1. Introduction
International water law, which regulates the uses of international watercourses that are situated partly in different States, is a highly topical sector of law. In 2014, after a time when no general agreements were in existence in the field, two conventions covering the same subject matter entered into force globally: the 1997 UN Convention on the Law of the Non-navigational Uses of International Watercourses (UN Watercourses Convention) [
1] and the 1992 United Nations Economic Commission for Europe (UNECE) Convention on the Protection and Use of Transboundary Watercourses and International Lakes (ECE Water Convention) [
2]. The process of codification of international water law—dating back to the 1966 Helsinki Rules of the International Law Association (ILA Helsinki Rules) [
3]—has thus culminated into binding international agreements, which are mutually compatible and complement each other [
4,
5,
6]. The general principles of the two conventions, such as cooperation, equitable and reasonable utilisation and the no-harm rule, correspond to customary norms of international water law [
7].
International water law has traditionally applied to inter-State relations concerning transboundary watercourses and not to the relationship between an individual and a State that defines the scope of international human rights law [
8]. In recent years, however, human rights have also been increasingly discussed within the sphere of international water law. While the General Assembly of the United Nations recognised the right to safe and clean drinking water and sanitation as a human right in July 2010 [
9], the 2004 ILA
Berlin Rules on Water Resources (ILA Berlin Rules) [
10] had already contained the right of access to water to meet every individual’s vital human needs (Art. 17). In the legal literature, the discussion on the relationship between the right to water and international water law began in the 1990s [
11].
At the same time as when the international water law conventions have entered into force, a water-food-energy nexus has become part and parcel of the development canon. The nexus approach emphasises the importance of recognising the complex relationship and interlinkages between the water, energy and food sectors and also aims to safeguard the human rights to water and food [
12,
13,
14]. Hoff underlines the need for a nexus approach as follows:
Improved water, energy and food security can be achieved through a nexus approach—an approach that integrates management and governance across sectors and scales. A nexus approach can also support the transition to a Green Economy, which aims, among other things, at resource use efficiency and greater policy coherence. Given the increasing interconnectedness across sectors and in space and time, a reduction of negative economic, social and environmental externalities can increase overall resource use efficiency, provide additional benefits and secure the human rights to water and food. Conventional policy- and decision-making in “silos” therefore needs to give way to an approach that reduces trade-offs and builds synergies across sectors—a nexus approach. Business as usual is no longer an option [
15] (p.7).
In international water law, the nexus approach is currently being discussed within the regime of the ECE Water Convention. The Convention’s program of work for 2013–2015 includes an assessment of the water-food-energy-ecosystems nexus that aims to improve the understanding of the interactions between water, food, energy and water-related ecosystems in international basins. Further, it intends to strengthen synergies and policy coherence between water, food and agriculture and land management sectors in the transboundary context [
16]. In a transboundary setting, while water, energy and agricultural issues are often strongly interlinked in the international watercourses and aquifers [
17], the possible frictions between the riparian countries and different interests make the nexus approach even more challenging than at the national level [
14,
18].
The legal regime of the Mekong River provides a concrete example of the challenges of a water-energy-food nexus approach in international river basins. As is well known, the Mekong River is one of the largest rivers in the world both according to its estimated length (4909 km) as well as its mean annual volume (475 km
3). The River supports a diverse and productive freshwater ecosystem and provides the basis of livelihoods for millions of people. While there are six riparian countries, Cambodia, China, Laos, Myanmar, Thailand and Vietnam, only four of them have signed the 1995 Agreement on the Cooperation for the Sustainable Development of the Mekong River Basin (1995 Mekong Agreement) [
19]. This means that China and Myanmar are not among the members of the Mekong River Commission [
20,
21,
22].
All the riparian countries of the Mekong River are going through periods of rapid changes and some are planning or have already realised large-scale water development projects. These include the construction of hydropower dams and irrigations projects, which on the one hand are important for the countries’ economic development, but on the other hand may have remarkable negative impacts on ecosystems and thus on the livelihoods of people [
20,
21,
22]. For instance, the hydropower dams in China have been suspected to cause a series of detrimental environmental impacts such as changes to the river’s natural flood-drought cycle and to the transport of sediment on the Lower Basin of the Mekong. In addition, the hydropower dams in Vietnam in the Sesan River, which is a tributary of the Mekong, have had adverse effects on, e.g., fishing and river-side farming and thus, on the livelihoods of the communities in Cambodia [
23,
24].
