Bright light from cities around the world is reducing the darkness of night. Years ago, when night-time fell, the dark arrived. Not today. A new study says artificial light at night grew in most countries by 2.2 per cent a year between 2012 and 2016. This is causing us many problems. The International Dark-Sky Association says it, "is not only [reducing] our view of the universe, it is [badly] affecting our environment, our safety, energy consumption and health".
Artificial light is a threat to our natural environment. A scientist called it a "pollutant that threatens nocturnal animals and affects plants and microorganisms". It is affecting bacteria, mammals, and humans. It is reshaping "entire social ecological systems". Environmentalists thought LED lights would help. However, cities are using more of these because they are cheaper. This is adding to the light pollution. Night-time light decreased in 16 countries.