1. Introduction
Around 99% of European Union (EU) citizens live under heavily light-polluted skies.Footnote 1 Artificial light is everywhere, from urban centres to natural ecosystems: emissions can travel hundreds of kilometres in the form of urban sky glow.Footnote 2 However, until recently, the term ‘light pollution’ was relatively unknown. It is now receiving increased attention for two main reasons: firstly, the scientific understanding of its harmful impacts is growing; secondly, light pollution itself is rapidly growing.Footnote 3 By some estimates, global light pollution has grown by 9.7% per year, while the brightness of the night sky doubles every eight years.Footnote 4 This sharp increase in artificial light has significant environmental consequences. Studies conclude that light pollution is a major driver of insect decline.Footnote 5 It has been linked to mass wildlife deaths, (marine) ecosystem disruption, and the breakdown of symbiotic relationships between plants and pollinators.Footnote 6 This has become more of an issue as the EU Member States continue to ‘light up’.
Despite the increased use of artificial lighting at night (ALAN), there are no binding regulations at the EU level that explicitly regulate light pollution, and EU Member States vary widely in their approaches to the issue.Footnote 7 A handful of Member States, ranging from France to Croatia, have attempted to reduce light pollution by adopting national or local legislation, ordinances, and soft-law guidelinesFootnote 8 for reasons ranging from energy efficiency to dark-sky protection.Footnote 9 Yet, these norms have not been able to curb the problem, in part because of the transboundary nature of light pollution.Footnote 10 The lack of harmonization and (regulatory silence) at the EU level is noteworthy. The EU has adopted hundreds of pieces of environmental legislation: from air, water, to nature conservation. Very few parts of the natural environment have remained untouched by EU law. However, the night environment, at least visibly, has escaped regulation.
With this in mind, the aim of this article is to interrogate whether the silence of EU law on light pollution equates to a lack of relevance. It asks: ‘How does the EU govern light pollution, albeit implicitly?’ To answer this, the article examines the role of shadow governance. ‘Shadow governance’ is a term coined to capture a web of relevant instruments. It consists of numerous spillover effects from one policy domain to another, in the absence of a stated intention to regulate the latter policy domain or achieve objectives within it. In turn, the article demonstrates how existing instruments (such as the Habitats DirectiveFootnote 11 and the Ecodesign RegulationFootnote 12) implicitly govern light pollution, while carving out pathways for reform.
To structure the analysis, the article addresses three sub-research questions: (i) What is light pollution, and why should we be concerned by its rise? (ii) What is the extent of explicit EU governance on light pollution, and why has it remained limited? (iii) How do spillovers from EU legal instruments shape outcomes for light pollution indirectly? A key finding is that leveraging shadow governance can offer a pragmatic pathway for mitigating light pollution while aligning with broader EU policy goals, such as biodiversity protection and sustainable product standards.
Section 2 defines light pollution and argues that artificial lighting at night (ALAN) can be categorized as a source of pollution based on the latest scientific evidence. Section 3 outlines the limited range of the EU’s explicit governance on light pollution, showing that the silence of light pollution is an anomaly in EU environmental law. Section 4 discusses how seemingly unrelated EU instruments continue to shape how much artificial light is emitted on the ground. It thus argues for a broader scope with regard to what should be considered EU governance on light pollution, challenging the notion that EU law is irrelevant on the topic. It maps the different layers of EU governance, proposing a new framework that includes the invisible. In the end, this sets out to make the invisible visible – in the context of light pollution mitigation – and to articulate the importance of doing so. Section 5 concludes.
2. The Scientific Case for Recognizing ALAN as Pollution
The following sections set out to define the concept of light pollution and examine its negative effects. This is an important starting point. Historically, light has had primarily positive connotations, reflected in common idioms such as ‘light at the end of the tunnel’, which frame light as a symbol of hope and progress. A sound justification is needed to help in explaining the change where ALAN shifts from a mostly beneficial technology to a potentially harmful one. Therefore, this section reviews the harmful effects of light pollution through various lenses, the most notable of which includes the impact of ALAN on biodiversity, human health, and energy usage.Footnote 13 The final part brings in the loss of the night sky, which is an increasing concern amongst (amateur) astronomers.Footnote 14 Together, these components illustrate why ALAN can, and should, be deemed an anthropocentric source of pollution.
2.1. Crafting a Definition of Light Pollution
Artificial light changes a delicate balance of natural light and darkness. In this sense, not all artificial light is created equal. Light bulbs come in various wavelengths, frequencies, colours, luminosity, and at different energy costs. This means that lighting planning is a balancing act. Certain wavelengths of artificial light may be more harmful to one species than another.Footnote 15 Yet, at its core, all light, whether natural or artificial, is simply electromagnetic radiation,Footnote 16 and this radiation is far from static. To elaborate, short and long radio waves and microwaves lie on one side of this electromagnetic spectrum; on the other, one can find short gamma and Rontgen radiation waves.Footnote 17 There are many more wavelengths than the human eye can perceive (which is limited between 380 and 750 nanometres).Footnote 18 During the day, natural wavelengths change, with warmer wavelengths (red-orange) at sunrise and sunset, and shorter, blue-enriched light dominating midday.Footnote 19 At the same time, the intensity and luminosity changes depending on the time of year, the cycle of the moon, and one’s geographical location. In turn, artificial light disrupts an ancient day–night cycle.Footnote 20 To mitigate this effect, both activists and ALAN researchers argue that lighting should be dimmed where possible, switched off when unnecessary, and designed using (warmer) ecologically friendly colour spectra.Footnote 21 Light pollution mitigation does not call for complete darkness but, instead, asks us to revisit the anthropocentric lens through which we view lighting policies. It also demands that we include other non-human perspectives (by tweaking our lighting practices).
