In 2000, «environmental sustainability» was institutionalized politically, but insufficiently, in Goal 7 of the Millennium Development Goals (MDGs) (Fehling et al. 2013). Goal 7 was «to ensure environmental sustainability» and one of its objectives was «to integrate the principles of sustainable development into national policies and programmes and reverse the loss of environmental resources». Unfortunately, MDG 7 oscillates between «strong» environmental sustainability in its title and the «weaker» form of sustainable development in its goals. It seems that the classic Western idea of growth-oriented extractive development has been regularly declared dead, but persists in zombie form (Gudynas 2011). The reality is that the root of the socio-ecological crisis, such as Nebbia (2012, p. 2). 97) says that in the «myth of economic `growth` and the endless increase of its only measure»: gross domestic product (GDP). GDP remains the dominant measure of development, growth and national power, despite persistent and growing criticism (Daly, 2013; Higgs, 2014). It is primarily a measure of market transactions and production that ignores social costs, inequality and environmental degradation (Hickel 2020). It has long been clear that «GDP . a poor approximation of society`s well-being, something it should never measure» (Ward et al., 2016, pp.

11-12). This leads to the paradox that fetishizing economic growth is counterproductive, as an increasing share of GDP consists of defensive or negative spending, such as adaptation and pollution costs (Stiglitz et al. 2020). In developed countries, growth has become virtually unprofitable because its benefits no longer exceed its costs (Kallis 2018). As a result, there is a growing demand to «resist the often unconscious temptation to accept gross domestic product as an objective measure of social well-being and economic progress» (England 1998, p. 102); and instead use alternative approaches such as Bhutan`s «Gross National Happiness Index» as a measure of progress (Brooks 2013). However, the obligation to promote sustainable development does not fully reflect the due diligence structure with respect to the nature of the objective to be achieved. Due diligence obligations are essentially negative duties, obligations to prevent something, such as damage to the rights of foreigners or the environment. Conversely, the commitment to promote sustainable development is positive in itself. Entities must take steps to enable the amendment; They must create the necessary conditions for the emergence of a new situation, a situation of sustainable development.

The commitment of resources to promote sustainable development is therefore much closer to that of the doctor to a patient. 
The doctor must strive to cure the patient without being able to promise success. However, it still has to create the necessary conditions for a new situation to arise: for the patient to be cured. Today, it is almost tautological to argue that development requires growth. Despite attempts by Sen (1999) and others to interpret development as freedom through the capability approach – leading to human-centred measures of development such as the Human Development Index – the concept of development remains irrevocably anthropocentric, economistic, extractivist and growth-oriented (UNDP n.d.). By the 1960s, development had become an ideological end in itself in the form of developmentalism; Caria, Sara, and Rafael Domínguez. 2016. Ecuador`s Buen Vivir: A New Ideology for Development.

Latin American Perspectives 43 (1): 18–33. doi.org/10.1177/0094582X15611126. Gellers, Joshua C. 2021. Earth system law and the legal status of nonhumans in the Anthropocene. Earth System Governance 7: 100083 doi.org/10.1016/j.esg.2020.100083. Sustainable development thus imposes an obligation of means on legal persons, an obligation to seek or promote it. The measurement tools used to assess compliance with this commitment will vary depending on the circumstances of each case, but the essential conceptual content of sustainable development requires that states at least integrate environmental concerns into economic development projects, prevent environmental damage, and work together to achieve it. In addition, treaty commitments related to sustainable development can further limit the behaviour of governments by defining the actions that must be taken to meet their commitment. Finally, sustainable development can also influence the interpretation process. The widespread use of sustainable development in international law has aroused great scientific interest. However, due to the evasive and flexible content of what has been described by the ICJ as a concept in the Gabcˇíkovo-Nagymaros case and, more recently, as an objective in the Pulp Mills case, academic commentary often struggles to determine the legal nature of sustainable development, which has proven to be a term that defies legal classification.

An interesting thesis was Lowe`s analysis of sustainable development as an interstitial or modifying norm that exerts its normative influence as an interpretive tool in the hands of judges. Its interpretative function is certainly of great importance. Judicial authorities have used it to legitimize the use of an evolving interpretation of contracts as a dispute resolution rule and even to redefine treaty obligations. Beyond this convenient hermeneutical function, sustainable development, by setting in hundreds of treaties an objective to be pursued, claims first and foremost to regulate the behavior of States. Its objective is not absolute, but a relative commitment to sustainable development. These commitments are called commitments of maximum means or efforts. Legal persons therefore have the ultimate duty to promote sustainable development. The question of whether the conditions of a means obligation are met is usually assessed in the abstract by comparing the conduct of the State to «standard conduct» which itself satisfies those requirements. In international law, this standard behavior is what is expected of good government. It will also take into account the specific circumstances of each case, including the level of development of the State.70 This will be particularly relevant in assessing the fulfilment of States` commitments to sustainable development, with expected efforts commensurate with each State`s own capacity. Beyond these general evaluation criteria, some are specific to the commitment to sustainable development. Despite its flexibility, it requires at least equity within and between generations, as well as the integration of environmental aspects into economic development projects.

This means that States are generally expected to take an identifiable list of measures to fulfil their commitment to promote sustainable development; This list includes, inter alia, prevention, sustainable use, including decision-making, financial and technology transfer, and poverty reduction.