Building Resilience through Urban Agriculture and Green Infrastructure: No Drop Left Behind
With 55% of the world’s population living in urban areas, cities have experienced an unprecedented rate of growth in the past decade. This trend will continue: by 2050, 70% of the global population is expected to live in cities (1).
Demographic growth in urban areas has serious economic, social and environmental repercussions: already today, cities consume 80% of the world’s energy, 70% of global food supply, they produce 60% of global greenhouse gas emissions and 70% of global waste. The high demand of urban consumers for water, energy, and food, is generating in many cases severe pollution, reducing surrounding arable agricultural lands. A more sustainable development path will have to focus stronger on making cities and urban and peri-urban agriculture more resilient, environmentally-friendly and productive.
Tough competition between cities and rural areas: the case of water
Many rural areas are experiencing growing inequality, as well as natural capital and resource degradation driven by the requirements of agriculture. This poses a significant stress on water, land and biodiversity resources and leads to unsustainable production patterns, including waste disposal, soil erosion and degradation, water quality deterioration, and resource depletion.
Growing urbanization is increasing the demand for water. Different sectors such as agriculture, industry and households will face stronger competition for scarce water resources. Severe water scarcity also leads to more desertification and increases migration from rural to urban areas with impacts on arable land loss and farming. Achieving sustainable urban development including food and water security requires sustainable production and consumption patterns by incorporating water valuation into integrated water resource management and transforming food systems from a major CO2 emitter to a major carbon sink.
Cities need to simultaneously consider urban and peri-urban water use, conservation and waste/nutrient recovery in the context of the water–food–energy–ecosystem nexus. Waste water treatment, reclaiming often abundantly available urban wastewater, including for greening urban and peri-urban areas, is a real possibility of starting a circular economy in this sector. Additionally, aquaculture-agriculture hybrid systems can use brackish and reclaimed water efficiently for fish farming, irrigation, cooling, and domestic non-potable purposes. Residuals from treatment can be returned to the system and conveyed to a larger, centralized treatment facility where recovery of energy and nutrients can be recovered.
Well-designed economic and environmental regulations can be an important driver of investments in water infrastructure, generating new markets for innovations like the re-use of urban wastewater and nutrient reclamation for irrigated agriculture and forestry. Regulations can increase investments in secure and better access to water and the demand for treatment technologies in water conservation and alternative sources of water supply (such as wastewater reuse, desalination and nonconventional water sources)2.
From a linear to a more circular economy
Fulfilling the Paris Climate Agreement and managing the natural resource base such as water sustainably to feed a growing world population, requires a sustainable development that needs to integrate urban agriculture and urban drainage or stormwater green infrastructures (GIs) into urban land use, planning and policy. Furthermore, we need to transition from a linear to a circular economy, interconnecting a range of environmental, economic, and social issues in urban, peri-urban, and rural areas through a sustainability lens.
Sustainable water and soil management play an essential role in protecting the resource base needed for agriculture, food security and nutrition, and to support ecosystem services and biodiversity, climate change adaptation and mitigation. Adapting to increased water scarcity through low-energy and renewable-energy water reuse and treatment, as well as desalination of brackish/seawater, also advances global agriculture mitigation goals. All of which sustainable urban planning and development would benefit.
Water scarcity and floods and droughts
Two main challenges related to water are affecting the sustainability of urban settlements: the lack of access to quality water, and the increasing water-related disasters such as floods and droughts. Around 140 million urban dwellers worldwide do not have access to improveddrinking water. As cities are frequently located in low-lying coastal deltas, 40% of the world population living in these coastal areas face flood risks. In 2022, flooding was reported to have killed approximately 7 000 people. Fluvial flood risks dominate in areas where large population shares are concentrated in low-lying river basins, such as the Brahmaputra (Bangladesh), Euphrates and Tigris (Iraq), Irrawaddy (Myanmar), Indus (Pakistan), Mekong (Cambodia, Laos, Vietnam), and Nile (Egypt, South Sudan), and coastal flooding dominates in countries with sprawling coastal urbanization (e.g., Guyana, Vietnam) and islands countries (e.g., The Bahamas, Fiji)4.
