Over the past two decades, European astronauts have taken more than a million photos of Earth at night with digital cameras to demonstrate the true extent of light pollution. A European research team processed these images and compared them over time, showing a marked increase in it in urban areas, as well as a transition to whiter and bluer emissions due to use now widespread use of light-emitting diode lamps, or LED technology.
However, according to scientists, the transition to white and blue light radiation disrupts the day-night circadian rhythm of living organisms, including humans, with negative effects on the health of species and ecosystems. Their study points in particular to the suppression of melatonin, often referred to as the sleep hormone; disruption of the phototaxic response of insects and bats, ie their ability to move according to a light source; and the lack of visibility of stars in the sky.
As Europe dims its lights in a need to save energy, scientists warn it shouldn’t just worry about cutting bills, but also preserving the night cycle of humans, animals and plants.