In this article, it is discussed whether international water law supports the water-food-energy nexus approach, which aims to reconcile the different water uses in international basins. The principles of international water law (cooperation, equitable and reasonable utilisation, no-harm) will be studied from the nexus perspective following especially the methodology of the UNECE for the nexus assessment [
13]. The analysis also covers the human rights to water and food from the nexus viewpoint. The legal regime of the Mekong River is used as an example of the possibilities and challenges of the nexus approach in international water law. Rather than providing complete answers on the relationship between international water law and the nexus approach, the article aims to add an important element to the nexus discussion, namely international water law.
The article consists of four sections. First of all, the relationship between the procedural features of the nexus approach and international water law is studied. Second, it is observed whether it is possible to reconcile different water uses in order for the nexus approach to be effective. Third, how the human rights to water and food—which the nexus approach aims to secure [
15] (p. 7)—are regulated in international law is discussed. Fourth, the conclusions are presented at the end of the article.
In regard to the UN Watercourses Convention and the ECE Water Convention, the two important sources of the article, it must be noted that none of the Mekong countries is a party to the ECE Water Convention and only Vietnam is a party to the UN Watercourses Convention. Therefore, international customary law in addition to the 1995 Mekong Agreement largely determines their rights and obligations regarding international waters. The general principles of the UN and ECE conventions can be regarded as a source of international customary water law also in the Mekong River context.
In general, the role of international customary law is notably significant in international water law. Especially, the UN Watercourses Convention is reckoned to reflect the fundamental rules of customary law [
17,
24]. As McCaffrey points out:
For the most part, it (the UN Watercourses Convention) should be viewed not as an instrument that seeks to push the law beyond its present contours, but as one that reflects a general consensus as to the principles that are universally applicable in the field [
7] (p. 261).
Also the non-formal ILA Helsinki Rules and ILA Berlin Rules are widely understood to reflect international customary water law, although some experts’ approach towards those parts of the ILA Berlin Rules that seek to incorporate the requirements of international environmental and human rights law has been a bit cautious [
25,
26].
4. Human Rights to Water and Food
The nexus approach aims to secure water, energy and food security in-line with human rights and basic human needs [
15]. While water security means sustainable access to adequate quantities of water of an acceptable quality for basic human needs, also availability and access to water for other critical human and ecosystem uses can be included in it from the nexus perspective [
15,
40]. Energy security is defined by the International Energy Agency as the uninterrupted availability of energy sources at an affordable price [
41], whereas for an individual it refers to access to clean, reliable and affordable energy services for cooking, heating, lightning, communication and productive uses [
42]. Food security for its part is defined to exist when all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food, which meets their dietary needs and food preferences for an active and healthy life [
43]. The rights to water and food are two of the most essential human rights from the nexus perspective.
In July 2010, the General Assembly of the United Nations recognised the right to safe and clean drinking water and sanitation as a human right [
9]. The recognition is a significant milestone in the debate that focuses on the rights related to access to water during the last decades [
44]. In the resolution, the United Nations recognises the right to safe and clean drinking water and sanitation as a human right that is essential for the full enjoyment of life and all human rights; and calls upon States and international organisations to provide financial resources, capacity-building and technology transfer, through international assistance and cooperation in particular, to developing countries in order to scale up efforts to provide safe, clean, accessible and affordable drinking water and sanitation for all [
9].
The General Assembly recalls in its resolution different human rights treaties and instruments that lend support to the right to water. These include, among others, the International Covenant on Economic, Social and Cultural Rights (ICESCR) and the International Covenant on Civil and Political Rights (ICCPR). Although water is not explicitly mentioned in these covenants, the right to water is usually derived from articles 11 and 12 of the ICESCR. According to articles 11 and 12 of the ICESCR, everyone has the right to an adequate standard of living including adequate food, clothing and housing and to the enjoyment of the highest attainable standard of physical and mental health. The right to water is seen to implicitly fall under the elements of the adequate standard of living [
45].
Within the framework of international water law, the right of access to water is recognised in the ILA Berlin Rules in substantially the same way as in the General Assembly resolution. Accordingly, every individual has a right of access to sufficient, safe, acceptable, physically accessible and affordable water to meet that individual’s vital human needs. States should ensure the implementation of this right on a non-discriminatory basis and progressively realise the right by various means (Art. 17). In regard to the right of access to water, the Berlin Rules are based on the national constitutions as well as human rights and water law instruments.
