Lighting Professionals versus Light Pollution Experts? Investigating Views on an Emerging Environmental Concern

Concerns about the potential negative effects of artificial light at night on humans, flora and fauna, were originally raised by astronomers and environmentalists. Yet, we observe a growing interest in what is called light pollution among the general public and in the lighting field. Although lighting professionals are often critical of calling light ‘pollution’, they increasingly acknowledge the problem and are beginning to act accordingly. Are those who illuminate joining forces with those who take a critical stance towards artificial light at night? We explore this question in more detail based on the results of a non-representative worldwide expert survey. In our analysis, we distinguish between “lighting professionals” with occupational backgrounds linked to lighting design and the lighting industry, and “light pollution experts” with mostly astronomy- and environment-related professional backgrounds, and explore their opposing and shared views vis-à-vis issues of light pollution. Our analysis reveals that despite seemingly conflicting interests, lighting professionals and light pollution experts largely agree on the problem definition and problem-solving approaches. However, we see diverging views regarding potential obstacles to light pollution mitigation and associated governance challenges.

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The duration of artificial light defines sexual signalling in the common glow-worm

Behavioral Ecology and Sociobiology ◽

10.1007/s00265-021-03093-2 ◽

2021 ◽

Vol 75 (11) ◽

Author(s):

Christina Elgert ◽

Topi K. Lehtonen ◽

Arja Kaitala ◽

Ulrika Candolin

Keyword(s):

Negative Impact ◽

Light Exposure ◽

Sensory Ecology ◽

Mitigation Measures ◽

Light Pollution ◽

Artificial Light ◽

Negative Effects ◽

Light At Night ◽

Night Time ◽

Sexual Signalling

Abstract Artificial light at night is increasing globally, interfering with both sensory ecology and temporal rhythms of organisms, from zooplankton to mammals. This interference can change the behaviour of the affected organisms, and hence compromise the viability of their populations. Limiting the use of artificial light may mitigate these negative effects. Accordingly, we investigated whether the duration of artificial light affects sexual signalling in female glow-worms, Lampyris noctiluca, which are flightless and attract flying males to mate by emitting glow that is interfered by light pollution. The study included three treatments: no artificial light (control), 15 min of artificial light, and 45 min of artificial light. The results show that females were more likely to cease glowing when the exposure to light was longer. Furthermore, small females were more likely to cease their glow, and responded faster to the light, than larger females. These findings suggest that glow-worms can react rapidly to anthropogenic changes in nocturnal light levels, and that prolonged periods of artificial light trigger females to stop sexual signalling. Thus, limiting the duration of artificial light can mitigate the adverse effects of light pollution on sexual signalling, highlighting the importance of such mitigation measures. Significance statement Interest in the effects of artificial light at night on animal behaviour has increased in recent years. With evidence for its negative impact accumulating, potential remedies, such as limiting the duration of light exposure, have emerged. To date, however, knowledge on the effectiveness of these methods has remained very limited. We show that female European common glow-worms, which are wingless beetles that glow to attract flying males to mate, responded to prolonged artificial light exposure by discontinuing their glow. Such non-glowing females are not expected to find a mate, making it difficult for them to reproduce. Hence, our study indicates that the duration of artificial light should be limited to protect this night-active beetle and its opportunities for effective sexual signalling. Because many other nocturnal species also need darkness, this study provides valuable information for the development and use of less disruptive night-time lights.

