If every person in the world lived as an average person living in the UK does, we would need three planets like Earth to sustain us. If every person lived as an average American, we would need five. With the developing carbon-based economies of India and China improving the living standards of over a third of the world's population, there will soon be an even greater squeeze on the Earth's limited resources. The Ministry of Defence in the UK announced in Spring 2006 that they are preparing the military for the extra conflict expected in 20-30 years' time caused to the lack of resources.
Something is sustainable if production can be kept constant indefinitely. For example, a logging company that is not sustainable will eventually cut down all the trees in the forest and go out of business, because it can no longer produce timber for its customers. A logging company that is sustainable will plant new trees in place of the ones it cuts down. Because of this, there will always be trees in the forest and the logging company will be able to keep producing timber for its customers indefinitely. Forestry is one of Finland's largest economic export sectors and it is sustainable. Finland relies heavily upon it, so it has a very strict code on replacing trees that have been cut down. Since the laws were introduced, the forests of Finland have actually grown to a record size and business is booming.
Forestry is not the only example of sustainability. Energy produced by the burning of fossil fuels is not sustainable, as we will eventually run out of the stocks we have. Energy produced by renewable forms is sustainable, as we will never run out of sunlight, wind or moving water. Mining is not sustainable, as there is only a limited amount of metal and stone in the ground, but recycling is sustainable because the materials get re-used over and over again.
Burning fossil fuels for energy is also unsustainable because of the impact it has on the environment. Global warming could cause drought and flooding, turning otherwise fertile farmland into useless wasteland.
Sustainability also relates to the amount of food and raw materials the planet can provide. There are 6 Billion people on Planet Earth. Many of those, including you and me, live in the rich part of the world where life is good and we have most of the things we need. We consume all the resources we can afford to pay for. The rest of the World's population have a much lower standard of living and are unable to consume the resources they wish they had. If those people were brought out of poverty and had the same standard of living that we do, the Earth would not be able to provide for everyone.
A sustainable World is one that is not built on unsustainable principles such as mining, fossil fuel burning and deforestation. A world economy that relies on renewable energy, sustainable timber and paper industries and recycling is sustainable, will not threaten the livelihoods of those who will inherit the planet from us and will enable hundreds of millions of people to be brought out of poverty without an adverse effect on the rest of the planet.