Yet, this opens a normative and technical dilemma: namely, when is light considered ‘pollution’? Defining light pollution presents unique challenges compared with other forms of pollution. For example, air pollution is a byproduct of a desirable effect, such as a running car or factory. However, light pollution can be both a byproduct and a desirable effect, changing the outdoor environment with a distinct and intended purpose. Some authors and non-governmental organizations (NGOs) have attempted to resolve this tension, by separating ‘wasted’ or ‘excessive’ light as a byproduct and ‘useful’ light as a desirable effect.Footnote 22 This is not without problems, because what is wasted or unwanted light pollution? In the end, who is to determine the outcome of this normative assessment, and who should be the subject that receives protection from said unwanted light?
Whilst this normative assessment is important and has merit for practice, relying on a narrow definition of light pollution may undermine the goal of this article – namely, to explore the different forms of EU governance addressing light pollution. Specific in-depth studies would be needed on how to quantify the exact contribution of a given instrument to light pollution and how to determine whether a specific threshold implied by the concept of ‘pollution’ has been reached in a given case. For the purpose of this article, light pollution can be defined as any artificial light emitted. More specifically, light pollution can be defined, in this broad sense, as ‘any anthropogenic ultraviolet, optical, or near-infrared radiation that affects the outdoor night-time environment’.Footnote 23 Here, the baseline is natural light, which can be objectively measured, observing the lunar and seasonal cycle.Footnote 24 This broader definition separates the political question of the level of ALAN that is socio-economically desirable from its environmental impact. This is because any artificial light – no matter how dim – can interfere with the life of a non-human animal. The following sections highlight the harm associated with ALAN, by reflecting on the various negative effects associated with its (poor) use.
2.2. Light Pollution Harms Ecosystems and Biodiversity
Conservation ecology has established robust findings on the negative impact of ALAN on individual species and ecosystems alike.Footnote 25 For example, light pollution has even been identified, in a few selected publications, to be one of the leading causes of the decline of the insect population.Footnote 26 To explain this, it is important to note that the cycle of night and day has been consistent throughout the evolutionary past, and thus all species have evolved to fit into a carefully orchestrated rhythm.Footnote 27 While some species are more vulnerable than others, artificial light negatively affects all nocturnal and diurnal species: from plants to mammals.Footnote 28 There is virtually no exception. This is because light serves not only as a resource, supporting processes such as photosynthesis and physiological recovery, but also as a biological signal, regulating circadian rhythms, spatial orientation, and key behavioural patterns.Footnote 29
A plethora of issues can occur when artificial light is introduced into vulnerable ecosystems. For example, a significant number of species, from small insects to migrating birds, rely on light to orient themselves and to navigate. Some have evolved to angle themselves towards celestial light, as a point of anchor for their flight.Footnote 30 In this case, a vacuum effect can occur whereby species are drawn to artificial light sources, trapping them. It has been estimated that a third of insects attracted to stationary light sources such as street lanterns perish before morning.Footnote 31 The insects that survive are obstructed and can no longer engage in activities that are fundamental for their survival, from pollination to reproduction.Footnote 32
Other species, however, avoid artificial light entirely, which in turn severs key migrating and foraging routes. For example, studies have found that ALAN prevents a range of nocturnal insects from moving between habitat patches, trapping them and halting pollination.Footnote 33 This results in habitat fragmentation, disrupted transboundary migration, reduced nocturnal pollination and foraging, and disturbed resting patterns.Footnote 34 In the same breath, light pollution reduces reproductive success in various species.Footnote 35 A notable example is that artificial light may cause aquatic species to deposit eggs in unsuitable, impermeable locations, while drawing hatchlings away from ancient migratory paths.Footnote 36 In other species, studies suggest that exposure to artificial light can have a negative impact on reproductive cycles by altering mating times and sex hormones.Footnote 37
Lastly, it is important to stress that exposure to ALAN can also invoke long-term biological changes within species. An intact circadian rhythm, brought on by the cycle between day and night, provides information about the relevant season.Footnote 38 As a result, exposure to ALAN can influence the biological make-up of an individual species, by speeding up or slowing down natural developmental cycles. This inevitably disturbs important symbiotic relationships between, for example, plants and pollinators, the natural patterns of which are normally in sync.Footnote 39 Altogether, this makes clear that light pollution, and the disappearance of the night, are a major threat to biodiversity.Footnote 40
2.3. Light Pollution Linked to Human Health Concerns
Research in the field of chronobiology has shown that all our cells have an innate biological clock that runs in cycles of 24 hours.Footnote 41 Light and darkness function as critical cues for regulating biological processes in the human body. As a result, exposure to ALAN at the wrong time activates our central nervous system, while suppressing melatonin production (which is a vital sleep hormone).Footnote 42 These disruptions carry significant physiological consequences. A disrupted circadian rhythm has been linked to depression, diabetes, hormone-related cancers, and sleep disorders, among other health issues.Footnote 43 For example, women are at an increased risk of developing breast cancer in overly bright neighbourhoods (compared to darker counterparts).Footnote 44 Other studies indicate that exposure to blue light at night increases the risk of disorders such as anxiety, bipolar disorder, post-traumatic stress disorder, and self-harm.Footnote 45 Similarly, sufficient exposure to natural light during the day was found to benefit the mental health of those observed.Footnote 46 In this context, the literature discussed does seem to warrant a precautionary approach, advocating smart, adaptive lighting systems designed to mimic natural light cycles, reducing blue light exposure at night. While there is no one-size-fits-all approach, with the objective of human health in mind, less light can be more.
