More than 80% of the world’s economic activities are concentrated in urban areas, making cities, by far the
largest source of greenhouse gas (GHG) emissions. Urbanization is associated with increasing consumption and economic growth which in turn are linked to increasing waste generation. In an unsustainable cycle, ever increasing consumption and demand for goods and services will lead to ever-increasing production of materials and waste and therefore ever-increasing damage to the environment including through GHG emissions.
In contrast with the conventional, linear, “take-make-use-dispose” model, in the “circular economy” resources go through the various stages of transition, retaining their value to society where nothing is wasted.
Frontier technologies can accelerate the progress to a circular economy. For example, modern signaling systems can optimize public transport operations reducing energy consumption; similarly, sensor-enabled rubbish bins can signal when they are full leading to optimal scheduling of rubbish collection and reduction of fuel wastage by collection trucks – a major expense in several cities.
Sensors can be used in food packaging to indicate whether the food is still good for consumption, avoiding the wastage of food disposed of by the “expiration date”. Bi-directional charging of electric vehicles to and from the grid can make renewable energy more viable and reduce dependence on conventional fuels. Advanced Metering Systems can reduce water losses in water supply networks, estimated to cost developing countries USD 3 billion annually.
However, the advancement in electronic technologies has also created its own challenges. The rapid obsolescence of electronic devices has led to increasing amounts of e-waste. According to the “The Global E-Waste Monitor 2017 Report,” 44.7 million metric tons of e-waste (defined as anything with a plug or battery) was generated globally in 2016.
The recovery of valuable materials from this waste is often carried out by the most vulnerable under hazardous conditions in dumpsites located in developing countries. In addition to the health-risks faced by these informal workers, the leachate from these dumpsites also pollute water sources. Efforts to develop a circular economy will need to consider how obsolescence is viewed and managed in the industry.
In the New Urban Agenda, a commitment was made to:
“ strengthening the linkages and responsible management of resources like land, water, energy, materials, food, oceans and seas, freshwater resources as well as the production and environmentally sound management of waste, minimization of hazardous chemicals, and the mitigation of e missions of greenhouse gases and air pollutants, taking into consideration urban-rural linkages, functional supply and value chains in the full-range of resource requirements vis-à-vis the environmental impact and sustainability, striving to a progressive transition towards a circular economy “
Cities, where businesses, consumers and the actual material resources are mainly located, is the natural arena where the circular economy can be promoted. The concentration of youth and educational institutions in cities can also lead to innovative technological solutions. For example UN-Habitat, worked with local innovators in Nairobi, Kenya using micro-electronic components from used electronic device to alert municipal officials to septic tank leaks which can pollute drinking water supplies.
To promote the circular economy effectively, cities need the support of national, urban, industrial, energy, transport, environment and other sector policies. The New Urban Agenda together with the Sustainable Development Goals (SDGs) particularly, SDG 12 (Sustainable Consumption and Production) and SDG 11 (Sustainable Cities and Communities) provide the basis for such coordination between sector policies and integration between national and local policies and implementation.