Empreintes de pas ?
BasicsA footprint has a size and a weight. Together they determine the impact on the area that supports the footprint. The footprint represents the consumption of resources per year.
Renewable resources are products made of plant and animal material, water, etc.. They are regenerated by the interactive functioning of nature, that is the balances of living beings and non-living material on Earth.
Non-renewable resources, such as fossil fuels, uranium, metals and minerals, are finite stocks, that are not renewed by nature.
Our human footprint consists of our annual consumption of renewables and non-renewables.
If our consumption of renewables is higher than their rate of regeneration, we will run out of food and fibre.
If our depletion rate of non-renewables is low in comparison to the available stocks, we can carry on for a relatively long period of time.
Sustainability refers to a level of human resource consumption that can be maintained for a very long time, theoretically forever. If our human footprint is too high it can not be sustained by the Earth for a long time.
Presently, our human footprint is too high, in almost all sectors of resource consumption. It is not sure, however, in which sector the depletion will first reach the critical point that may lead to a collapse of the human socio-economic structures. It could be lack of food, clean water, an illness, toxification and pollution, lack of fossil energy or something else.
Climate change and its effects are a result of air pollution by greenhouse gases (mainly carbon dioxide, methane, CFCs and water vapour). Climate change is under way and not stoppable. Carbon dioxide cannot be sequestered by human efforts, nor by nature within human time scales. (The Kyoto protocoll will not help since its mechanisms are technically not workable and its goals are far below the level that is required.)
What is our human time scale?
How sustainable are our socio-economic ways of living? How long can we carry on "business as usual"?