2.4. The Energy-Climate Nexus of Light Pollution
The third problem relates to the energy usage of lighting infrastructure throughout the EU. Installing and maintaining ALAN requires substantial energy input which is, at least in part, derived from non-renewable (‘grey’) sources. In fact, 29.2% of the EU’s energy grid is (still) powered through fossil fuels.Footnote 47 Here, it is crucial to note that not all lighting is useful: studies suggest that in developed parts of the world, nearly a third of lighting is redundant, meaning no one benefits from its use.Footnote 48 For example, empty office buildings that are continuously lit emit thousands of lumens into the night sky, and cause environmental harm with limited social benefit.Footnote 49 Other times, light may be wasted as a result of poor shielding, causing light to spill into areas where it serves limited to no purpose. In fact, some estimate that up to 60% of light may be wasted in this way.Footnote 50 Lighting and energy policies are, in this sense, intertwined. This is also reflected in practice: national light pollution laws have been adopted in part to comply with climate targets.Footnote 51 In turn, changing existing attitudes towards light waste can yield considerable co-benefits for climate mitigation policies.Footnote 52
2.5. Cultural and Astronomical Losses
A final concern relates to the cultural and scientific value of preserving the night sky. Over the past decades, the loss of dark skies to light pollution has caused deeply embedded cultural shifts. For example, places where one can witness the full spectacle of the Milky Way (or a starry night sky) have diminished significantly: most Europeans do not have access to this natural wonder.Footnote 53 In this sense, light pollution has severed our connection, and that of other species, with the universe above. This loss is difficult to quantify in terms of damage, but it has led activists and astronomers to coin the term ‘noctalgia’ to reflect this sense of loss.Footnote 54 ‘Noctalgia’ comes with tangible impacts. The starry sky has inspired artistic expression and spiritual practice across cultures, has been a source of countless art pieces and religious ceremonies, often at the core of Indigenous traditions.Footnote 55 Furthermore, while this experience has carried a profound significance for past cultures, this may not be true for future generations.Footnote 56 Recent research indicates that what is left of the night sky is predicted to evaporate further in the Western world, should current trends continue. Kyba and co-authors demonstrate that a child born today in a moderately lit area could see ‘their visible star count drop from 250 to around 100 by the time they turn 18’.Footnote 57
3. The (Limited) Explicit Governance of Light Pollution within the EU
The previous sections have underscored the significance of ALAN as an anthropogenic source of pollution – from its adverse effects on biodiversity, disrupting ecosystems and species behaviour, to its implications for human health. This section turns to the central focus of the article: the governance of light pollution at the EU level. It investigates the extent to which these problems are addressed explicitly in EU law, if at all. The concept of EU governance is complex, from the sheer number of EU instruments to the broad scope of EU laws and conflicting national implementations. An exhaustive definition of EU governance, on its own, requires a separate contribution. For the purposes of this article, explicit EU governance on light pollution refers to all legal instruments and policies that mention ALAN as a source of pollution and operate at the supranational (EU) level.
With this in mind, explicit references to light pollution in EU law remain exceedingly rare.Footnote 58 Among the few existing examples, EU public procurement standards referencing light pollution have been cited as a modest but important first step.Footnote 59 These requirements can be imposed within procurement procedures to ensure that a contractor meets specified environmental standards. Moreover, the European Commission’s Directorate-General for Environment (DG ENVI) recently published a policy brief on light pollution, which includes guidelines for responsible outdoor lighting, urging Member States to take action.Footnote 60 Light pollution is also mentioned in the EU Taxonomy RegulationFootnote 61 and the Environmental Impact Assessment (EIA) Directive, in which it is identified as a possible pollutant within definitional provisions.Footnote 62 Finally, the newly adopted Nature Restoration Law mentions light pollution reduction in ecosystems as a possible ‘restoration example’ of a measure under the Regulation.Footnote 63
However, as things stand, binding laws and regulations do not go beyond defining the issue; nor do they provide an overarching target for EU-wide reduction.Footnote 64 These instruments fail to set an explicit goalpost, with a deadline, quotas or interventions shared between Member States. Unsurprisingly, the combined effect of these explicit measures has not been sufficient to curb the growth of light pollution on the European continent. Various authors have stressed this failure of EU law: a recurring critique is that the EU lacks (effective) legislative initiatives on light pollution mitigation.Footnote 65
