International Environmental Law

Author: Abbas Poorhashemi

Required knowledge: Public International Law

Learning objectives: This chapter book aims to discuss and present the essential elements of the foundation and emergence of international environmental law as a new branch of international public law. Furthermore, it tries to provide some knowledge of the sources and principles of international environmental law.  Environmental challenges such as climate change, desertification, air pollution and sea pollution are amongst the most urgent that requires an immediate and collective response from the international community. Understanding the opportunities and challenges facing the international community is crucial for the future development of international environmental law.

A. Emergence of International Environmental Law

Some sources define “Environment” as the air, water, and land in or around which people, animals, and plants live. The environment is a balanced set of biotic and abiotic elements that surround a body and can interact with it. The concept of “environment” includes (but is not limited to) spaces, resources, natural land and marine environments, sites, day and night landscapes, air quality, living beings and biodiversity, biological processes, soils and geodiversity.

International Environmental Law as a new branch of public international law, emerged in the 1970 decades. Hence, environmental protection has become a significant concern and preoccupation of the international community. Climate change, air pollution, lack of safe drinking water, hazardous wastes, soil erosion, loss of biodiversity as well as noise and light pollution are the global challenges of humanity. To respond to these environmental challenges and problems, the international community has recognized that environmental protection must be addressed holistically and expansively. Moreover, the international community has become aware that local issues cannot be separated from national, regional, or even global conditions. There are various definitions of "International environmental law". According to the definition given by Alexander Kiss and Dina Shelton, international environmental law is one of the newest branches of public international law, which aims to protect the environment. Some also define international environmental law as "a set of rules of international law which the purpose is to prevent environmental pollution and to protect the environment." While the above definitions are positive, they are not exhaustive. It may seem that “International environmental law” is a body of international law concerned with protecting the global environment by applying legal norms and regulations that address transboundary, regional, or global environmental issues.

Since the United Nations Conference on the Environment in Stockholm in 1972, environmental protection has been the subject of several treaties and declarations which illustrate the willingness of the international community to protect the environment, encourage sustainable development and attenuate the imbalance between North and South. These conventions accepted and ratified by the States could be considered global responses to contemporary environmental problems. Moreover, international environmental treaties unite developed and developing countries by ensuring that developed countries “assume their historical responsibility” for global environmental degradation.

Some of the leading environmental conventions are:  

-    Climate change: Vienna Convention for the Protection of the Ozone Layer (1985), Montreal Protocol (1987), United Nations Framework Convention on Climate Change (UNFCCC) (1992), Kyoto Protocol (1997) and 2015 Paris Agreement on climate change.

-    Environmental Accidents and Civil Protection: Helsinki Convention on Industrial Accidents (1992), Barcelona Convention (1976), Helsinki Convention on the Baltic Sea (1992), OSPAR Convention (1992), Bonn Agreement (1983), Lisbon Agreement (1990), Convention on the Protection of the Black Sea Against Pollution, Bucharest, (1992), Helsinki Convention on Industrial Accidents (1992).

-    Biotechnology and Chemicals: Cartagena Biosafety Protocol (2000), Stockholm Convention on Persistent Organic Pollutants (2001), Rio Convention on Biological Diversity (1992) and its Supplementary Protocol on Liability and Redress (2010), Rotterdam Convention on Prior Informed Consent (1998), Minamata Convention on Mercury (2013).

-    Human rights and environment: Aarhus Convention on access to information, public participation in decision making and access to justice in environmental matters(1998),Protocol on Pollutant Release and Transfer Registers (2009), and the Espoo Convention on Environmental Impact Assessment (1991).

-    Biodiversity: Convention on Wetlands of International Importance, Ramsar, (1971), Convention on International Trade in Endangered Species of Wild Fauna and Flora, (known as CITES Convention) (1973), Bonn Convention on the Conservation of Migratory Species CMS (1979), Convention for the protection of vertebrate animals used for experimental and other scientific purposes (1986),Bern Convention on European Wildlife and Habitats (1979), Convention on Biological Diversity CBD (1992), International Tropical Timber Agreement (ITTA) (1994), Agreement on the conservation of African-Eurasian Migratory Waterbirds (AEWA-CMS) (1995), Alpine Convention (1991), Cartagena Protocol on Biosafety (2003), Convention for the Conservation of Antarctic Marine Living Resources (1980), Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of the Benefits arising from their Utilization, Nagoya (2010) and Agreement on the Protection and Sustainable Development of the Prespa Park Area (2010).

-    Water protection: Barcelona Convention (1976) and its protocols, Bonn Agreement (1983), Danube river basin convention (1987), Helsinki Convention on Watercourses and International Lakes (1992), OSPAR Convention (1992), Convention on the Protection of the Black Sea Against Pollution, Bucharest (1992), Helsinki Convention on the Baltic Sea (1992), Rhine river basin convention (1999).

Some of the non-binding international instruments to protect the global environment are the United Nations Conference on the Human Environment, 5-16 June 1972, Stockholm, the World Charter for Nature of 1982, Rio Declaration on Environment and Development (1992), Agenda 21 UNCED, 1992,  United Nations Millennium Development Goals (2000), Johannesburg Declaration (2002), Rio+20 Declaration (2012), the 2030 Agenda for Sustainable Development (2015) and the 17 Sustainable Development Goals (SDGs).

