The concept of sustainable development is intrinsically evolutive, and is adaptive to the circumstances according to the time, the area or the subjects concerned.3 Although it originated from international environmental law discourse, today it has evolved from the original meaning of sustainable use of natural resources, to a concept with more anthropocentric and socioeconomic substance.4 Despite the universal acceptance of this concept, whether and to what extent sustainable development could amount to a legal norm is not a settled issue.
The evolution of the concept of sustainable development
The international community noticed the close relationship between development and environment long ago. The concept of sustainable development was first incorporated in the global development agenda in the Brundtland Report in 1987.5 This landmark report contains a commonly accepted definition of sustainable development:
Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs. It contains within it two key concepts:
- the concept of âneedsâ, in particular the essential needs of the worldâs poor, to which overriding priority should be given; and
- the idea of limitations imposed by the state of technology and social organization on the environmentâs ability to meet present and future needs.6
Under this definition, sustainable development should be perceived as a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional change are all in harmony and enhance both current and future potential to meet human needs and aspirations.7
Global efforts for developing an effective legal regime to address sustainable development began in Rio de Janeiro, which marks the point at which sustainable development becomes a primary focus of the international agenda.8 Through its milestone documents, i.e. the Rio Declaration on Environment and Development (Rio Declaration)9 and Agenda 21,10 the United Nations Conference on Environment and Development (UNCED) has made sustainable development a âleading concept of international environmental policyâ.11
Until the 1990s, sustainable development was largely limited to the context of environmental law, aiming chiefly at addressing the potential incompatibility between economic development and environmental protection. Such an observation can be drawn from the Rio Declaration, which states that âIn order to achieve sustainable development, environmental protection shall constitute an integral part of the development process and cannot be considered in isolation from itâ.12
Though sustainable development has its origin in the environmental discourse, the scope of this concept is no longer limited to serve the needs of the environment.13 In 2002, the World Summit on Sustainable Development (WSSD) was held in Johannesburg, South Africa. The main outcome of the WSSD, the Johannesburg Declaration on Sustainable Development (Johannesburg Declaration),14 overlaps significantly with the Rio Declaration. Yet the main contribution of the WSSD to the sustainable development regime was adding a third pillar to the concept of sustainable development, i.e. along with environmental protection and economic development, social development became a recognized element of sustainable development.15 The Johannesburg Declaration expressly states that:
Accordingly, we assume a collective responsibility to advance and strengthen the interdependent and mutually reinforcing pillars of sustainable development â economic development, social development and environmental protection â at the local, national, regional and global levels.16
This statement is shared globally, and has been repeatedly cited in many international instruments, such as the 2005 World Summit Outcome.17
A more comprehensive understanding of sustainable development has been offered by the International Law Association (ILA) Committee of International Law on Sustainable Development. In 2002, the ILA Committee drafted the New Delhi Declaration of Principles of International Law Relating to Sustainable Development (New Delhi Declaration), which identifies seven related principles:
- The duty of states to ensure sustainable use of natural resources;
- The principle of equity and the eradication of poverty;
- The principle of common but differentiated responsibilities;
- The principle of the precautionary approach to human health, natural resources and ecosystems;
- The principle of public participation and access to information and justice;
- The principle of good governance;
- The principle of integration and interrelationship, in particular in relation to human rights and social, economic and environmental objectives.18
One may observe that the principles identified in the New Delhi Declaration in essence echo the various principles contained in the Rio Declaration and Johannesburg Declaration.19 Despite the enrichment of the concept of sustainable development, a clear definition of sustainable development remains missing.
Today, despite the universal recognition of sustainable development, the exact content of this concept remains unclear.20 The concept is often understood as a balancing paradigm. It has been suggested that the essence of this concept is to strike a balance of the different elements thereof, with the goal of the preservation of our ecosystems as the very basis of our existence and the achievement of the best possible world for all of humanity.21 Indeed, the New Delhi Declaration implies such a balancing paradigm by proposing the principle of integration and interrelationship of the elements. In judicial practice, such a balancing paradigm is also implied. As the ICJ Judge Weeramantry held in his separate opinion in GabÄĂkovo-Nagymaros, âthere is always the need to weigh considerations of development against environmental considerations, as their underlying juristic basesâthe right to development and the right to environmental protectionâare important principles of current international lawâ.22
Sustainable development as a legal norm
It has been proposed that sustainable development has become an established concept with normative status in international law,23 and forms a part of modern international law.24 Yet it is also argued that the status of sustainable development as a legal norm in the international law system remains largely uncertain.25 Partly for such reasons it has been argued that, although sustainable development has been on the international agenda for decades, difficulties persist in developing an effective regime to address it.26
In this respect, reference should be made to Article 38(1) of the ICJ Statute, which provides for sources of international law, according to which the binding sources of international law include international conventions, international customs and general principles of law. A legal norm becomes binding upon states as âhard lawâ if it forms a part of a treaty, a customary rule or a general principle of law. Thus, the legal status and binding force of sustainable development as a legal norm should be assessed within this system as well.
First, sustainable development has been widely incorporated in an increasing number of international treaties and other legal instruments in the past decades. While many of these treaties are IETs, some are in other fields, such as trade treaties. Some of these treaties are landmarks, such as the UN Convention on Biological Diversity of 1992 (CBD), the UN Framework Convention on Climate Change of 1992 (UNFCCC) and the Paris Agreement of 2015.27
The treatification of sustainable development may take two modes. One mode is to incorporate sustainable development in the treatyâs preamble, thus making it one of the treaty objectives. For instance, the Agreement Establishing the World Trade Organization (Marrakesh Agreement) provides in its preamble that:
Recognizing that their relations in the field of trade and economic endeavour should be conducted with a view to raising standards of living, ensuring full employment and a large and steadily growing volume of real income and effective demand, and expanding the production of and trade in goods and services, while allowing for the optimal use of the worldâs resources in accordance with the objective of sustainable development, seeking both to protect and preserve the environment and to enhance the means for doing so in a manner consistent with their respective needs and concerns at different levels of economic development.
A second mode is to incorporate sustainable development into the treatyâs functional provisions, which is often found in IETs. For instance, Article 3(4) of the UNFCCC provides that:
The Parties have a right to, and should, promote sustainable development. Policies and measures to protect the climate system against human-induced change should be appropriate for the specific conditions of each Party and should be integrated with national development programmes, taking into account that economic development is essential for adopting measures to ...