3.1. The Competence Question: Can the EU Regulate Light Pollution?
The lack of EU regulatory intervention could be explained by the lack of competence to legislate. In EU law, not every policy issue is conferred on Brussels, such as education policies, which remain fully in the hands of Member States. Even in areas of shared competence, EU action must adhere to the principles of subsidiarity, requiring intervention only when objectives cannot be sufficiently achieved by Member States, and proportionality, ensuring that any action is limited to what is necessary to achieve its aims.Footnote 66 It could thus be argued that lighting policies are a local matter on which the EU should not legislate. However, it is argued in this section that the EU has the legislative competence to intervene in light pollution. The first of such relevant competences relates to the environment (Article 191 of the Treaty on the Functioning of the EU (TFEU)Footnote 67), while the second competence pertains to the internal market, more specifically the free movement of goods, as well as competitive distortions between lighting producers (Article 114 TFEU).
In short, as a matter of EU constitutional law, in areas of shared competence the EU may act only where ‘the objectives of an action cannot be sufficiently achieved by the Member States, but can be better achieved at the EU level, by reason of the scale and effects of the proposed action’.Footnote 68 This legal constraint is designed to prevent unnecessary intervention. However, with this in mind, there is a strong case that light pollution is best regulated at the EU level. Whilst a careful case-by-case analysis is required, the transboundary nature of light pollution (as a result of skyglow), the migration of affected species, and the cross-border elements of affected ecosystems provide robust arguments in this case.Footnote 69 ALAN can travel hundreds of kilometres, with the result that light emitted in Belgium may have an impact on a natural ecosystem in Germany, and vice versa. These physical spillovers from one Member State to another invite an EU approach.Footnote 70 This is even more apparent when it comes to the regulation of lighting products, which will fall under the internal market provision (Article 114 TFEU). Harmonizing standards for more eco-friendly lightbulbs naturally lends itself to EU intervention, as conflicting standards may impede the proper functioning of the EU internal market and distort competition between Member States.Footnote 71
Lastly, it should be stressed that in order to meet the various targets set out in key EU policies, a coherent response to the problem of light pollution is essential. For example, the EU Biodiversity Strategy strives to halt the decline of genetic diversity before the year 2030, whereas the Zero Pollution Action Plan seeks to bring an end to all pollution by 2050.Footnote 72 Moreover, the EU Pollinators Incentive, adopted in 2018, reaffirms the need to tackle the primary causes of pollinator decline, which include ALAN.Footnote 73 Given the high wildlife mortality associated with light pollution (as set out in Section 2), these targets cannot be met without addressing the growth of artificial light throughout the EU. This raises the need to reflect on why the EU legislator has thus far remained silent on light pollution, despite a clear competence and incentive to intervene. The following section examines the possible reasons for this inaction.
3.2. Exploring the EU’s Regulatory Silence on Light Pollution
While there is a strong case that light pollution should be regulated at the EU level, the remaining question is, why is it not? One contributing factor is the persistent lack of awareness regarding the issue. In the scientific community, the harmful effects of light pollution on ecology and public health have only begun to receive significant attention in recent years.Footnote 74 Social scientists began to engage with the issue even later.Footnote 75 This delay may partly reflect a ‘diurnal bias’ in research and policymaking alike, as observed by Owens and co-authors.Footnote 76 According to this view, an inherent biological bias in favour of daytime might lead humans to see light through a positive lens.Footnote 77 As a result, light risks being perceived predominantly as a source of comfort by legislators, policymakers, and the general public, with few drawbacks.
Another explanation for the regulatory delay is the relatively late mobilization of civil society around this issue. The first wave of mobilization by actors originated among amateur astronomers, who gradually noticed constellations disappearing from the night sky over a period of 40 years.Footnote 78 Yet, as an isolated group, they did not have the impact they desired. It was not until the literature on conservation ecology widely established the negative impact of light pollution on biodiversity that a second wave of mobilization unfolded, this time within the environmental movement. At present, groups mobilizing around light pollution are highly diverse, ranging from ‘astronomers, environmentalists, heritage preservationists, politicians, industry actors, and lighting designers’.Footnote 79 Remarkably, Zielińska-Dąbkowska identifies a threefold increase in light pollution-related litigation on a global level since the 1990s.Footnote 80 However, this too is a recent development, with most cases clustering in the past two decades. As is often the case, the law lags behind: it has yet to catch up with the literature on ALAN research in the fields of conservation ecology and human endocrinology.Footnote 81
In sum, explicit EU governance on light pollution remains highly limited. However, it is important to note that explicit law and governance is far from the only matter of importance for light pollution mitigation. Indirect governance may be far more extensive at present than its explicit counterpart.
