The ozone layer is thinning in places around the equator

The planet’s natural protection from UV radiation may be in danger over some of the world’s most populous areas.

Backstory: Huge ozone loss hit Earth in the 1980s, especially above Antarctica. The Montreal Protocol banned the chemicals that were responsible for the depletion, and ozone levels in the upper stratosphere grew again.

What’s new: In a paper published in Atmospheric Chemistry and Physics, researchers explain that the ozone in the lower stratosphere is now thinning at lower latitudes. Near the equator, where billions of people live and sunlight is at its most intense, the resulting loss of UV protection could be a disaster.

What’s causing it? That’s still unclear. It may be that changes in atmospheric circulation due to global warming are shifting ozone toward the poles. Or some industrial chemicals once thought to safely break down in the lower atmosphere may, in fact, make their way high enough to account for the damage.