Biodiversité

Exposure to artificial light at night (ALAN) is a risk factor for organisms. Considering the spread and increasing intensity of night brightness across the globe, and the key role of light at all biological levels, alterations of ecosystems are expected. Yet, we cannot predict the severity of the effects of ALAN in several biomes because little information is available outside the temperate zone. We reviewed current knowledge and identified traits that could be targeted to fill this knowledge gap in order to contribute to the elaboration of a biogeographical framework for the study of ALAN at the global scale.

A central aim of the “lighting revolution” (the transition to solid-state lighting technology) is decreased energy consumption. This could be undermined by a rebound effect of increased use in response to lowered cost of light. We use the first-ever calibrated satellite radiometer designed for night lights to show that from 2012 to 2016, Earth’s artificially lit outdoor area grew by 2.2% per year, with a total radiance growth of 1.8% per year. Continuously lit areas brightened at a rate of 2.2% per year. Large differences in national growth rates were observed, with lighting remaining stable or decreasing in only a few countries. These data are not consistent with global scale energy reductions but rather indicate increased light pollution, with corresponding negative consequences for flora, fauna, and human well-being.

La pollution lumineuse (note scientifique n°37 - janvier 2023) - OPECST de En perturbant les cycles naturels de lumière et d’obscurité qui structurent le monde vivant et en fragmentant spatialement et temporellement les habitats, la lumière artificielle nocturne participe, au même titre que d’autres pressions anthropiques, au déclin de la biodiversité. En outre, elle soulève de réelles préoccupations en matière de santé publique.

Quelles sont les conséquences de l'éclairage artificiel nocturne sur la faune, la flore, les écosystèmes? Et quels sont les effets suspectés ou avérés sur la santé humaine?