People need a daily dose of natural dark skies at night in the same way we need daylight.
More than 99% of people living in Europe and the US are looking up at light-polluted skies.
A study in Science Advances shows the Milky Way is hidden from more than one-third of humanity, including 60% of Europeans and nearly 80% of North Americans.
National Parks and Wildlife Service Mayo Dark Sky Park Development Officer Georgia MacMillan told Newstalk Breakfast why natural night time light is important.
"It's part of our make up and the way we've evolved," she said.
"In the same way that we need to see daylight and we need our daily dose of daylight, equally so chronobiologists say that we need natural night time to reset.
"It's a question of balance".
Artificial sky brightness as a ratio to the natural sky brightness. Image: American Association for the Advancement of ScienceMs MacMillan said people are moving more towards having some kind of light all the time.
"We have a tendency to go towards 24/7 light in some capacity," she said.
"All we're saying is to just take it down a notch and to try and have that dose of darkness, in the same way that people are familiar with going out and having sunlight in daytime."
Europe’s artificial sky brightness, in twofold increasing steps, as a ratio to the natural sky brightness. Image: Image: American Association for the Advancement of ScienceMs MacMillan said most of the Irish night sky has been degraded.
"It's really only the western seaboard - Mayo where I am, down in Kerry, Connemara and Donegal - the west coast really has what's left of our natural dark skies," she said.
"We're probably the darkest in Europe because all of mainland Europe has certainly degraded to a much greater extent.
"The young people who live in those areas, even in Ireland, never sea a natural night sky - and that has inspired so much in the past of art, literature [and] science.
"It's not just us that suffers, it's our ecological system and our ecosystem that suffer if we have constant light in our world," she added.
Ms MacMillan said there needs to be a new approach to our relationship with artificial light with a "growing movement" to change things.
