KEY TAKEAWAY
Sustainability is ability to maintain or support a process over time.

Definition
Sustainability is an important social objective that aims to provide humans with long term safe living. Specific sustainability concepts are hard to accept and therefore differ from literature and time. The concepts are suited for guiding decisions globally at a personal, national or international level such as sustainable living. In daily usage this term usually concentrates on environmental issues. During the last two decades, environmental problems have become major: climate change, loss of species diversity, loss of ecosystem services, degradation of forests and contaminated soils.
Modern use of the term “sustainability” was strongly influenced by the 1983 UN Commission on Environment and Development, also known as the Brundtland Commission. In the commission’s 1987 report titled Our Common Future (also known as the Brundtland Report), sustainable development is defined as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs.”
The report helped bring “sustainability” into the mainstream policy discourse and popularize the concept of “sustainable development”. In everyday usage of the term, “sustainability” is often focused mostly on the environmental aspects, as can be seen in publications by the United Nations Environment Programme (UNEP).
Types
There are three types of sustainability – environmental sustainability, social sustainability and financial sustainability.
Environmental sustainability concerns the biosphere and humanity coexisting. Usually we think of this is climate change, ecosystem collapse, ocean acidification, air pollution, and ozone depletion. On the solution side, the conceots that come to mind are renewable energy, protecting endangered species, reducing emissions, and recycling.
Social sustainability is about making our society work for everyone. This means maintaining a stable and peaceful global community of nations. The way we could achieve this is by ensuring everyone has access to healthcare, housing, and education.
Financial sustainability is about good fiscal stewardship. The approach to this is being prepared for economic recessions and investing money as a society with a long-term view. Reducing national debt and regulating financial industry is part of it.
As we see there are many definitions to the word. If we can continue basing sustainability in the three pillars of the environment, social and economic aspects we can get to the protection not only of our planet but also to our species and our development model.