City supply networks: The climate risk bubble that could undermine urban resilience

Contributor: Will Bugler

To its inhabitants a city can feel like an island. If you are one of the many billions of people who live and work in a large conurbation, then you might know the feeling: the city becomes the stage for all of ones daily realities.

This impression of separateness has real impacts on the way city dwellers think and react to events. For instance, the isolation of urban populations has led to a disconnect with the natural world that is now a recognised medical disorder. It was also striking that one of the first reactions to the UK’s decision to leave the European Union was for many Londoners to call for their city to become independent from the rest of the country: the online petition currently stands at nearly 180,000 people.

Centres of risk

However, the impression of a city’s separateness, of its self-containment, belies an uncomfortable reality: that urban settlements are fragile and dependent on continuous supplies of essential materials. Cities are, in fact, concentrated centres of risk.

Risk concentrates in cities for many reasons: because land values are high; because they are centres of government, finance and law; because they are major drivers of the wider economy; and because many millions of people live in them. We have seen this time and again in cities around the world, from hurricanes Katrina and Sandy in the US, to heatwaves in Delhi and Central Europe, to flooding in Bangkok or Maputo – the list goes on. When shocks like those from climate driven extreme events affect a city, their impact is magnified.

But cities are also at risk because they are hungry. Cities demand energy, water, building materials, food and infrastructure in vast quantities. Their prosperity and resilience are dependent on the complex supply networks that that feed them.

Risk in urban supply networks

Many municipal governments are taking action to make their cities more resilient to climate shock, but the vast majority of their efforts are focused on protecting urban infrastructure within the city limits. It is easy to understand why they are behaving in this way: direct climate risks to property from flooding, for instance, can be mapped out and understood relatively easily. But what it is far harder to understand the myriad potential impacts of climate change on urban supply networks.

The consequences of a major city running out of vital supplies can well be imagined. Rising tensions and widespread disorder would surface incredibly quickly. In 2007 the then head of the UK’s Countryside Agency, Lord Cameron of Dillington, warned that food supplies for cities were very precarious, famously saying that the UK cities were ‘nine meals from anarchy’. His prediction sounded hyperbolic until a year later when widespread looting and rioting occurred in New Orleans as people ran out of food in the aftermath of Hurricane Katrina.

In order to better prepare for climate risks to urban supply chains, cities first need to understand what they look like. Mapping the supply networks of essential goods is the first step to understanding the climate vulnerabilities that might affect them. But are there steps that can be taken to increase the resilience of urban supply chains in absence of a full understanding of the risk?

Just in time

The simple answer to that question is yes. However, in order to achieve increased resilience some basic tenants of efficient supply chain management will need to be challenged.

Principal among these is efficiency. Increasing efficiency has been the goal for supply chain managers for many years. Few question it merits: faster delivery times, lower costs, and fewer environmental impacts. What is not to like?

Well the trend toward efficiency has undermined the resilience of supply chains, leaving very little slack in the system. In short a highly efficient supply chain works very well, so long as nothing goes wrong.

Such models are often known as ‘just in time’ distribution. The food supply network is a case in point. Food is transported into the city each day, and dispersed to a large number of small shops, serving their local populations. This is highly efficient, but it means that there are very few stocks of food held within the city itself. Disruption to supply networks would mean the city would run out of food alarmingly quickly.

To understand the fragility of the system we can look back to the year 2000, where in the UK there were a series of strikes by fuel tanker drivers protesting against high petrol (gas) prices. Supermarkets at the time warned that they had just 3 days of supplies left, leading to panic buying in stores in major cities accros the country.

Understanding supply chains and building resilience

In order to build resilience, municipal governments should begin to develop an understanding of their vulnerabilities and of their capacities to adapt. Arup’s recently released ‘City Resilience Index’ (CRI) provides a good starting point to bench-mark current resilience of urban areas. Committing to a process of regular vulnerability assessments such as the one undertaken by the City of London is also important to identify areas of high exposure and sensitivity to climate impacts.

But cities must also go beyond this. They will need to begin the process of understanding the vulnerabilities of their supply networks, especially of critical supplies such as water, energy, food staples and communications networks. The first step is will be to simply map these networks, get at least a basic understanding where supplies come from – knowledge simply does not exist for most cities at present.

This understanding will open up a new frontier of risk identification for urban areas, allowing them to have a much fuller appreciation of their vulnerability to climate impacts, and allow municipal governments to plan and prepare for shock.

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