Problems

Problems of light pollution:

Biological

Health

Cultural and natural heritage

Energy

Light pollution as a threat to biodiversity

A biological rhytm of day and night is natural to several species, habitats and ecosystems and indispensable for a healthy funcitoning of the biosphere. Artificial light affects the growth of plants and their resistance to infestations and disease, and influences the growth, feeding, reproduction and migration patterns of a number of animals.

Although more ecological impacts of light pollution are expected to be known as the research in the field progresses, sufficient evidence exists about the importance of darkness for a number of animal and plant species. It is our responsibility to protect them, especially if the solutions are simple.

Light pollution as a threat to human health

The biological rhytm of day-light and darkness is natural also to humans and thus vital to our health. By suppressing melatonin production and interfering with the circadian rhythms, intrusive street lighting entering into bedrooms at night may lead to sleep deprivation, depression and impaired thinking. Research has shown that long-lasting increase of systolic blood pressure could be linked with an increase of risk of cardiovascular diseases like stroke and myocardial infarction. High night-light intensity has also been associated with the higher incidence of breast cancer, pointing to the possibility that exposure to light at night may be the most powerful factor in breast cancer besides genetic defects.

Although further research is needed health effects demonstrated so far are alarming enough to urge a response.

Light pollution hinders enjoyment of (nocturnal) nature

Artificial skyglow is becoming an ever more serious hindrance to enjoyment of the starlight and astronomical research. Professional astronomy as it has been developing over the past centuries is a key to understanding our world. Not only scientists, each individual has a right to an unpolluted night sky that has a aesthetic, cultural and spiritual value.

These and many more values of pristine night sky have been recognised in the Declaration in Defense of the Night Sky and the Right to Starlight, adopted in La Palma in 2007. Among others, protected areas are “called to include the protection of clear night skies as a key factor strenghtening their mission.”

Light pollution is a waste of energy and considerably contributes to climate change

Unshielded lighting emits up to 50% of light in the sky. Production of this unnecessary energy has considerable economic and environmental impacts. These are greatly at odds with the efforts to reduce energy inefficiency and greenhouse gas emissions.

Avoiding light pollution is not only an ecologically but also economically viable solution. Finally, only ecological outdoor lighting is consisent with the principles of sustainable development.

• See Bibliography for further information.