download/eurobats/Bats%20and%20light%20pollution.pdf ]. Presetnik, P., Koselj, K., Zagmajster, M. (ur.) 2009. Atlas netopirjev (Chiroptera) Slovenije,
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KLEDMHIAU IUCNcd/m2 lxkelvin, unit for correlated colour temperature of a lamp (the higher the value of colour tem -perature the greater the share of the blue part of the spectrum the emitted light contains) light-emitting diode metal-halide lampInternational Astronomical Union International Union for Conservation of Nature candela per square metre is the unit for expressing the luminance of surfaces lux is the unit for measuring illuminance (1lx = 1 lumen per square metre (1 lm/m 2))Photopic and scotopic vision Œ day and night vision Introduction Light pollution is destroying the nocturnal image of nature The rapid increase of light pollution The in˜uence on the environment of illuminating objects of cultural heritage Legislation governing light pollution in Slovenia and in other countries Legislation protecting animal species and their habitats Light pollution of an inappropriately illuminated smaller country church White LED lamps pose a great threat to nature at night The impact of arti˚cial light on people and animals Research within the Life at Night project on the in˜uence of church illumination on moths and bats The in˜uence of lighting on moths The in˜uence of external lighting on bats Recommendations for nature-friendlier illumination of objects of cultural heritage Sources List of acronyms and units Contents
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Introduction This brochure o˛ers a collection of recommendations for nature-friendlier illumination of objects of cultural her -itage prepared within the LIFE+ Life at Night project in cooperation with the Slovenian National Commission for UNESCO. Humans of course require light at night; however, exaggerated and inappropriate illumination may lead to a series of negative consequences that disturb natural processes, cause long-term health risks, hinder astronomical obser -vations and unnecessarily increase energy consumption. The LIFE+ Life at Night project focused on objects of cultural heritage. Slovenia is known for its many churches scattered all over the country. According to information from the Slovenian Bishops™ Conference, there are 2864 Catholic churches in Slovenia. In 2013, 1445 of them were entered in the Slovenian Register of Immovable Cultural Heritage as cultural monuments. Most churches are illuminated. Unlike the case of public lighting and illumination of buildings, for which it is prohibited to use lamps that emit light above the horizontal plane, cultural monuments may be illuminated from the ground up. Such illumination causes a lot of light pollution. The key purpose of this project was to contribute to long-term reduction of negative impacts caused by illumina -tion of churches and other objects of cultural heritage and thus improve the conservation status and biodiversity of nocturnal animals. Our goal was to ˚nd proper technical solutions for nature-friendlier and more energy-e˝cient ill- umination for objects of cultural heritage. We developed a lamp to improve the existing lighting of 21 pilot church -es. The results of three years™ research by biologists have shown that improved lighting reduced the negative impact of illumination on moths and bats. With the improved lighting, we also managed to reduce energy consumption by 40% to 90% depending on the energy consumption of original lighting at an individual church. However, reducing energy consumption is by far not the most important criterion of improvement. It is more important that negative impacts of illumination at night on environment, people and animals be reduced. Some objects in this brochure are not named because their lighting will be improved in the near future. Recom -mendations represent an upgrade of the Decree on Limit Values due to Light Pollution of Environment (OG RS, No 81/2007; hereinafter: Decree) governing the illumination of cultural monuments by taking into consideration the latest ˚ndings of biologists. We hope that the new ˚ndings will be used both in Slovenia, in the EU and worldwide. Light pollution is destroying the nocturnal image of nature We live on a planet where the astounding beauty and variety of nature inspire us and enrich our lives. To many, contact with nature represents an opportunity to get in contact with oneself and loved ones. We live in a world of paradoxes, and most of humanity wishes for more rapid development mostly measured in the length of new roads, surface of cultivated areas, number of shopping centres, in energy infrastructure and in material goods with a questionable service life. Due to anthropogenic release of greenhouse gases, the average temperature of the environment increases. Glaciers are melting, snow is becoming increasingly rare in winter, and during summers, temperatures are reaching record levels. The increased thermal energy of oceans results in more intense weather phenomena which will a˛ect the majority of the world™s population in coming decades. Previously ordinary weather phenomena such as droughts, storms and winds