Lesson 14 min 20 XP
International Environmental Law
How international law addresses climate change, biodiversity loss, and pollution through treaties, principles, and institutions.
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How international law addresses climate change, biodiversity loss, and pollution through treaties, principles, and institutions.
International environmental law is one of the fastest-growing fields of international law. The 1972 Stockholm Declaration, which established the principle that states have a responsibility to ensure activities within their jurisdiction do not damage the environment of other states, launched the modern era. The 1992 Rio Earth Summit produced the Framework Convention on Climate Change (UNFCCC), the Convention on Biological Diversity (CBD), and Agenda 21.
Key principles include the precautionary principle (lack of scientific certainty should not delay action against serious environmental threats), the polluter pays principle, the principle of common but differentiated responsibilities (all states share environmental obligations but developed countries bear greater responsibility due to their historical contributions to pollution), and the principle of sustainable development, which seeks to balance economic growth with environmental protection.
The international climate regime is built on three layers. The UNFCCC (1992) established the framework and the principle of common but differentiated responsibilities. The Kyoto Protocol (1997) set binding emission reduction targets for developed countries but exempted developing countries, which led the US to reject it. The Paris Agreement (2015) took a different approach: all countries submit nationally determined contributions (NDCs) setting their own targets, with a review mechanism every five years to ratchet up ambition.
The Paris Agreement's strength is near-universal participation: 195 countries have ratified it. Its weakness is that NDCs are not legally binding in their ambition, and current pledges are collectively insufficient to limit warming to 1.5 degrees Celsius. The loss and damage fund agreed at COP27 in 2022 was a breakthrough for climate justice, acknowledging that vulnerable countries deserve compensation for climate impacts they did not cause, but funding remains far below estimated needs.
International environmental law faces the same enforcement challenges as other areas of international law, compounded by the fact that environmental harm is diffuse, cumulative, and often difficult to attribute to specific actors. There is no international environmental court, though proposals have been made.
Increasingly, enforcement is happening through domestic courts. Climate litigation has exploded, with over 2,600 cases filed worldwide as of 2024. The Urgenda case in the Netherlands (2019) was a landmark: the Dutch Supreme Court ordered the government to reduce emissions by 25 percent by 2020, based on the European Convention on Human Rights. Similar cases have succeeded in Germany, France, and elsewhere. The ICJ's advisory opinion on climate obligations, requested in 2023, may establish authoritative guidance on states' legal duties.