21 Nov 2014

Light pollution - easy solutions, difficult implementation

Moritz M writes:*

Can’t sleep? Feel depressed? Chances are that the reason might be in front of your window: more and more studies suggest that light pollution is causing many health problems, including sleep deprivation, depression and various forms of cancer. This light pollution map illustrates how bright your city/district looks from space. Although the topic remained relatively disregarded in the past, governments and municipalities more and more realize the impact of excessive use of light on the environment, health and public spending. Many examples show how light pollution can be limited with additional technology: Fully shielded streetlights stop light to shine anywhere else than where it is needed – the street. But if we look closer at the “success cases”, we see that no of them were realized on a broad national basis. Since these technological solutions are relatively expensive to implement everywhere in a country and usually only find support, if the impact is felt directly by the population, e.g. if the area is famous for its clear night sky and there are no tourists anymore, because the sky has become too bright to watch the stars.


Therefore we must come up with other, more “globalizable” solutions. We have to work with what we already have (which is a lot of lights) and simply reduce the usage. As one of the first, France has stepped forward with a national regulation of the usage of light in public areas. Since June 2013 these regulations have been in place and the government claims to save energy equivalent to 250.000 tons of carbon dioxide annually (this is about as much energy as 750.000 household use in France). While the effect seems quite big, the actual regulations are not as excessive as one might think:
  • Interior lights have to be turned off one hour after the last staff leaves the building
  • Exterior lighting that illuminates facades and window lightning have to be turned off by 1am and can be turned on one hour before sunset (more details)
So far the regulations have been very successful in the country and should encourage policy makers to move on to other sources of light overuse. We still see the bright illuminated advertisements everywhere, even in the middle of the night. Why not also shut them off during the late night and ask for a progressive tax on every consecutive hour of the night? Companies will think twice about the reach of their advertisement and whether that is justified by higher costs.

Bottom Line: The solutions are right there. Just make them look attractive.

* Please comment on these posts from my environmental economics students, to help them with unclear analysis, other perspectives, data sources, etc.