Although these conventions have been signed, accepted and ratified by the majority of the States, the commitments made by the States seem minimalist and insufficient concerning the gravity of problems and challenges facing the development of international environmental law.

B. Generations of International Environmental Law

International environmental law is developing as one of the branches of public international law. Although the conservation of some species of animals and plants dates back to the pre-1970s, the basis for the formation of international environmental law, in its modern concept, is the Stockholm Declaration of the United Nations Conference on the Human Environment in 1972. In general, international environmental law is historically divided into three periods:

First generation: before the formation of international environmental law until the 1972 Stockholm Conference

The first generation began mainly in the 18th century with the signing of especially bilateral agreements in the field of fisheries and marine life resources. Its expansion to other fields, including wildlife, rare and endangered plants and animal species, continued into the early twentieth century. The most important feature of this historical period is its regionality and the creation of contractual obligations between states to protect a particular region or species. The 1960s, generally known as the decade of student movements (the women's movement, the environmental movement, and the postmodern movement), marked a turning point in the destructive process of modernity and addressed many fundamental issues, including environmental matters. Subsequently, environmental activists and scientists declared that if industrial progress continued the same way, the world would be destroyed. As a result, by the end of the decade and the beginning of the 1970s, the states were forced to hold the Stockholm Conference of 1972. The Stockholm Conference of 1972 recognizes the right of development to be closely linked to the environment by identifying the right to a healthy environment as a fundamental human right. Furthermore, by considering the establishment of international institutions, it integrated the process of global cooperation in the field of the environment. It provided the direction for the further development and evolution of the relevant international rules to protect the global environment.

Second generation: from the Stockholm Conference 1972 until the Rio Conference 1992

According to the recommendation of the United Nations General Assembly, the International Conference on the Protection of the Environment was held from 5 to 16 June 1972 in Stockholm. The Stockholm Conference was a significant international conference in which more than 6,000 people represented 113 countries, and about the same number of representatives of international organizations and 700 observers. Delegations from 400 international non-governmental organizations participated. The purpose of this conference was to pay attention to the world's environmental issues and their relationship with human rights, as well as to warn of the harmful effects of human activities on the environment.

The Stockholm Declaration of 1972 contained 26 principles. According to the declaration, environmental issues should be at the forefront of international concerns and marked the start of a dialogue between developed and developing countries on the link between economic growth, the pollution of the air, water, and oceans and the well-being of people around the world. In addition, the Action Plan contained three main categories: a) Global Environmental Assessment Programme (watch plan); b) Environmental management activities, and (c) International measures to support assessment and management activities carried out at the national and international levels. In addition, these categories were broken down into 109 recommendations.Another important outcome of the conference was the establishment of an international body called the United Nations Environment Program (UNEP). UNEP is a United Nations-affiliated environmental protection program that has been one of the most important pillars of environmental protection in the world. One of the important tasks of UNEP is the Global Environmental Assessment, which publishes a collection annually that describes the state of the world's environment. UNEP is also coordinating and managing the world's environmental protection in cooperation with the states worldwide. According to this mandate, UNEP does not have the right to directly interfere in the environmental issues of other states, but all UNEP actions are carried out with the cooperation and participation of governments at the regional and global levels. This means that the United Nations allocates funds and credits to protect the environment of countries so that these countries can take the necessary measures to protect their environment. The Stockholm Declaration has strongly influenced the further development of International Environmental Law.

In addition, in this generation, several international treaties, bilateral and multilateral, were signed, adopted and ratified by the States. This generation's normative and structural evolution has strongly influenced the further development of International Environmental Law.

Third generation: from the Rio Conference 1992 until the present

The third generation of International Environmental Law begins with the 1992 Rio Conference on Environment and Development. The UN General Assembly approved holding an international conference on the environment and development. Accordingly, the Conference's preparatory committee was formed with the active participation of representatives of all member states and representatives of international organizations, both governmental and non-governmental. Subsequently, the United Nations Conference on Environment and Development was held on June 3, 1992, in Rio de Janeiro, Brazil, with the participation of more than 30,000 people from 176 countries, including 116 heads of state and representatives of 1,400 international non-governmental organizations working in the field of environment. In addition, the 1992 United Nations Framework Convention on Climate Change (UNFCC) and the Convention on Biological Diversity (CBD), drafted before the Conference, were opened in Rio for signature. Discussing the issue of the environment as a global problem, the Rio Conference stressed the need to coordinate the development process of countries with the protection of the environment and introduced environmental protection as an essential international issue for the next century. The proposal to establish international environmental regulations to achieve sustainable development marked a new turning point in the process of developing international environmental law. In addition, the Conference strengthened existing institutions and created new ones to coordinate further the international community's efforts to protect the environment within the framework of international institutions. Finally, the Rio 1992 Conference concluded with the adoption of three non-binding instruments, including the Conference Final Statement as a Rio Declaration (one introduction and twenty-seven principles), Agenda 21 (Charter for the Future) and the Principles of Forest Conservation.

The Rio 1992 Declaration affirms that States should always be concerned with the environmental preoccupations in economic development and industrial growth. They should consider sustainable development as an approach in their national development plans. The States should consider the "principle of sustainable development" in the formulation of programmatic and ordinary laws, as well as in the drafting of bilateral or multilateral binding instruments. They should recognize the role of social groups and non-governmental organizations in protecting the national, regional, and global environment.

