Light pollution: wasted energy seen from space

Because emissions come from so many sources, the exact amount of energy wasted on inefficient or unnecessary artificial light is difficult to estimate. But

the International Dark Sky Association estimates that 35% of artificial light is wasted by being poorly aimed or unshielded. This equates, in the US alone, to about $3 billion per year spent on “making the sky glow”.

This article originally appeared on BBC News – World