We all know about automobile pollution and the exhaust from combustion engines. But another kind of pollution – light pollution – is largely overlooked and even unnoticed.
Light pollution is one of the results of human development. As we’ve continued to evolve and progress throughout the 19th and 20th centuries, we’ve attempted to alter the night sky by filling it with light.
As a result, much of the nighttime skies of the United States and Japan are full of light, ranging from highways to brightly lit cities. Even in the South Atlantic waters, the intensely bright glow of a squid fisherman’s halide lamp can be seen from space.
In most cities the sky looks as though it has been emptied of stars. Many people have grown so accustomed to this artificial, dominating light that the original glory of a naturally unlit night lies beyond our experience and thought.
However, the benefits of such mass applications of artificial lighting come with ecological consequences. Some aspect of life – such as migration, reproduction and feeding – is negatively affected. Scientists are only now beginning to study such results.
For many nocturnal species, light is a powerful biological force and acts as a magnet. Such effects are being studied by researchers such as Travis Longcore and Catherine Rich, co-founders of the Los Angeles-based Urban Wildlands Group.
For example, when birds migrate at night, they are apt to collide with brightly lit, tall buildings. This causes the younger birds on their first journey to suffer disproportionately. Unlike astronomers, most of us may not need a clear view of the night sky for our work. However, like most other creatures, humans need the rhythms of day and night.
Darkness is as essential to our biological welfare, our natural internal clockwork, as light itself. Exposure to excessive levels of light disrupts our circadian rhythms and has been found to lead to increased stress and fatigue levels.
Furthermore, researchers also suggest a link between exposure to light at night and the risk of breast cancer, due to suppression of the normal nocturnal production of melatonin.
‘ The good news is that light pollution represents a problem that can easily be remedied. Instead of allowing artificial light to shine outward and upward into the sky, where it is not wanted, it should be focused downward, where it is needed. Simple changes like this in lighting design and installation would yield immediate changes in the amount of light that spills into the atmosphere and, consequently, immediate energy savings.
The International Dark Sky Association was founded in 1988 to raise awareness about light pollution and the importance of preserving the natural nighttime environment. Largely due to the efforts of organizations like this, efforts to control light pollution have spread around the globe. For example, entire countries, such as the Czech Republic, have committed themselves to reducing unwanted glare.
It is essential that other nations, particularly large consumers of energy such as the United States, take steps to preserve the natural night sky that is so vital to us.
Khan is a member of
the class of 2012.