The South Pole’s ozone hole is currently the smallest on record since it was first detected in the 1980s, according to NASA.
NASA reported the hole in Earth’s protective ozone layer averaged only 3.6 million square miles. Normally, the ozone hole grows to a maximum area of about 8 million square miles around late September to early October.
“That’s really good news,” NASA scientist Paul Newman said. “That means more ozone over the hemisphere, less ultraviolet radiation at the surface.”
Ozone in the stratosphere absorbs some of the sun’s harmful ultraviolet radiation. Ultraviolet radiation can cause skin cancer, cataracts, suppress immune systems and damage plants.
However, NASA scientists said the shrinking ozone hole is most likely from weather changes, not recent efforts to cut pollution.
“It’s important to recognize that what we’re seeing this year is due to warmer stratospheric temperatures,” Newman said. “It’s not a sign that atmospheric ozone is suddenly on a fast track to recovery.”
Chlorine in the air needs cold temperatures in the stratosphere and clouds to convert into a form of the chemical that eats ozone, Newman said. The clouds go away when it warms up.
This year temperatures were 29 degrees warmer than average right below the stratosphere.
Man-made chlorine compounds, which can last in the air for 100 years, damage the ozone, creating a gap. The effects are most evident over the Antarctic, "because of the special atmospheric and chemical conditions that exist there and nowhere else on the globe," according to the National Oceanic and Atmospheric Administration.
The 1987 international Montreal Protocol banned many of the chlorine compounds used in refrigerants and aerosols, like hairspray, to lessen the damage. Since then, the size of the ozone hole has slowly declined but remains large enough to produce significant ozone loss.
Scientists project the Antarctic ozone to recover back to its 1980 level around 2070.
The hole reaches its peak in September and October and disappears by late December until the next year.