Antarctic ozone layer hole shrinks by 4 million kilometers

Scientists at MIT and other locations have been eyeing the hole in the ozone layer since it came to the forefront in the '80s. The fear when the hole in the ozone layer was first discovered was that it might lead to harm for humans around the world since we need the ozone layer to protect us from all sorts of deadly things that come from space. The good news is that scientists have announced that the ozone layer hole has shrunk significantly since 2000.

According to the team of scientists, the ozone hole has shrunk by more than 4 million square kilometers since 2000. To put 4 million square kilometers in perspective a bit, that it about how large half the area of the contiguous US is. Scientists have also noted that the healing of the ozone layer hole has also slowed for the first time and the finger is pointed at volcanic eruptions.

The hole in the ozone layer was caused in part by CFCs, banned for decades now. CFCs were emitted by dry cleaning, refrigerators, and aerosol cans but were virtually eliminated in 1987 when just about every country in the world signed the Montreal Protocol to ban the use of CFCs. Scientists track ozone depletion using measurements taken in October of Antarctic ozone.

Measurements of the ozone hole have shown that ozone depletion starts in late August as winter ends in Antarctica and the hole is fully formed by early October. Other than CFCs, the ozone hole is also affected by chlorine in the atmosphere. The team believes that half the hole shrinkage was due to reduction in atmospheric chlorine. "It's been interesting to think about this in a different month, and looking in September was a novel way," Diane Ivy says. "It showed we can actually see a chemical fingerprint, which is sensitive to the levels of chlorine, finally emerging as a sign of recovery."