are becoming ever more extreme and destructive. In the shadow of global warming, nature is undergoing degradation which is no less important than the releasing of greenhouse gases. Biodiversity is reducing extremely rapidly and so is the share of natural environment. The living environment of plants and animals is shrinking and fragmenting due to construction and ever more intense agriculture. The International Union for Conservation of Nature (IUCN) is warning that the extinction of animal and plant species has never been as rapid as it is now, and it is increasing annually. Unlike many other European countries, Slovenia still has a small percentage of land where its inhabitants can enjoy nature in its pristine state. Unfortunately, this applies only during the day. When it gets dark, the sky takes on an orange colour and stars are fiwashed outfl and we are left with only a faded version of the natural starry sky. In Europe too, light pollution has fiwashed outfl the stars from the sky. The night sky above most beautiful natural 2
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parks has become light polluted. There is not a single piece of land in Europe where one can enjoy a natural starry sky as it was for instance 100 years ago, even from big but modestly illuminated cities. When it is cloudy, sky bright -ness in the urban environment can increase even tenfold (Kyba et al. 2011). When snow falls, the re˜ection of light from snow causes additional increases in light pollution. Cerknica from Slivnica. Maribor from Pohorje. Even on mountain summits we cannot experience nature in its pristine state at night because light pollution is spreading through clouds. The Horsehead Nebula in the constellation of Orion. In the declaration for the 2009 International Year of Astro -nomy, UNESCO wrote: fiThe sky is our common and universal heritage and is a part of the human environment.fl The disappearance of the natural environment is a subject of increasing international awareness. In cooperation with UNESCO and in the presence of numerous international organizations, the StarLight Declaration was adopted in La Palma in 2007, calling for the preservation of the night sky as a world heritage site and a˝rming the right of all the people of our world to admire and explore the starry sky. The rapid increase of light pollution Measurements point to a rapid increase in light pollution ranging from 2% to 8% annually depending on the location. Both satellite images and measurements of light pollution performed by several thousand amateur astronomers and environmentalists con˚rm this increase. This rapidly increasing exponential curve is worrying us deeply. If nothing is done, it is quite possible that in a few decades the brightness of the night sky will be more than twenty times greater than it is today. This means that the sky above natural parks which are usually the darkest areas would only show a few brightest stars. And in the darkest nights we would be able to read at night without the help of arti˚cial lighting. 3
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Legislation governing light pollution in Slovenia and in other countries Of all countries, Slovenia has the most advanced legislation on light pollution for objects of cultural heritage. In the Decree on Limit Values due to Light Pollution of Environment (OG RS, No 81/2007), the following sections are important: The Decree was adopted in 2007 when disputed white LED light sources had not yet begun to be marketed. White light did not then represent a serious environmental problem. The environmentalists also managed to negotiate with the relevant Ministry for the Environment that all lamps should be limited to the enhanced yellow part of the spectrum. Unfortunately this provision was left out of the Decree. Limitation on the spectrum is the most important serious shortcoming of the Decree. Even though the deadline on the harmonization of lighting of cultural monu -ments with the Decree expired at the end of 2013, it is not reasonable to hurry since it is crucial to ˚nd a technically and economically most suitable solution which is also as nature-friendly as possible. Article 4 (Illumination with environment-friendly luminaires) (1) For lighting, only luminaires with 0% of light emission above the horizontal may be used. – Article 10 (Illumination of façades) (1) ˜ose illuminating façades must ensure that the luminance of the illuminated part of the façade calculat -ed as the average value of the entire illuminated façade surface does not exceed 1 cd/m 2.