|Home | Archives | About | Login | Submissions | Subscribe | Contact | Search|
Copyright © 2010 by the author(s). Published here under license by The Resilience Alliance.
Go to the pdf version of this article The following is the established format for referencing this article:
Hölker, F., T. Moss, B. Griefahn, W. Kloas, C. C. Voigt, D. Henckel, A. Hänel, P. M. Kappeler, S. Völker, A. Schwope, S. Franke, D. Uhrlandt, J. Fischer, R. Klenke, C. Wolter, and K. Tockner. 2010. The dark side of light: a transdisciplinary research agenda for light pollution policy. Ecology and Society 15(4): 13. [online] URL: http://www.ecologyandsociety.org/vol15/iss4/art13/
Perspective The Dark Side of Light: A Transdisciplinary Research Agenda for Light Pollution Policy
1Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, 2Leibniz Institute for Regional Development and Structural Planning, Erkner, 3Leibniz Research Centre for Working Environment and Human Factors, Dortmund, 4Leibniz Institute for Zoo and Wildlife Research, Berlin, 5Technische Universität Berlin, Department of Urban and Regional Planning, 6Dark Sky Germany, Museum am Schölerberg, Osnabrück, 7Leibniz Institute for Primate Research, Göttingen, 8Technische Universität Berlin, Department of Energy and Automation Technology, Berlin, 9Astrophysikalisches Institut Potsdam, 10Leibniz Institute for Plasma Science and Technology, Greifswald, 11Freie Universität Berlin, Institute for Space Sciences, 12Helmholtz Centre for Environmental Research, UFZ, Leipzig, 13Freie Universität Berlin, Institute for Biology
Although the invention and widespread use of artificial light is clearly one of the most important human technological advances, the transformation of nightscapes is increasingly recognized as having adverse effects. Night lighting may have serious physiological consequences for humans, ecological and evolutionary implications for animal and plant populations, and may reshape entire ecosystems. However, knowledge on the adverse effects of light pollution is vague. In response to climate change and energy shortages, many countries, regions, and communities are developing new lighting programs and concepts with a strong focus on energy efficiency and greenhouse gas emissions. Given the dramatic increase in artificial light at night (0 - 20% per year, depending on geographic region), we see an urgent need for light pollution policies that go beyond energy efficiency to include human well-being, the structure and functioning of ecosystems, and inter-related socioeconomic consequences. Such a policy shift will require a sound transdisciplinary understanding of the significance of the night, and its loss, for humans and the natural systems upon which we depend. Knowledge is also urgently needed on suitable lighting technologies and concepts which are ecologically, socially, and economically sustainable. Unless managing darkness becomes an integral part of future conservation and lighting policies, modern society may run into a global self-experiment with unpredictable outcomes.
Key words: artificial light; energy efficiency; lighting concept; light pollution; nightscape; policy; sustainability; transdisciplinary
In 2009, the UN’s Year of Astronomy drew worldwide attention to an area affected by a long neglected environmental stressor: the increasing illumination of our nightscapes. The Year of Astronomy coincided with the 400th anniversary of Galileo’s first observations with a telescope in Padua. However, to look at today’s firmament Galileo would have to escape to remote areas for his research. This is because the Earth has become brighter at night. The rapid proliferation of electric lights has drastically reordered nightscapes across the globe, in terms of both light intensity and light spectrum (Cinzano et al. 2001, Elvidge et al. 2007). Although artificial lighting has clearly enhanced the quality of human life (Jakle 2001, Doll et al. 2006), the benefits are accompanied by hidden costs. Astronomers were the first to recognize that sky glow hampers the detection of faint celestial objects, obliging them to conduct their observations from darker areas or from orbit (Riegel 1973, Smith 2009). It is only very recently that the multiple negative effects of artificial lighting on ecology, human health, and social well-being have gained broader recognition (Jakle 2001, Rich and Longcore 2006, Navara and Nelson 2007).