Another development of international environmental law in this period is the organization of the World Summit on Sustainable Development taking place from 26 August to 4 September 2002 in Johannesburg. The Conference announced the eight Millennium Development Goals for development, including eradicating poverty and hunger, achieving universal primary education, promoting gender equality, women's empowerment, reducing child mortality, improving mothers' status, Fighting against AIDS, malaria, and other diseases. The eight Millennium Development Goals for development are:

1. to eliminate extreme poverty and hunger;

2. to achieve global primary education;

3. to empower women and promote gender equality;

4. to reduce child mortality;

5. to promote maternal health;

6. to fight malaria, HIV/AIDS, and other diseases;

7. to promote environmental sustainability; and

8. to develop a universal partnership for development.

Twenty years after the Earth Summit on Development and the Environment in Rio in 1992, and ten years after the Sustainable Development Conference in Johannesburg, the Rio + 20 Conference in Brazil is an essential step towards consolidating sustainability and environmental protection. It is the background of economic, social and environmental development. Therefore, the international community met again on June 20-22, 2012, in Rio de Janeiro to review the 20-year achievements of the Rio Conference in the direction of sustainable development and the prospects of the agreed programs. The Rio + 20 Conference, while emphasizing the commitments made at the Rio Conference of 1992, known as Agenda 21, seeks to introduce a new type of engagement in which business, governments and civil society are vital leaders for the protection of the global environment.

The Rio + 20 conference was a new opportunity for the international community address through deliberations existing barriers to the development of international environmental law. For example, one of the most significant steps toward achieve sustainable development in the last decade (from Johannesburg 2002 to Rio 2012) was identifying the causes of recession and economic crisis in the previous decade and combining economic issues with environmental criteria.

Another remarkable event in this period is the 2030 Agenda for Sustainable Development. The purpose of this Agenda is a plan of action for sustainable development strengthening universal peace, eradicating poverty. The 17 Sustainable Development Goals and 169 targets demonstrate the scale and ambition of this new universal Agenda. It seeks to build on the Millennium Development Goals and complete what these did not achieve. It aims to realize the human rights of all and achieve gender equality and the empowerment of all women and girls. The Agenda create a balance between the three dimensions of sustainable development: the economic, social and environmental.

Therefore, the third period of the process of development of international environmental law could be called the period of realism, universalism, reforms. During this period, international environmental rules and regulations have evolved within the concept of sustainable development and, if necessary, have been amended to be in line with global realities and to be enforceable in practice, as well as to form new rules and regulations.

The United Nations Human Rights Council, on October 8, 2021, adopted a resolution recognizing the human right to a clean, healthy and sustainable environment as an essential human right. While this right is already recognized in more than 150 national jurisdictions, its international recognition paves the way for its effective incorporation into international law and strengthened implementation at the national and international levels.

C. Principles of International Environmental Law

Principles of international environmental law are the basic ideas for the development of this field of law. They are general in nature, applicable to all relevant actors, and environmental protection around the world. Some of them are enshrined in the multilateral environmental agreements, and in this case, they obtain clear meaning for the specific international environmental regime. However, even if a treaty does not explicitly recognize a principle in its text, the principle still can play a role in the interpretation and development of the treaty. General environmental principles also can supplement specific rules and express gap-filling functions. International environmental law is generally based on legal principles affirmed in many declarations (soft law) and included in several conventions (hard law). These principles are very numerous and have continued to develop in recent years. But some of them are important to be mentioned here:

I. Principle of sovereignty over natural resources and responsibility not to cause transboundary environmental damage

In the classical approach of public international law, the concept of sovereignty was based on independence and equal sovereignty with other states, which is interpreted as an "absolute sovereignty" of the state. In this perspective, the state's power is supreme, unlimited and non-subordinate. However, with the development of international environmental law, the sovereignty of states is reduced. States, in some cases, in favor of international order, accepted some restrictions on their sovereignty. From the twentieth century, the international community, based on the restriction of the national sovereignty of states, recognized a set of international rules such as human rights, environmental law and other international regulations limiting states' sovereignty.

The principle of sovereignty is one of the basic principles of international environmental law. In public international law, the principle of sovereignty is based on customary law. In the Trail smelter case (United States v. Canada) of 16 April 1938 and 11 March 1941, the Tribunal found that "under the principles of international law, as well as of the law of the United States, no State has the right to use or permit the use of its territory in such a manner as to cause injury by fumes in or to the territory of another or the properties or persons therein, when the case is of serious consequence, and the injury is established by clear and convincing evidence."

This principle is also affirmed in Principle  21 of the 1972 Stockholm Declaration, according to which "States have, in accordance with the Charter of the United Nations and the principles of international law, the sovereign right to exploit their own resources pursuant to their own environmental policies, and the responsibility to ensure that activities within their jurisdiction or control do not cause damage to the environment of other States or of areas beyond the limits of national jurisdiction"

Moreover, the sovereignty of states has two bases; one is to recognize the sovereignty of states in the use of their natural resources, and the other is not to cause harm to other territories under the control of other states or areas that are not under the control of states, such as the high seas. The turning point in the principle of sovereignty is in Article 21 of the 1972 Stockholm Declaration, which, with a slight modification, was contained in the second principle of the Rio 1992 Declaration, which states: " States have, in accordance with the Charter of the United Nations and the principles of international law, the sovereign right to exploit their own resources pursuant to their own environmental and developmental policies, and the responsibility to ensure that activities within their jurisdiction or control do not cause damage to the environment of other States or of areas beyond the limits of national jurisdiction."

