In an urbanising world, in which the consumption patterns of cities define human environmental impacts as never before, urban development needs to undergo a profound paradigm change. This means first and foremost that ways must be found for cities to minimise their systemic dependence on fossil fuels and the unsustainable use of resources. Whilst the renewable energy supply to cities is a crucially important issue, efforts to make them into fully regenerative systems need to go beyond that. The primary metaphor of relevance here is the ‘metabolism of cities’.
Like other organisms, cities have a definable metabolism. The metabolism of many modern cities is essentially linear, with resources flowing through the urban system without much concern about their origin, or about their final destination. Inputs and outputs are considered as largely unrelated. This is profoundly different from nature’s circular metabolism, where waste does not exist: every output by an organism is also an input which replenishes the whole living environment. Planners seeking to design regenerative urban systems should start by studying the ecology of natural systems. On a predominantly urban planet, cities will need to adopt circular metabolic systems to assure their own long-term viability as well as that of the rural environments on which they depend. Outputs will need to become inputs into the urban production system.
Any strategy for a resilient urbanising world should be based on the following elements:
Renewable energy can be used to meet all energy demand in cities for electricity, heating and transport. Renewable energy sources can be found within the city, but in particular larger cities need to take advantage of resources from the metropolitan region or even further afield (‘energy subsidiarity').
Worldwide, hundreds of energy efficiency policies have been implemented and proven more or less successful. Despite these efforts over the last 15 years, energy consumption has still increased considerably. In order to reverse this trend, policy makers around the world must do more. They must adopt comprehensive policies which tackle market imperfections and consumer ignorance, and promote efficient technologies. There is no one-size-fits-all solution, instead cities, regions and countries have to compile a strong and equitable package of measures with regard to their economic, political and social situation to overcome barriers and imperfections.
Read more in our energy efficiency section.
More than 95 per cent of all global motorized movements depend on oil: whether it is cheap and extremely polluting bunker crude oil being burnt by the global shipping armada, or subsidized aviation kerosene keeping millions of travellers aloft. Our urban lifestyles have grown accustomed to relying on this untenable situation. Intra-urban mobility is another critical issue.
Today's call is for a 100 per cent renewable electricity based urban transport system. It is becoming clear that regionally supplied wind or solar energy can power urban public transit systems - note the success of Calgary's C-Train which is powered by Albertan wind farms.
The other approach is to find ways to supply vehicles with the renewable energy sourced locally – and the batteries of these vehicles can even be used as floating storage systems - for electricity peak shaving, for example. Electric and hybrid vehicle technology can greatly reduce urban air and noise pollution. In China’s cities a switch to electric bikes – and increasingly cars as well - has greatly reduced pollution and has cut energy costs by up to 80 to 90 per cent.
The vision of a regenerative city incorporates a full circle of waste avoidance and re-use. If waste is produced it must be treated as a resource which can be used to create new products or generate energy. Products must be designed with a life cycle approach, taking their handling after the end of their initial uses into consideration. Recovering value and creating markets for the secondary products and energy become the basis for policy solutions. However, circular waste management and product design must, primarily, be regulated on national and even international level. The role of cities is focused on the development of a sustainable waste recycling programme which incorporates modern sorting processes, the erection of state of the art incineration, recycling and biogas plants.
Cities, directly and indirectly, use vast quantities of water which end up as waste water. Efficient water use has to be closely linked with the recycling and reuse of plant nutrients and carbon contained in waste water. A regenerative city will assure that these materials are returned to farmland growing food for cities in a closed nutrient cycle.
The issue of local food is one of the most commonly and enthusiastically embraced of all the issues around localisation. From British allotment gardening, to community supported agriculture, to Cuban urban agriculture, to Japanese rooftop gardens - there are more and more examples of intra-urban and peri-urban areas being transformed into productive food-growing land. Producing food locally, even in an urban environment, means shorter transport routes, and less processing and packaging. In the U.S., these parts of the value chain consume more than a third of all energy used for food production. Limiting these activities can substantially reduce the carbon footprint of each meal. In addition, urban food policies encourage consumption of nutritious food, provide food security and sovereignty. Members of the community can be become involved and jobs are created. Local agriculture projects create solidarity, cohesion and purpose among the communities, sustaining morale and building community pride.
Read more in our FuturePolicy.org Agriculture and food section.
Some industries or cities pride themselves on fostering carbon sink projects in far-away places such as Amazonia as attempts at 'offsetting' their fossil fuel sins – and many emissions trading schemes are based on this idea. But if a city offsets its greenhouse gas emissions in its own bioregion it has an extra reason to ensure that they are well managed. If a city establishes its own carbon sink it will ensure that its own regional ecosystems benefit. Whilst open space and waterway management, forestry and agriculture practices may all help to absorb carbon, only deliberate planning for biological carbon sequestration can really make a significant contribution. Using open space for urban gardens and forests, relocalising food supplies, wetland development and water management: all this can contribute to lowering a city's carbon footprint.