The director of the Census of Marine Life on broadening the scope of global change to include illumination and noise.
“Son et lumi?re”—sound and light—may stir thoughts of a clamorous and brilliant display on a holiday evening, animating Versailles, the pyramids of Giza, or Delhi’s Red Fort with guns, gongs, and fireworks. But I would like to draw attention to other more serious dimensions of sound and light. A quarter century ago, in 1983, I was the scribe for a report of the US National Academy of Sciences titled “Toward an International Geosphere-Biosphere Program: A Study of Global Change.” To researchers in environmental sciences and many more people concerned about Earth’s nature, the phrase “global change” has become familiar. Global change brings to mind shifts in the climate induced by humanity, perhaps 1°C since the first telephone rang and electric lamp glowed. Global change conventionally also embraces climate’s cousins, such as alterations in land and ice cover, acidification of the oceans, and ozone depletion.
Yet, if the inventor of the telephone, Alexander Graham Bell, were to return to his beloved Nova Scotia in 2009, he would find this year’s climate little changed from one of the warm years of the 1890s when he passed by Bras d’Or Lake. However, the night sky would shock Bell. In 1909, over Bras d’Or, Bell’s Silver Dart made the first plane flight in the British Empire. Had the Silver Dart scouted by night, pilot J.A.D. McCurdy would have seen that Nova Scotia after sunset meant darkness except for moonshine and starlight. Illumination was dim and costly, more than 100 times per lumen the price today. The technology of Thomas Edison, Bell’s light-working contemporary, had not yet diffused. When their generation looked up at the night sky a century ago, they saw swathes of stars. Today, however, our most familiar starry image may be satellites and astronauts looking down, observing the lights on Earth at night. The populated regions of the developed world, as well as China and India, are ablaze.
Babylonians and Mayans would not have invented astronomy under a nighttime sky whitened by modern light. The loss may not only be our everyday closeness to the heavens, which we now approach instead with platforms in space. My concern is that we have scarcely begun to think about the ecological effects of nighttime illumination. Bats and night owls aren’t the only oncs affected. A large fraction of insects behave sensitively to light, and the Moon modifies the action of microbes. So we may conjecture that the global change of nighttime illumination is rippling through Earth’s ecosystems. I wonder if some of the changes experts attribute to carbon dioxide and global warming may owe more to nocturnal photons and their associates.