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A Systematic Review of Research Investigating the Combined Ecological Impact of Anthropogenic Noise and Artificial Light at Night

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.765950 ◽

2021 ◽

Vol 9 ◽

Author(s):

Wouter Halfwerk ◽

Paul Jerem

Keyword(s):

Systematic Review ◽

Observational Studies ◽

Ecological Impact ◽

Experimental Studies ◽

Ecological Impacts ◽

Anthropogenic Noise ◽

Light Pollution ◽

Artificial Light ◽

Light At Night ◽

The Impact

Levels of anthropogenic noise and artificial light at night (ALAN) are rapidly rising on a global scale. Both sensory pollutants are well known to affect animal behavior and physiology, which can lead to substantial ecological impacts. Most studies on noise or light pollution to date have focused on single stressor impacts, studying both pollutants in isolation despite their high spatial and temporal co-occurrence. However, few studies have addressed their combined impact, known as multisensory pollution, with the specific aim to assess whether the interaction between noise and light pollution leads to predictable, additive effects, or less predictable, synergistic or antagonistic effects. We carried out a systematic review of research investigating multisensory pollution and found 28 studies that simultaneously assessed the impact of anthropogenic noise and ALAN on animal function (e.g., behavior, morphology or life-history), physiology (e.g., stress, oxidative, or immune status), or population demography (e.g., abundance or species richness). Only fifteen of these studies specifically tested for possible interactive effects when both sensory pollutants were combined. Four out of eight experimental studies revealed a significant interaction effect, in contrast to only three out seven observational studies. We discuss the benefits and limitations of experimental vs. observational studies addressing multisensory pollution and call for more specific testing of the diverse ways in which noise and light pollution can interact to affect wildlife.

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Impact of Dim Light at Night on Urinary 6-Sulphatoxymelatonin Concentrations and Sleep in Healthy Humans

International Journal of Molecular Sciences ◽

10.3390/ijms21207736 ◽

2020 ◽

Vol 21 (20) ◽

pp. 7736

Author(s):

Katarina Stebelova ◽

Jan Roska ◽

Michal Zeman

Keyword(s):

Sleep Quality ◽

Real Life ◽

Artificial Light ◽

Health It ◽

Negative Effects ◽

Light At Night ◽

Healthy Humans ◽

Home Based ◽

Fragmentation Index ◽

Melatonin Production

Artificial light at night can have negative effects on human wellbeing and health. It can disrupt circadian rhythms, interfere with sleep, and participate in the progress of civilisation diseases. The aim of the present study was to explore if dim artificial light during the entire night (ALAN) can affect melatonin production and sleep quality in young volunteers. We performed two experiments in real-life home-based conditions. Young volunteers (n = 33) were exposed to four nights of one lux ALAN or two nights of five lux ALAN. Melatonin production, based on 6-sulphatoxymelatonin/creatinine concentrations in urine, and sleep quality, based on actimetry, were evaluated. Exposure to ALAN one lux during the entire night did not suppress aMT6s/creatinine concentrations but did aggravate sleep quality by increasing sleep fragmentation and one-minute immobility. ALAN up to five lux reduced melatonin biosynthesis significantly and interfered with sleep quality, as evidenced by an increased percentage of one-minute immobility and a tendency of increased fragmentation index. Our results show that people are more sensitive to low illuminance during the entire night, as previously expected. ALAN can interfere with melatonin production and sleep quality in young, healthy individuals, and both processes have different sensitivities to light.

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The preference and costs of sleeping under light at night in forest and urban great tits

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2019.0872 ◽

2019 ◽

Vol 286 (1905) ◽

pp. 20190872 ◽

Cited By ~ 8

Author(s):

Zeynep N. Ulgezen ◽

Teemu Käpylä ◽

Peter Meerlo ◽

Kamiel Spoelstra ◽

Marcel E. Visser ◽

...

Keyword(s):