The evolution of the concept of "sovereignty" in international environmental law demonstrates that States have the freedom to use their territory. Still, at the same time, they have obligations under which their activities should not harm other countries or regions beyond the limits of their sovereignty. The principle of sovereignty obligates all States to preserve and protect the environment in its entirety, both for States on their territory and areas outside any national jurisdiction, such as the high seas, Antarctica or outer space.

II. Principle of cooperation

The principle of cooperation is a customary international obligation and one of the inseparable principles of the Charter of the United Nations. It is one of the features of contemporary international law. The principle of cooperation is binding in accordance with the Charter of the United Nations. Given its transnational nature, this principle is more necessary in international environmental law because the environment has no border.

Protection of the global environment is beyond the capacity of one or more States. It requires the international community's cooperation to prevent, reduce, and eliminate the harmful effects of environmental degradation and pollution. According to this principle, States have a duty to work together in all circumstances and in good faith to protect the environment. International cooperation could be considered in various fields such as information exchange, technology transfer, financial resources, participation in international conferences, and even emergency assistance through bilateral or multilateral agreements. Although each sovereign state is free to conduct its external relations according to what it considers to be its best interests, modern international law has developed a general obligation to cooperate with others to resolve problems that concern the international community as a whole.

The obligation of cooperating in environmental issues arises from the very existence of general public international law. More than a thousand international treaties recognize the need to collaborate with other states at different levels: bilateral, regional or global. In this context, the creation of numerous international organizations also corresponds to the need for institutional cooperation in environmental protection. International conventions or treaties constitute the most effective instrument for international cooperation, mainly because their content is mandatory under the principle of  Pacta sunt servanda recalled in Article 26 of the Convention of Vienna of 1969 on the law of treaties.

In addition to the general obligation of United Nations member states to cooperate in good faith with the organization and among themselves, the particular need to cooperate to preserve the environment is expressed in several legal instruments, including the soft law. Moreover, cooperation in international environmental law most often emerges in the context of international organizations, whether they already exist or are created for a particular environmental issue or sector.

Finally, due to the transboundary nature of the environment, states are obliged to cooperate in all circumstances in good faith to protect the environment.

III. Principle of Sustainable development

Since the late 1980s, the term sustainable development has dominated environmental law and policy. In 1987, the World Commission on Environment and Development (WCED) published the «Our common future» report. The Brundtland Report stated that critical global environmental problems were primarily the result of the enormous poverty of the South and the non-sustainable patterns of consumption and production in the North. It called for a strategy that united development and the environment – described by the now common and widespread term «sustainable development.» Sustainable development is defined as follows: «Sustainable development is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs.» In 1989, the UN General Assembly debated the Report, which decided to organize a UN Conference on Environment and Development. The sustainable development principle presupposes that development policies should aim to eradicate poverty, improve economic, social and cultural conditions, preserve biological diversity, essential ecological processes, and life-sustaining systems. In addition, environmental conservation should be considered an integral part of the planning and carrying out of activities at all stages.

According to the principle, States should review national policies and plans for environment and development to enact effective laws and regulations that use economic instruments where appropriate and establish and strengthen institutional structures and procedures to integrate environmental and development issues into all decision-making spheres fully. In addition, the integration of environmental, social and economic policies also requires transparency and broad public participation in decision-making by the authorities.

The principle of sustainable development is confirmed in many international legal instruments, including the Rio Declaration of 1992. The concept of sustainable development is an evolutionary process that meets the current generation's needs without diminishing the ability of the next generation to meet their needs, in other words, to provide an opportunity for everyone to live forever on the planet. Today, sustainable development is one of the most fundamental issues of international environmental law. Without a doubt, it can be named the primary goal of the development of international environmental law.

However, the implementation of sustainable development confronted some challenges in its forms and contents. In terms of content, it lacks a comprehensive approach for including indigenous people, local cultures, good governance, consuming resources, producing goods and services, freedom of expression, employment, identifying the roots of poverty and gender discrimination.

The principle of sustainable development is a framework for economic, social, and environmental progress that seeks to meet the needs of the present without compromising the ability of future generations to meet their own needs. This principle recognizes that the long-term health and prosperity of society depend on balancing economic, social, and environmental factors, and it emphasizes the importance of responsible resource management, conservation, and equity. In this regard, Sustainable development is based on the fact any development should meet the needs of the present without compromising the ability of future generations to meet their own needs.

The three-pillar conception of sustainability (social, economic and environmental), usually represented by three intersecting circles with overall sustainability at the center, has become ubiquitous. However, some research finds that there is no single point of origin for this three-pillar conception but rather a gradual emergence of various critiques in the early academic literature of the economic status quo from the point of view. Moreover, conceptualizing the three pillars of Sustainable development is complicated in international environmental law. Nevertheless, there is a  theoretically rigorous description of the three pillars of sustainable development.

Sustainable development is based on principles such as “environmental protection” to protect ecosystems and natural resources for future generations. Secondly is based on the “precautionary approach,” which is crucial to anticipate and avoid potential environmental, economic, and social risks before they become a problem. Thirdly, it relies on “economic growth” to encourage equitable and sustainable economic development. It is crucial that economic activities not compromise the ability of future generations to meet their economic needs. Fourthly, Sustainable development depends on “social equity,” which could promote a fair and just society where all individuals have access to basic human needs such as food, water, shelter, education, and health care. Finally, it counts on “participatory decision-making”. This will assist in involving all stakeholders in the decision-making process to ensure their perspectives and concerns are considered.

