Science Magazine – June 16, 2023 issue: A wild little penguin (Eudyptula minor) stands silhouetted against the city of Melbourne, Australia. Increasing levels of light pollution are having adverse effects on humans and the natural world.

Losing the darkness

For most of history, the only lights made by humans were naked flames. Daily life was governed by the times of sunrise and sunset, outdoor nighttime activities depended on the phase of the Moon, and viewing the stars was a common and culturally important activity. Today, the widespread deployment of outdoor electric lighting means that the night is no longer dark for most people—few can see the Milky Way from their homes. Outdoor lighting has many legitimate uses that have benefited society. However, it often leads to illumination at times and locations that are unnecessary, excessive, intrusive, or harmful: light pollution.

Potential for recovery of declining reef sharks

Data on shark populations in coral reefs raise concern and hope for recovery

Sharks and their relatives are some of the most threatened vertebrates on Earth, with approximately one-third estimated or assessed as threatened with extinction (1). This is a major problem because as predators that help keep the food web in balance, these animals play a variety of vitally important ecological roles (2) and in doing so help to keep healthy many ecosystems that humans depend on. Coral reefs provide homes for countless fish species that are vital for fisheries and are therefore an especially important ecosystem for humans—and one where the decline of shark populations seems to be especially acute