(2) Façade luminance is established by luminance measurements in at least 10 points of the illuminated façade equally distributed across the entire illuminated façade surface. Measurements of façade luminance are performed at the distance of a maximum of 50 m away from the illuminated façade or, if possible, from behind the luminaires that illuminate the façade, whereas the luminance meter should be placed not more than 2 m above the ground. (3) ˜e façade of the building can be illuminated in a manner laid down in the ˚rst paragraph of this article only if the building is in the area of a settlement with public lighting and the illuminated wall of the build -ing is not more than 240 m away from the external edge of the closest illuminated public surface, measured horizontally, where the illuminated public surface is considered to be a public surface with an average illumi -nance of more than 3 lx. Article 11 (Illumination of cultural monuments) (1) ˜ose illuminating façades must ensure that the luminance of the illuminated part of the cultural mon -ument calculated as the average value of the entire illuminated surface of the cultural monument does not exceed 1 cd/m 2. (2) Luminance of the cultural monument is established by luminance measurements at a minimum 10 points of the illuminated part of the cultural monument equally distributed across the entire illuminated surface. Measurements of cultural monument luminance are performed at the distance of a maximum of 50 m away from the cultural monument or, if possible, from behind the luminaires that illuminate the cultural monument, where the luminance meter should be placed not more than 2 m above the ground. (3) If it is technically impossible to illuminate the cultural monument with luminaires meeting the require -ments from Article 4 of this Decree, light ˛ux should be directed in such a way that the external edge of the illuminated surface of cultural monument is at least 1 m below the lower part of the roof or 1m beneath the top of the monument for monuments without roofs. No more than 10% of light ˛ux may go past the façade of the cultural monument. Article 12 (Protection of endangered species) If according to regulations governing the preservation of nature the habitat of endangered species in the illu -minated building or object from Article 10 or 11 of this Decree is protected, the surfaces of such an object or building where ˛ight openings of endangered species are located should not be illuminated. Article 28 (Adjustment of existing luminaires) (6) ˜e existing illumination of cultural monuments shall be adjusted by 31 December 2013. 5
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In Italy, the majority of regions have legislation on reducing light pollution. Luminance of façades and cultural mon -uments is limited to 1 cd/m 2. For illumination of roads and streets in the surroundings of cultural monuments only lamps may be used that do not emit light above the horizontal. One of the newest regional laws in Friuli Œ Venezia Giulia already includes limitations on the blue part of the spectrum since it limits the colour temperature of lumi -naires to a maximum of 3300 K (Legge Regionale 18/06/2007, N. 015). Legislation in Chile limits the share of blue light to less than 15% of emitted light in the spectral band under 500 nm. Such is also the recommendation by the International Astronomical Union (IAU) concerning the protection of sky from light pollution. Numerous countries have general legislation addressing light pollution but without exec -utive acts (Croatia, Czech Republic). Among other things, the French legislation requires that façades should not be illuminated after 1.00 hours. In numerous countries with no legislation on light pollution, lighting of façades is switched o˛ after 1.00 hours as well. Legislation protecting animal species and their habitatsLight pollution is one of the factors endangering nocturnal animals and their biodiversity. The relevant ministry for the environment recognised this fact and decided to include protection of endangered species in article 12 of the Decree. Conserving biodiversity in the broadest sense of the term is of great public importance; thus all plants, animals and their habitats are under special state protection. As a result of numerous regulations, nocturnal animals are protected as well. The framework Nature Conservation Act (OG RS, No 96/2004) prohibits the degradation of the living conditions of plants and animals to a point that a species is endangered. This act also determines that, when encroaching on nature, ways, methods and technical appliances should be used which contribute to a favourable conservation status of a species. Since each outdoor lamp kills numerous insects, it is important to use lighting with the smallest possible impact on insects. The Decree on Ecologically Important Areas (OG RS, No 48/2004) protects the habitats of living plant and animal species that importantly contribute to the conservation of biodiversity. The protection of wild animal species is more thoroughly governed by the Decree of Protected Wild Animal Species (OG RS, No 46/2004) which among other things prohibits disturbance to animals. Article 4 de˚nes disturbance as fiany action because of which an animal at the place of disturbance stops nesting, wintering, reproducing, hiber -nating, breeding, using its space during migration or satisfying other living needsfl. If ˜ight openings for bats are also illuminated in places where bats give birth, the light may have a negative impact on the entire colony Œ this is considered a disturbance. A study accompanying the Life at Night project con˚rmed that lesser horseshoe bats prefer to roost in churches that are not illuminated and have appropriate ˜ight openings (Herzog 2013). They may even completely abandon a newly illuminated roost (Downs et al. 2003). The list of endangered animal species in Slovenia based on the Decree of Protected Wild Animal Species includes all 28 bat species and 54 moth species. The conservation of biodiversity in Slovenia is not only important for our country but also for the European Union and all the people of our planet. With the Decree on Special Protection Areas (Natura 2000 sites) (OG RS, No 49/2004), Slovenia protects species and habitat types, the conservation of which is also in the interest of the European Union. 6
