A/HRC/19/34 debate has involved a number of difficult questions. For example, what is the benefit of formulating a new human right to a healthy environment? Some individuals have noted that the international community should not proclaim new human rights whose content is difficult to define with clarity. Others have noted that national courts have been capable of providing meaningful content to the right to a healthy environment in national constitutions, and that international tribunals have been able to articulate State responsibilities in connection with the environmental dimension of protected rights. 12. Another issue widely debated in legal literature is whether international law already recognizes a right to a healthy environment. This debate rests on an analysis of the traditional sources of international law. Some commentators note that the recognition of a right to a healthy environment in national constitutions sets the stage for a discussion focused on an emerging rule of custom. Others point to the fact that certain international instruments already recognize the right to a healthy environment and that, accordingly, for the parties to those treaties, the relevant question is not one of recognition but of implementation and monitoring. 13. Yet another question concerning the legal implications of the recognition of a right to live in a healthy environment is who are the right-holders and duty-bearers? This is particularly relevant where environmental degradation results from the activities of private actors, such as legal entities and transnational corporations. 14. It is apparent that these theoretical debates have led to a rich discussion on the relationship between human rights and the environment. They have also informed the development of a human rights-based jurisprudence on environmental issues at the regional level, as well as the development and adoption of a number of international instruments that reflect the growing relationship between human rights and environment. III. Major environmental threats to human rights 15. Environmental degradation has the potential to affect the realization of human rights. This section identifies key environmental threats and their impact on human rights and vulnerable populations. 16. First, atmospheric-related environmental impacts are becoming more predominant as a result of increasing human activity, population growth and continued economic growth. These activities exacerbate atmospheric emissions, leading to air pollution, climate change and ozone-layer depletion. 17. Second, there are numerous land-based environmental threats, which include land degradation, deforestation and desertification. The impacts here tend to be more regional, although land degradation has global effects. Each is environmentally destructive, with adverse impacts on continued human well-being. 18. Third, the United Nations Environment Programme points out that development and the water environment are interconnected. Degradation in water quality, freshwater scarcity and stresses on oceans, such as fisheries collapse, are all prevalent environmental problems. These issues come with potential human rights implications. 19. Fourth, hazardous waste, chemical contamination and pollution are pervasive environmental threats with visible human rights implications. Unfortunately, chemical production, use and disposal are not always performed in line with adequate safety protocols, leading to chemicals being released into the environment. Aware of this threat, States are beginning to strengthen their regulation of chemicals, including at the international level through several multilateral environmental agreements. 5