Light pollution is now a widely accepted term for adverse effects of artificial light on nature and humans (Longcore and Rich 2004, Navara and Nelson 2007). Nearly all living organisms, including human beings, have evolved under a natural rhythm of day and night. Interestingly, around 30% of all vertebrates and more than 60% of all invertebrates world-wide are nocturnal (Hölker et al. 2010). As lighting becomes brighter and extends farther into rural areas and offshore in marine systems (see Appendix 1), the distinction between day and night becomes blurred. Our understanding of the adverse effects of light pollution is vague and based mostly on purely observational case studies. Nonetheless, there is clear evidence that artificial lighting can alter physiology, including hormonal balance, as well as behavior, orientation, organism fitness, food web interactions, and biotope connectivity (Rich and Longcore 2006, Navara and Nelson 2007). The artificial disturbance of the natural day/night cycle may, as a result, have serious psycho-physiological and even medical consequences for humans, along with ecological and evolutionary implications for animals, plants, and even entire terrestrial, freshwater, and marine ecosystems (Rich and Longcore 2006, Navara and Nelson 2007). Light pollution is most probably an important but underestimated driver behind the erosion of provisioning, e.g., loss of light-sensitive species and genotypes; regulating, e.g., decline of nocturnal pollinators such as moths and bats; and cultural ecosystem services, e.g., loss of aesthetic values such as the visibility of the Milky Way (Rich and Longcore 2006, Carpenter et al. 2009, Smith 2009). The principal effects become most apparent at the interfaces between the physiological, ecological, and socioeconomic realms (Fig. 1). The problem is escalating worldwide as artificial lighting is rapidly increasing by around 6% per year (range: 0-20%; Table 1).
Artificial lighting consumes 19% of total global electricity, accounting for greenhouse gas emissions of 1900 Mt of CO2 per year (OECD/IEA 2006). It is no surprise that current artificial lighting policies focus primarily on energy efficiency and greenhouse gas emissions (e.g., OECD/IEA 2010), although safety, astronomical, and other considerations appear sporadically (see Appendix 2). The International Energy Agency has calculated that the systematic use of ‘least life-cycle cost’ lighting solutions (see Appendix 3) from 2008 onward would reduce the electricity consumption attributable to lighting until 2020 by 1311 TWh and 763 Mt of CO2 emissions per year compared to projections on the basis of current policies (OECD/IEA 2006).
Recently, the European Ecodesign Directive established a framework to phase out the incandescent lamp and other particularly energy-intensive lighting products, e.g., high-pressure mercury lamps (The European Parliament and the Council of the European Union 2009). This step could reduce CO2 emissions in the EU by approximately 42 Mt per year, corresponding roughly to a 10% reduction of the greenhouse gas emissions the EU promised to achieve under Kyoto (Denneman 2009, Managenergy 2010). In the United States, President Obama has proposed a scheme for more energy-efficient lamps and lighting equipment as part of his climate change policy. This would result in savings of approximately 20 Mt CO2 annually (The White House 2009). Similar activities are reported inter alia for China, Australia, and New Zealand (OECD/IEA 2006, 2010).
Within such policy frameworks, many countries, regions, and communities are developing new lighting programs and concepts. For example, the EU has launched a number of programs, e.g., GreenLight www.eu-greenlight.org, E-Street www.e-streetlight.com, to adopt efficient lighting systems and to initiate a permanent market transition. Although most of these programs and concepts are driven by energy efficiency motives alone, there remain causes for concern. For example, technological innovations that help improve the efficiency of energy appliances and systems often lead to greater energy use because of direct ‘rebound’ effects (Herring and Roy 2007, Charles 2009). New technologies and reduced costs could generate steep increases in the overall use of lighting and may stimulate innovative additional uses for lighting (Herring and Roy 2007, Fouquet and Pearson 2006). Lighting efficiency has doubled over the past 50 years in the UK; however, per capita electricity consumption for lighting increased fourfold over the same period (Fouquet and Pearson 2006). Due to the development and use of new lighting technologies, e.g., compact fluorescent lamp (CFL), light-emitting diode (LED), organic light-emitting diode (OLED), we can expect a dramatic drop in the cost of lighting services, a desirable end in itself, but with possibly higher energy consumption and wider loss of dark nightscapes as a consequence. Technological innovations should, therefore, not only save consumers money, but also consider human health, ecological, and socioeconomic aspects.
