The principle of Common but Differentiated Responsibility (CBDR) is one of the cornerstones of sustainable development. It has emerged as a principle of International Environmental Law and has been explicitly formulated in the context of the 1992 Rio Earth Summit. It finds its origins in equity considerations and equity principles in international law. It informs in particular the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol.
Principle 7 of the Rio Declaration provides the first formulation of the CBDR, and it states:
"In view of the different contributions to global environmental degradation, States have common but differentiated responsibilities. The developed countries acknowledge the responsibility that they bear in the international pursuit of sustainable development in view of the pressures their societies place on the global environment and of the technologies and financial resources they command."
The CBDR has two matrices. The first is the common responsibility, which arises from the concept of common heritage and common concern of humankind, and reflects the duty of States of equally sharing the burden of environmental protection for common resources; the second is the differentiated responsibility, which addresses substantive equality: unequal material, social and economic situations across States; different historical contributions to global environmental problems; and financial, technological and structural capacity to tackle those global problems. In this sense the principle establishes a conceptual framework for an equitable allocation of the costs of global environmental protection.
Particularly important is the relationship that the CBDR establishes between the past economic exploitation of global commons and the responsibility to carry out actions that remedy or mitigate the consequences of such exploitation. It anchors responsibility on past harm done, or culpability. Prior to Rio differentiated responsibilities were based on different capabilities and needs were often recognized in International Agreements through differential treatment provisions. The novelty of the CBDR is the emergence of the historical responsibility dimension. This aspect and the inequality of economic, social and institutional development conditions generate then different priorities and agendas across countries, which must be reconciled in the international forum where nations meet to tackle common environmental, economic and social issues. Another consequence of the principle is, for some scholars, that it entails a duty to participate in international efforts to address global environmental problems.
The CBDR can be said, in synthesis, to express the need to evaluate responsibility for the remediation or mitigation of environmental degradation based on both historical contribution to a given environmental problem and present capabilities: it is a guiding principle of international cooperation and solidarity.
As for the legal status of the principle, it is a generally recognized principle of International Environmental Law, as supported by growing evidence of State practice; however the belief that such practice is determined by a legal obligation (opinio iuris) is lacking in at least some members of the international community. Notably, the United States has issued an interpretative statement at the United Nations Conference on Environment and Development, stating as follows: "The United States understands and accepts that Principle 7, highlights the special leadership role of the developed countries, based on our industrial development, our experience with environmental protection policies and actions, and our wealth and technical expertise capabilities. The United States does not accept any interpretation of principle 7 that would imply a recognition or acceptance by the United States of any international obligations or liabilities, or any diminution in the responsibilities of developing countries". The same approach is shared by a number of other developed countries. This makes it difficult to configure the CBDR as a norm of customary international law.
Common but Differentiated Responsibility and Sustainable Development
The recognition of the importance of the inextricable links that tie the CBDR to all three pillars of sustainable development (environmental protection, economic development and social progress) brings forth the understanding that the historical responsibilities for environmental degradation are but one of a larger set of consequences stemming from an unequal distribution of the benefits deriving from the exploitation of natural resources along the North-South axis, and the second sentence of Principle 7 of the Rio Declaration clearly provides a normative framework in this respect: "The developed countries acknowledge the responsibility that they bear in the international pursuit of sustainable development in view of the pressures their societies place on the global environment and of the technologies and financial resources they command".
The International Law Association in its 2002 New Delhi Declaration of Principles of International Law Relating to Sustainable Development, maintains that the principle entails "a duty to co-operate in the achievement of global sustainable development," and requires the recognition of "the special needs and interests of developing countries and of countries with economies in transition," and those "affected adversely by environmental, social and developmental considerations."
Application of the principle in the Climate Regime
The practical consequences of the CBDR are that differential obligations are imposed on the parties to a Multilateral Environmental Agreement. The prime example is the Kyoto Protocol, where only countries listed in Annex I (developed countries and countries with economy in transition) have quantified emissions reduction obligations under the agreement. Additionally, the UNFCCC) and the Kyoto Protocol establish general obligations of cooperation towards technology transfer, and provide for financial assistance for mitigation and adaptation to developing countries through the Global Environmental Facility (GEF). The GEF operates two funds under the UNFCCC, the Special Climate Change Fund and the Least Developed Countries Fund; it also operates the Kyoto Protocol Adaptation Fund. These are all mechanisms aimed at operationalizing the CBDR.
The preamble of the UNFCCC acknowledges "that the global nature of climate change calls for the widest possible cooperation by all countries and their participation in an effective and appropriate international response, in accordance with their common but differentiated responsibilities and respective capabilities and their social and economic conditions". Article 3(1) of the Convention adds the leadership role that developed countries should take, and after reaffirming the principle of common but differentiated responsibility, it states that "the developed country Parties should take the lead in combating climate change and the adverse effects thereof."
- D. French, 2000. Developing States and International Environmental Law: The Importance of Differentiated Responsibilities. International and Comparative Law Quarterly, Volume 49, Number 1
- L. Rajamani, 2000. The Principle of Common but Differentiated Responsibility and the Balance of Commitments under the Climate Regime. Review of European Community and International Environmental Law (RECIEL), Volume 9, Number 2
- M.-C. Cordonier Segger, A. Khalfan, M. Gehring, & M. Toering, 2003. Prospects for Principles of International Sustainable Development Law after WSSD: Common but Differentiated Responsibilities, Precaution and Participation. Review of European Community and International Environmental Law (RECIEL) Volume 12, Number 3
- International Law Association, 2002 New Delhi Declaration on Principles of International Law Relating to Sustainable Development (London: ILA, 2002)