4. The EU’s Indirect Governance of Light Pollution
The preceding sections outlined the scientific foundations of light pollution, demonstrating why the increasing use of ALAN poses a significant environmental challenge in the EU. It also touched on the lack of explicit EU law and governance on light pollution. Yet, as the following sections argue, this silence does not mean that the EU’s regulatory framework bears no relevance for the issue. On the contrary, this article introduces the concept of ‘shadow governance’ to capture the ways in which EU law exerts influence on the issue of light pollution through regulatory impacts that are unseen, unintended, or indirect.
4.1. Defining Shadow Governance
Shadow governance captures additional, often indirect, ways in which the EU governs a topic that it has not addressed directly. This form of governance operates through what this article refers to as the cumulation of ‘regulatory spillover effects’. This type of governance arises when a spillover effect is generated by an EU instrument that is not related directly to the governance issue at hand.Footnote 82 It is important to note that spillover effects are understood in different ways across the literature. For example, knowledge spillover effects have been cited as the positive impacts that ‘subjects not involved in the knowledge creation can receive’.Footnote 83 Spillovers are also brought up in the context of the unintended consequences of monetary policies, the impact of public norms on private workplace inequality, and in relation to the positive and negative co-benefits associated with climate mitigation policies.Footnote 84 As a final example, in the environmental sphere, spillovers have been used to describe how the reduction of one pollutant through regulatory intervention can lead to an increase in the use of ‘other non-regulated pollutants’.Footnote 85 Despite its varied use, the term ‘spillover’ often refers to effects that are unintended, unexpected, indirect, or ancillary.
Crucially, in this context, a spillover effect arises when legislation or soft law that does not mention light pollution explicitly nonetheless has a potential bearing on it. This article introduces a taxonomy distinguishing between spillovers with negative and positive effects.Footnote 86 Negative spillover governance refers to instances where regulatory frameworks unintentionally exacerbate light pollution, often as a result of conflicting priorities or design flaws that overlook ecological impacts.Footnote 87 Positive spillover governance, in contrast, describes binding norms that mitigate light pollution indirectly by embedding broader environmental protection or sustainability requirements.Footnote 88 This article argues that recognizing these cumulative spillovers as a form of governance opens a new lens through which to map and study domains that we perceive as unregulated at best and forgotten at worst.
The following sections identify several examples of shadow governance. They also propose forms of intervention to remedy the negative spillover effects while capitalizing on potential positive effects. One important caveat is that not all potentially relevant instruments can be discussed. However, the selection criteria for this analysis are designed to ensure comprehensive coverage across various subsections of EU law. Specifically, the selected instruments must (i) represent diverse areas within EU environmental law, adopted under different legal bases from internal market to the environment, as well as auxiliary instruments developed by standard-setting bodies; (ii) have the potential to create a significant impact on Member State policy and legislation, which is limited to instruments that either bind Member States or significantly influence national-level governance.Footnote 89 Lastly, particular attention is given to instruments that (iii) reflect recent advancements or revisions in the field of environmental law. With these criteria in mind, this analysis focuses on the CEN Lighting Standards,Footnote 90 the Energy Labelling Directives,Footnote 91 the Ecodesign for Sustainable Products Regulation,Footnote 92 and the Habitats Directive,Footnote 93 with brief reference to recent revisions in EU consumer law under the European Green Deal.Footnote 94
4.2. Negative Spillover
CEN Road Lighting Standards
The first regulatory spillover can be found embedded within the CEN Road Lighting Standards.Footnote 95 These standards are non-binding but are relied on ubiquitously, drawn up by the European Committee for Standardization (CEN), and widely used throughout the EU as the gold standard in project development for, most notably, road lighting projects.Footnote 96 Šubic notes, for example, the difficulty in challenging these standards by local residents, noting that they are at times ‘completely powerless’ to do so because of the authoritative status of such standards, which is on a par with legislation.Footnote 97 Two key spillovers can be identified.Footnote 98
Firstly, as a result of relatively high minimum lighting levels and uniformity requirements, the CEN Road Lighting Standards often lead to excessive illumination in low-need, rural areas.Footnote 99 Another related critique is that the standards do not sufficiently encourage the usage of warmer colour temperatures (≤ 2200 or 2700K), despite growing concerns about the negative ecological effects of blue-rich illumination in sensitive areas.Footnote 100 As a result, a remote alpine mountain village risks being treated in a similar way to a busy urban intersection: a linear grouping of lights, at a low interval.Footnote 101 It is noteworthy that many of these low-need sites warrant softer, targeted, orientational lighting at strategically placed points.Footnote 102 Precisely because the CEN Standards fail to reflect such site-specific lighting needs, they have been reported to hinder local initiatives to reduce light pollution.Footnote 103
In conclusion, while these standards do not explicitly seek to regulate light pollution, they have significant consequences because of their tendency to push for over-illumination.Footnote 104 To address this spillover, CEN Standards ought to be updated in line with the best available techniques on light pollution mitigation (which maintains visibility).Footnote 105 To achieve this, input from civil society and ecologists should be central in CEN standard-setting procedures. Although the European Parliament has long advocated the inclusion of a more diverse range of stakeholders in these procedures, progress in this respect has been slow.Footnote 106 Moreover, the outcome of these standards remains inaccessible to the public (behind a paywall), despite having significant implications for the application of EU law.Footnote 107 Therefore, the spillover uncovered above strongly supports the existing calls for increased transparency and accountability on the part of the CEN.Footnote 108
EU Energy Labelling Regulation and Energy Efficiency Requirements
The Energy Labelling Regulation is the second relevant example that contains a notable spillover with regard to light pollution mitigation.Footnote 109 This instrument enacts a uniform label on the package of lighting products, which allows consumers to quickly verify a product’s energy rating. The energy classes span from the top-rated green ‘A’, indicating high efficiency, to the lowest-rated red ‘G’, signifying poor efficiency. This has turned out to be a successful instrument: the Eurobarometer showed that 93% of consumers recognize the label, and almost 80% of consumers take it into account when deciding which product to purchase.Footnote 110 It is, therefore, one of the most important means of nudging consumers to influence the sales of lighting sources.Footnote 111 In turn, the aim of the Energy Labelling Regulation is also to encourage manufacturers to produce more energy-efficient lamps and, above all, to increase the market share of energy-efficient light emitting diode (LED) lamps.
