Anne Hennig

Christmas time is coming and all cities and homes get dressed up with lights. Thanks to the invention of affordable and highly efficient, energy-saving LED lights, homeowners do not longer have to worry about there energy bills at the end of the months since then.

But as researchers recently revealed in the Science Advances, the use of LEDs has an unintended side effect. Satellite data show that from 2012 to 2016 the artificially lit area of the Earth at night has grown by 2.2 percent every year.

Previous research on the economical perspective of lighting has shown that over time and geographical context, humans constantly tend to spend around 0.7 percent of GDP on artificial light.

With lights using less energy in the past years, lighting has increased, because people tend to switch off the lights less and institutions like churches tend to floodlight their buildings more, explained Christopher Kyba from the German Research Centre for Geosciences in the latest BBC Science Hour. Finally, this lessens the energy-saving effects and increases light pollution.

Light pollution has verifiable impact on flora, fauna, human well-being and astronomical programs. Influencing genes, physiology, migratory and reproductive behavior as well as mortality are well documented and, as stated in a research paper by Gaston et al. (2015), „[t]here is almost a complete lack of published examples in which no effect was documented.

But that is not to say that LEDs in general are condemnable. Kyba rather pointed out that „LEDs are the only way to go.“ On the one hand, because other lights are not going to be sold any more. On the other hand, because LEDs support different, more efficient and visionary ways of lighting.

„You can choose which color you want exactly […], you can run them at very low levels, you can raise and lower the level instantaneously, and you also have a lot of directional control of where light goes,“ concluded Kyba.

This means, the amount of light can be controlled, for example in sparsely populated areas, where LEDs can be used to create a softer, less intense lighting. „All of those properties put together mean that you can really come up with new ways to light places,“ said Kyba.