International water law also includes a concrete tool for the implementation of the human right to water in the form of the 1999 UNECE Protocol on Water and Health to the ECE Water Convention [
8]. According to the Protocol, the Parties must pursue the aims of access to drinking water and the provision of sanitation for everyone (Art. 6) and take all appropriate measures for the purpose of ensuring adequate supplies of wholesome drinking water as well as adequate sanitation (Art. 4). National and local targets for the standards and levels of performance are revised periodically (Arts. 6–7). In general, the UNECE Protocol on Water and Health represents a step that international water law is taking in the direction of the protection of the right to water also at the domestic level [
8].
Unlike water, food is explicitly mentioned in Article 11 of the ICESCR as an element of the right to an adequate standard of living. The right to food or the right to adequate food is defined as a right to all nutritional elements that a person needs to live a healthy and active life and to the means to access them [
46]. The right to food is realised when everyone has physical and economic access at all times to adequate food or means for its procurement [
47].
In order to have access to food, a person must be able to either buy or produce their own food. The rights to food and water are interlinked in a way that the right to food necessitates the access to safe drinking water for personal and domestic uses such as food preparation and food production. In addition, the obligation to fulfill the right to food means that States have to strengthen people’s access to and use of resources such as water for food production [
46].
The special regard and preference given to the vital human needs in the UN Watercourses Convention (Art. 10.2) and ILA Berlin Rules (Art. 14) respectively combined with the resolution on the human right to water, the right of access to water in the Berlin Rules (Art. 17) as well as the right to food provide strong grounds for the priority of the indispensable water use to meet basic human needs over other uses. However, also in this regard the possible alternatives to the water uses (Art. 6 of the UN Watercourses Convention) must be taken into account. The priority of indispensable water use needed to meet basic human needs is very much in line with the nexus approach, which aims, as stated earlier, to secure the human right to water and food.
The relevant question is, however, whether international water law provides wider support than the traditional inter-State dimensions in regard to the regulation of international waters for the human rights to water and food. From the traditional point of view, the priority of indispensable water use in international water law proves only partial and indirect help for the protection of individual needs through inter-State claims that cannot deal with situations pertaining to exclusively domestic waters. Nevertheless, first of all the UNECE Protocol on Water and Health is redirecting this tradition through a strong emphasis on the access to water and sanitation and with its mainly domestic scope of application [
8]. Secondly, the ILA Berlin Rules reflect the requirements of international environmental and human rights law in addition to traditional international water law by including waters within a State in their scope (Art. 1) and by the specific provision on the right of access to water (Art. 17). Thus, international water law is gradually taking steps in the direction of securing the basic human needs related to water uses in a wide geographical scope.
The 1995 Mekong River Agreement contains no specific provisions on how to guarantee the basic human needs for water and food in the River Basin. However, the Agreement regulates the maintenance of the flows on the mainstream from diversions, storage releases or other actions of a permanent nature (Art. 6). Accordingly, for instance, during the dry season the minimum monthly natural flow is to be maintained at the acceptable level through cooperation between Parties. The maintenance of flows, for its part, makes it possible that there is enough water for individuals to meet basic needs for water and food.
According to Article 2 of the ICESCR, States have to take steps by themselves but also through international cooperation, to the maximum of their available resources, with a view to achieving progressively the full realisation of the rights recognised in the Covenant. The means for this purpose include particularly the adoption of legislative measures. Thereby, the ICESCR also obligates that the rights to water and food are taken into account in the cooperation between watercourse States.
5. Conclusions
It is obvious that there are many challenges for the water-food-energy nexus cooperation in the regime of international water law. One may start by mentioning, for example, the general nature of the procedural and substantive provisions of international water law and its weakness in situations where riparian countries are not willing to cooperate. However, at the same time, international water law provides a very useful platform for the cooperation between States and different sectors aiming at guaranteeing water, food and energy security. It not only allows but also supports the nexus approach in the cooperation between States.
International water law and especially its two conventions (UN Watercourses Convention and ECE Water Convention) provide footsteps that riparian States can follow in their cooperation and when concluding bi- and multilateral water agreements. While the 1995 Mekong Agreement offers an encouraging example of the possibilities of international water law in enhancing cooperation, it also includes serious deficiencies from the nexus and holistic water management perspectives: not all of the basin countries are members of the Mekong River Commission, there are no specific provisions for development on tributaries and a transboundary environmental impact assessment is not required in the Agreement although it nowadays is a part of international customary law. All in all, the Agreement emphasises the sovereignty of States more than the UN and ECE conventions and international customary water law [
21]. However, the Agreement also provides the tools and possibilities for the Basin countries to develop their cooperation in the direction of the nexus approach.
