Restoring the transboundary harm principle in international environmental law

Abstract

One of the oldest and central principles of international environmental law is the transboundary harm principle. This sets out the requirement that States should prevent activities on their territory causing significant harm or damage to the environment of another State or ‘areas beyond national control’. 1 In selecting a very old and established principle to analyse in my judgment, I aim to show how international law as machinery for global governance has been and continues to be complicit in our excessive consumption of nature in the Anthropocene. 2 The transboundary harm principle continues to support the idea that States in international law are its only subjects and ignores the wider and broader interests that Planet Earth itself would have in protecting itself against the narrow interests of States. 3 The transboundary harm principle was most recently discussed in the context of the San Juan River case. 4 In this case, the Court did not really develop the principle and related rules supporting it, because it had already done so in the Pulp Mills decision. 5 However, in the San Juan River case, the transboundary harm principle and norms central to its implementation were put to the test when Costa Rica and Nicaragua took actions against each other claiming, amongst other things, that they had each breached the requirement in international law to carry out an environment impact assessment (EIA) and to consult with the other as a result of their activities along the San Juan river. Nicaragua argued that it had rights in relations to a channel from the San Juan river which flowed through the territory of Costa Rica. It also argued that it was under no obligation to carry out an EIA because the dredging along the channel did not risk causing significant environmental harm to Costa Rica generally and also the wetlands of international significance that were within the reach of the channel. The Court found that the channel flowing from the San Juan river belonged to Costa Rica and not Nicaragua as had been argued, but that the dredging work did not risk significant harm to Costa Rica and its wetlands.