Sustainability is a state or condition that can be maintained over an indefinite period of time.
Sustainable Development, as defined by the World Commission on Environment and Development (the Brundtland Commission), is "the capacity to meet the needs of the present without compromising the ability of future generations to meet their own needs." Yes, I believe that we should try to achieve sustainability because with the unprecedented growth of the human population and technologies it has impacted on the environment.
The amount of human impact has steadily increased in scale. The evidence indicates that human activities now effect ecological cycles and the earth's ability to support living things.
While human impact has increased, scientific knowledge and public awareness of the environment and our dependence on it have increased as well. The more interest in sustainability the more the understanding.
History shows that society has dealt with environmental problems in a reactive way. For example species that were disappearing were protected after the population got to critical levels and then threatened by extinction.
Water quality policies were introduced after some rivers were so polluted that fish and aquatic life died.
Still, we have achieved allot of success in resolving many local and regional environmental problems by using scientific knowledge and technological tools on a case-by-case basis. For example in my field of work, Civil engineering, the introduction of GPT (Gross Pollutent Traps) for the discharge of stormwater into our waterways has been implemented by most Council's.
However in the 80's & 90's brought to light environmental problems in a global scale, climate change, ozone depletion and loss of biodiversity.
Many policy makers now acknowledge that a more comprehensive, integrated, long-term approach is needed. Thinking in terms of sustainability may be an important part of this approach.
Another factor, which has affected people to think in terms of sustainability, is the growing awareness that environmental problems are often linked to social and economic problems.
Some people may think that the depletion of our natural resources is not a major concern. They believe that before the particular resource runs out we would have found an alternative. For example the use of coal/coke to heat homes is not widely used anymore as we have alternatives ways to do so. Maybe instead of fossil fuel to power our cars we might have invented a more efficient way of harnessing the solar energy to power them. But I think we don't won't to take that chance.
The extreme pressure on our ecosystem in the last few decades has resulted from the doubling of our global population, quintupling of world economic output, and extreme disparities in income distribution (Postel 1994). It would seem that there are three potential scenarios – unrestricted growth of population and economy, limitations on growth imposed by natural systems, or a self-imposed limit to growth (Meadows et al. 1972). Realistically, only the latter two scenarios are possible, and the last is the most desirable by far. Sustainability is about establishing self-imposed limits to growth and finding a self-imposed state of balance Just as human decisions affect the environment at many levels, so too the need for sustainability exists at many levels. Even with agreement that sustainability is a priority, there may be disagreement on the methods or practices that best stimulate movement toward the goal. Different factions within a community, different engineers or managers within a corporation, or different political leaders at the national or international level may have very different ideas about what policies will make a community, company, nation, or the world more environmentally, economically, and socially sustainable. And ideas about how sustainability can be achieved are sure to continue to evolve.
In summary, the concept of sustainability implies working toward a balance between the needs of all people, present and future, and the needs of the environment, in part because the environment is the source that provides for all human needs.