The vast majority of impacts on society and the environment, both positive and negative, arise from the way in which money is spent. Not just the way, but the amount.

The ecological footprint includes carbon, but captures more costs and benefits. There is a direct correlation between the size of a country’s and an individual’s ecological footprint and their spending power.

This is why the Welsh government’s ecological footprint calculator – to be used by applicants and is one planet development planning policy – uses spending as a proxy.

Of course footprints arise from production as well as consumption. These need to be factored in as well; often goods are not produced in the territory in which they are consumed.

We have climate & extinction emergencies because environmental & social costs have been left off the balance sheets by governments and businesses. They have been regarded as free, but they are not free.

We are now experiencing these costs in increasingly dramatic ways.

If everyone in the world lived the way we do in the UK for example we would need three beautiful planet Earths to support us. Already 1.6 Earths are needed to support how the population as a whole lives. Of course we only have one planet so we need to learn to live within planetary boundaries or we will perish.

Does this mean that we all have to consume less? Certainly it’s true that conspicuous consumption and overconsumption should be viewed critically. Something like the richest global 5% are responsible for about half of the environmental damage on the planet.

What we at the One Planet Centre propose is a comprehensive ‘one planet’ framework that will cause system change over time to reduce the impact of our way of life to the level that the planet can provide, and reintroduce more, and more varied, nature into our environment.

Any public or private body can use the framework to optimise all their spending (and ultimately planning) decisions in order to achieve the goal of making the region reduce its ecological and carbon footprint to a measurably sustainable level.

It means they can capture many benefits not reached by a piecemeal approach.

A key point is measurability, to verify that they are doing the right thing and not wasting time and money.

Optimising spending decisions in this way affects supply chains. It creates a market for a new kind of player in the economy, one that embraces ‘closed loop’ production and consumption (where nothing is wasted, as in nature), and the use of energy efficiency and renewable energy.

It often means more local production and supply (cf the Preston model), an end to waste, more jobs, greater prosperity and improved health.

There is everything to gain.

An administration, such as the UK government, would define the time period to reduce the footprint to one planet, in much the same way that the Climate Change Act has five yearly budgets aiming to reduce emissions to zero by 2050.

Targets focus minds. So setting a target of getting to ‘one planet’ in, say, 10 or 20 years is a way to get everyone thinking along the same lines.

It’s also easy to communicate to everyone; an ‘umbrella’ rallying cry to generate enthusiasm; and it’s possible to check progress on the target.

This type of thing is already happening in Wales, where it’s required by the Well-Being of Future Generations Act (since ecological footprint is an indicator & spending for the care of future generations is the Act’s purpose).

The Big Issue’s John Bird is proposing a similar Bill to be passed in England.

For these reasons, adopting an exciting ‘one planet’ city or country target as part of a response to declaring a climate emergency sends out all the right signals and leaves nothing out.

We offer modelling tools to make visible the impacts of different versions of budget spends.

(We also offer courses and publications to help individuals and households reduce their ecological footprints at a smaller scale.)