Introducing One Planet Cities: sustaining humanity within planetary limits

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Posted May 22 2019 by David Thorpe of The One Planet Life
One Planet City

David Thorpe of One Planet Life shares the ideas and aspirations behind his new book One Planet Cities, outlining his vision for sustainable urban communities.

How can the essential needs of the growing human population be met without breaking the Earth’s already-stretched life-support system? This is the question I set myself to answer with my new book, One Planet Cities: Sustaining Humanity within Planetary Limits.

It is linked to my new campaign for cities to declare an ambition to reduce their ecological footprint, beginning in Wales, as a response to the twinned climate and extinction emergencies, which I am running with the Global Footprint Network. It is also a key textbook for a new postgraduate certificate in #OnePlanet Governance at the University of Wales Trinity St David, that civil servants and other students can undertake via distance learning from anywhere in the world, and gain CPD points. I want to train the next generation of civic leaders in how to save the world.

Although I started my work before Kate Raworth’s Doughnut Economics came out, it builds on it and the work of the Global Footprint Network, whose president, Matthis Wackernagel, was extremely helpful during its writing. It is based on interviews with a great many urban leaders around the world and webinars conducted with them during my time as curator of the sustainable cities collective web forum, as well as much supplementary research.

It’s also a follow-up to my previous book The One Planet Life, which is a manual to help individuals and households to reduce their ecological footprint and live lightly on the earth. At the end of that book there are twenty case studies, the last of which are set in cities.

Contraction and convergence

Four out of five people are predicted to be urban dwellers by 2080. No country or city in the world now meets the needs of its citizens in a truly sustainable fashion (within Raworth’s doughnut). One Planet Cities proposes a pathway to this genuine sustainability for cities and neighbourhoods, using an approach based on ‘contraction and convergence’.

The book examines all aspects of modern society, from food provision to neighbourhood design, via industry, the circular economy, energy and transport, through the critical lens of the ecological footprint and relevant supporting international standards and indicators. There are recommendations for managing supply chains and impacts and considerations of how the transition to a world within limits might be financed, followed by a deep examination of the Welsh government’s pioneering efforts.

It discusses how the dystopic stories we tell ourselves about the future can influence the future we make and concludes with an imagined vision of what a genuinely sustainable future might be like, based on the examples in the book, and an appeal for ‘one planeteers’ everywhere to step up to the challenge.

What would setting a target to be a ‘one planet’ city mean?

It means adopting a framework for working over time so that all activities over which a city has power and influence combine together to reduce its ecological footprint (which includes carbon and biocapacity) to a measurably sustainable level. The time period is defined. The main tools are shifts in collective awareness and in the way all money is spent. The objective is to address the combined climate, resource and extinction emergencies at the same time with win-win-win solutions to create a flagship healthy, successful and resilient city.

One Planet City: resource dependence graph

Credit: David Thorpe

The 6-step path towards a ‘one planet’ city

  1. Obtain community buy-in and raise awareness
  2. Decide which standards and goals to use
  3. Determine the baseline – the current situation of biocapacity and resource use
  4. Set targets to ratchet down consumption and boost biocapacity for each sector over realistic timescales (e.g. 5 year intervals up to 2030 and then up to 2050)
  5. Set in place ways to measure them
  6. Keep checking and refining

The basic ‘one planet’ city requirements

  1. An aim to reduce the ecological footprint to ‘one planet’ (e.g. by 2050) would become an underlying principle of all planning and policy as a verifiable regenerative strategy
  2. The same set of social and environmental criteria would be used to assess all planning applications and procurement (i.e. a reduction of ecological footprint and increase in biocapacity, step-changing incrementally over time to the level currently applied to One Planet Developments in the open countryside under TAN6 in Wales)
  3. The criteria would be informed by appropriate indicators including life-cycle and ecological footprint analysis, using the simple Net Present Value+ tool which allows you to compare all potential and actual projects for their impacts and benefits (see below)
  4. Official policy would support all areas and sectors to become more productive, more bio-diverse and regenerative e.g. supporting more food growing in the city
  5. There would be a reduction of excessive consumption by a shift to a closed loop economy using procurement tools and believing that meeting basic needs is sufficient for everybody

How spending bodies would proceed

Every project initiated by public bodies would be evaluated relative to the overall goal as follows:

  • Where does a city want to be resource-wise in 2030 and 2050 to position itself for success?
  • What Ecological Footprint reduction does this imply? (relative to the baseline survey – see below)
  • What is the financial budget of the city for projects over the time period (for instance up to 2030 or 2050)?
  • By dividing the reduction by the expected budget, one gets a minimal performance standard for all projects
  • Every project that does not beat this benchmark becomes a liability and should be avoided. Favour the best performing projects and learn from them.

This implies 2 questions about all spending (in line with WBFGA)

To make sure all of a city’s investments are effective in helping to achieve the defined objective, they would need to pass two evaluations:

  1. Is the investment producing a positive financial return (ROI)? If not, the project will not be replicable. The higher the ROI, the faster it can be scaled.
  2. Is the investment advancing resource security sufficiently rapidly? If not, a city will not be prepared for the future we anticipate. (Resource security is defined by biocapacity, population, resource (including carbon) flows).

Tools to help:

1. Ecological Footprint accounting

  • Provides a biological view and joins all the human pressures – water, climate, biodiversity, food, energy, etc. This allows us to solve them all together.
  • Ecological Footprint results are understandable by ordinary people (unlike carbon)
  • Makes the economic self-interest clear and obvious. It emphasises resource security
  • It allows policy analysts to identify which options reduce the resource dependence of an economy and by how much.
  • Sustainable investments that satisfy investors need to meet both the resource and the fiscal criteria

To achieve this use:

2. The Net Present Value+ tool

  • Expands on classical NPV. See:
  • It compares different scenarios for a given spend
  • Can help you evaluate how much the spending benefits social, financial and environmental criteria
  • It also clarifies what the assumed future is within which the spend has to operate
  • Ensures all the relevant costs & benefits are counted within the WBFGA’s 5 ways of working


We can offer a city baseline evaluation and capacity building which can be applied to any supply/consumption chain and procurement life-cycle analysis strategy. A city assessment as baseline is typically around £50,000. A city would be provided with a Consumption Land Use Matrix (measuring biocapacity against resource use) which it can regularly update itself. The result would be the beginning of win-win strategy: a city would have nothing to lose and everything to gain.

About the author

David Thorpe of One Planet Life is a Lecturer in One Planet Living at UWTSD and a Patron of the One Planet Council.  The author of several books and thousands of articles, he also works for Calon Cymru Network, was a Special Consultant at Sustainable Cities Collective and is a former editor of Energy and Environmental Management magazine.