The artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world of light from our artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world has reached such high levels that it is reducing the darkness of artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world . A century ago, when night-time fell, the artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world of night arrived. Things are different artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world . A new study reports that artificial light at night is increasing around the artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world . Scientists say it grew by 2.2 per cent a year between 2012 and 2016. This artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world of artificial light is causing us many artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world . The International Dark-Sky Association says it, "is not only impairing our artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world of the universe, it is adversely affecting our environment, our safety, our energy artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world and our health". Dr Franz Holker said artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world light is a artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world to our natural environment. He called it a " artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world that threatens nocturnal animals and affects artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world and microorganisms". He added that it is affecting artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world from bacteria to artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world , including humans. He said it is reshaping " artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world social ecological systems". Environmentalists thought LED lights would help. However, artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world are using more LED lights because they are cheaper. This is adding to the light pollution. Night-time light decreased in 16 artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world , including artificial brightness cities consumption countries dark entire everything intrusion mammals nations night plants pollutant problems threat today view world at war, like Yemen and Syria.