‘Science’ in Court – the Importance of Specificity, by E Lees and T Paloniitty

To generalise about the use of scientific information by Member State courts in cases involving the Habitats Directive is not only impossible, but also hides crucial dimensions in the day-to-day practice of EU Environmental law. It is important, instead, to take account of the role that the language used in the Directive plays; the process by which it is interpreted; and the nature of the ‘scientific’ information before an adjudicator. In short – when considering how the Habitats Directive works – specificity, and a deep interrogation of context, is critical.


Decision-making in courts relating to the Habitats Directive inevitably engages that court in reviewing or assessing scientific information. It is the very essence of the Directive that it requires all decision-makers, be they administrative or judicial, to be ‘guided by the science’. However, as the pandemic showed so clearly, it is one thing to state that one is ‘following the science’ and quite another to know where that science leads. Indeed, that experience demonstrated that scientific information is but one part of the puzzle when attempting to make complex decisions based on assessment of risk, long and short-term predictions, and the operation of natural forces.

Nonetheless, the Court of Justice of the European Union (CJEU) in much of its case law emphasises the importance of relying upon clear and definitive scientific information so that no doubts remain. In the context of the Habitats Directive, this means that the Court instructs Member State administrations to effectively refuse authorisations for plans or projects where it cannot be proved beyond doubt that they will not harm protected environments. This interpretation of articles 6 and 12 of the Directive sits in line with the expressed purpose of the Directive, and with the overarching concerns of the precautionary principle.

However, the matter cannot rest there, for it remains to be seen how, in the administrative set-up of each Member State, the power to resolve the question as to whether there is pertinent scientific doubt and uncertainty is distributed. Furthermore, each authority or court may interpret the scientific information before them differently. It therefore seems likely that such information will be used and discussed in a range of ways in Member State courts. To find out whether this was true was the aim of this collective research project.

In this first chapter of the book, we explored two central questions. First, what is the decision-making framework established by the Habitats Directive and how and when are scientific information and uncertainty important within the operation of that framework? Second, what is scientific information properly understood, and therefore how should we think of ‘science’ in court?

Exploring Variation in Member State Courts – The Directive as a Framework

In this edited collection, we have brought together country studies from a range of current and former Member State courts, as well as perspectives from Australia, to ask how power to interpret, create and resolve scientific information and uncertainties is distributed between court and administrative authority. This required an examination not only of the case law under the Habitats Directive itself, but an extensive review of the ways in which courts in each state review information relied upon by administrative authorities. Unsurprisingly, there is a great deal of variation. This emerges from the different constitutional underpinnings of each state, their administrative culture, and even the procedural and funding aspects of the court service.

In order to build this research, in the first chapter, we began by unpacking the ways in which the text of the Directive itself indicates that such information should be used. In doing so we were aiming to map the ways in which the Directive might engage with scientific information, and where uncertainty therefore fits into the picture.

We identified four key questions in understanding how the tests established by the Directive work in practice.

1. Who gets to decide?

2. Upon which information will their decision be based?

3. What processes must be undertaken so that this information is of recognised legal quality?

4. To what extent will the decision-maker interrogate decisions or information provided by an alternative decision-maker?

It is clear that there will be variation in how these questions are answered. By looking closely at the Directive, one can see that the answers to these questions will vary even within a single Member State depending on which part of the Directive is under examination.

Exploring Variation – Constitutional Underpinnings

To understand how science is used in court, the first step is to understand what the legislation itself is asking from that scientific information. But this is only the first step. The second step is to understand what power to interrogate that information has been given to each court – not by the Directive itself – but by the constitutional and administrative underpinnings of the state. Here variation sits across multiple dimensions and depends not only on the identity of the state, but the precise judicial forum, the level of authority of a court, their procedural rules, their expertise and resources, and the factual context of the dispute in front of them.

