On land, more than 80 percent of the planet’s population lives under light-polluted skies. More than a third of the world, around 2.5 billion people, can no longer see the Milky Way. That pollution has far-reaching consequences that threaten all our senses: from the loss of familiar creatures that live for the night, to unique interpretations of our position in the world.
In Australia, only 2 to 5 percent of the population can see the Milky Way from their backyards due to urban and industrial light pollution. For Aboriginal people living in large, urban areas like Sydney or Melbourne who carry knowledge about the night sky, a loss of access to the stars can have devastating long-term effects.
Ambient light pollution can cause chronodisruption — the disruption of circadian rhythms, which can impact brain wave patterns, hormone secretion, and neuronal activities. Humans have adapted to day and night, and without extended periods of darkness, sleep-wake patterns can impact the production of melatonin in the body. Reduced melatonin levels have been linked to higher rates of diabetes, obesity, anxiety, and depression.