The Intergovernmental Panel on Climate Change reports that 8.7 million people can be expected to be displaced by 2050 from sea level rise in Asia alone if the current trend continues. Globally, this would affect 280 million people, according to the report, based on 136 megacities (port cities with more than one million inhabitants in 2005). In addition, the population suffering from water scarcity would double, leading to food insecurity through decreased crop yields and nutrition value, which would trigger significant migration from rural to urban areas.
Greening the cities
Transitioning towards greener and regenerative cities will be essential to make cities more resilient. Maintaining healthy food value chains and having more green spaces in urban and peri-urban areas will reduce the risks of droughts and floods. It is very encouraging that already more than 800 million people worldwide are practicing urban agriculture. The benefits of urban and peri-urban agriculture are obvious: shortened supply chains, increased availability of fresh produce, and more healthy dietary lifestyles and better local economic opportunities.
The environmental benefits of urban and peri-urban agriculture, such as rooftop and balcony gardens, hydroponics, energy-conscious greenhouse and vertical farming, include: the reduction of energy and water demand, improvement of air quality, capturing of rainwater and reduction of storm water runoff and discharge as well as a lowering temperatures during heatwaves. In addition, increased urban and peri-urban agriculture makes cities more food secure and self-reliant in the event of an unexpected shock. Agriculture nature-based solutions can provide a triple benefit when deployed properly, in terms of building agricultural production and resilience, mitigating climate change, and enhancing nature and biodiversity.
FAO’s Green Cities Initiative helps cities to better integrate agriculture, forestry, and food systems into urban policy, planning and action. It offers data and geospatial tools as well as technical support for national and city governments in planning urban agriculture and green infrastructure. It interacts with farmers as they work to provide safe food production through water and wastewater treatment, composting of waste, and sustainable land and soil management.
Creating enabling environments for continued innovation, adjustment and recalibration is a key catalyst for transformative change.
Supporting policies for transforming towards a circular economy may entail the following:
- Placing water and food security at the heart of urban planning: Urban planning will need to limit the footprint that cities have on water quality, quantity, and on energy and agri-food systems, including food loss and waste. A combination of five policy categories can make a good start: vision, engagement, economic incentives, urban management and regulations.
- Responsible consumption: Cities need to raise awareness about the power consumers have in sustainable urban development, as regards the unprecedented amounts of waste and wastewater they generate. Raising awareness and targeting a change in consumer behavior can radically reduce waste and support consumption patterns that facilitate circularity.
- Recovering and valorizing organic materials: Cities must implement programs to better recover and valorize organic materials, including from wastewater and food waste, to generate revenue from the production of energy and compost. Decayed organic material can be used as fertilizer.
- Recycling and reuse: Private industry needs to support the collection, recycling, reuse and repurposing of used consumer items, transforming what would otherwise be solid waste into the production of new goods and services.
- Solid waste and resource efficiency and productivity: cities need to ensure that materials are used efficiently at all stages of their lifecycle (extraction, transport, manufacturing, consumption, recovery and disposal) and throughout the supply chain.
Integrated urban-rural planning and governance need to recognize the role of water in development. This would reconcile a comprehensive mix of values, from food security to climate resilience, enabling multi-stakeholder processes that are important for sustainable urban development and the 2030 Agenda for Sustainable Development that leaves no one and no drop behind.
1United Nations, Department of Economic and Social Affairs, Population Division (2019). World Urbanization Prospects: The 2018 Revision (ST/ESA/SER.A/420). New York: United Nations
2FAO NonConventional Water Symposium https://www.fao.org/land-water/events/ncwsymposium19/ts1/en/
3The Great Flood report of 2022 https://reliefweb.int/report/world/great-flood-rising-waters-and-food-insecurity-october-2022
4NATURE COMMUNICATIONS | doi.org/10.1038/s41467-022-30727-4
5Ellen MacArthur Foundation. 2019. City governments and their role in enabling a circular economy transition: an overview of urban policy levers