This distribution depends not only on technological, economic, social and cultural variables but also on the political-institutional structure of the diverse States. Different societies and cultures react differently to comparable uncertainties.

The new factors that have appeared in recent years are the questions associated with climate change. The scientific community considers that global warming is undeniable, and that it is highly likely that, over the next few decades, the planet will have to face the serious climate changes brought about by anthropic activities, changes that will be very dangerous both for the people and for the ecosystems that co-habit on the planet. Global warming happens because certain gases accumulate in the atmosphere. These gases can retain the infrared radiation emanating from Earth: changes in the terrestrial energy balance determine the increase in global temperatures.

While the increase in CO2 emissions, the main climate altering gas, is almost entirely the result of the use of fossil fuels and to the changes in soil use, (e.g., deforestation), the other two main greenhouse gases, methane (CH4) and nitrous oxide (N2O) are mainly generated by agricultural and zootechnic activities. The problem of emissions resulting from food production is more important in the short term, whereas CO2 emissions resulting from burning fossil fuels are, in the long term, the real heart of the problem.

To stabilise the concentrations of greenhouse gases in the atmosphere and, hence, the temperature of the planet, there must be a substantial reduction in the emissions of climate-changing gases in coming decades. Policies aiming to mitigate climate change must involve all sectors, not only those, such as the production and consumption of energy, that are among the most responsible for global emissions.

Thus, climate regulation measures must be taken at an international level, given that the environment is supranational so it can only be regulated at an international level through agreements between States. At the international level, the first attempt to combat polluting emissions was made on the 9th May 1992, when, under the aegis of the United Nations, the Rio di Janeiro Convention United Nations Framework Convention on Climate Change - UNFCCC, was approved. The objectives of this document were to stabilise the concentrations of greenhouse gases in the atmosphere to prevent and avoid dangerous interference with the climate system.

However, this Convention had little impact, it was efficacious in that it was a “soft law”, not mandatory and called upon the Parties to commit to a generic pledge to reduce CO2 emissions to their 1990 levels.

The international community did make legally binding commitments in the Kyoto Protocol, which offered the first means of actualising the UNFCCC “Framework Agreement”. In this Protocol, the Parties committed to reducing their overall greenhouse gas emissions by 5.2%, with respect to 1990, in 2008-2012.

To reduce emissions specific “Units” (called Assigned Amount Units - AAU) were allocated to each country which then had to stay within the limits of the units it had been assigned. To meet these obligatory targets, the States that had signed could use specific “credits” by adopting any of three options for flexibility: joint implementation, clean development and emission trading. Of the three, emission trading plays the most crucial role. Emission trading implies setting a cap on the emissions permitted, with a system for allocating “emission quotas” and then, trading them. Art. 17 of the Protocol establishes that those countries that receive these AAUs, and who can manage to keep their emissions below their target, can then sell their “surplus” AAUs to other countries that, by buying them, are able to reduce theirs, i.e., offset their excess emissions and, by doing so, “meet” their obligatory reduction target.

Nowadays, the rules and regulations for the battle against climate change are those laid out in the Paris Agreement, drawn up in December 2015. One hundred and seventy-five countries attended the opening ceremony, which marked the signing of the agreement, This was followed by a rapid ratification process, which enabled the Agreement to come into force on the 4th of November 2016. This Agreement marked an important moment in the development of international action, with respect to its predecessor the Kyoto Protocol, which latter had had a rigid conceptual and normative structure, and, almost 20 years after its adoption, in 1997, no longer reflected the needs, or aims, of the international community. Thus, the Paris Agreement overcame the rigidity of the Kyoto Protocol and began to replace it in the international community’s actions to thwart climate change by implementing the objectives and the principles, sanctioned by the framework convention of 1992, on climate change that still underlie international actions on the question.