International water law offers an institutional framework for the nexus approach but does not offer concrete specifications for its procedural elements. It is up to States sharing the same watercourse to implement the main features of the nexus assessment (participatory process, knowledge mobilisation, sound scientific analysis, capacity building and collective effort [
13]) into their cooperation within joint bodies or other arrangements. International water law provides a clear basis for the participatory process between States as well as knowledge mobilisation and analysis. In addition, capacity building and collective effort can be included in the cooperation.
The most difficult part of the nexus cooperation in the framework of international water law is the reconciliation of different water uses in a situation where there is not enough water to meet all the competing needs. International water law contains the general provisions on equitable and reasonable utilisation and on the minimisation of harmful transboundary effects. From the nexus perspective the most relevant factors of equitable and reasonable utilisation are the social and economic needs of the watercourse States concerned, the population dependent on the watercourse and the availability of alternatives for a particular planned or existing use. While existing uses of the watercourse is also one of the factors to be taken into account when deciding on equitable and reasonable utilisation, the nexus approach requires that States understand their common interests in enhancing water, food and energy security in a transboundary context and are willing to negotiate on the changes to existing use patterns.
The understanding of the community of interests of watercourse States can lead to fruitful negotiations and mutual gains agreements for international watercourses. If, however, watercourse States are not willing to cooperate, international water law does not contain any strong enforcement provisions to back up the compliance of its general norms. After all, very few international water disputes, for instance, have been dealt with in the International Court of Justice [
17]. As for the Mekong context, the enforcement tools of the Mekong River Commission consist mainly of diplomacy, negotiation and persuasion [
24]. Thus, in order to put the nexus cooperation in action in the framework of international water law, watercourse States have to understand its benefits to them. In this regard, the negotiations based on the nexus approach must include the different goals, actors and development alternatives that are attempting to maximise the long-term benefits of intersectoral cooperation between riparian States along the lines of the UNECE methodology for the nexus assessment of an international basin.
International human rights law as well as international water law supports the idea of the nexus approach to secure human rights to water and food. They lend clear support to the prioritisation of access to water to meet basic human needs over other water uses at both the international and national level. Therefore, when planning the uses of waters of international basins such as the Mekong, the rights to water and food must be guaranteed before allocating international waters for other purposes. At the same time, however, it must be taken into account that there might be alternative water resources such as national waters to be allocated for meeting these basic human needs. All in all, the traditionally strict divisions between international and national waters as well as inter-State and internal legal relations are gradually reshaping in the field of international water law by taking into account e.g., the emphasis on the access to water in the UNECE Protocol on Water and Health and the ILA Berlin Rules.
The general nature of the procedural and substantive requirements of international water law is a problem and an advantage at the same time from the nexus perspective. On the one hand, the rules on cooperation, on data gathering and analysis and on equitable and reasonable utilisation are ambiguous and concentrate on the uses and protection of international waters with no clear references to the energy and food sectors. On the other hand, international water law does not place any restrictions whatsoever on the consideration of energy and food sectors when the joint bodies of riparian countries cooperate and when different needs for water uses are reconciled. However, the thorough consideration of energy and food issues requires also viewpoints that go beyond the scope of traditional international water law.
The nexus approach to transboundary cooperation requires a long-term capacity and trust building between riparian States to create new opportunities through cooperation. It cannot be emphasised too much that it is of the utmost importance to create a reliable institutional structure as a basis for that cooperation. Cooperation is a step-by-step process that starts, for example, with the regular meetings of a joint committee and develops towards the in-depth nexus approach with intersectoral working and expert groups and public hearings. The essential building blocks of the cooperation are reciprocity and good faith between States as well as mutual benefits [
27,
30]. The nexus approach to the transboundary watercourses cooperation requires that riparian States perceive that the cooperation is in their common interests in the long term.
Of the two international water law conventions there are no institutional provisions in the UN Watercourses Convention, while the ECE Water Convention regulates on the Meeting of the Parties and the Secretariat with a view to be able to review the implementation of the Convention (Arts. 17–19). Thus, the ECE Water Convention is a living and dynamic convention [
27] that offers a regime where the nexus approach can be developed further in the general framework of international water law.
The water sector provides an entry point for a nexus analysis and international water law is thus one of the starting points for the discussion on the nexus approach and law [
18]. However, that discussion requires specific attention also from the viewpoints of energy and food law and national laws. It is a massive task to try to combine all the elements of the nexus approach and law and would require long-term cooperation between States and different organisations such as the UN, Food and Agriculture Organization of the United Nations (FAO) and UNECE. In addition to the coordinated and intersectoral discussions between the representatives of States, international non-governmental organisations such as the International Law Association could play an important role in enhancing the nexus approach in the context of international law.