From the medieval candle to phosphorescent trees and glow-in-the-dark concrete, Daryl Mersom charts the trajectory of urban light, and asks how the problem of light pollution can be tackled in the modern era
The ever-increasing demand for the 24-hour illumination of cities is blighting urban residents with two distinct forms of pollution. Current lighting solutions rely on vast amounts of energy, of course, much of which is not yet generated from renewable resources. According to the International Energy Agency, lighting accounts for almost 20% of global electricity consumption – and thus high levels of carbon emissions.
But there is also an increasing acknowledgement that light itself constitutes a form of pollution – and mounting evidence that our exposure to urban lighting at unnatural times is making us ill. It is reported that the glow of Los Angeles is visible to planes 200 miles away, while in Reykjavik, light pollution is obscuring the northern lights.
With our current lighting technologies being called into question, it is time we considered the numerous alternative lighting solutions being pioneered. Indeed, 2015 was declared the International Year of Light and Light-based Technologies, in recognition of the critical role that photonics (the science of light particles) now plays in our urban lives and communications.
Some of the most interesting plans to tackle the two-fold problem of urban light pollution include experiments with phosphorescent trees, light emitting algae, glow-in-the-dark concrete and light scheduling based on big data. […]