Finally, the principle of sustainable development emphasizes the importance of balancing economic, social, and environmental factors in all decision-making to ensure we can create a prosperous and sustainable future for ourselves and future generations.

IV. Principle of prevention

The prevention of environmental degradation and pollution is regarded as the "golden rule" in international environmental law based on economic and ecological reasons. For instance, extinction of plant or animal species, soil erosion, loss of human life and leakage of pollutants into the sea create irreparable damage in a way that, even when the damage can be compensated, restoring them to their previous state is not possible. The Prevention Principle in International Environmental Law is to prevent national and transboundary harm due to the activities of the state. Often recognized as a part of the precautionary approach or sustainable development, the prevention principle deserves more attention and investigation to clarify states’ duty and to ensure definitional clarity to other entwined norms in environmental law.

This principle forms the basis of many international environmental agreements and conventions, such as the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal (1989). The principle aims to minimize hazardous waste generation and combat illegal dumping. Many environmental laws are designed to respond to disasters, but preventing damage to the environment is cheaper and easier than replying to damage that has already occurred, and the environmental impact is less. The principle is the rationale behind international and national regulations governing the climate change, transport, treatment, storage and disposal of hazardous wastes.

V. Precautionary Principle

This principle imposes a duty on states to prevent environmental damage.  Under this rule, a state may be obligated to take precautionary measures to prevent damage within its jurisdiction. The number of international environmental treaties confirms this duty of stats. In this perspective, Article 3 of the United Nations Framework Convention on Climate Change (UNFCC) states that: “The Parties should take precautionary measures to anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects. Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing such measures, taking into account that policies and measures to deal with climate change should be cost-effective so as to ensure global benefits at the lowest possible cost”.

The precautionary principle applies when there is uncertainty about the risk of environmental harm. This principle allows or requires protective measures to be taken without waiting until the harm materializes. So, it deals with potential environmental damage and serves as a tool to bridge uncertain scientific information and political responsibility. The principle has been applied globally to guide policy on issues such as chemicals and food safety, air quality or climate change. According to the EU law, it tends towards strict precaution and follows the “better safe than sorry” approach. In this regard, the EU’s environmental policies are based on a strict application of the precautionary principle, making them the most restrictive ones globally.

VI. Principle of notification

This principle is one of the basic principles that can be traced back to the International Court of Justice from the 1949 Corfu Strait case and other international sources such as environmental treaties and agreements. According to this principle, States have an obligation to notify other states in case of transboundary damages. There are also some other principles and concepts, such as the common heritage of humanity in international law and the rights of future generations. This obligation is primarily related to international cooperation based on a system of information and prior consultation and notification to achieve optimum use of natural resources without causing damage to the legitimate interests of other states. According to this principle, prior notice obligates acting States to provide timely notification and relevant information to every state that may be adversely affected by its environmental activities. states shall immediately notify other States of any natural disasters or other emergencies likely to produce transboundary effects. In addition, notification is fundamental when there is a nuclear accident and transboundary pollution.  

VII. Polluter-pays Principle

The Polluter-pays Principle (PPP) is set out in many national and international regulations. According to this principle, polluters must bear the costs resulting from measures to prevent, reduce and fight pollution. This principle was adopted by the Organization for Economic Co-operation and Development (OECD) in 1972 as an economic principle for allocating the costs associated with pollution control. This is one of the essential principles underlying environmental policies in developed and developing countries. The Declaration of the United Nations Conference on Environment and Development in 1992 recognized this principle as one of the twenty-seven guiding principles for future sustainable development. According to principle 16 of the declaration: “ National authorities should endeavor to promote the internalization of environmental costs and the use of economic instruments, taking into account the approach that the polluter should, in principle, bear the cost of pollution, with due regard to the public interest and without distorting international trade and investment”.

The objective of the polluter pays principle is to reduce and control the impact of human activity on the environment by promoting non-polluting activities. It means that polluters must bear the expenses relating to preventing this pollution. The international community recognized the principle in many recommendations and international treaties. The PPP is an internationally recognized environmental principle that influences the development and environmental policy at national and international levels. This principle is developed from political slogans to legal rules. In fact, the principle’s scope has expanded in recent years. Initially, it only concerned the costs of preventing and combating pollution. Then, the principle is extended to the costs of measures taken by the authorities due to pollutant emissions. Finally, it rose to environmental liability.

VIII. Principle of Common but differentiated responsibilities (CBDR)

The Principle of Common but differentiated responsibilities (CBDR) is one of the crucial principles of international environmental law. According to the principle, all States are responsible for protecting the environment but with different types of responsibilities. Developed countries have a more significant burden due to their historical contributions to environmental degradation. As a result, they should assist developing countries with transferring new technologies and supporting them financially.

According to Principle 7 of the 1992 Rio Declaration, States should cooperate in a spirit of partnership to conserve, protect and restore the health and integrity of the Earth's ecosystem. Given the diversity of roles played in global environmental degradation, States have common but differentiated responsibilities. Developed countries recognize their responsibility in the international effort to promote sustainable development, given their societies' pressures on the global environment and the technologies and financial resources at their disposal.

