A recent study published in the Remote Sensing journal used newly acquired images of Earth at night, taken from space, to study the variations of light pollution in cities across the world. What they found was that not all cities are lit equally and the most intriguing find was the difference between American and German cities.
Germany and the United States are at comparable levels when it comes to economic development, so it was a little surprising when the researchers found American cities to be significantly brighter from space than German cities of an equivalent size and population density.
This division was so significant that the researchers themselves began to doubt their own data, still believing that there is a chance of error in the data or even bias effecting the results.
However there are some plausible causes if the data is in fact accurate. German cities are much older than any American city and that carries over to the infrastructure, including lighting that can be decades old. American cities also have less tree cover to possibly hide the emittance of light from the images taken in space.
Another interesting find was that East Berlin emits much more light per capita than West Berlin, creating a noticeable remnant of the city’s past Cold War division. This actually reigns true for most East versus West German cities.
Two factors are believed to play a potential role in the difference between East and West Berlin. More than 40,000 gas lamps, which are more difficult to detect from space, are still used throughout Berlin, and a majority of them are in the West. Berlin also has a lighting policy that advises outdoor light use only when it is necessary or makes sense.
It is clear that something as simple as lighting can paint a very unique picture not only about a country or town’s current state, but also its past.