Oxalic Acid ◽

White Light ◽

Cognitive Abilities ◽

Daily Activity ◽

Activity Patterns ◽

Spectral Composition ◽

Green Light ◽

Artificial Light ◽

Negative Effects ◽

Light At Night

Artificial light at night (ALAN) is an increasing phenomenon associated with worldwide urbanization. In birds, broad-spectrum white ALAN can have disruptive effects on activity patterns, metabolism, stress response and immune function. There has been growing research on whether the use of alternative light spectra can reduce these negative effects, but surprisingly, there has been no study to determine which light spectrum birds prefer. To test such a preference, we gave urban and forest great tits (Parus major) the choice where to roost using pairwise combinations of darkness, white light or green dim light at night (1.5 lux). Birds preferred to sleep under artificial light instead of darkness, and green was preferred over white light. In a subsequent experiment, we investigated the consequence of sleeping under a particular light condition, and measured birds' daily activity levels, daily energy expenditure (DEE), oxalic acid as a biomarker for sleep debt and cognitive abilities. White light affected activity patterns more than green light. Moreover, there was an origin-dependent response to spectral composition: in urban birds, the total daily activity and night activity did not differ between white and green light, while forest birds were more active under white than green light. We also found that individuals who slept under white and green light had higher DEE. However, there were no differences in oxalic acid levels or cognitive abilities between light treatments. Thus, we argue that in naive birds that had never encountered light at night, white light might disrupt circadian rhythms more than green light. However, it is possible that the negative effects of ALAN on sleep and cognition might be observed only under intensities higher than 1.5 lux. These results suggest that reducing the intensity of light pollution as well as tuning the spectrum towards long wavelengths may considerably reduce its impact.

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Working with Inadequate Tools: Legislative Shortcomings in Protection against Ecological Effects of Artificial Light at Night

Sustainability ◽

10.3390/su12062551 ◽

2020 ◽

Vol 12 (6) ◽

pp. 2551 ◽

Cited By ~ 7

Author(s):

Sibylle Schroer ◽

Benedikt John Huggins ◽

Clementine Azam ◽

Franz Hölker

Keyword(s):

Adverse Effects ◽

Environmental Law ◽

Population Level ◽

Light Pollution ◽

Artificial Light ◽

Legal Analysis ◽

Light At Night ◽

Environmental Laws ◽

Legal Obligations ◽

Special Protection

The fundamental change in nocturnal landscapes due to the increasing use of artificial light at night (ALAN) is recognized as being detrimental to the environment and raises important regulatory questions as to whether and how it should be regulated based on the manifold risks to the environment. Here, we present the results of an analysis of the current legal obligations on ALAN in context with a systematic review of adverse effects. The legal analysis includes the relevant aspects of European and German environmental law, specifically nature conservation and immission control. The review represents the results of 303 studies indicating significant disturbances of organisms and landscapes. We discuss the conditions for prohibitions by environmental laws and whether protection gaps persist and, hence, whether specific legislation for light pollution is necessary. While protection is predominantly provided for species with special protection status that reveal avoidance behavior of artificially lit landscapes and associated habitat loss, adverse effects on species and landscapes without special protection status are often unaddressed by existing regulations. Legislative shortcomings are caused by difficulties in proving adverse effect on the population level, detecting lighting malpractice, and applying the law to ALAN-related situations. Measures to reduce ALAN-induced environmental impacts are highlighted. We discuss whether an obligation to implement such measures is favorable for environmental protection and how regulations can be implemented.

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Satellite measurements of artificial light at night: aerosol effects

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3157 ◽

2020 ◽

Vol 499 (4) ◽

pp. 5075-5089

Author(s):

S Cavazzani ◽

S Ortolani ◽

A Bertolo ◽

R Binotto ◽

P Fiorentin ◽

...

Keyword(s):

Cloud Cover ◽

Temporal Evolution ◽

Aerosol Concentration ◽

Light Pollution ◽

Artificial Light ◽

Satellite Measurements ◽

Light At Night ◽

Lunar Cycles ◽

Aerosol Effects

ABSTRACT The study of artificial light at night (ALAN) by satellite is very important for the analysis of new astronomical sites and for the long-term temporal evolution observation of the emission from the ground. The analysis of satellite data presents many advantages but also some critical points because of fluctuations in measurements. The main result of this paper is the discovery of a correlation between these fluctuations and the aerosol concentration combined with cloud cover and lunar cycles. In this work, we also present a mathematical empirical model for the light pollution propagation study in relation to the aerosol concentration detected by satellite. We apply this model to the astronomical site of Asiago (Ekar Observatory) providing a possible explanation for the temporal ALAN fluctuations detected by satellite. Finally, we validate the results with the ground collected data.

