Alejandro Sánchez de Miguel
Researcher in the Instrumental and Extragalactic Astrophysics group at the Complutense University of Madrid and leader of the citizen science project Cities at Night
The article seems quite robust. In this case, humans are being used as sensors. Human physiology is not going to change for a long time and therefore, when it comes to very large amounts of data, [the human eye] is more reliable than satellite images. The conclusions of the paper are along the same lines as those we published a few months ago about what satellites can say. The study allows us to see that light pollution is growing around the world, but it does not allow us to know exactly where.
This research indicates that the growth of light pollution is much faster than we expected and that it is global. The most important thing is not the loss of visible stars (that is a secondary issue): what is really worrying is the environmental impact.