According to the ozone monitoring data of NASA and the National Oceanic and Atmospheric Administration, the average area Antarctic ozone hole this year is second to the smallest in the past 20 years. Not only that, but the minimum ozone concentration at the center of the hole is second to the largest in the past 20 years.
The area of the ozone hole this year averaged at 6.9 million square miles and reached a maximum of 8.2 square miles last September 22. The largest area ever recorded was 11.5 square miles on September 6, 2000. Hence, this year’s ozone hole is three-fifths that of 10 years ago.
These changes are due to the increase in stratospheric temperatures, according to NASA scientists. The annual changes in area of the Antarctic ozone hole are attributed to the natural fluctuations in weather patterns. Cooler stratospheric temperatures result to larger ozone hole and lower ozone concentration at the center of the hole.
The ozone layer in the stratosphere shields all living organisms from detrimental effects of sun’s UV rays. Its depletion started to be apparent in the 1980’s, and the ozone hole during those times can’t be achieved starting from its current state, not until around 2065, according to NASA atmospheric scientist Paul Newman.
This rather long recovery is due to the fact that the compounds that eat up ozone survive for a very long time up there in the atmosphere. The CFC’s produced during the 1970’s are chemically inert and are invulnerable to UV rays for about a century. Only after which do they succumb to UV rays and emanate their chlorine ions that catalyze the breakdown of ozone to oxygen. These chlorine ions, after finally breaking free since the CFC’s were brought into the atmosphere, will continue on depleting the ozone for years before they go down from the atmosphere and get washed away.
Now, scientists say that the overall atmospheric ozone is no longer is decreasing because these ozone-depleting substances are decreasing. This is the outcome of global awareness and action on regulating the production of certain chemicals that are harmful to the environment and the people as well.
[via EurekAlert]
