TRUE / FALSE / NOT GIVEN عمیق: بازنویسی و قیدهای محدودکننده

A. Artificial light at night has become so common that many city children have never seen the Milky Way. Street lamps, advertising screens and lit office windows send light upwards, where it is scattered by dust and water in the air and produces a glow over the whole city. Astronomers were the first to complain about this glow, but in recent years biologists have also become concerned. B. Researchers have shown that light at night can confuse some species of migrating birds, which normally use the stars to find their way. Large numbers of birds are attracted to brightly lit buildings, and many are killed when they fly into glass. Insects are affected too: moths circle street lamps until they are exhausted, and fewer moths means less food for bats. However, not every species suffers. Some spiders and bats actually hunt more successfully near lamps, at least in the short term. C. In 2019 the town of Harwood decided to test whether its streets could be darker without making people feel less safe. The council replaced 4,000 old orange lamps with LED lights that point downwards, and it dimmed them by half between midnight and five in the morning. Lights in a few quiet residential streets were switched off completely after one a.m. D. The results after two years were mostly positive. The council's electricity bill for street lighting fell by 38 per cent. Contrary to the fears of some residents, police figures showed no rise in burglary or car crime in the dimmed areas. Road accidents at night did not increase either, although the council admits that two years is too short a period to be certain. A survey found that seven out of ten residents had not noticed that the lights had been dimmed at all. E. Not everyone was satisfied. Older residents in the streets where lights were switched off said they no longer felt comfortable walking home late, and the council later restored lighting in two of those streets. Some critics also point out that the new LED lamps, although cheaper to run, produce a whiter light, which may be more harmful to wildlife than the old orange glow. F. In my view, Harwood's experiment shows that most towns light their streets far more than they need to. Dimming lights in the middle of the night costs almost nothing and saves a great deal of money. That said, switching lights off entirely is a step too far: people's sense of safety matters, even when the crime figures do not support their fears. Councils should also choose warmer-coloured lamps, even if they are slightly more expensive.