One of the first legal instrument (Hard Law) which elaborate this principle is the 1992 United Nations Framework Convention on Climate Change (UNFCCC). According to this document, the Principle of Common but differentiated responsibilities is as a pathway to balance the shared responsibility of all States to address climate change. Based on this convention,  developed countries are historically responsible for greenhouse gas emissions. The principle recognizes that developed countries have benefited from exploiting natural resources and using fossil fuels, resulting in a disproportionate share of greenhouse gas emissions in the atmosphere.

This principle explains the differentiation between States by their unequal contribution to environmental degradation, on the one hand, and by the recognition that accounts must be taken of their respective economic situation, on the other. In this perspective, the principle was later included in the 1997 Kyoto Protocol , which sets binding emission reduction targets for developed countries. Based on the Kyoto Protocol, developed countries are responsible for reducing their greenhouse gas emissions by an average of 5% below 1990 levels over the period 2008-2012. In contrast, developing countries were not subject to binding emissions reduction targets but were expected to take voluntary actions to address climate change.

This principle provides a pathway to balance the shared responsibility of all nations for addressing environmental issues with the recognition of historical commitment and capacity.

D. Sources of International Environmental Law

International environmental law borrows traditional sources from public international law. Thus, Article 38 of the Statute of the International Court of Justice indicates the different possible sources of public international law applicable to international environmental law. However, these sources are not limited to traditional sources of public international law. Therefore, to better understand the sources of international environmental law, it could be discussed at two different types of non-binding (soft) and binding (hard) sources:

I. Hard Law

Hard law is a binding law that imposes obligatory rules and regulations on governments to take international responsibility in environmental issues. Therefore, it is essential to consider that the sources of international environmental law go beyond public international law.

Although the traditional sources of public international law apply to international environmental law, as mentioned in article 38 of the Statute of the International Court of Justice, the other sources also apply here, such as Jus Cogens rules (Peremptory norms of general international law) , Erga Omnes obligations and obligatory resolutions of international organizations. However, International Environmental Treaties, including Multilateral Environmental Agreements (MEAs) and Bilateral Environmental Agreements (BEAs), are crucial for international environmental law's current and future development. This source of Hard Law aims to provide a binding legal instrument to protect the environment. Therefore, international environmental law treaties have unique characteristics compared to public international law. First, many environmental treaties aim to create a permanent structure to expand cooperation between the member states by building institutional organizations or referring to an existing international organization. Secondly, environmental treaties include executive mechanisms to implement and monitor the execution of the agreements. In addition, international environmental law treaties generally possess dispositive regarding amendment and revision.

The convention-framework system is one of the unique features of international environmental treaties. This mechanism is usually about the general treaties that the States want to compile their principles and general obligations in a legal text under the convention's name and subsequently sign and approve other legal documents or texts in line with the convention's goals. This type of text is called a protocol. Convention framework exists in international environmental law more than public international law. The contracting parties reach an agreement, but the agreement details depend on future contracts negotiated and accepted under the protocol.

In addition, another source of international environmental law is the “international customary law”. Even with the multiplication of international treaties, customary law remains crucial in this branch of law. Customary law is an unwritten rule binding on states in most circumstances and is established through repeated behaviour between states. It refers to: “international obligations arising from established international practice, as opposed to obligations arising from formal written conventions and treaties. Customary international law results from a general and consistent practice of states they follow by accepting legal obligations. In this context, the obligation to prevent transboundary harm and the “duty to prevent” can be considered examples of “Customary law.

II. Soft Law

According to some research, the concept of "Soft" law is a paradoxical term for defining an ambiguous phenomenon. It is paradoxical because, from a general and classical point of view, the rule of law is usually considered "hard," i.e., compulsory, or it simply does not exist. Ambiguous because the reality thus designated, considering its legal effects and manifestations, is often difficult to identify clearly. Soft law is a source that is not binding and has no specific warranties. These sources are including statements, resolutions, agendas, action plans, and the rules that guide governments. The primary purpose of soft law is to express the non-obligatory principles and rules that guide governments to protect the environment. It is essential to mention that even though these resources are not binding, they have a crucial impacts on the development of international environmental law. The most significant examples of these sources are the 1972 Stockholm Declaration, the 1982 Universal Charter of Nature, the 1992 Rio Declaration and Agenda 2030 for sustainable development. In addition, the soft law core idea is to affirm or declare general principles and define a guideline for states to protect their environment in a flexible manner.

The variations of the sources in Hard Law and Soft Law will assist the evolution of international environmental law, such as the global climate change regime. For instance, the Paris Agreement combines harder procedural commitments with softer substantive provisions, potentially encouraging flexible responses to changing conditions within a stable, long-term architecture. However, the Agreement’s softer, transparency-based compliance framework provides limited assurance that countries will make and fulfill ambitious commitments.

Nevertheless, international environmental law based on “soft law” is not only available to international judges or arbitrators. They can also be helpful for inter-State diplomacy. They may also effectively be taken into account by municipal judges in evaluating the legality, concerning international law, of any internal administrative action having had or can have some damaging impact on the environment beyond national boundaries. Furthermore, municipal judges may consider these international standards to give a correct interpretation of supremely generally formulated international obligations.

Finally, the drafting and implementation of these sources of law allow governmental and non-governmental actors to cooperate together.

