Images of the Earth at night, taken from space are always a stunning sight, with cities, countries and whole continents glittering like jewels. But this beauty comes at a price. It used to be that anyone looking up on a clear night could see the Milky Way. As more and more of us are drawn to live in urban areas, our view of the sky is blotted out by the glare of our lights. Astronomers have known about the growing problem of light pollution for a long time. Now ecologists are becoming concerned that our artificial lights are affecting more than our view of the stars.
Researchers at the University of Exeter studying the ecological impact of artificial lighting have noted changes in distribution of invertebrate communities around artificial lighting which could affect the broader wildlife that depend on them. Simply put, it is easier for predators to find their prey, and harder for the prey to hide, in brightly lit areas. Streetlights may also be disrupting the natural rhythms of both fauna and flora, changing hibernation patterns and flowering times. It may also be affecting our own circadian rhythms as well as being a colossal waste of energy, an estimated $2.2 billion per year in the U.S. alone! On average, 30% of the light from a streetlight shines up and out.
Light pollution is a growing problem. Artificial lighting is increasing at the rate of 6% each year globally and is only going to get worse, as developing nations use more and more electric light. Since 1988 The International Dark-Sky Association has campaigned to protect and preserve the night environment and promote energy efficient options. Light what you need, when you need it, they say.
One of their projects is the International Dark Sky Places program which certify locations with exceptional nightscapes, either as communities, parks or reserves. The Kielder Forest and adjacent Northumberland national park covering 400 square miles in the UK is the latest area hoping to join the 12 dark sky reserves already recognised by the IDA worldwide. Such status can bring economic advantages too, astronomy is rapidly growing in popularity and with it astronomy based tourism, offering dark skies, observing opportunities and star parties and star camps.
Losing the stars can have a lasting impact on our culture too. Think of all the art, literature and music that have been inspired by the night sky. As we become increasingly disconnected from nature the stars are one of our most important links. There are many people today who have never been able to look up and see the Milky Way arching over their heads. Looking up at the stars allows us a vital opportunity to engage with the larger questions posed by the universe.