As regards the juridical nature of the Accord, one could argue that it is a binding international treaty as defined by Art. 2, par. 1, lett. a) of the Convention of Vienna. Indeed, it can indubitably be defined as a written agreement drawn up between States and regulated by international law regardless of what it has, in reality, been termed. This is true even though many of the provisions of the Paris Agreement do not establish precise obligations for actions or for results, but it could also be defined as provisions of “due diligence” as has been, correctly, stated. The main evidence of this is that there are no binding obligations for the Parties to reduce their greenhouse gas emissions, something which, in the Paris Agreement, was replaced by a system of non-binding mitigation, to be set up autonomously, and voluntarily, by each Party. Whether or not these national contributions are respected, is subject only to indirect, facilitative checks carried out by the institutions provided for in the Agreement.

The non-binding nature of most of the provisions of the Paris Agreement is confirmed by the fact that, as regards the non-binding national mitigation contributions, many countries have opposed the use of the word “shall” instead of “should” when establishing the obligations of the Parties. Furthermore, with the use of the phrase “non-binding national contributions” instead of “binding obligations for reducing”, which was used in the Kyoto Protocol, there is a clear and unequivocal desire, of the Parties, not to be subjected to binding obligations such as those enshrined in the Paris Agreement.

At the European level the Kyoto Protocol was ratified by the EU on the 2nd of June 2002, while the Directive proposal, presented on the 25th of October 2001, was adopted two years later, on the 13th of October 2003 (Directive 2003/87/EC of the European Parliament and Council 13 10 2003 that set up a system for exchanging emission quotas of greenhouse gases in the Community which modified Directive 96/61/EC of the Council). The Directive introduced an exchange system (that was to become operational on the 1st of January 2005) on the basis of which plant managers were assigned a certain number of quotas of emissions that they were permitted to produce. The total number of quotas assigned determined the maximum limit, the cap, of emissions that all the participants in the system could produce globally. Those who managed to stay at, or below, this cap were considered to be “emission creditors” who could concede “credits” to other States that had exceeded theirs. The reward function of this regulation is clear, in that those who do not manage to reduce their emissions must acquire “credits” from others in order to “achieve” their cap level which they have exceeded.

In general, the Directive rests on two pillars: the authorisations, which all plant managers participating in the system must acquire, and the emission quotas themselves, measured and expressed in equivalent tons of CO2, which allow their owner (the plant manager) to emit one ton of carbon dioxide per year. Each year, by the 30th of April, plant managers must declare the emissions released by the plant during the previous solar year and these must correspond to those noted in the Register. When they the quotas available have been exceeded, they risk sanctions.

The Directive provides for another important institute: the National Register. Given that the quotas only exist in electronic form, each interested party can hold quotas and withdraw them from the market so long as they have an open account with the National Register. National Registers are essential, not only as a way of supervising exchanges at the level of companies, but also to check that the commitments, made by the member States through the Agreement to share the burdens, are being respected.

The 2003 Directive was subsequently modified by the “Linking Directive” emanated in 2004 (Directive 2004/101/EC of the European Parliament and Council of 20th of October 27 contains a modification of Directive 2003/87/EC that sets up a system permitting the exchange of emission quotas for greenhouse gases in the Community, in relation to the mechanisms of the project in the Kyoto Protocol) with the aim of opening up the Community system of exchanging emission quotas to project-based mechanisms (JI and CDM).

The 2003 Directive was further modified by the 2009/29 Directive (Directive 2009/29/EC of the European Parliament and Council of 23rd April that modified Directive 2003/87/EC with the intent of perfecting and extending Community system for exchanging quotas for emissions of greenhouse gases), which sought to resolve some problematic issues that had emerged after Directive 2003/87 had been emanated, and which had sought to rationalise, and extend, the scope of application of the ETS system.

Currently, the Emissions Trading System, as updated in the light of Directive n. 2018/40, falls within the wider circle of the “Package for climate and energy 2020 and, consequently, also within that of the “Framework for climate and energy 2030. In this latter, the European Union has committed to reducing greenhouse gas emissions to at least 40% below 1990 levels.

In line with the international trend, in this important mitigation plan whose measures are, on the one hand, improvements of at least 32.5% as regards energy efficiency and, on the other, an increase of at least 32% in the amount of energy from renewable sources consumed, there is a note: “European strategy for adapting to climate changes”, that seeks to minimise the economic, environmental, and social impact of climate change.

