Sustainable cities: the nexus between resilience and resource efficiency
A new report explores how cities can increase their resilience and resource efficiency – but highlights possible tensions between these two environmental agendas.
The 11th Sustainable Development Goal explicitly commits to making cities and human settlements more resilient and sustainable, while the 'New Urban Agenda' references 'resilience' and 'efficiency' almost 30 times each.
The concepts of resilience and resource efficiency provide useful frameworks for understanding and shaping urban development. And while these two objectives can complement each other, they can also conflict: building resilience in urban spaces can negate resource efficiency and vice versa.
The link between resilience and resource efficiency in urban spaces was discussed at length in the preparatory meetings hosted by UN Environment and the Rockefeller Foundation that helped to shape the New Urban Agenda.
Details of these expert discussions were not enumerated in the outcome document, but are explored in a new report from UN Environment and IIED, 'Resilience and resource efficiency at the city level'. The report was launched this week at the ICLEI Resilient Cities Congress, and includes a series of case studies ranging from Lima (Peru) to Guangzhou (China), and Lusaka (Zambia) to Semarang (Indonesia).
Why are resilience and resource efficiency so crucial for cities?
Cities occupy two to three per cent of the planet's land surface, but as much as 70-75 per cent of natural resources are consumed within them. Cities import food, water, energy and other resources from far beyond their boundaries, requiring complex transport infrastructure systems. The social and ecological impacts of urbanisation therefore stretch far beyond municipal boundaries.
With their concentrations of people, infrastructure and economic activity, cities are hotspots of vulnerability. Urban population growth is often concentrated in hazard-prone areas such as deltas and coastlines where urban residents are exposed to floods, sea-level rise and storm surges. Climate change will exacerbate these risks.
When resilience and resource efficiency conflict: the case of New York City
In October 2015, Hurricane Sandy swept across the Northeast of the United States. More than 90 people died, thousands of homes were destroyed and hundreds of thousands of people were left without electricity.
Since the hurricane, New York City has made its electricity grid more resilient by establishing interconnected microgrids supported by energy storage systems. If any individual module or connecting node is damaged, operators can reconfigure the other microgrids to maintain electricity supply. This minimises the number of homes affected in the event of a blackout.
This new system is indeed less susceptible to shocks, but it also produces more electricity than the city needs to operate. This redundant power supply would be essential in the event of a hazard, but is not an efficient use of material or money. New York has found there are trade-offs between resilience and resource efficiency.
Resilience and resource efficiency working hand in hand: the case of Johannesburg
Johannesburg's history of apartheid has generated stark social and spatial inequalities. Although average incomes are high, unemployment is over 30 per cent and the city is famous for its gated communities. The physical layout of the city excludes low-income residents from economic opportunity, public services and political participation.
With its evocatively titled Corridors of Freedom initiative, the government of Johannesburg aspires to transform the city's form and function. In particular, it is developing affordable bus and rail networks. Wherever these transport systems intersect, the government is promoting nodes of:
- Public services, such as schools and clinics
- Employment hubs, such as office buildings
- High-density residential buildings, and
- Green spaces, such as parks, urban forests and nature reserves.
Green space increases a city's resilience by absorbing run-off and reducing the urban heat island effect (whereby concrete, asphalt and other manmade substances retain the sun's heat). This also means that people do not need to spend as much on risk reduction and air conditioning.
Looking forward: mitigating tensions, seizing opportunity
Cities are strategically positioned to be leaders of change. As hubs of people and economic activity, they foster innovation and knowledge sharing. Dense populations reduce the economic and environmental cost of providing most infrastructure and services. A collective urban identity can also mobilise businesses and civil society to support a city's environmental agenda, adding dynamism and creativity to local initiatives.
This new report demonstrates possible tensions between resource efficiency and resilience objectives. New York City shows how cities can be made more resilient to shocks and stresses, but that this can also lead to inefficient use of resources. Overcoming these potential conflicts will require more integrated and responsive urban planning and governance.
Yet we also find that achieving resilience and resource efficiency at the city scale can help to meet broader sustainability objectives. Interventions can complement and reinforce each other, as Johannesburg is discovering.
Successfully aligning these two agendas may be a challenge – but it is also an opportunity that cities cannot afford to miss.
Sarah Colenbrander (email@example.com) is a researcher in IIED's Human Settlements research group. Sharon Gil (firstname.lastname@example.org) is a programme officer in the Cities Unit of UN Environment, based in Paris, France.