Crucially, the final fora which decides how these questions of constitutional and administrative power are answered will be the courts of the Member States, not the CJEU. When the CJEU dictates that the decision to authorise a plan or project must be based on scientific information with no caveats, that is up-to-date, and in relation to which there remains no reasonable doubt, ‘[h]ow an adjudicator envisages the role that science should play in answering these questions is of central importance, and that in turn, depends on two things: what they think science is and how central they think that should be to answering the question at hand’ (ch 1). The identity (lower Court, purely judicial bench or scientific bench etc) and Constitutional role of the adjudicator as an actor within a wider political system will, amongst other factors, heavily influence their perspective on scientific information.

Furthermore, because scientific information is never a neutral baseline from which one can derive absolute certainty, that a judge has to cope with this uncertainty is an inevitability. But how they cope with it is not a consequence only of the kinds of uncertainty that are actually present in the information. It is also a consequence of the tools – both legal and practical – at the court’s disposal when determining whether the science is ‘too’ uncertain or not. Therefore, as we argue in the opening chapter of the book, ‘[t]he different handling of science in environmental cases then is not only a consequence of more or less certain science; but also of more or less expertise embedded within a decision-making process; of more or less experience with the science, and, most importantly, is a consequence of the type of decision being made’ (ch 1).  

What is ‘science’?

The final question we address in the chapter is asking what science is for the purposes of our analysis. Of course, this is a question which is irresolvable: what is and what is not scientific information is contested. Science is not an immutable store of facts and so what distinguishes ‘science’ from other processes of information generation is always a matter of degree and doubt. If it is not possible to provide a precise definition to science, however, that does not mean that we cannot begin to explore possible meanings. In the chapter we explore two: scientific information as factual statements derived from the application of the scientific method, i.e. the testing of a hypothesis; and scientific information as the opinion of a person who has expertise in relation to a particular area of scientific inquiry. In court, a judge is more likely to be faced with this second form of scientific information. In practice this means that the mode of presentation of that opinion, the qualifications of the opinion-giver, and their own certainty in their own opinion will all be part and parcel of the scientific information which a court is required to interrogate.

The Importance of Specificity

This chapter, therefore, brings together two arguments. First, the division of power within the Directive, and through the constitutional and administrative underpinnings of the Member State, will profoundly influence how scientific uncertainty affects the operation of the Directive. Because this will vary from Member State to Member State, so too will the application of the Directive itself. Second, that scientific information is at least two things – the provision of factual information derived through the scientific method, and the opinion of a person with relevant expertise. When a court is faced with the latter, the way the scientific information influences the adjudicatory processes depends upon factors not limited to the nature of the information itself.

For our research project as a whole, the primary lessons of these conclusions were threefold. First, when thinking about EU environmental law and the operation of the precautionary principle, the precise legal forms, through which the principle percolates, matter. The language used in a Directive, the role it assigns to decision-makers, and the kind of information which becomes relevant will shape how risk is managed. Second, just as the precise language of a Directive or Regulation matters, so too does the wider administrative law of the relevant Member State. Here the specific rules of judicial review will have a profound influence on how a Court addresses itself to these scientific disputes. Finally, the specifics of the scientific information provided to the Court will also change how the court handles it when making precaution-driven environmental decisions. This is a question of substance and form. In short, it is not only impossible to generalise about how Member State courts will handle scientific information when adjudicating on disputes arising under the Habitats Directive, to attempt to do so would obfuscate the way in which the Directive creates a complex network of power divisions between different organs of the state.

Posted by E Lees and T Paloniitty

Emma Lees is Academic Director and Professor of Transnational Law at the School of Transnational Law at the European University Institute. She is also Professor of Environmental and Property Law, University of Cambridge, and the Peter Wilson Fellow at Fitzwilliam College.

Tiina Paloniitty is Postdoctoral Research at Helsinki Institute of Sustainability Science and Eric Castrén Institute, Faculty of Law, University of Helsinki.

Suggested citation: E Lees and T Paloniitty, “‘Science’ in Court – the Importance of Specificity”, REALaw.blog available at https://wp.me/pcQ0x2-tc