The average area covered by the ozone hole over Antarctica this year was the second smallest in the past 20 years, according to satellite data from NASA and the National Oceanic and Atmospheric Administration (NOAA) satellites. Scientists attribute the change to warmer temperatures in the lower Antarctic stratosphere.
The ozone hole reached its maximum size on 22 September, covering 21.2 million square kilometers, or the area of the United States, Canada and Mexico combined. The average size of the ozone hole 2012 was 17.9 million square kilometers. On September 6, 2000 recorded the largest ozone hole of history, with no less than 29.9 million square kilometers.
“The ozone hole is caused mainly by chlorine chemicals produced by man, and these levels are still considerable chlorine in the stratosphere of the Antarctic,” said NASA atmospheric scientists. “Natural fluctuations in weather patterns resulted in stratospheric temperatures warmer this year. Such temperatures led to a smaller ozone hole”.
The ozone layer acts as a natural shield the Earth from ultraviolet radiation, which can cause skin cancer. The ozone hole phenomenon began to make annual appearance in the 1980s. The ozone layer in Antarctica probably not return to its state of the early eighties to 2065. Recovery is long due to the long life of substances that deplete the ozone layer in the atmosphere.
The global atmospheric ozone is no longer decreasing as they do the concentrations of ozone-depleting substances. The decrease is the result of an international agreement that regulates the production of certain chemicals.
This year also marked a change in the concentration of ozone over Antarctica. The minimum value of the total ozone ozone hole was the second highest level in two decades. Total ozone measured in Dobson units (DU) DU 124 reached on October 1. The ground-based measurements at the South Pole 136 DU recorded on October 5.