Whereas air, noise, or water pollution have been high priority policy issues for decades, light pollution remains scientifically, culturally, and institutionally in the dark. Given the dramatic increase in artificial light in recent years, we see an urgent need for research on the physiological, human health, ecological, and socioeconomic significance of the loss of the night that addresses how illumination can be improved both technically and institutionally yet having fewer adverse effects. Managing darkness has to be an integral part of future conservation planning and illumination concepts. If not, our modern society may run into a global self-experiment with unpredictable outcomes (Fig.1).
Any attempts to reduce light pollution run up against positive connotations of lighting which are deeply ingrained in modern societies. Culturally, light is a symbol of enlightenment, modernity, urbanity, and security (Jakle 2001). Policy initiatives against light pollution therefore need to take into consideration the many advantages of artificial lighting, real and perceived, for economic production, social lifestyles, and security while at the same time addressing its negative side effects. For this, a sound understanding of the historical, socioeconomic, and cultural reasons for the emergence and dissemination of lighting systems is needed. We then need to ask how far recent changes in attitudes, in particular relating to the environment and human health, are creating openings for a shift in policy and practice. Part of this process involves identifying and building up a coalition of interest around the light pollution issue, incorporating such diverse stakeholder groups as ecologists, astronomers, and health professionals, but also electricity utilities, lamp manufacturers, property owners, local businesses, city planners, or those concerned about nighttime security.
Thus, the research needed is transdisciplinary, i.e. it should cut across boundaries between scientific disciplines and between science, policy, and practice and should address facts, practices, and values (Wiesmann et al. 2008). The following natural, social, and engineering science questions are central to this research agenda:
Such research should validate indicators and guidelines, set priorities for human health and environmental protection, identify technical and economic possibilities for improvements in lighting, and develop sustainable lighting concepts and techniques for future nightscapes.
With our present understanding, there is little choice but to develop guidelines in accordance with energy efficiency criteria and the few available case studies on the ecological and health impacts of lighting. The Commission Internationale de l’Éclairage (CIE), the International Dark-Sky Association (IDA; www.darksky.org), and the Illuminating Engineering Society of North America (IESNA 2000) provide preliminary recommendations, illustrating how local lighting ordinances and innovative designs may promote low impact, energy-efficient and aesthetically pleasing lighting systems (e.g., CIE 1997, 2000, 2003). Promising options are, for example, lamps that direct their light more accurately toward where it is needed, lamps that emit light with a spectral distribution causing minimal harm, timers and sensors to turn lights on only when needed, and the consideration for light-sensitive areas, especially the periphery of residential areas, forests, parks, and shores of water bodies. The comprehensive and transdisciplinary research advocated here will result in more advanced regulations and guidelines at, in particular, the national level and the development of intelligent, i.e., adaptive and context-dependent, lighting concepts for local communities. These will help countries, regions, and cities to maximize the social and economic benefits of artificial light at night, while minimizing its negative and unintended ecological and health impacts. On this basis, future generations will be able to experience nightscapes comparable to those which Galileo knew without having to travel to the Australian Outback or the Chilean Andes.
Responses to this article are invited. If accepted for publication, your response will be hyperlinked to the article. To submit a response, follow this link. To read responses already accepted, follow this link.
ACKNOWLEDGMENTSWe are grateful to Steve Carpenter, Jens Krause, Elisabeth K. Perkin, and Michael Monaghan for helpful comments. This work was supported by Milieu (FU Berlin), the Leibniz Association, the Senatsverwaltung für Bildung, Wissenschaft und Forschung, Berlin, and the Federal Ministry of Education and Research, Germany.
