The ozone layer is healing, because chlorine dispersed into the atmosphere is slowly disappearing, according to a study by NASA.
The ozone hole over Antarctica has formed every year in spring since 1985, when it was first reported. The culprit is human-made chlorofluorocarbons, or CFCs, which have risen to the stratosphere. Ultraviolet rays break up the CFCs, releasing chlorine, which destroys ozone. The resulting hole exposes life on Earth to harmful ultraviolet rays. CFCs were banned in 1996, but their lifetime is around 50 to 100 years.
In 2016, scientists observed that the hole had started to open later in the spring, as well as being smaller, and not as deep. Now, NASA has direct measurements that show ozone destruction is lessening, and the amount of chlorine in the atmosphere is declining.
Since 2005, NASA has measured atmospheric gases in the Antarctic winter—the 24-hour darkness ensures any deterioration of UV can’t be attributed to the sun—and has recorded a 20 per cent decrease in ozone depletion during the winter months. Meanwhile, chlorine levels have been declining about 0.8 per cent every year. According to projections, the hole may be fully healed in 2080.