An additional complication in this respect, however, stems from the ‘LED paradox,’ as identified by Schulte-Römer and others.Footnote 112 LEDs are gradually replacing older lighting structures to comply with climate targets and reduce energy consumption.Footnote 113 Here, three main factors are of concern from the perspective of light pollution mitigation. Firstly, LEDs naturally emit a blue wavelength, which is considerably more harmful to biodiversity and human health because of its resemblance with daytime lighting.Footnote 114 Secondly, LEDs are prone to over-illumination as a result of their luminous efficacy. A few watts of energy used translate to much brighter environments compared to past technologies.Footnote 115 In the past, energy usage was a good predictor of the luminosity for city planners and consumers alike, but LEDs have changed this. Thirdly, LEDs eliminate the need for local governments or consumers to conserve the usage of ALAN for economic reasons because of their low usage costs.Footnote 116 This dynamic, commonly referred to as the LED paradox, highlights the fragmentation and problem-shifting between biodiversity protection and climate mitigation policies.Footnote 117
With this in mind, the LED paradox results in a negative spillover effect on light pollution. The current labelling system for lighting products focuses solely on energy consumption. As the label does not take into account factors such as colour temperature and brightness, it allows LED products with characteristics harmful to biodiversity and human health to receive a ‘green’ label. This can mislead consumers into believing their choice is environmentally sound. Therefore, these standards are not only a missed opportunity to inform the public about the impacts of light pollution, but also actively promote a narrow understanding of sustainability.
A potential solution is to incorporate additional variables into the benchmark of the existing label to determine a comprehensive sustainability rating of lighting products. These variables could include brightness, spectral composition, and adaptive dimming capabilities, depending on the product in question. However, this will require a revision of the EU Energy Labelling Regulation and may face resistance as such, as energy efficiency is an important metric for consumers.Footnote 118 A promising alternative, therefore, is to create a second complementary EU ‘dark sky’ label through the newly Revised Regulation for EU Sustainable Products.Footnote 119 This revised Regulation creates an opportunity to certify dark-sky lighting, as it provides a mandate for the EU Commission to design specific sustainability labels through Implementing Regulations.Footnote 120 This approach has the potential to address the shortcomings of the current narrow labelling system, which feeds into the LED paradox, while informing small-scale consumers, large businesses, and (local) governments on the broader sustainability impact of their purchase.
EU Eco Design laws
A third regulatory spillover emerges from the Ecodesign Directive and its implementing acts.Footnote 121 This Directive establishes legal requirements for energy-related products before they can be circulated in the EU’s internal market. It sets design parameters, requiring lighting manufacturers to comply with minimum standards for energy efficiency and safety. The design of lighting products may play a critical role in shaping usage patterns. Theoretically, it provides an ideal framework to address light pollution by regulating artificial lighting for commercial and public usage at the source.
It is noteworthy that past iterations of the Ecodesign Directive did include such provisions on light pollution mitigation. For example, the 2009 Directive stipulated that light-spill going upward should be no more than ‘1% for all road classes and lumen outputs in sensitive areas’.Footnote 122 However, these provisions have subsequently been removed to ‘streamline the implementation’.Footnote 123 As a result, the spillover that remains can be summarized as follows: the legal design of lighting products is bound primarily by energy efficiency and safety constraints, and not by the light pollution they can potentially cause. The Directive does not define strict standards on the broader environmental impact of lighting, leaving products designed for the outdoors (or sensitive ecological areas) with limited constraints on (blue) colour temperatures, excessive luminosity, or the dimmability of products.Footnote 124
Yet, from a legal perspective, there is room for a more stringent approach to address this spillover. In 2023, the Ecodesign framework was revised through the adoption of the Ecodesign for Sustainable Products Regulation under the EU Green Deal.Footnote 125 This Regulation broadens the product standards that can be harmonized, empowering the European Commission to establish sustainability requirements on products addressing ‘any negative or positive change in the environment during its life cycle’.Footnote 126 This new mandate allows for two complementary approaches to light pollution.