Agence de l'Environnement et de la Maîtrise de l'Energie (ADEME). 2007. Energie et Patrimoine Communal, Enquête 2005. [online] URL: http://www2.ademe.fr/servlet/getDoc?cid=96&m=3&id=48956&ref=19684&p1=B.
Campaign to Protect Rural England (CPRE). 2003. Night blight! Campaign to Protect Rural England, London, UK.
Carpenter, S. R., R. DeFries, T. Dietz, H. A. Mooney, S. Polasky, W. V. Reid, R. J. Scholes. 2009. Science for managing ecosystem services: beyond the Millennium Ecosystem Assessment. Proceedings of the National Academy of Sciences USA 106:1305-1312.
Carrasco, B. E., A. Carramiñana, F. J. Sanchez-Sesma, and F. J. Lermo. 1998. Protection of the observatorio astrofisico "Guillermo Haro". Astronomical Society of the Pacific Conference Series 139:141-149.
Charles, D. 2009. Leaping the efficiency gap. Science 325:804-811.
Commission Internationale de l’Éclairage (CIE). 1997. Guidelines for minimizing sky glow. CIE Technical Report 126-1997, Vienna, Austria.
Commission Internationale de l’Éclairage (CIE). 2000. Guide to the lighting of urban areas. CIE Technical Report 136-2000, Vienna, Austria.
Commission Internationale de l’Éclairage (CIE). 2003. Guide on the limitation of the effects of obtrusive light from outdoor lighting installations. CIE Technical Report 150-2003, Vienna, Austria.
Cinzano, P. 2000. The growth of light pollution in North-Eastern Italy from 1960 to 1995. Memorie della Società Astronomica Italiana 71:159-165.
Cinzano, P., F. Falchi, and C. D. Elvidge. 2001. The first world atlas of the artificial night sky brightness. Monthly Notices of the Royal Astronomical Society 328:689-707.
Denneman, J. 2009. Light relief. Parliament Magazine 281:42.
Doll, C. N. H., J.-P. Muller, and J. G. Morley. 2006. Mapping regional economic activity from night-time light satellite imagery. Ecological Economics 57:75-92.
Elvidge, C. D., P. Cinzano, D. R. Pettie, J. Arvesen, P. Sutton, R. Nemani, T. Longcore, C. Rich, J. Safran, J. R. Weeks, and S. Ebener. 2007. The nightsat mission concept. International Journal of Remote Sensing 28:2645-2670.
Fouquet, R., and P. Pearson. 2006. Seven centuries of energy services: the price and use of light in the United Kingdom (1300-2000). The Energy Journal 27:139-177.
Garstang, R. H. 1989. The status and prospects for ground-based observatory sites. Annual Review of Astronomy and Astrophysics 27:19-40.
Garstang, R. H. 2004. Mount Wilson observatory: the sad story of light pollution. The Observatory 124:14-21.
Hänel, A. 2001. The situation of light pollution in Germany. Preserving the Astronimical Sky IAU Symposium 196:142-146.
Herring, H., and R. Roy. 2007. Technological innovation, energy efficient design and the rebound effect. Technovation 27:194-203.
Hölker, F., C. Wolter, E. K. Perkin, and K. Tockner. 2010. Light pollution as a biodiversity threat. Trends in Ecology and Evolution 25:681-682.
Illuminating Engineering Society of North America (IESNA) 2000. Technical memorandum on light trespass: research, results and recommendations. TM-11-00, IESNA, New York, New York, USA.
Isobe, S., and H. Kosai.1998. Star watching observations to measure night sky brightness. Astronomical Society of the Pacific Conference Series 139:175-184
Jakle, J. A. 2001. City lights. Illuminating the American night. John Hopkins University Press, Baltimore, Maryland, USA.
Krisciunas, K. 1997. Optical night-sky brightness at Mauna Kea over the course of a complete sunspot cycle. Publications of the Astronomical Society of the Pacific 109:1181-1188.
