As defined in the 1987 Brundtland Report, which is now one of the most widely recognised definitions:
"Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs".
The definition contains two key concepts within it:
- The concept of needs, and in particular the essential needs of the world's poor, to which overriding priority should be given; and
- the idea of limitations imposed by the state of technology and social organisation on the environment's ability to meet the present and future needs.
Sustainable development can essentially be broken into three components: environmental sustainability, economic sustainability and socio-political sustainability.
Environmental sustainability is about ensuring the process of keeping the environment is as close to ideal-seeking behaviour as possible.
Economic sustainability describes the ability of an economy to support a defined level of economic production indefinitely.
Socio-political sustainability is based on the thought that human needs cannot be sufficiently met just by providing an ecologically stable and healthy environment, but that legitimate social and cultural needs ought to be taken care of as well.
Sustainability can be viewed as a process of a development of all aspects of human life affecting sustenance. It relates to resolving the conflict between various competing goals and involves the parallel pursuit of economic prosperity, environmental quality and social equity, which as three dimensions is known as the triple bottom line. It is a continually evolving process as the destination of sustainability is not fixed, but is instead a set of wishful characteristics.
An unsustainable situation occurs when natural resources are used up faster than they can be replenished, whereas sustainability requires that human activity only uses natures resources as quickly as they can be replaced naturally. Theoretically, the long-term result of environmental degradation is the inability to sustain human life. Such degradation on a global scale could imply extinction for humanity.
During the last 15 years, different organisations have tried to measure and monitor what they consider to be sustainability by implementing metrics and indices.
Green development can be differentiated from sustainable development in that Green development prioritises the first component environmental sustainability over economic and cultural/social considerations. Some argue therefore that cutting-edge green development is unattainable as it does not allow for the fact that the environment is a combination of nature and culture.