The Ecological footprint is a concept – and measure – relating to the impact we have on the planet. It measures how much land and water area a human population requires to produce the resources it consumes and to absorb its wastes using current, prevailing technologies.

If we measure total impact across the planet, we find that mankind currently uses the equivalent of 1.4 planets – with some nations (such as America) using far more than their ‘share’.  In fact, if America covered the planet, we would need the resources of 5 planets to support the population.

What in effect we are doing is converting resources into waste much faster than we re-convert that waste into fresh resources.

The measure allows nations to calculate their own footprint and assess the damage they are doing to the planet, the share of resources they are consuming and then to explore ways in which they might move closer to ‘balance’.  It also allows those nations that have a surplus of resources to plan strategies for the future that allow them to exploit that surplus.

Unfortunately, there are more nations using more than their ‘share’ than those ‘in credit’.  As these lower-use nations develop, however, further problems will occur as resources get scarcer – and therefore more expensive.

Of course the measure applies at levels lower than nations – certainly at the regional and city level.  As cities grow – and as the global population migrates to cities – it is the performance of cities that will determine overall ecological performance.

These issues are explored on the website of the Global Footprint network – www.footprintnetwork.org.