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Artificial Light at Night Reduces Anxiety-Like Behavior in Female Mice with Exacerbated Mammary Tumor Growth

Cancers ◽

10.3390/cancers13194860 ◽

2021 ◽

Vol 13 (19) ◽

pp. 4860

Author(s):

William H. Walker ◽

Raegan M. Kvadas ◽

Laura E. May ◽

Jennifer A. Liu ◽

Jacob R. Bumgarner ◽

...

Keyword(s):

Tumor Growth ◽

Mammary Tumor ◽

Anxiolytic Effect ◽

Sucrose Preference ◽

Artificial Light ◽

Negative Effects ◽

Light At Night ◽

Tumor Bearing ◽

Tumor Onset ◽

Mammary Tumor Growth

Artificial light at night (ALAN) is a pervasive phenomenon. Although initially assumed to be innocuous, recent research has demonstrated its deleterious effects on physiology and behavior. Exposure to ALAN is associated with disruptions to sleep/wake cycles, development of mood disorders, metabolic disorders, and cancer. However, the influence of ALAN on affective behavior in tumor-bearing mice has not been investigated. We hypothesize that exposure to ALAN accelerates mammary tumor growth and predict that ALAN exacerbates negative affective behaviors in tumor-bearing mice. Adult (> 8 weeks) female C3H mice received a unilateral orthotropic injection of FM3A mouse mammary carcinoma cells (1.0 × 105 in 100 μL) into the fourth inguinal mammary gland. Nineteen days after tumor inoculation, mice were tested for sucrose preference (anhedonia-like behavior). The following day, mice were subjected to an open field test (anxiety-like behavior), followed by forced swim testing (depressive-like behavior). Regardless of tumor status, mice housed in ALAN increased body mass through the first ten days. Tumor-bearing ALAN-housed mice demonstrated reduced latency to tumor onset (day 5) and increased terminal tumor volume (day 21). Exposure to ALAN reduced sucrose preference independent of tumor status. Additionally, tumor-bearing mice housed in dark nights demonstrated significantly increased anxiety-like behavior that was normalized via housing in ALAN. Together, these data reaffirm the negative effects of ALAN on tumorigenesis and demonstrate the potential anxiolytic effect of ALAN in the presence of mammary tumors.

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Artificial light at night increases growth and reproductive output in Anolis lizards

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2019.1682 ◽

2020 ◽

Vol 287 (1919) ◽

pp. 20191682 ◽

Cited By ~ 2

Author(s):

Christopher J. Thawley ◽

Jason J. Kolbe

Keyword(s):

Reproductive Output ◽

Urban Environments ◽

Egg Laying ◽

Endocrine Function ◽

Artificial Light ◽

Negative Effects ◽

Light At Night ◽

Brown Anole ◽

Negative Impacts ◽

Growth And Reproduction

Since the invention of electric lighting, artificial light at night (ALAN) has become a defining, and evolutionary novel, feature of human-altered environments especially in cities. ALAN imposes negative impacts on many organisms, including disrupting endocrine function, metabolism, and reproduction. However, we do not know how generalized these impacts are across taxa that exploit urban environments. We exposed brown anole lizards, an abundant and invasive urban exploiter, to relevant levels of ALAN in the laboratory and assessed effects on growth and reproduction at the start of the breeding season. Male and female anoles exposed to ALAN increased growth and did not suffer increased levels of corticosterone. ALAN exposure induced earlier egg-laying, likely by mimicking a longer photoperiod, and increased reproductive output without reducing offspring quality. These increases in growth and reproduction should increase fitness. Anoles, and potentially other taxa, may be resistant to some negative effects of ALAN and able to take advantage of the novel niche space ALAN creates. ALAN and both its negative and positive impacts may play a crucial role in determining which species invade and exploit urban environments.