E. Global environmental problems and challenges

Despite all global efforts, to develop binding and non-binding legal instruments, environmental concerns and threats such as global warming, climate change, desertification, and deforestation are not only remaining but also increasing.

Today's world's environmental concerns and threats go beyond the predictions of the experts and scientists present at Stockholm's first environmental Conference in 1972.

I. State sovereignty

Regardless of the concept of the sovereignty of states in international law, one of the main obstacles for the development of international environmental law, is the non-acceptance of governments, to delegate or limit their sovereignty, in favour of environmental organizations. Another conflict also exists between developed and developing countries in enforcing regulations. For instance, according to the principle of Common but Differentiated Responsibilities, developed countries should take additional actions such as transferring technologies or contributing finance to developing countries, but this principle is not respected properly.

This principle clearly set out in many international environmental treaties, such as United Nations Framework Convention on Climate Change (UNFCC). According to this convention, developed countries should provide financial resources to assist developing countries in implementing the objectives for protecting climate change.

II. Diversity of sources

Another substantive challenge to developing international law is the diversity of binding and non-binding sources, which is caused confusion and vagueness in the implementation of international law. Absence of a globally applicable environmental treaty, sufficient judgments of international courts and the customary legal status of the most critical environmental principles, this branch of the law will always be caught on the horns of a dilemma between generally applicable but non-binding principles on the one hand, and unique or sectorial treaty regimes thoroughly regulating specific environmental problems, but without the ability to transcend these treaties to inform the corpus of universally applicable customary rules of international environmental law itself.

International environmental law has fallen between the development of general environmental principles, mainly enunciated in non-binding international instruments (such as the 1992 Rio Declaration on Environmental and Development) and binding international environmental treaties which are nevertheless sector-specific in their orientation, or even when comprehensive in their approach to (several) environmental threats, are regional in their geographical scope of application. This developmental ‘gap’ between general environmental principles and specific treaty rules points towards a substantive failing within international environmental law as a viable subdiscipline of public international law generally. The lack of general application of even cornerstone principles of and incasing new sources of international environmental law could be a normative gap in this field of law.

III. Insufficient guarantee of implementation

Many international rules and regulations, including multilateral treaties, are confronted with a deficiency of compliance mechanisms to protect the environment. The failure to provide financial mechanisms in international environmental treaties is one of the principal points of concern of the international community to implement environmental obligations, especially in developing countries. Principle 9 of the Rio Declaration stated, “States should cooperate to strengthen endogenous capacity-building for sustainable development by improving scientific understanding through exchanges of scientific and technological knowledge, and by enhancing the development, adaptation, diffusion and transfer of technologies, including new ones and innovative technologies.”

IV. Institutional challenge

With the growing importance of global environmental protection since the 1972s, international governmental organizations, have tried to play their role in environmental protection.

As active subjects of international law, international organizations have a serious task to achieve in this regard.

One of the essential reflections holding the Stockholm Conference was to establish the United Nations Environment Program as the global and executive arm for the international protection of the environment. However, the UNEP has limited capacity to protect the global environment.

As a result, is it time to evaluate possibilities for creating a new organization for environmental protection like World Environmental Organization?

V. Emergence of environmental Challenges in the world

From the early 90s, environmental threats became alarming: the destruction of the stratospheric ozone layer, climate change, sea level rise, ecosystem acidification, sheer loss of biological diversity, overexploitation of marine resources, increased technological risks, etc. The emergence of increasingly unpredictable risks enticed the authorities to base their policy on an anticipatory model. This model can be linked to understanding scientific expertise's limitations. While prevention is based on a particular risk, the new model is distinguished by the intrusion of uncertainty.

The world is confronted with several environmental problems and challenges, such as climate change, global warming, air, water, soil and light pollution, resource depletion, massive disappearance of plant and animal species, the depletion of biodiversity and other environmental degradations. These challenges could have significant implications for human health, social stability and economic development.

Climate change is one of the major challenges of the current world. According to the report released by the Intergovernmental Panel on Climate Change (IPCC) for 2022: “Human-induced climate change is causing dangerous and widespread disruption in nature and affecting the lives of billions of people around the world, despite efforts to reduce the risks. People and ecosystems least able to cope are being hardest hit, said scientists in the latest Intergovernmental Panel on Climate Change (IPCC) report. “This report is a dire warning about the consequences of inaction....It shows that climate change is a grave and mounting threat to our well-being and a healthy planet. Our actions today will shape how people adapt, and nature responds to increasing climate risks.” The world faces unavoidable multiple climate hazards over the next two decades with global warming of 1.5°C (2.7°F). Even temporarily exceeding this warming level will result in additional severe impacts, some of which will be irreversible. Risks for society will increase, including to infrastructure and low-lying coastal settlements. The Summary for Policymakers of the IPCC Working Group II report, Climate Change 2022: Impacts, Adaptation and Vulnerability was approved on Sunday, February 27 2022, by 195 member governments of the IPCC…”

F. Conclusion: Future of International Environmental Law

Global challenges need global solutions: in this perspective, international cooperation between states plays a vital role.  Economic growth and increasing technological advances in the contemporary period have caused real damage to the environment.

The states should be willing to participate actively in drafting, signing, ratifying and implementing new treaties on environmental issues such as water pollution and climate change in a sustainable way.