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Light pollution of an inappropriately illuminated smaller country church Analysis of sky brightness. A smaller country church. The photograph was taken in clear weather with somewhat increased air humidity as is usual at night. The photo clearly shows light beams that miss the belfry and illuminate the sky. The photo taken with a Sky Quality Camera (˜sheye) was taken a few hun -dred metres away from the church. It captures all 360 degrees of the sky. This is the standard method for measuring light pollution of the sky at a certain point. Software was used to analyse the levels of sky brightness. The results show a light polluted horizon and the sky surrounding the church where light beams spread in all directions. The bel -fry cuts the light beam from one of the re˛ectors and causes one half of the sky to be approximately 50% more illumi -nated (light polluted) than the other half. Even though this phenomenon is local, we should not forget that light spreads through the atmosphere more than 200 km away from the source and that light pollution at a certain location is the sum of all radiation in a circle with radius of 200 km. Improving the standard of lighting at only one site results in a measurable decrease in light pollution at a distance of several kilometres. Photo taken with Sky Quality Camera. 7
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Figure 1: The scattering of the extremely violet colour is sixteen times greater than the scattering of the extremely red colour (2 4 or 2 x 2 x 2 x 2).White LED lamps pose a great threat to nature at night Only a few years ago, LED lamps became su˝ciently e˛ective for exterior lighting. Recently, LED lamps have often been used for exterior lighting that emits white light with a high percentage of blue colour (a colour temperature of 4200 K) Œ hereinafter, white LED lamps. The technology has been improving and will probably dominate indoor and outdoor lighting in a few years. The majority of LED lamps for domestic use have a colour temperature of 2700 K. Such a lamp emits little blue col -our and shines in yellow-white light. Such, for instance, is a normal bulb with a ˚lament and an emphasis on warm colours. In domestic applications, we use lamps with 2700 K or even 2500 K. This is not only more comfortable in the evening but also less harmful to health. For people and animals, light interrupts melatonin (also known as sleep hormone) production at night. When it gets dark, organisms start to synthesise melatonin and its production peaks in the middle of the night. Red coloured light has almost no in˜uence on interrupting melatonin production while blue interrupts it even at low illumination levels. Cajochen et al. (2005) have shown that even an illumination of 5 photopic lux with a wavelength of 460 nm causes signi˚cantly greater melatonin suppression after 40 minutes. Scattering of light in the atmosphere by molecules and very small particles is described by the Rayleigh law, which states that scattering is inversely proportional to the fourth power of the wavelength. If we assume that an extreme -ly violet light that the eye detects has a wavelength of 390 nm and an extremely red colour has a wavelength of 780 nm, the ratio of wavelengths between the two extremes is exactly one to two. Thus, the Rayleigh scattering of the extremely violet colour is 16 times greater than the scattering of the extremely red colour (Figure 1). Of course, luminaires do not emit light in the extreme part of the visual spectrum, but bluish luminaires, emitting light close to the violet part of the spectrum, will cause far more light pollution than yellowish ones. A white LED lamp at 4000 K causes approximately up to 3 times (300%) more light pollution than a yellow high-pressure sodium lamp (2100 K) for scotopic (night) vision. In the evening, people prefer to choose luminaires with warm colour; thus, there is no reason for the lighting of streets and cultural monuments to be in cold colours. Unfortunately this has been going on for some years now Œ white LED lamps with 4000 K are becoming a standard in outdoor lighting. Even though white LED lamps are somewhat more e˝cient, this criterion should not prevail if we know that white LED lamps cause harm to the environment Œ the more light pollution there is and the more intense it gets, the greater the interruption to mela -tonin synthesis and other negative impacts on animals. For the majority of animal species, this in˜uence cannot be estimated. Wavelength (nm) Relative sky brightness due to scattering 8
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