The protection of the dark skies

On June 27, 2023, the decree that identifies areas with scientific and research value for astronomical observation was published in Chile's official newspaper. In addition, the country's new illumination standard, which extends protection from three regions to the entire territory, is expected to be published soon. The above, together, seek to reduce light pollution both for astronomical research and the care of biodiversity.

Credit: Y. Beletsky

Chile is known worldwide for the quality of its dark skies, which, being located over the Atacama Desert, remain clear and stable. For this reason, it is currently an astronomical power due to the fact that nearly 40% of the infrastructure created to study the Universe is in its territory. By 2030, according to the Chilean Astronomy Society, this number will increase to 55%.

However, this privileged condition is threatened due to the rapid growth of artificial lighting in cities, roads and mining sites. If in the past an astronomical observatory located in the middle of the Atacama Desert at an altitude of more than 2500 meters, such as the Las Campanas Observatory of the Carnegie Institution for Science, could operate in complete darkness, today there are indisputable artificial light sources shining all night long on the horizon.

This excess of artificial light, relative to what is actually needed to illuminate, is known as light pollution, and according to research published in January 2023 in the journal Science, it is increasing by approximately 10% per year across the planet. 

"The issue of light pollution and its control directly affects Chile's competitiveness as a world center for the development of astronomy. The Atacama Desert has always been an extremely dark place, which has unique conditions for astronomical observations, but the advance of this pollution, at the rapid and accelerated rate we are currently seeing, puts at risk the viability of the operation of astronomical observatories in the next 30 years", mentions Guillermo Blanc, Associate Director of Strategic Initiatives for Carnegie Observatories and  Las Campanas and President of the Fundación Cielos de Chile, a private, non-profit institution whose essential purpose is to protect the quality of the night skies in the country.

The night sky is a world heritage that Chile must take care of, says Blanc. "We risk losing the best, if not the only, place from which many observations can be made to understand and learn about the Universe," he emphasizes.

This situation is of concern to the scientific community present in the country, who since the late 1990s have advocated for the application of strict regulations to prevent the proliferation of light pollution, along with the publication of the first Chilean illumination standard (DS 686) in 1998.

A major step in this struggle was the publication in Chile's Official Gazette on June 27, 2023, of Decree No. 43.586, which creates areas with scientific and research value for astronomical observation or "astronomical areas", covering a total of 31 of the 34 communes present in the regions of Antofagasta, Atacama and Coquimbo.

This change protects the privileged conditions for the new areas of interest for astronomical research, but also has repercussions outside this science. Light pollution has a negative impact on human beings, since, among other things, it causes sleep disturbances. In addition, several studies indicate that it also negatively affects flora and fauna, so it should also be considered an environmental pollutant.

The road to the decree of protected areas

"Chile recognized the importance of astronomy by welcoming foreign observatories to its territory in the 1960s, granting them special privileges and also declaring the properties a protected zone for the purposes of mining practice, and even a little further. With the passage of time astronomy has grown in the country and is so important worldwide that it is very important to continue protecting this activity", says Leopoldo Infante, Director of Las Campanas Observatory, LCO, and legal representative of the Carnegie Institution for Science in Chile.

The protection of the dark skies is an issue of concern to the Chilean astronomical community, which has sought various ways to raise awareness among the community and the authorities about light pollution. Together with the professional observatories installed in the country, they have been available to provide information, data and opinions regarding the measures that should be implemented.  

Illuminating the sky increases the noise in the images obtained by the telescopes, which makes it more difficult to detect faint objects. "In the case of LCO, the increase in noise is marginal up to this point, if we compare it with the effect on other observatories, for example Cerro Tololo, due to the contamination of the city of La Serena. However, the illumination of Route 5 affected quite a bit and may be worse in the near future given the illumination in nearby cities that continue to grow. As a result, there has been a certain reluctance to develop large-scale projects in the area," says Infante.

In 2018, work began on the creation of a law to implement stricter light regulations, the enactment of which occurred a year later. During the legislative process members of the scientific community such as Eduardo Unda-Sanzana, academic at the University of Antofagasta, Guillermo Blanc of Las Campanas Observatory, and Pedro Sanhueza, director of the Office for the Protection of the Quality of the Sky of Northern Chile (OPCC), defended the need for this project in front of the environmental commissions of the Chamber of Deputies and the Senate. Finally, Law 21.162 adds artificial luminosity to the list of pollutants and requires the preparation of an environmental impact study for projects that could generate light pollution in areas of value for astronomical observation for scientific research purposes. 

