NASA has recently announced that the ozone hole over Antarctica is at its smallest since 1988. The U.S. space agency and National Oceanic and Atmospheric Administration have been checking on the ozone hole, with ground-based instruments, weather balloons, and satellites, since it was first detected in 1985.

 A Smaller Ozone Hole

The ozone hole, which forms over Antarctica each September, reportedly reached its peak on Sept. 11, measuring a size equivalent to an area two and a half times that of United States' size. Thereafter, the size shrunk throughout September and October.

NOAA said that a warmer and unstable Antarctic vortex decreased polar stratospheric cloud generation in the lower stratosphere. The development led to fewer clouds that are the first steps that result in chlorine- and bromine-catalyzed reactions, which destruct ozone.

“The Antarctic ozone hole was exceptionally weak this year,” said NASA Earth Sciences chief scientist Paul A. Newman. “This is what we would expect to see given the weather conditions in the Antarctic stratosphere.”

However, the researchers have said that a smaller ozone hole this year is not a sign of rapid healing but rather caused by a natural variability. Moreover, the ozone hole still covers an area that is more than two and a half times Australia’s size, measuring nearly 20 million square kilometers.

The Ozone Layer

It was in the 1970s that researchers understood that the thin ozone layer above Antarctica was being worn down by chlorofluorocarbons. The ozone hole became a global sensation from the mid-1980s through the 1990s.

The public feared for the well-being of scientists stationed in the South Pole and wondered if ultraviolet radiation would burn their skin or blind them even as they were studying the hole.

Increased fear of the ozone hole deteriorating and leading to more cases of skin cancer led to the signing of the Montreal Protocol. Later on, the number of nations that had signed the treaty rose to 197.

The treaty galvanized action toward addressing the hole in the ozone layer. There has been a worldwide effort to lower the use of substances such as chlorofluorocarbons that were once commonly used as refrigerants and in aerosols, which cause damage to the ozone layer.

NASA scientists expect that the ozone hole will return to the 1980 levels sometime around 2070. Incidentally, the ozone hole peaked to its largest measurement in 2000, when it reached a width of 11.5 million square miles.

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