Firstly, it could provide a pathway to revisit overarching product standards for light sources that take into account the ecological harm of ALAN, with specific requirements depending on their intended use. For example, stricter constraints should be applied to lighting products designed for sensitive applications, as was the case under past iterations.Footnote 127 Secondly, the Ecodesign Directive provides an opportunity to standardize specialized dark-sky (or ecologically friendly) lighting throughout the EU to combat fragmentation in design standards.Footnote 128 Light pollution laws have been adopted across the EU, from France to Croatia, increasing the demand for dark sky-friendly lighting fixtures and products.Footnote 129 However, given the breadth of national laws, EU-wide standardization can help to ensure that these products are competitive and, crucially, mass-produceable.Footnote 130 In sum, this intervention may actively reduce light pollution, without sacrificing necessary flexibility based on contextual lighting and/or safety needs.
4.3. Positive Spillover
EU Habitats Directive
So far, we have reviewed negative spillovers that have the potential to worsen light pollution at present. However, the EU Habitats Directive accounts for a positive spillover effect, stemming from its open-ended conservation aims.Footnote 131 This does not constitute an unintended spillover but rather a broad norm that indirectly addresses light pollution through regulation.Footnote 132 In short, the Habitats Directive seeks to ensure that protected areas and species achieve a favourable conservation status.Footnote 133 When natural ecosystems are in poor conservation condition, these obligations become even more critical, reinforcing the need for Member States to act promptly to achieve these aims (rather than creatively stalling obligations).Footnote 134 The poorer the state of nature, the more stringent these obligations become. With 81% of the EU’s protected areas currently in poor condition, the key question arises: When might the mitigation of light pollution become a legal requirement under the Habitats Directive, even if only implicitly?Footnote 135
The spillover consists of three parts.Footnote 136 Firstly, while light pollution is not addressed explicitly within the Habitats Directive,Footnote 137 the mitigation of light pollution may be required in order to maintain a favourable conservation status for protected species and sites, in line with Articles 6(1) and 2(2) of the Habitats Directive. In these provisions, the Directive establishes a requirement for the Member State to adopt ‘necessary conservation measures’ within protected areas that ‘correspond to their ecological requirements’.Footnote 138 While an assessment has to be made on a case-by-case basis, when the favourable conservation status of a protected area is negatively affected by light pollution, positive action is required to mitigate these effects.Footnote 139 Specifically, measures must be adopted for light-sensitive species and habitat types listed in the Annexes of the Directive. One example from practice is the management plan of the protected site Voormalig Klooster Mariahoop in the Netherlands.Footnote 140 While darkness is the baseline in the protected area itself, the plan also alters lighting practices in the vicinity of the protected site, such as reducing the height of street lanterns, limiting their usage, and prescribing the use of amber colours.Footnote 141
Secondly, Article 6(2) prohibits subsequent deterioration of protected areas.Footnote 142 Deterioration can be qualified as ‘any process and/or event that causes the habitat type to lose its representativity, impacting its structure and/or functions’.Footnote 143 Here, ecological research has clearly established that a loss of natural darkness has an impact on representativity, especially as growing brightness levels cause a deviation from the recorded baseline. The scientific evidence of potential deterioration is mounting; from the disruption of symbiotic relations between plants and pollinators, altered predation, reduced mating and the fragmentation of foraging routes.Footnote 144 As a result, the Directive requires Member States to formulate conservation goals tailored to the needs of individual sites that reflect ‘the threats of degradation and habitat destruction to which … species are exposed’.Footnote 145 More specifically, this norm encapsulates a legal obligation for protected areas to be kept naturally dark, to avoid such deterioration. This is also in line with the precautionary principle, which entails that where there is scientific evidence of potential harm to the environment or biodiversity, even in the absence of full certainty, measures must be taken to prevent or mitigate the risk.
Finally, it is noteworthy that excessive levels of ALAN can cause a deliberate disturbance of protected species, which holds relevance for Article 12 of the Habitats Directive.Footnote 146 However, in order to establish whether a disturbance and/or killing is deliberate, it must be proven that the entity either acted with intent or, as is relevant for light emissions, ‘accepted the outcome of their actions’.Footnote 147 There is a clear consensus in the ecological literature that ALAN disturbs the natural behaviour of species.Footnote 148 As a result, in severe cases, light emissions within natural reserves may meet the threshold under Article 12. To prevent breaches of this provision, the level of protection is to be adapted based on ‘the needs and conservation status of the species in question’.Footnote 149 The bottom line is that the national system must be ‘coherent and coordinated of a preventative nature’.Footnote 150 Member States must enforce these prohibitions effectively and ‘take preventative measures to protect said species’.Footnote 151 These may, for example, entail campaigns to raise awareness, the prevention of disturbances by monitoring, and the adoption of robust conservation plans.Footnote 152 The Habitats Directive, in turn, obligates Member States to mitigate the risk of disturbances caused by ALAN, particularly with regard to resting places and breeding sites.Footnote 153 Crucially, all acts that lead to disturbance of resting and/or breeding sites, whether deliberate or not, are to be prohibited.