However, this law does not indicate exactly which areas are protected. This work was left in the hands of the Ministry of the Environment, which was to recommend to the Presidency, through a commission of experts, which were the areas to be protected.

Finally, this commission of astronomers was created in 2020 by the new Ministry of Science, Technology and Innovation. It was chaired by Eduardo Unda-Sanzana and integrated by Manuela Zocalli, academic of the Pontificia Universidad Católica de Chile; Ricardo Bustos, academic of the Universidad Católica de la Santísima Concepción; Amelia Ramírez, academic of the Universidad de La Serena, Rodrigo Reeves, academic of the Universidad de Concepción and María Teresa Ruiz, academic of the Universidad de Chile. This group was accompanied by Luis Chavarria, who at the time was an astronomer at the National Agency for Research and Development (ANID) and is now a representative in Chile of the European Southern Observatory (ESO), and Paulina Assman, from the Ministry. 

In February 2021, the proposal was sent to the Government and, finally, on June 27, 2023, the norm that identifies areas with scientific and research value for astronomical research was published. 

This new norm protects a radius of 150 kilometers around the main astronomical observatories, identifying as "astronomical areas" 8 communes in the Antofagasta region, 7 in the Atacama region and 14 in the Coquimbo region. 

"This decree values the scientific vocation of the territories of these 29 communes, generating the enabling conditions for the development of the local economy through science and related activities. It sends a clear message that as a country we are committed to protecting our natural heritage, and offers a model for other countries to follow," said Daniela González, Executive Director of the Fundación Cielos de Chile. "With the implementation of this decree, Chile consolidates its position as a world leader in the astronomical field, recognizing the efforts of scientists, non-profit organizations and passionate individuals who have advocated for the preservation of our night skies. By safeguarding the dark sky, we defend the right of every person to connect with nature's most captivating spectacle," she adds.

This norm has been applauded by the national and international scientific community, but the fear of non-compliance is latent.  

"The big problem is oversight. The Chilean state does not have sufficient resources to effectively enforce an illumination standard. The Superintendency of the Environment should oversee and sanction, but the existing programs are not really effective and it is difficult for them to be effective in the near future," says Blanc.

Fundación Cielos de Chile seeks to help in this area by carrying out awareness and education programs and developing citizen oversight projects. The Carnegie Institution for Science, says Leopoldo Infante, is also available to provide technical support for monitoring.

"As an observatory we can't do direct monitoring, but we can measure the brightness of the sky above the observatory to have some capacity to react to any nearby sources of pollution, and support any monitoring effort.  The companies of any type are going to have to carry out, from now on, an environmental impact study, including light pollution, in all the declared areas. Therefore, these companies will require the support of specialized agencies, and they, of course, can rely on the observatory to acquire their data", says Infante.

Next steps

In 2021, driven by Chilean scientists, including Guillermo Blanc, Eduardo Unda-Sanzana and Pedro Sanhueza, the revision of the supreme decree 43 of the Ministry of Environment that regulates illumination standards, created in 2012, was carried out. This decree, still in force, regulates the color of light, intensity, direction, among other things, but only in the regions of Antofagasta, Atacama and Coquimbo. 

"It is good that there are restrictions but they are not so demanding, mainly on the issue of the color of the light. When this decree was made, the technology of warm LED luminaires was very immature. So, they did not demand as warm a light as they should have because it was not very feasible at that time. In this revision of the standard, a restriction similar to the one that exists today in three regions of Chile was requested to be extended to the whole country, and it should soon be published definitively", emphasizes Blanc.

This revision creates two levels of regulation. One, similar to that existing today in the regions of Atacama, Antofagasta and Coquimbo but extended to the entire territory, and another more demanding one for protected areas. This change, says Blanc, is a recognition that light pollution is not only a problem for astronomy, but also has impacts on human health, energy efficiency and biodiversity. "When the update is finalized, Chile will have one of the best environmental illumination regulations in the world, with protected areas and strict restrictions on them," he adds. 

