In the current geological era of Anthropocene with the human as the principal agent of global environmental change, environmental concerns have become ever so prominent [1] . As a response, the recent decades since the 1970s saw an emergence of a growing – albeit fragmented – body of substantive rules related to environmental protection and the subsequent increase in environmental litigation. However, with more than one thousand environmental treaties signed on global and regional levels, there is still no centralized judicial authority dedicated exclusively to environmental matters [2] . In its absence, other international courts – including the ICJ, the WTO Appellate Body, the International Tribunal for the Law of the Sea, as well as human rights courts – have been called upon to adjudicate disputes involving environmental issues, thereby creating situations of inter-legality characterized by an overlap between their own legal regimes and environmental law [3] .¶{p. 466}

In particular, in light of the close connection between the environmental quality and the enjoyment of human rights, human rights courts and treaty bodies have become the main fora for litigating environmental justice claims [4] . Although the strong link between human rights and the environment has been affirmed since the very inception of international environmental law dating back to the 1972 Stockholm Declaration on the Human Environment, the relationships between the two legal frameworks have been far from straight forward. While some scholars stress the contribution that human rights law has made in advancing environmental causes, others describe their relationships as a failing attempt of “fitting the potentially round peg of environmental concerns into the square hole of staunchly anthropocentric human rights” [5] .

This chapter aims to contribute to this debate by examining the relationships between environmental law and human rights law at the Inter-American Court of Human Rights (“the IACtHR”) through the lens of inter-legality, understood as a normative perspective that aims to give fair consideration to both regimes applicable to the case in hand [6] . In particular, the main argument advanced herein is ¶{p. 467}that, in contrast to the adjudication of environmental claims exclusively through the existing human rights framework, the adoption of inter-legal approach by the IACtHR helps to underscore the status of environment as an intrinsic public good and as a result, represents a more efficient way of advancing environmental justice.

In constructing this argument, the chapter will start by examining international environmental law as an inter-legal phenomenon, in particular by distinguishing between internal inter-legality situations, characterized by the interaction between various environmental agreements regulating the same issue, and external inter-legality situations, arising out of interaction between environmental law as a whole with other branches of international law, including human rights. The remaining sections will focus upon the latter interplay by first contrasting two different understandings of the objectives of environmental law: “the instrumental” approach viewing environmental protection as a precondition for the enjoyment of individual human rights and the broader “intrinsic” approach concerned with the protection of ecosystem as a value in its own right. After opting for the second position, which underscores the overlapping but different objectives of the two regimes, the chapter explores both potential contributions and limitations of the human rights framework in advancing environmental agenda. This is done through examination of three different approaches to environmental protection identified in the case law of the Inter-American Court, namely the human rights “greening”, the “environmental democracy” approach focused on procedural environmental rights, and the “genesis theory” advocating for the recognition of an autonomous right to a healthy environment. In particular, it will be demonstrated that while all three human rights approaches advance the environmental cause in one way or another, they rate differently from the perspective of upholding environmental protection as an end goal in itself. Finally, the last section will summarize the argument, highlighting the normative value of inter-legal reasoning in promoting environmental justice.¶{p. 468}

International environmental law represents a double interest from the perspective of inter-legality [7] . On the one hand, from an internal perspective, the discipline has historically developed as a fragmented battle field in which multiple legalities – in the form of regimes or sub-regimes created by multilateral environmental agreements – interact in an uncoordinated manner. On the other hand, from an external perspective, international environmental law represents a legality of its own, characterized by a common body of rules and principles, which enter into interaction with other regimes of international law, including human rights. Both of these dimensions will be explored below.

In contrast to human rights law which blossomed after the World War II, international environmental law only emerged in late 1970s, as public awareness of unfolding ecological crisis grew globally [8] . The birth of the discipline is traditionally traced to the UN Conference on the Human Environment (UNCHE), held in Stockholm in 1972, which catalyzed the development of international environmental law for the decades to come [9] . The Stockholm Declaration on the Human Environment, the outcome document of the UNCHE, was adopted with the view “to inspire and ¶{p. 469}guide the peoples of the world in the preservation and enhancement of the human environment” [10] . To this end, the UNCHE, among other things, established the UN Environment Program (UNEP), charged with the mandate to promote and coordinate international cooperation in the field of environmental protection within the UN and outside [11] . Although the normative development of international environmental law did not initially feature among the UNEP functions, in the subsequent decades, it pioneered the conclusion of no less than forty-eight multilateral environmental agreements (MEA) [12] , including the landmark 1985 Vienna Convention on the Protection of the Ozon Layer, the 1989 Basel Convention on the Control of Transboundary Movements of Hazardous Wastes, the 1992 Convention on Biological Diversity and others [13] . This extensive proliferation of multilateral environmental agreements continued in the subsequent decades up until the 1992 Rio Conference on Environment and Development (UNCED), which marked the “coming of age” of modern environmental law as a fully-developed discipline [14] .