Given the constraints and obligations that weigh upon States, and the centrality of the principle of the effectiveness of the safeguards, the quaestio of the remedies for climate change is crucial. One particularly important aspect is the controversial opportunity offered for individuals to challenge international and European obligations in Courts. One of the principles for such judicial action can be found not only in the already mentioned international Conventions, but also in the Oslo Principles on Global Climate Change Obligations of 1st March 2015. This Charter of principles, drawn up by a group of internationalists from various countries, affirms that notwithstanding the fact that there are no binding treaties, and that States do have a margin of discretion when deciding how they will fulfil their obligations, both international law, above all the precautionary principle, and individual national legal systems, may well be able force governments to adopt all measures that aim to prevent any climate change that could lead to a rise of more than 2°C above that of the level of the pre-industrial era.

Among the various actions against governments, both those announced and those underway, is that brought before the Supreme Court of the Netherlands which resulted in a recent sentence regarding the climate emergency. This sentence stated that the National Government must reduce the levels of both CO2 and other greenhouse gas emissions by 25%, with respect to 1990 levels, by the end of 2020. Unlike the fiscal approach, according to which an order to “create legislation” is not admissible and that it would have an impact on the system of the separation of powers, the Court recognised that there was a real and proper positive obligation for the State to protect the lives and health of its citizens.

Furthermore, in support of the Court’s reasoning, Articles 93 and 94 of the Dutch Constitution establish that the State must observe every disposition of the European Court of Human Rights, in that every part of these is binding; thus, since the Netherlands comes under the jurisdiction of the European Court of Human Rights (ECHR), Dutch Courts must interpret the articles of the Convention in the light of the same hermeneutic parameters as those adopted in The Court in Strasbourg.

The guarantees enshrined in Articles 2 and 8 of the European Court of Human Rights — the right to life and to respect for private and family life — mean that there is a need to take steps to prevent, even from the standpoint of the precautionary principle, prejudices related to climate change.

Since measures of mitigation must be taken to reduce greenhouse gas emissions by at least 25%; from the emissions of greenhouse derives, according to the logic of the decisum, the fact that the Court can order that such measures be adopted. If it were not so, it would infringe a fundamental rule of constitutional democracies, that of the right to effective recourse: Article 13 of the UDHR. Thus an “order to create legislation” would be admissible, since there is no general prohibition of interference on the part of the Courts within the political decision-making process so, when necessary, as laid down in Article 94 of the Dutch Constitution, “the courts must disapply legislation if any binding provisions of treaties entail such.”

According to the Dutch Supreme Court, conflicts with the principle of the separation of powers would only occur if the Courts were to order the creation of legislation with a specific, concretely defined content; identifying the “final aim”, that of reducing greenhouse gas, would not affect the freedom of State legislators to choose the measure or measures to be adopted to achieve their desired objectives, in the best, and most efficient, way.

Still in the Netherlands, in a more recent case on the 26th of May 2021, the District Court of Aja ordered Royal Dutch Shell to reduce its CO2 emissions by 45%, with respect to 1990 emission levels, by 2030. The Judge decided that the Company was obliged to adopt a Company policy that would reduce their CO2 emissions. The decision is based on the unwritten principle of due care, established by the Dutch Civil Code and interpreted by judges in the light of international soft law.

The sentence is important, (perhaps even revolutionary) because violation of the obligation to reduce emissions is not envisaged and, indeed, improvements in the sustainability of the activity is recognised. However, there is a perceived lack of concreteness, connected to individual responsibility for climate change. This responsibility is not linked to State actions, and it manifests as an obligation of result and of best efforts with suppliers and clients upon whom the company is asked to use its influence through the Group’s internal policies. Thus, the Company does have a free choice in how it will meet the objective of reducing emissions, but is obliged to do so, to meet the objective(s).

In light of the above, it has to be noted that climate change is a sensitive global issue that requires strong international cooperation. Several measures have already been taken both at an international and European level. However, to stabilise the concentrations of greenhouse gases in the atmosphere and, hence, the temperature of the planet, policies aiming to mitigate climate change that involve all sectors are necessary. In addition, the challenge of international and European obligations remains a crucial point for individuals, with a jurisprudence still in constant evolution.