In summary, although the Habitats Directive does not explicitly set targets to reduce light pollution, it does generate obligations that are relevant to light pollution. Addressing light pollution becomes a crucial, if implicit, obligation. However, in practice, not a single Member State has reported on light pollution mitigation in respect of the implementation of the Habitats Directive.Footnote 154 Moreover, management plans of protected areas frequently fail to formulate targets to mitigate light pollution, even when there is a clear reason to do so (for instance, because of the presence of a light-sensitive species).Footnote 155 As noted by Schroer and co-authors, this can be explained partly by the fact that local governments struggle with a lack of awareness of light pollution, resulting in deficits in conservation practice.Footnote 156
To resolve this, there lies a dual role for the EU Commission and civil society alike to ensure compliance with EU law. For example, it will be necessary to promote best practices in EU implementation manuals. At the same time, enforcement of current obligations is key, either through infringement proceduresFootnote 157 instigated by the EU Commission, or through renewed advocacy efforts, such as campaigns or legal action, to ensure compliance with the Habitats Directive.Footnote 158 At present, one can raise questions about whether minimum requirements are met in most Member States when reviewing the level of light pollution within and near protected ecosystems.Footnote 159
EU consumer protection law
The Directive on Empowering Consumers for the Green Transition,Footnote 160 which revises certain parts of EU consumer law, contains a final spillover which captures obligations on light pollution. The instrument creates far-reaching obligations for retailers when those retailers make environmental claims. An environmental claim means ‘any non-mandatory message in a commercial context’ that suggests ‘a product, brand or trader has a positive, neutral or comparatively reduced impact on the environment’.Footnote 161 Many retailers of lighting products in online shops claim as part of their marketing strategy that energy-efficient light bulbs are ‘good for the environment’. This applies also to excessively bright (outdoor) lamps with a blue colour index (above 5500K) solely because of their respective energy efficiency.Footnote 162 These claims can be characterized as an environmental claim, as defined under the Empowering Consumers Directive.
The positive spillover stems from the fact that, under the new law, it is impossible to assert that an environmental claim applies in relation to future environmental performance without ‘clear, objective, publicly available and verifiable commitments, with measurable and time-bound targets, set out in a detailed implementation plan and regularly verified’.Footnote 163 The Directive builds on the existing Unfair Commercial Practices Directive, whereby retailers will have to consider a much broader range of variables when advertising lighting products as ‘sustainable’ to the general public and procuring governments.Footnote 164 This may reasonably encompass factors such as colour temperature, brightness, and the broader ecological and health impacts of a lighting fixture. The new Empowering Consumers Directive, therefore, may help in preventing misleading marketing practices and tackle the LED-paradox in the process.Footnote 165
5. Conclusion
This article has outlined how the EU governs light pollution. It posits that this is done in two ways. Firstly, the EU’s explicit governance of light pollution is limited. Light as a source of pollution is an outlier in EU environmental law, in that it is not the object of overarching targets. Explicit interventions at the EU level are limited to soft guidelines or superficial mentions in instruments such as the Environmental Impact Assessment Directive. This remains the case even though there are strong arguments in favour of a more ambitious legislative programme. Ultimately, the silence of the EU on this topic is indicative of the anthropocentric lens through which ALAN has long been favourably perceived.
Secondly, the article has opened up a wider scope of inquiry for potentially relevant instruments, pushing back on the notion that EU law is irrelevant for light pollution governance in the absence of direct regulation. It argues that light pollution is subject to ‘shadow governance’, which arises from the cumulation of regulatory spillovers from one policy domain to another. Five examples have been given, ranging from the EU Habitats Directive to the Energy Labelling Regulation. It should be noted in this context that light pollution mitigation demands a sense of urgency. Many species are deprived of darkness while they depend on it, and children may grow up in a Europe where stars are no longer visible in the night sky. Failure to regulate light pollution has potentially irreversible biodiversity, health, and cultural implications. This article concludes that to halt this trend, the EU ought to address the diffuse and indirect ways in which it contributes to this emerging environmental problem.Footnote 166
Acknowledgements
This article benefited from discussions during the Doctoral Workshop on EU Law at the European University Institute, Florence (Italy), and the Living Law Conference at Wageningen University, Wageningen (The Netherlands). I am especially grateful to Joanne Scott, whose critical insights and warm support have profoundly shaped this work. I would also like to thank Emily Barritt for her formative conceptual suggestions, and Deirdre Curtin, Marina Chernenko, Tine Deschuytere, Saverio Della Corte, Valerie Albus, Ieva Huna and Arianna Crosera for their thoughtful comments on earlier drafts. A warm thanks is further extended to the two anonymous TEL peer reviewers for their excellent feedback. AI was not used for research or analysis; language support tools were employed for style.
Funding statement
This research was made possible with support from the Dutch Organisation for Internationalisation in Education (NUFFIC) and Dienst Uitvoering Onderwijs (DUO).
Competing interests
The author declares none.
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