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National Scale Spatial Variation in Artificial Light at Night

Remote Sensing ◽

10.3390/rs12101591 ◽

2020 ◽

Vol 12 (10) ◽

pp. 1591 ◽

Cited By ~ 2

Author(s):

Daniel T.C. Cox ◽

Alejandro Sánchez de Miguel ◽

Simon A. Dzurjak ◽

Jonathan Bennie ◽

Kevin J. Gaston

Keyword(s):

Human Health ◽

National Parks ◽

Urban Areas ◽

Infrared Imaging ◽

Natural World ◽

Light Pollution ◽

Artificial Light ◽

Light At Night ◽

Challenges And Opportunities ◽

Per Capita

The disruption to natural light regimes caused by outdoor artificial nighttime lighting has significant impacts on human health and the natural world. Artificial light at night takes two forms, light emissions and skyglow (caused by the scattering of light by water, dust and gas molecules in the atmosphere). Key to determining where the biological impacts from each form are likely to be experienced is understanding their spatial occurrence, and how this varies with other landscape factors. To examine this, we used data from the Visible Infrared Imaging Radiometer Suite (VIIRS) day/night band and the World Atlas of Artificial Night Sky Brightness, to determine covariation in (a) light emissions, and (b) skyglow, with human population density, landcover, protected areas and roads in Britain. We demonstrate that, although artificial light at night increases with human density, the amount of light per person decreases with increasing urbanization (with per capita median direct emissions three times greater in rural than urban populations, and per capita median skyglow eleven times greater). There was significant variation in artificial light at night within different landcover types, emphasizing that light pollution is not a solely urban issue. Further, half of English National Parks have higher levels of skyglow than light emissions, indicating their failure to buffer biodiversity from pressures that artificial lighting poses. The higher per capita emissions in rural than urban areas provide different challenges and opportunities for mitigating the negative human health and environmental impacts of light pollution.

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Ecological Impact of Artificial Light at Night: Effective Strategies and Measures to Deal with Protected Species and Habitats

Sustainability ◽

10.3390/su13115991 ◽

2021 ◽

Vol 13 (11) ◽

pp. 5991

Author(s):

Annika K. Jägerbrand ◽

Constantinos A. Bouroussis

Keyword(s):

Protected Areas ◽

Ecological Impact ◽

Measurement Methods ◽

Ecological Impacts ◽

Mitigation Strategies ◽

Light Pollution ◽

Artificial Light ◽

The European Union ◽

Light At Night ◽

Landscape Characteristics

When conserving or protecting rare or endangered species, current general guidelines for reducing light pollution might not suffice to ensure long-term threatened species’ survival. Many protected areas are exposed to artificial light at levels with the potential to induce ecological impacts with unknown implications for the ecosystems they are designated to protect. Consequently, it is recommended that precautionary methods for the avoidance and mitigation of light pollution in protected areas be integrated into their management plans. This paper’s aims are to present an overview of best practices in precautionary methods to avoid and mitigate light pollution in protected areas and to identify and discuss what ecosystems should be considered light-sensitive and how to prioritise species and habitats that need protection from artificial light, including examples of legislation covering ecological light pollution in the European Union and in Sweden. The important aspects to include when considering light pollution at a landscape level are listed, and a proposal for prioritisation among species and habitats is suggested. Sensitive and conservation areas and important habitats for particularly vulnerable species could be prioritised for measures to minimise artificial lighting’s negative effects on biodiversity. This may be done by classifying protected natural environments into different zones and applying more constrained principles to limit lighting. The light pollution sensitivity of various environments and ecosystems suggests that different mitigation strategies and adaptations should be used depending on landscape characteristics, species sensitivity and other factors that may determine whether artificial light may be detrimental. Issues of the currently used measurement methods for artificial light at night are reviewed. We also propose and discuss the principles and benefits of using standardized measurement methods and appropriate instrumentation for field measurements of artificial light concerning the environmental impact of light pollution.

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