- Global light pollution has increased by at least 49% over the past 25 years.
- The increases in light pollution have been most pronounced in Asia, South America, Oceania and Africa.
- Light pollution, from streetlights and other sources, can have major impacts on the natural environment.
The night sky on Earth is really not as dark as it used to be.
In fact, according to a new study, global light pollution has increased by at least 49% over the past 25 years.
“The worldwide spread of artificial light is eroding the natural night environment,” said lead author of the study, Alejandro Sánchez de Miguel of the University of Exeter in the UK.
“This study provides clear evidence not only of the seriousness of light pollution as a global problem, but also that it continues to worsen, and possibly at an increasingly rapid rate,” he said. he added, in a statement.
The study found that increases in light pollution were most pronounced in Asia, South America, Oceania and Africa.
He also details what he calls the “hidden impact” of the transition to solid-state light-emitting diode (LED) technology.
LEDs emit more blue light than previous lamp technologies, according to the study, but satellite sensors are “blind” to this blue light and therefore underestimate the level of light pollution. Correcting this, the study’s authors claim that the actual increase in the power emitted by outdoor lighting, and therefore in light pollution, can be up to 270%.
This is probably the case in Europe and North America, where satellites seem to detect a stabilization or even a decrease in light pollution.
“To take the UK as an example, if you ignore the effect of the switch to LEDs – which has been huge – you get the false impression that light pollution has recently declined,” said Sánchez de Miguel. “However, correcting for this effect shows that it has actually increased, and potentially very significantly.
“Contrary to popular belief, the installation of ‘wide white’ LED street lights, while potentially saving energy, has increased light pollution as well as the impacts on organisms such as moths,” he said. he declares.
A study done earlier this year, also from the University of Exeter, found that animals such as moths can be confused by artificial night lights, which can affect their place in the food chain.
Numerous other studies have indicated that light pollution, from streetlights and other sources, can have major impacts on the natural environment. Such pollution probably played a role in the massive decline of insect populations in some areas.
The International Dark-Sky Association suggeststhe increased and widespread use of artificial light negatively affects the environment, our health and safety, as well as energy consumption.
“There is no clear scientific evidence that increasing outdoor lighting deters crime,” according to the IDSA. In addition, research suggests that “artificial light at night can have a negative effect on human health, increasing the risk of obesity, depression, sleep disturbances, diabetes, breast cancer and more.”
The association, which was not affiliated with the study, aims to “protect the night from light pollution,” according to its website.
Ruskin Hartley, executive director of the association, said in a statement that the transition to LED lighting hascontributed to the increase in light pollution.
“Without concerted action to reverse this trend, the impact on the natural environment will accelerate,” Hartley said, “further exacerbating the biodiversity crisis, wasting energy and meaning that an entire generation will grow up in a perpetual twilight “.
The study was published in the journal Remote Sensing.