With roughly 84 million acres of national park lands, some of them hundreds of thousands of acres on their own, you’d think finding a quiet, dark space in one would be easy. Not so, say scientists in the Natural Sounds and Night Skies Division of the National Park Service, who have monitored light since 1999 and sound since 2000. “We found noise almost everywhere,” says senior scientist Kurt Fristrup, who was particularly surprised by the ubiquity of aircraft noise.
Night skies and natural sound are valuable natural resources, just like clear mountain streams and healthy forests. Their loss not only degrades our experiences at national parks, unnatural levels of light and noise in general can increase stress and affect our health. Excess noise and light affect wildlife as well, interfering with an animal’s ability to find prey or avoid becoming prey, hindering reproduction, increasing stress, and even causing animals to leave otherwise useful habitat.
A recent study found that elevated noise levels resulted in a one-third reduction in the number of bird species in parts of northern New Mexico. Excessive light at night can change the normal daily rhythms of wildlife, shift seasonal activities such as breeding or migration, and even change expression of some of their genes.
According to Fristrup, noise and light pollution are growing faster than the population of the United States, doubling or tripling every 20 to 30 years. Commercial and general aviation flights increase every year. Eighty-three percent of the land area of the continental U.S. lies within six-tenths of a mile from a road. But there’s good news too: Efforts to mitigate noise and light pollution can have an immediate impact. In the meantime, here are the Division’s recommendations for where to find the quiet and dark.