Light pollution: Reclaiming the night

Light pollution, with its negative effects on people, animals, and plants, is increasing worldwide. Regulations governing artificial lighting at night can help counteract this trend.

By Katja Dombrowski

In the city, only the brightest stars are visible. But when the night sky is undisturbed by other light sources and is moonless and cloudless, people can see several thousand stars with the naked eye. However, the places where this is possible are becoming increasingly rare: you have to travel to the desert, climb high mountains, or venture far out to sea to fully enjoy the experience. Artificial lighting at night is increasing sharply worldwide – with negative consequences.

Light pollution is considered a form of environmental pollution because artificial light alters the natural nighttime environment and can affect plants, animals, and people. One reason for the increase in artificial lighting is population growth: more people, more settlements, more industrial facilities, and more infrastructure also mean more light emissions. But these emissions are increasing faster worldwide than the global population – which means there is also more lighting per person. According to a study based on satellite data, light emissions on Earth increased by 16 percent between 2014 and 2022, while the population grew by only around 10 percent.

According to the study, published in April in the scientific journal Nature, this trend is primarily driven by advancing urbanization worldwide, infrastructure expansion, and increasing access to electricity. The largest increases in nighttime lighting are consequently occurring in countries in Africa and Asia, with Somalia, Burundi, and Cambodia leading the way. In absolute terms, however, large economies are far ahead, with the United States in first place, followed by China, India, Canada, and Brazil.

In Europe, light emissions decreased by four percent over the period studied, with the largest declines recorded in France, Belgium, and the Netherlands.The main reasons are technological advances and environmental policy measures. “The underlying causes are the widespread replacement of older, less efficient streetlights, such as high-pressure sodium lamps, with modern, directional LED systems, as well as strict national energy-efficiency requirements and measures to protect dark night skies,” Zhe Zhu, a professor at the University of Connecticut and one of the study’s authors, told the Reuters news agency.

According to Yana Yakushina, however, the switch to LEDs in the EU has also had negative consequences. “It was done to save energy, not to protect the environment,” says the lawyer, who is pursuing a doctorate at Ghent University on the regulation of light pollution as an environmental issue and prepared the VDE’s current position paper Artificial Light at Night Certification. She criticizes the fact that “LED streetlights are generally very bright and emit white light. They are usually not well shielded, either.” There is another issue: because LED lamps are inexpensive, they are used more than necessary. “LEDs were introduced to save energy, but ultimately this led to a rebound effect, with higher energy consumption, greater environmental impacts, and an increase in light pollution,” says Yakushina.

She sees the greatest potential for limiting light pollution in legal regulation, which is now being introduced in an increasing number of countries. “There are two reasons for this: protecting human health and the environment.” The issue is gaining momentum, partly because research into the effects of light pollution has increased over the past 50 years. Today, we know that the human biorhythm is strongly dependent on the natural alternation between day and night, light and darkness, and that disrupting this rhythm – for example through artificial light at night – not only deprives us of sleep but can also make us ill over the long term. A whole range of hormone-controlled processes are affected, as are metabolism and mental health. Possible long-term consequences include cardiovascular diseases such as coronary heart disease, heart attacks, and strokes. There are things people can do to reduce exposure to light at night, such as avoiding looking at their phones after a certain time. Blackout blinds can help against streetlights, while a sleep mask can be useful when traveling – for example, on a train. Animals and plants do not have these options. They, too, suffer from disrupted day-night cycles. Scientists point out that artificial light at night has become a potential threat to biodiversity.

A successful example of night-sensitive architecture: At Parnü Golf Club in Estonia, only the immediate surroundings are illuminated with warm light. Shielding improves visual comfort while preserving the view of the night sky. Dimming options allow the brightness to be adjusted as needed.

| BM Light OÜ

A large proportion of the animal kingdom is nocturnal, with around 70 percent of mammal species being active at night. Artificial light can disrupt feeding, reproduction, and migration patterns: insects fly toward lights, migratory birds lose their way, and sea turtles mistake artificial lights for the moon, leading their hatchlings away from the sea. Many of the consequences have yet to be researched. For example, scientists at the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin are investigating how artificial light at night affects freshwater ecosystems.

The fact that there are harmful environmental consequences, however, is undisputed. Countries that have already responded with national regulations include Peru and China, as well as a number of European countries. In Germany, several regionally different regulations are already in place. At the national level, Section 41a of the Federal Nature Conservation Act regulates the “protection of animals and plants from the adverse effects of lighting.” However, the provision has not yet entered into force, as the Federal Ministry for the Environment, Climate Action, Nature Conservation and Nuclear Safety (BMUKN) must first define limits for light emissions and specify in greater detail the technical and structural requirements and protective measures to be met. To this end, the Federal Agency for Nature Conservation has commissioned several research projects. Asked about the current status, a BMUKN spokesperson said: “Work on the scientific foundations has progressed significantly, and the results are currently being evaluated while the next targeted steps are being considered.”

According to Yana Yakushina, the author of the VDE paper, however, it is not enough to simply enact laws; they also need to be enforced. “France is a very good example of this,” says Yakushina. Violations of the country’s comprehensive requirements for reducing light pollution are subject to penalties – “including significant fines.” In addition to penalties, she considers incentives useful, for example by giving preference in public tenders to providers whose lighting products are certified as biodiversity-friendly.

The VDE supports lighting manufacturers in applying for the most widely used certification from DarkSky International. “We are the first testing institute in Europe to be recognized as a DarkSky Recognized Test Lab,” explains Artem Masorin, Technical Specialist at VDE. With its position paper, the VDE aims to raise awareness of light pollution and bring all relevant stakeholders to the table – from environmental organizations and researchers to the lighting industry, specialist planners and architects, and public authorities. There are already good examples of how this can be put into practice, says Masorin.

One company that already uses certification from DarkSky International is LED Linear GmbH from Duisburg, a manufacturer of linear architectural lighting. “We have high sustainability standards,” explains Franziska Heckmanns, Product Manager at LED Linear. “With our lighting products, we want to help prevent light pollution.” This would also be possible without certification, but “the DarkSky standard is playing an increasingly important role. We are seeing more and more that it is becoming part of tender specifications. This allows lighting designers, architects, and landscape planners to meet tender requirements with certified products.” Three products for outdoor lighting – for example, for façades or bridges – have already been certified, with more in the pipeline. Heckmanns sees it as the government’s responsibility to establish regulations for nighttime lighting that go beyond street lighting. “For example, it could be stipulated that the color temperature of outdoor lighting may not exceed 3,000 Kelvin. It has been proven that warm light is significantly less harmful to wildlife and plants.” Lighting Europe, the association representing the interests of the lighting industry at the European level, is also advocating for uniform requirements across the EU. It points out that different applications require different rules: city centers generally have different requirements than rural areas or national parks. The lowest levels of light emissions are actually permitted in places where stars are observed, such as around observatories. In the Rhön Dark Sky Reserve, located where Bavaria, Hesse, and Thuringia meet, an entire region has even committed itself to protecting the night sky. Astro-tourism there is becoming increasingly popular.

VDE position paper:

https://www.vde.com/position-paper-alan-certification