Key Selling Points Light pollution is threatening the survival of plants and animals all over the world and the ecosystems they depend on. For example, millions of migratory birds die every year because of light pollution. More than 80 percent of the world lives under skyglow from artificial lights. Two-thirds of the U.S. population and more than one-half of the European population can't see the Milky Way with the naked eye. The skyglow from Los Angeles can be seen by a plane 500 miles away. Light pollution and artificial lights like LEDs have a detrimental effect on human health and upsets our circadian rhythm.

It has also been linked to some cancers. Plants and animals have adapted to live in darkness over millions of years. Darkness is as necessary as daylight for their survival. Stephen Aitken is a biologist and the author ofListen Up, also in the Orca Footprints series.