|Each riparian state to an international watercourse is entitled to make use of the waters of an international watercourse within its own territory, a fundamental corollary to the concept of territorial sovereignty. It is the principle of sovereign equality (or ‘equality of right’) which stipulates that every riparian state has a right to the utilisation of the watercourse which is qualitatively equal to the rights of the co-riparians.202 However, this must not be mistaken for the right to an equal share of the uses and benefits of the watercourse; nor does it imply that the water resource itself has to be divided into equal shares.203
Since it is based on the notion of equity, the concept demands the weighing and balancing of the competing (reasonable) interests of states, taking into account all relevant factors and circumstances (see Article 6 – Factors relevant to Equitable and Reasonable Utilisation).
Equity has many different meanings, and the precise nature of the concept is somewhat obscure. As a set of legal principles, or found in broader ‘general norms,’ it has a long history in both common and civil law systems. Equity can be described as a supplement to rather strict rules, giving the judge some leeway in their application, where it would seem too rigid or harsh otherwise. In international law equity is often used as a synonym for fairness or justice with both procedural and substantive dimensions.204 While the procedural part is concerned with reaching decisions through ‘right process’, the substantive part tries to achieve distributive justice.205
Based on the perspective that fairer proceedings lead to fairer outcomes, the two dimensions of equity are often seen as being interlinked.206 One example here is the concept of environmental justice, which aims at guaranteeing procedural equity through a participatory decision-making process, in turn leading to outcomes which treat all affected stakeholders fairly. The movement pushing for environmental justice emerged as a result of the correlations between race and poverty and the allocation of environmental burdens. The argument is that greater equity in the allocation of both benefits and harm (distributive justice) can only be achieved by overcoming the traditional exclusion of minority groups in the decision-making process (procedural fairness).207
In the climate change debate the substantive dimension of ‘equity’ (distributional justice), is at the centre of the discussion – consisting of three domains:208
These basic elements have been translated into several approaches introduced to international climate change negotiations. The concept of egalitarian equity states that every individual has an equal right to pollute and to be protected from pollution.209 Thus, each state would be allowed to emit greenhouse gases (GHGs) in proportion to its population. In contrast, the theory of sovereignty demands that all states have an equal right to pollute and to be protected from pollution; leading to a reduction of global GHG emissions in proportion to states’ status quo right by maintaining the relative differences in emission levels between them.210 Applying a horizontal approach, where states with similar economic characteristics have similar rights to emit GHGs, would entail equalising net welfare changes across nations. Finally, the polluter pays principle distributes the economic burden of mitigation in accordance with each state’s (historical) emissions.
Complicating things further, each of these approaches can have different nuances, depending on the indicators applied for implementation. One prominent example here is the distinction between emissions due to secure fundamental basic needs and ‘luxury’ emissions.
The ongoing climate change debate points to the fact that defining what exactly is meant by ‘equitable’ will always remain a challenging and moving target, since governments transcribe their individual interests into various competing concepts of equity.
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