There is literally only one Planet Earth, and we rely on its amazing biological capacity to regenerate the goods and services we use - often without thinking: our food and drink, our clothes, our homes, how we stay warm and how we move around and stay healthy.

he Ecological Footprint is one way of measuring our use of the world's natural resources and ecological services. The footprint is the area, expressed in global hectares, needed to keep producing the food and fibre we use, absorb our wastes, generate the amount of energy we consume and provide the space for the roads, buildings and other infrastructure we rely on. Currently the world average individual footprint is 2.2 global hectares - but Earth can sustain just 1.8 global hectares for each one of us. That means together we are using nearly the equivalent of one and a quarter planets.

Heavy footprint
The map shows how we are doing, country by country. Blue countries are those where people are using less than the global average, and red ones are where people are using more. It is not surprising that the countries of the North, with their high levels of consumption, have the heaviest footprint, while the poorer countries of the South are often, in ecological terms, living sustainably.

Quality of life
Pakistani economist Mahbub ul Haq believed 'people often value achievements that do not show up at all, or not immediately, in income or growth figures: greater access to knowledge, better nutrition and health services, more secure livelihoods, security against crime and physical violence, satisfying leisure hours, political and cultural freedoms and a sense of participation in community activities. The objective of development is to create an enabling environment for people to enjoy long, healthy and creative lives.' His creation - the United Nations Human Development Index - quantifies these aspects of life. Produced annually, the Index shows higher quality of life in Northern countries. But are these lifestyles sustainable?

Living on less, living on more, 2001

The ecological footprint of an average resident in 69 out of the 150 countries illustrated is larger than 1.8 global hectares - the amount available per person worldwide. In 33 countries, the average person uses more than double, in 13 countries more than three times that.

		Countries using more than three times the worldwide average biocapacity available per person
		Countries using between twice and three times the worldwide average biocapacity available per person
		Countries using between the entire and twice the worldwide average biocapacity available per person
		Countries using between half and the entire worldwide average biocapacity available per person
		Countries using less than half the worldwide average biocapacity available per person
		Insufficient data

Sustainable living
Aurélien Boutard married these two measurements, plotting the Human Development Index together with the Ecological Footprint. His diagram suggests that, as we develop a better quality of life, so we move further away from living sustainably in ecological terms. No one country has yet achieved that magic mix - an ecologically sustainable, high-quality lifestyle. Now there's a challenge for us all.