Krisciunas, K., D. R. Semler, J. Richards, H. E. Schwarz, N. B. Suntze, S. Vera, and P. Sanhueza. 2007. Optical sky brightness at Cerro Tololo Inter-American Observatory from 1992 to 2006. Publications of the Astronomical Society of the Pacific 119:687-696.
Lockwood, G. W., D. T. Thompson, and R. D. Floyd. 1990. Sky glow and outdoor lighting trends since 1976 at the Lowell Observatory. Publications of the Astronomical Society of the Pacific 102:481-491.
Longcore, T., and C. Rich. 2004. Ecological light pollution. Frontiers in Ecology and the Environment 2:191-198.
Managenergy. 2010. Key information related to energy efficiency. European Commission on Energy. [online] URL: http://www.managenergy.net/ee.html.
Massey, P. and C. B. Foltz. 2000. The spectrum of the night sky over Mount Hopkins and Kitt Peak: changes after a decade. Publications of the Astronomical Society of the Pacific 112:566-573.
McNeill, G. 1999. Street lighting: a development and economic history since 1924. Lighting Journal 64:37.
Narisada, K., and D. Schreuder. 2004. Light pollution handbook. Springer, Dordrecht, The Netherlands.
Navara, K. J., and R. J. Nelson. 2007. The dark side of light at night: physiological, epidemiological, and ecological consequences. Journal of Pineal Research 43:215-224.
Organisation for Economic Co-operation and Development (OECD)/International Energy Agency (IEA). 2006. Light’s labour’s lost - policies for energy-efficient lighting. OECD/IEA, Paris, France.
Organisation for Economic Co-operation and Development (OECD)/International Energy Agency (IEA). 2010. Energy efficiency policies and measures database. [online] URL: http://www.iea.org/textbase/pm/?mode=pm.
Pedani, M. 2009. Sky surface brightness at Mount Graham: UBVRI science observations with the large binocular telescope. Publications of the Astronomical Society of the Pacific 121:778-786.
Rich, C., and T. Longcore, editors. 2006. Ecological consequences of artificial night lighting. Island Press, Washington, D.C., USA.
Riegel, K. W. 1973. Light pollution. Science 179:1285-1291.
Smith, M. 2009. Time to turn off the lights. Nature 457:27.
Stalin C. S., M. Hegde, D. K. Sahu, P. S. Parihar, G. C. Anupama, B. C. Bhatt, and T. P. Prabhu. 2008. Night sky at the Indian astronomical observatory during 2000-2008. Bulletin of the Astronomical Society of India 36:111-127.
Teare, S. W. 2000. Night sky brightness at Mt. Wilson observatory. The Observatory 120:313-317.
The European Parliament and the Council of the European Union. 2009. Directive 2009/125/EC of the European Parliament and of the Council of 21 October 2009 establishing a framework for the setting of ecodesign requirements for energy-related products. Official Journal of the European Union L 285:10-35.
The White House, Office of the Press Secretary. 2009. Obama Administration launches new energy efficiency efforts. Press Release, The White House, Washington, D.C., USA. [online] URL: http://www.whitehouse.gov/the_press_office/Obama-Administration-Launches-New-Energy-Efficiency-Efforts/
Walker, M. F. 1973. Light pollution in California and Arizona. Publications of the Astronomical Society of the Pacific 85:508-519.
Wiesmann, U., G. Hirsch Hadorn, H. Hoffmann-Riem, S.Biber-Klemm, W. Grossenbacher, D. Joye, C. Pohl, and E. Zemp. 2008. Enhancing transdisciplinary research: a synthesis in fifteen propositions. Pages 433-441 in G. Hirsch Hadorn, H. Hoffmann-Riem, S. Biber-Klemm, W. Grossenbacher-Mansuy, D. Joye, C. Pohl, U. Wiesmann, and E. Zemp, editors. Handbook of transdisciplinary research. Springer. Dordrecht, The Netherlands.
|Home | Archives | About | Login | Submissions | Subscribe | Contact | Search|