The Growing Concern of Environmental Light Pollution

Dense concentrations of brightly lit buildings are often synonymous with rapid development and economic prosperity. Of the 3 billion dollars spent yearly for sky lighting, it is estimated that over one third of the lighting is wasted. In addition to economic ramifications, artificial lighting has documented deleterious effects on sea turtles, warblers, deciduous trees, and humans.

“Environmental light pollution” (ELP) is a term commonly used to describe the disruption of the natural light cycle experienced within the ecosystem caused by artificial light. There is growing concern ELP is contributing to occupational illnesses in shiftwork, mass mortality of key species, and ecosystem collapse. Researchers have observed ELP’s effects on the disorientation in sea turtle hatchlings seaward as they mimic the starlight’s reflection on dark bodies of water. This navigation failure is also well documented in field crickets, northern mockingbirds, and in particular migratory birds, which have been observed to be so captivated by high-intensity urban light installations that they die due to fatigue from circling the source.

Attraction to artificial light also increases vulnerability of being preyed upon. There is evidence certain species are able to adapt to artificial light and exploit its visibility in order to hunt its prey. However, these seemingly beneficial effects on one species may negatively impact the ecosystem at large. Over predation changes the community structure and causes ecological cascades. Certain key species may be out-competed or predated to extinction.

The loss of biodiversity does not only affect conservation efforts but may also force others who rely on the key species to go extinct. Animals are not the only ones affected by ELP. Canada’s largest endemic tree populations are found in the deciduous forests. Scientists have discovered within recent years, deciduous trees near ELP have dropped their leaves later than those that are unobscured. This leads to poor transitions into winter as a result many trees are not able tolerate the decrease in temperature. ELP also exhibits detrimental effects on humans. In a study done, of the nurses who worked rotating night shifts of over 15 years had a 35% higher risk of developing colorectal cancer and those who worked over 30 years had a 36% higher incidence of breast cancer. New Mexico has instituted the Night Sky protection act; while in the Czech Republic and Arizona, light has legally been included as a pollutant. In Ontario, an average of 2278 bird casualties had previously occurred annually but were reduced to only a few once lighting from the power plant in question was changed.

Local governance has begun to create legislations; however, municipalities often lack incentive to enforce lighting ordinances which leads to what scientists are calling a race to the bottom. Experts are asking the public to assert consumer pressure over companies to be more socially responsible, the education system to integrate light pollution as part of the curriculum and the federal government to recognize the risks of ELP to human health and the environment.