It is also crucial to recognize the right of public participation in the environmental decision-making process and implementation. The right to “environment” and right to “economic development” as a “human right” should be considered in the concept of sustainable development as a common concern of humanity. Now is the time for the international community to impose absolute responsibility or strict liability to states for any damage and harm to the environment at the national and international levels.

It is essential to note that the role of non-governmental organizations (NGOs) is crucial in the future development of international environmental law. Although the classic approach of international law recognizes mainly the role of States and governmental organizations, international environmental law recognizes that NGOs could have different roles in setting priorities and assisting in creating and enforcing national and international norms and regulations.

In the future, international environmental law will continue to develop significantly. From the 1972 Stockholm Conference, a shift occurred in the various States’ policies at the national and international levels. In this perspective, normative evaluation such as the International conventions on ozone protection (1985), the conservation of Antarctic marine fauna and flora (1980), the control of transboundary movements of hazardous wastes (1989), the Paris Agreement on climate change (2015) and many others are negotiated and ratified and enter into force within more than five decades. Regarding the structural evolution of international environmental law, the United Nations and UNEP reform are crucial for the future development of international law.  

Finally, international peace and security are necessary to ensure sustainable development for humanity, regardless in developed or developing countries.

Further Readings

• Alexandre Kiss, Dinah Shelton, Guide to International Environmental Law, (Martinus Nijhoff Publishers, 2007)
• UNEP, Training Manual on International Environmental Law, (Publication of the United Nations Environment Programme)
• Abbas Poorhashemi, Emergence of International Environmental Law: as a new branch of International Public Law, (CIFILE Journal of International Law, Canada, V. 1, Issue 2, 2020, P. 33-39)
• Laurence Boisson De Chazournes, La protection de l'environnement global et les visages de l'action normative internationale, (In: Mélanges en l'honneur de Michel Prieur. Paris : Dalloz, 2007. p. 41-57)
• Philippe Sands, Jacqueline Peel, Adriana Fabra, Ruth MacKenzie, Principles of international environmental law, (Cambridge, United Kingdom ; New York, NY : Cambridge University Press, 2018)
• Alexandre Kiss, Le droit international à Rio de Janeiro et à côté de Rio de Janeiro. In: Revue Juridique de l'Environnement, n°1, 1993. pp. 45-74.
• POLIN, R., « Le concept de souveraineté et ses conséquences internationales », dans Roland Drago et al., Souveraineté de l’État et interventions internationales, Paris, Dalloz, 1996
• Abbas Poorhashemi, Quel développement pour le droit international de l'environnement au 21ème siècle?. CIFILE Journal of International Law, 2020, 2(3), 76-87. doi: 10.30489/cifj.2020.238827.1018
• Alam, Shawkat, Atapattu, Sumudu, Gonzalez, Carmen G. and Razzaque, Jona, International Environmental Law and the Global South, edited by, published by Cambridge University Press, 2015, 631 pp.
• Ulrich Beyerlin and Thilo Marauhn, International Environmental Law, Oxford: Hart/Beck Publishing 2011; 484pp, ISBN 978-1-84113-924-1
• Razzaque, J. The Oxford Handbook of International Environmental Law, edited by Daniel Bodansky, Jutta Brunnée and Ellen Hey. Oxford: Oxford University Press, 2007, xxviii 1056 (index) 24pp ISBN 13: 978-0-19-926970-9. Legal Studies, 28(2), 309-312. doi:10.1111/j.1748-121X.2008.00089_2.x
• Pierre-Marie Dupuy, Jorge E. Viñuales, International Environmental Law, Cambridge University Press, 2018, ISBN: 1108539971, 9781108539975.
• Malgosia Fitzmaurice, Meagan Wong, Joseph Crampin, International Environmental Law: Text, Cases and Materials, Edward Elgar Publishing, 2022, ISBN: 1785367803, 9781785367809.
• DE SADELEER, NICOLAS, ‘The Polluter-pays Principle’, Environmental Principles: From Political Slogans to Legal Rules (Oxford, 2002; online edn, Oxford Academic, 1 Jan. 2010), https://doi.org/10.1093/acprof:oso/9780199254743.003.01, accessed 15 Feb. 2023.
• Stenis, J., Hogland, W. The Polluter-Pays Principle and its Environmental Consequences for Industrial Waste Management. Environment, Development and Sustainability 4, 361–369 (2002). https://doi.org/10.1023/A:1024120026032
• Paddock, L. The impact of the Paris Agreement on international environmental law. International Journal of Climate Change Strategies and Management, (2017). 9(4), 472-488.
• Abbott, Kenneth W., and Duncan Snidal. “Hard and Soft Law in International Governance.” International Organization 54, no. 3 (2000): 421–56. http://www.jstor.org/stable/2601340.
• Jonathan Pickering, Jeffrey S McGee, Sylvia I Karlsson-Vinkhuyzen, Joseph Wenta, Global Climate Governance Between Hard and Soft Law: Can the Paris Agreement’s ‘Crème Brûlée’ Approach Enhance Ecological Reflexivity?, Journal of Environmental Law, Volume 31, Issue 1, March 2019, Pages 1–28, https://doi.org/10.1093/jel/eqy018
• Duvic-Paoli, L. (2018). The Prevention Principle in International Environmental Law. In The Prevention Principle in International Environmental Law (Cambridge Studies on Environment, Energy and Natural Resources Governance, p. Iii). Cambridge: Cambridge University Press.