Towards a green economy

cities accounts for approximately 30 per cent of their total ecological footprint (Steel 2008). More broadly, urbanisation is usually accompanied by a loss of nearby arable land and a rise in demand for processed foods by urban consumers. While there is some way to go to see a substantial reduction in the food footprints of highly consumptive cities such as London and New York, there is evidence that farmers’ markets are successfully re-establishing links between inner cities and regional agriculture. Other cities benefit from their location at the heart of rich agricultural landscapes, which reduces the need for long and expensive travel of food products. In Milan, Italy, up to 40 per cent of daily produce is grown within a four-hour radius of travel, reflecting the city’s proximity to the agricultural plains of the Po Valley and the Mediterranean Sea.

Approximately 15-20 per cent of the world’s food is produced in urban areas, with urban crops and animal products often representing a substantial part of the urban annual food requirement (Armar-Klemesu and Maxwell 2001). The extensive role of food production in cities is a common feature of many developing world cities. Estimates suggest that 35 per cent of households of Nakuru, Kenya were engaged in urban agriculture in 1998 and nearly half of households in Kampala, Uganda in 2003 (Foeken 2006; David 2010). In Accra, Ghana 90 per cent of the city’s vegetable supply is produced within the city’s boundaries (Annorbah-Sarpei 1998). Successful urban agriculture projects are scattered across some Western cities, albeit usually on a small scale, making use of communal gardens, roof spaces and unused urban spaces. In shrinking cities such as Detroit, urban farms have been established in some of the areas with particularly low development pressures on land (Kaufman and Bailkey 2000).

4.7 Waste

By concentrating people and activities, cities have become centres of the waste economy, which plays a dominant role in a city’s ecological footprint. Yet, cities have demonstrated considerable resilience in finding green solutions that

reduce overall waste,

increase recycling and pioneering new forms of environmentally friendly treatment of unavoidable waste. In developing world cities which typically suffer from insufficient formal waste collection, it is a large workforce of mostly informal recyclers and reclaimers,

such as the Zabbaleen in Cairo, who have implemented sophisticated reuse and recycling systems (Bushra 2000 in Aziz 2004). However, these jobs mostly do not match decent work requirements and green waste strategies in these contexts often fail

to recognise

the potential role of these actors (Medina 2000) and implement

expensive, technology-driven recycling models (Wilson et al. 2006).

In many European cities, recycling levels are in the region of 50 per cent, while Copenhagen only sends three per cent of its waste to landfills (C40 Cities 2010f). In 1991, Curitiba established a green exchange programme (cambio verde) that incentivises people to exchange recyclable waste for fresh fruits and vegetables acquired by the city from local surpluses (Anschütz 1996). Composting is a further critical component for greening waste. Positive examples range from Dhaka’s decentralised composting to San Francisco’s municipal food composting programmes (Zurbrügg et al. 2005).

4.8 Infrastructure and digital technology

The assessment of digital technology on greener cities lies outside the scope of this section of the Report, but a growing body of evidence suggests that cities are the natural sites of investment in smart infrastructure to deliver more sustainable environments. Cities provide a critical mass of potential users for a wide range of IT-based services which build upon complex physical infrastructure (such as roads, rail, cabling and distribution systems). The digital infrastructure of the internet and data centres create an intelligent infrastructure that connects people to people, people to city systems and city systems to each other, allowing cities and their residents to respond to changing circumstances by adapting in near real-time and to recognise patterns to help make informed decisions.

In addition, smart transport systems are being used to tackle congestion, facilitate road user charges or supply real-time information on traffic problems. Examples include Stockholm’s congestion tax and Singapore’s electronic road pricing. They also facilitate bike hire schemes in many cities around the world. Amsterdam currently trials smart work centres that allow workers to use local office facilities rather than commuting to their main office (Connected Urban Development 2008).

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