Outdoor artificial lighting may be a fact of modern life, but it is costing the environment dearly.
Astronomers estimate that in the UK alone, wasted electricity from street lights emits carbon dioxide equivalent to an extra 160,000 cars on the road each year.
It is not just wasted electricity, artificially lighted night skies disrupt the natural cycles of plants and animals, changing habitats and ecosystems.
Residents on the Isle of Sark in the Channel Islands, however, are turning down artificial lighting as part of a scheme to reduce light pollution and return the island to its natural day-night cycle.
Chu Owen, an amateur astronomer, finds out how wildlife and communities are reaping the benefits of dark skies in the Isle of Sark - declared the world's first dark sky island.
earthrise can be seen each week at the following times GMT: Tuesday: 2230; Wednesday: 0930; Thursday: 0330; Friday: 1630; Saturday: 2230; Sunday: 0930; Monday: 0330; Tuesday: 1630.
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