Scientists from the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) revealed on Oct. 30 that the ozone hole over Antarctica attained its peak size for the year on Sept. 11 and that the size of the hole measured 24.1 million square kilometers or about the size of North America.

While the size of the ozone hole may seem alarming, it actually indicates that the Antarctic ozone hole is not getting any bigger. NASA said that this year's maximum area was virtually identical to the size in 2013, which spanned 24 million square kilometers. It is also comparable to the size recorded in the years 2010 and 2012 but smaller than the biggest ozone hole on Sept. 9, 2000, which reached 29.9 million square kilometers.

"The good news is that our measurements show less thinning of the ozone over the South Pole during the past three years," said Bryan Johnson from NOAA's Earth System Research Laboratory.

The ozone layer, also known as the ozone shield, helps protect life on Earth from the potentially damaging ultraviolet (UV) radiation, which can cause cancer, genetic damage, cataracts and damage to plants and phytoplankton by absorbing most of the UV radiation from the sun.

Concerns over the harmful effects of the depletion of the ozone layer has led to the Montreal Protocol, an international treaty that intended to protect the ozone layer by phasing out substances that are known to cause the depletion of the ozone, such as bromine-containing halons and chlorofluorocarbons, which were once widely used as fire-extinguishing agent, refrigerant and dry cleaning solvent.

The international agreement is hailed to be pivotal in the recovery of the ozone hole in Antarctica with climate projections showing that the ozone layer could be back to its 1980 levels between the years 2050 and 2070. In 2014, the levels of ozone depleting substances over Antarctica have dropped by about nine percent compared with the maximum recorded four years ago.

"Year-to-year weather variability significantly impacts Antarctica ozone because warmer stratospheric temperatures can reduce ozone depletion," said Paul Newman from NASA's Goddard Space Flight Center. "The ozone hole area is smaller than what we saw in the late 1990s and early 2000s, and we know that chlorine levels are decreasing."

Scientists are now working to determine if the trend in the size of the ozone hole is caused by the increase in temperature or chlorine declines.

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