As beautiful as our earth can be, most of us rarely ever consider the nearly invisible layer of protective gases that keeps life on our planet safe from harmful ultraviolet rays. But scientists are all too familiar with this crucial portion of our upper atmosphere, and a recently-discovered depletion in ozone above the Arctic has left them scratching their heads.

Earlier this year, researchers detected a gaping hole in the Arctic ozone layer where over 80% of the existing ozone was completely obliterated. Post-winter ozone depletion in the Arctic is a regular occurrence, but the level of this year's destruction was record-breaking.

Researchers from the Jet Propulsion Laboratory in California believe they have a handle on the mechanism that created the hole. They think unusually cold air in the stratosphere formed clouds which created a form of chlorine that is toxic to ozone molecules. The real mystery is why the stratosphere was so chilly for so long, and whether it could happen again.

One explanation is climate change. As the climate of the earth on ground level warms due to greenhouse gasses and other manmade environmental hazards, the stratosphere actually cools. This cooling may be setting the dominos in motion and leading to the depletion of the ozone layer. The research is still ongoing, and scientists aren't ready to pin down a cause just yet, but record-breaking holes in our planet's protective shield aren't good news for anybody.

This article originally appeared on Tecca

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