In an article from ten years ago, addressing the issue of climate litigations, the legal disputes concerning climate change, the author noted that most of them were brought against governments to introduce limits or controls on greenhouse gas emitting activities or against companies involved in their production (especially oil multinationals) to comply with existing regulations. Only in recent years, the article continued, have disputes emerged that address the issue of liability for the damages caused by climate change. These, however, did not provide specific evidence against the alleged responsible parties and did not refer to specific weather events (the two most notable disputes of the time were brought in 2006 by some Northeastern US states against companies that produced electricity using coal and by California against car manufacturers).

Since then, climate disputes have progressively increased - a "now global phenomenon", as described in a 2019 review - due to many concurrent factors: the worsening damage caused by climate change, the Paris Agreement coming into force, the fundamental decisions issued by Dutch courts in the famous Urgenda case, and the spread of protest movements. In recent years, legal actions seeking compensation for damages caused by specific atmospheric events against those deemed responsible for the events or their exacerbation have also increased.

This is the result of advancements in climate science and the development of a specialized discipline known as attribution science.

The path to recognizing the damage

In reality, the issue of liability for climate damages appeared in international negotiations over thirty years ago. In 1991, during the negotiations preceding the approval of the Framework Convention on Climate Change, AOSIS, a newly formed association representing small island states most exposed to the consequences of climate change, raised the issue. They proposed not compensation hypotheses but the establishment of an international insurance fund financed by developed countries to compensate victims of rising sea levels. The proposal was not even considered due to the opposition of all industrialized countries, even though it was easy to predict that the issue would resurface strongly in the following years as climate change would cause significant and sometimes irreversible damage to the most vulnerable states.

However, it took more than twenty years for, in the face of the increasingly evident failure of mitigation policies and the difficulties of implementing adaptation strategies, especially in the non-industrialized countries of the so-called Global South¹, during the Framework Convention's Conference of Parties (COP-19) held in Warsaw in 2013, the issue of climate change damages became the subject of a specific discipline: the Warsaw International Mechanism for Loss and Damages (WIM). The term loss and damages refers to the impacts of climate change that are not or cannot be controlled through adaptation strategies and cause permanent harm.

Finally, in 2015, with the Paris Agreement, the damage caused by climate change was added to mitigation and adaptation and recognized as the third pillar of the ccc containment policy. However, the provisions introduced were influenced by the compromise necessary due to the opposition of industrialized countries, especially the United States, who feared that the acknowledgment would lay the groundwork for damage compensation requests from countries most affected by climate change effects against those historically considered responsible. Thus, Article 8.1 states that "Parties recognize the importance of avoiding and minimizing loss and damage associated with the negative effects of climate change, including extreme weather events and slow-onset events, and of addressing them and also recognize the importance of sustainable development's role in reducing the risk of loss and damage", while Article 8.3 refers to cooperation to exclude any liability profile.

For added security, developed countries insisted on the inclusion of a clarification in the Decision (the text that forms the Paris Outcome with the Agreement): paragraph 51 states that Article 8 does not constitute "a basis for liability or compensation claims"².

The attribution science

Actions seeking compensation for damages caused by climate change would not be possible without the contributions of climate sciences and the development of a scientific discipline known as attribution science. Until a few years ago, while subsequent IPCC reports provided increasingly alarming scenarios on the effects of global warming, the impossibility of attributing specific atmospheric events to anthropogenic causes was considered a certainty. However, the situation changed rapidly. With the development of attribution science, it became possible to statistically demonstrate the anthropogenic influence on individual atmospheric events, not only quantifying the probability of their occurrence but also the magnitude of the effects.

The first major research in this area was conducted in 2004 by a group of scientists from the University of Oxford, who demonstrated that the heatwave that hit Europe in 2003, causing over 70,000 deaths, was twice as likely due to human influence on the climate. Since then, the number of studies and the precision of the methodologies have grown rapidly.

Today, attribution science is a fundamental element in climate change disputes: it allows identifying the role of anthropogenic activities in specific atmospheric events and provides the necessary evidence in legal actions.

In addition, this new discipline contributes to the awareness of the impact of human activities on the climate, reinforcing the need for prompt and effective action.

The contribution of attribution science in the field of climate change disputes can be considered twofold: on the one hand, it allows identifying the liability of specific subjects, on the other hand, it provides the necessary evidence to support legal actions. Furthermore, the results of this discipline, by highlighting the impact of human activities on the climate, contribute to raising awareness and mobilizing public opinion, and consequently, also the political world.