The most serious challenge before states today is pursuing economic development without causing further damage to the global environment. The 1987 Brundtland Report, titled 'Our Common Future', warned that traditional patterns of economic growth were not sustainable in the long term, especially considering the demands of the global South for further industrial development.

To achieve this balance, the Rio Declaration established that states shall cooperate in the spirit of global partnership to conserve, protect and restore the Earth's ecosystem. The key principle adopted was that of 'common but differentiated responsibilities'. This means that while all states share responsibility for environmental protection, the developed countries must bear greater responsibility due to the pressures their societies place on the global environment and the technological and financial resources they command.

The developing countries of the global South argue that much of the ecological degradation is the product of industrial development undertaken by the developed countries of the global North. Therefore, they must not be subjected to the same restrictions that apply to developed countries, as they are still in the process of industrialisation. Their special needs must be taken into account in the development and application of international environmental law.

Thus, achieving sustainable development requires compromise and accommodation between the North and South, where developed countries take greater responsibility for undoing environmental damage while allowing developing countries to pursue their developmental goals with appropriate support and flexibility.