The new illumination standard provides background information related to the effects of light pollution and poor lighting on biodiversity and people's health. "Given this background, it incorporates biodiversity as an object of protection and extends the scope of protection to the entire national territory, increasing the restrictions related to the emission spectrum of luminaries in the near infrared, visible and near ultraviolet portions and setting greater requirements in areas of environmental and astronomical relevance. In addition, it incorporates time restrictions for sports and advertising lighting, as well as ornamental and decorative lighting. It also improves preventive control through new restrictions on the commercialization of luminaires and the control of outdoor lighting projects throughout the national territory and prioritizes the protection of natural environments by giving less time for the adaptation of luminaire parks when they are located near areas of environmental relevance", says Pedro Sanhueza, former director of the OPCC, and advisor on lighting issues to the Ministry of the Environment.

"If the update of DS N°43/2012 of the Ministry of the Environment is implemented in the short term, stricter regulations will be established for these areas regarding outdoor lighting -their shapes, magnitudes and schedules-, with the aim of reducing light pollution and promoting responsible lighting practices. By implementing comprehensive measures, the decree will help combat the harmful effects of excessive lighting. This new combined legislation will not only ensure uninterrupted observation of our universe, but will also benefit wildlife, human health and energy efficiency," emphasizes Daniela Gonzalez.

According to Cristian Villagra, PhD in Sciences with a mention in Ecology and Evolutionary Biology at the University of Chile, light pollution causes innumerable damages to animals and plants. "Damage includes death, injuries, affectation of nutrition, physiology and development, changes in behavior and untimely growth and reproduction. In plants, exposure to light pollution seriously affects their biological (or circadian) rhythms, triggering stress responses, shortening life span, reproduction and the resources of vegetative tissue, flowers and fruits on which other organisms depend," explains Villagra, who is also an academic at the Institute of Entomology of the Universidad Metropolitana de Ciencias de la Educación.

On the other hand, adds the scientist, constant exposure to artificial light during the night can deregulate the biological rhythms of animals, including reproduction, feeding and rest.

Regarding fauna, several studies indicate that light pollution alters behavioral patterns, natural cycles and ecological interactions. 

"Perhaps most noticeable and easy to observe is that artificial lights affect the relationship between plants and pollinators. For example, nighttime lights at altitude attract insects, drawing them away from plants and thus decreasing pollination, which impacts reproductive success. Other impacts include the alteration of their seasonal rhythms and the ability to perceive and react to natural light afterwards," says Carolina Saavedra, Environmental Biologist and Head of the Natural Culture Program at the Museo Interactivo Mirador, MIM.

There are studies regarding the impact of light pollution on Chile's avifauna. Saavedra highlights the one carried out by the Chilean Network of Bird and Wildlife Observers, who identified around 17 species of seabirds affected by light pollution, among which she highlights the Pink-footed Shearwater, a migratory species that nests in Chilean territory and is classified as vulnerable.

"It is important to respect the natural conditions of flora and fauna habitats as much as possible to avoid interrupting their biological processes. As for light pollution, the best way to avoid any impact is to avoid any type of intervention that is not strictly necessary," adds Saavedra.

Unfortunately, these effects are not only harmful to the species that receive this excess of artificial light. "At the ecosystem level, the effects of lighting on a given species can have consequences for other ecologically related species, as they depend on each other for food, shelter or reproduction," emphasizes Villagra.

As artificial lights flood cities and urban spaces, the harmful effects of this form of pollution often go unnoticed. However, uncontrolled outdoor lighting alters the natural rhythms of light and darkness, which, according to numerous scientific studies, has important consequences for the flora and fauna of ecosystems. Hence the relevance and breakthrough of the new lighting standard that will soon come into force in Chile.

"This is not only an astronomical issue. It is not only important to have a dark sky for astronomy. Light pollution affects the ecosystem, the different environments, so the new standard seems to me to be quite consistent and comprehensive in this sense. That is, if you protect astronomy you are also protecting these ecosystems that live at the surface level on Earth. For humans this protection is also important. Night illumination can be seen as a plus for human coexistence, but it also has its problems in daily life, especially in night life. So there are many aspects. It is a global issue," reflects Leopoldo Infante.

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