Tuesday, 27 December 2016

The Need for Sustainable Urban Systems

Population growth, urbanisation and climate change represent three of the greatest challenges for sustainable development. Cities need sustainable urban systems to integrate all components of its strategic infrastructural plans. 

Dealing with urbanisation

The explosion of urbanisation is widely regarded as a chief contributor of carbon emissions, resource depletion, and climate change.  They are the seats of all government and all knowledge, culture, opportunities and innovation but at an awful environmental cost. 

More than half of the world’s population now live in cities.  And those cities consume over 2/3 of the world’s energy.  Furthermore, our cities span less than 3% of the world’s land area, but their ecological footprint extends far beyond urban boundaries to the forests, croplands, coal mines and watersheds that sustain their inhabitants.

European cities with a long history such as London and Paris have the advantage of mass transit infrastructure which can support a densely packed city and reduce travel-related emissions.  But these typically European cities suffer from poor building stock in terms of energy efficiency and environmental performance. North American and Australian cities have large power, transport and building footprints but also access to a wealth of natural resources.

In the developing world a large percentage of a traditionally rural populace is moving into cities like Delhi and Mumbai that were not designed for mega populations.  They are bursting.  Suddenly the challenge is of the urban poor being worse off than the rural poor, with poor basic standards of living, pollution exposure and a lack of services.

Decision-makers therefore face complex policy choices as the conflict between nature and human development finds its battleground.  Can we make urban living work better in future?

Making it happen

There are a lot of elements to influence to make urbanism work and create sustainable cities of the future. The solution lies in the total rethinking and redesign of our present urban model at all levels, social, economic and environmental. Most of our cities that we presently inhabit today have grown organically and naturally to meet market demands. This has been a linear process and indeed most of the engineering systems that serve us are simple linear processes. Input-process-output and waste. Rarely is there any real cross over of these systems or sharing of resource. For example, rarely is the city’s power plant placed near the sewage plant despite the fact that as a by product of sewage processing methane is produced which could be used directly to generate power and heat (where needed) for the community. 

An alternative model that has been put forward by people such as Herbert Giradet is that we should view our cities more as holistic metabolic processes which are integrated and linked, sharing wastes and resource to maximise efficiencies and minimise waste production (and costs).

This will require a new approach to urban design and master planning that involves an integrated team of engineers, planners, urban designers and architects. Understanding the cities ecological footprint will provide a better grasp of the impacts of each part of a city’s infrastructure, identifying where attention is required the most, and will have the greatest effect. 

Recognising that there is ultimately a balance in resource availability and demand will bring a focus to replicating nature’s processes in the built environment.  Waste, heat, water, materials and energy can actually work together in an integrated way, with by-products from each benefiting the delivery of others.  For example, waste can be used to create electricity, heat, and water can be reused for cooling and irrigation.  

The success of this integrated approach to infrastructure is dependent on learning and resourcing in areas of technology, heritage conservation and environmental management.  If achieved successfully it links people, buildings, infrastructure and the environment as a single living unit.

But success is also only achieved by one party taking the helicopter view and drawing together all the specialist contributors to a city’s infrastructure as part of a collaborative design process. We should call this the delivery of a ‘sustainable urban system’ - a system that can be applied to the masterplan of a future city, to integrate all component parts of the strategic infrastructure plans.