The argument for switching off lights at night

Fabrice Coffrini/AFP/Getty ImagesThe light pollution produced by street lamps, advertising boards, flood lights and our homes is so bad that 80% of the world's population lives in the haze of a perpetual glow in the hours of darkness.It started like any other day for Stephen Maciejewski. He woke up at 04:30 and by 05:30 he was in downtown Philadelphia ready to start his patrol. Maciejewski – a volunteer with the conservation non-profit Audubon Pennsylvania – has walked the exact same route for years, looking for birds lying on the pavement.The unfortunate creatures end up there after crashing into the city's brightly-lit skyscrapers. Maciejewski bags and labels dead birds and scoops up those that are simply dazed, moving them out of the way of hurrying commuters.But the morning of Friday 2 October 2020 was different. Maciejewski was kneeling on the pavement picking up a clutch of dead birds when someone ran up and pointed out another cluster around the corner. A few minutes later, some...