Sustainability extends justice into the future. Sustainability can be defined as meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. Humans are consuming or degrading many resources (such as fossil fuel energy, topsoil, and water) today faster than they can be naturally replenished, which means they will not be available to people in the future. The ethical principle of justice is at play because it underpins the need to equitably balance the needs of those alive today (the rich and poor) with future generations. Thus, environmental ethics takes the notion of fundamental fairness and stretches it to include those yet to be born. To apply the principle of sustainability to an environmental decision, humans should ask:
1. What are the immediate and long-term effects of the problem before us?
2. Who - humans and otherwise - is affected today by the problem before us and who will likely be affected by this problem in the future?