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Harvard College Library News: News from around the libraries

Illuminating the Impacts of Light Pollution

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Map showing night sky brightness in North America. (Courtesy Istituto di Scienza e Tecnologia dell'Inquinamento Luminoso)


October 8, 2010 – When the first commercially-viable electric lights began appearing in homes and businesses in the late 1870s, the technology was heralded as revolutionizing American life – the new lights allowed for greater home and workplace safety, extended the workday, and allowed people to enjoy leisure time late into the night.

Along with those benefits, however, have come unintended consequences. The exponential growth of artificial light has in recent years sparked concerns about light pollution and its effects on everything from astronomy to the reproduction of sea turtles.

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A new exhibition, ‘Blasted with Excess of Light’: the Effects of Light Pollution on the Natural World, opening October 13 at Cabot Science Library, asks viewers to consider how artificial light has changed nearly every corner of the world, and the consequences that result when we never have to be in the dark.

“In the scientific community, the issue of light pollution has been a concern for decades,” said exhibition curator Reed Lowrie, Science Reference and Cartographic Librarian at Cabot. “In the 1940s, the Mt. Wilson Observatory in Los Angeles was relocated due to light pollution.”

In addition to a map showing the national power grid, visitors to the exhibition can examine several satellite images that starkly illustrate how artificial light and the resultant light pollution are heavily concentrated in some parts of the world, but not in others. The images show much of North America and Europe exploding with light, while South America, Australia and Africa are almost uniformly dark. The brightest spot in South America, in fact, isn’t part of the continent at all, but is a massive fleet of ships around the Falkland Islands that uses lights to draw fish to the surface. Other images in the exhibition highlight the differences between the pre- and post-electrical world.

Lowrie’s attention was first drawn to the issue by a 2007 New Yorker article which examined the astronomical aspects of light pollution by highlighting the very few places in the U.S. where people can go to see the night sky as it would have looked before the advent of electric light. Spurred by the article, he began setting items aside for a future exhibition. The publication earlier this year of Jane Brox’s book, “Brilliant: The Evolution of Artificial Light,” convinced him now was the time to move forward.

While it was astronomers who first voiced concerns about light pollution, the impacts range far beyond that community. Aside from obscuring astronomical research, the rise of artificial light has been linked with changes in people’s sleep patterns, changes in animal reproduction and migration and the cost of providing well-lit communities is a growing issue for many municipal budgets.

In addition to ecological concerns, Lowrie said, there is also an issue of waste. Many streetlights and exterior lights spray as much as 70 percent of their light into the air rather than toward the ground, according to some estimates. The solution, advocates say, is to use “shielded” lights that are designed to direct light downward. By ensuring light is directed only where it’s needed, the lights reduce light pollution, conserve energy and save money – all important considerations given today’s straightened times.

For many years, Lowrie said, light pollution was thought to be an issue only in very specific areas, like sea turtle reproduction or astronomy. But as the impacts of light pollution have grown in recent years, so too has the public’s concern.

“The public is now seeing the impact of light pollution in a number of ways,” Lowrie said. “I think it’s important for people to think about artificial light, what we have lost and what we have gained from it.”

‘Blasted with Excess of Light’: the Effects of Light Pollution on the Natural World will be on display in Cabot Science Library through January 21, 2011.