Sustainable development involves two main concepts: the needs of the world's human population and the limitations involved with meeting those needs. Limitations can involve any factors that make it difficult to meet the needs of the world's population. For instance, insufficient technology, excessive government regulation and scarcity of natural resources all limit the global population's ability to meet its needs.
Sustainable development is a set of ideas and methods that seek to continue the progress and advancement of humanity, while at the same time ensuring that future generations inherit a planet able to support them. Because of this, proponents of sustainable development suggest a view of global development as a vast, interconnected system, rather than a patchwork of many different nations responsible solely for their own development.
This systematic view of development stems from the fact that one nation's actions, for better or worse, have repercussions not just in that nation, but around the world. For instance, reforestation in Brazil improves air quality for the entire planet, because air currents eventually travel around the world. For the same reason, pollution generated within the United States or China can have the opposite affect on global air quality.
While many global problems were created by nations and organizations that held an individualist view, proponents of social development claim that the same sort of view cannot solve these problems. Because modern global issues are systematic, resolving them requires systematic thinking and action.