divide or exclude people.
Division among actors becomes the root cause of why even a well-planned and adequately financed intervention can go into disarray to instead invite detrimental impacts of climate change. The gathering of global audience for the 2016 UN-Habitat III event, which has perhaps ended a dozens of hours ago, in Quito to renew and reset New Urban Agenda is a fine moment to soberly reflect and come out with clear path and plan of how greening cities can be responsibly financed. We are also in another exciting season to see the Paris Agreement on Climate Change (PACC) ratified by 83 countries globally as at October 5, 2016. Sustainability leadership is required to enable the PACC and goal #11 of agenda 2030 recognise green urban agriculture, in addition to other global strategies, in building resilient and sustainable cities. Whatever approach is applied; if you are urban grower, you are indeed a climate change champion as the Toronto Urban Growers would say. And, for National Geographic, you are ‘growing a green future’. In my own view, you are a planet sustainer and not involved in an industry that is in ‘sacks’ but abundantly blessed for green success in future.
 UN-Habitat, 2009. Planning sustainable cities: global report on human settlements 2009. UN Human Settlements Programme. Earthscan: London.
 McDonald, G. and Patterson, M.G., 2007. Bridging the divide in urban sustainability: from human exemptionalism to new ecological paradigm. Urban Ecosystems 10 (2) 169-190.
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 Lorenzo, G.C. 2016. Integrated solutions: the case of refrigeration. A paper presented at UNIDO/CEU Green Industry Course, held July 11-22, 2016. Budapest, Hungary.
 Cleveland, D. A., Phares, N.; Nightingale, D. K.; Weatherby, L. R.; Radis, W.; Ballard, J.; Campagna, M.; Kurtz, D.; Livingston, K.; Riechers, G. and Wilkins, K., 2017. The potential for urban household vegetable gardens to reduce greenhouse gas emissions. Landscape and Urban Planning 157: 365-374.
 Dubbeling, M. and de Zeeuw, H. 2011. Urban agriculture and climate change adaptation: ensuring food security through adaptation. RUAF Foundation, Netherlands.
 McPhearson, T.; Parnell, S.; Simon, D.; Gaffney, O.; Elmqvist, T.; Bai, X.; Roberts, D. and Revi, A., 2016. Scientists must have a say in the future of cities. Nature 538:165-165.