Sir

In his Commentary 'Time to turn off the lights' (Nature 457, 27; 2009), astronomer Malcolm Smith argues for darker skies. Ecologists would also do well to support the International Year of Astronomy, considering the potentially severe impact of light pollution on some biological systems. Moths, for example, as well as the bird migrations Smith mentions, are adversely affected by light pollution.

In most instances, the origin of atmospheric and ecological light pollution is identical. So ecologists should back initiatives stimulated this year by physicists, to help raise awareness of the undesirability of light pollution across different disciplines.