The ozone hole that forms in the upper atmosphere over Antarctica each September was slightly above average size in 2018, NOAA and NASA scientists reported today.
The ozone hole that forms in the upper atmosphere over Antarctica each September was slightly above average size in 2018, NOAA and NASA scientists reported today.
Colder-than-average temperatures in the Antarctic stratosphere created ideal conditions for destroying ozone this year, but declining levels of ozone-depleting chemicals prevented the hole from as being as large as it would have been 20 years ago.
“Chlorine levels in the Antarctic stratosphere have fallen about 11 percent from the peak year in 2000,” said Paul A. Newman, chief scientist for Earth Sciences at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "This year’s colder temperatures would have given us a much larger ozone hole if chlorine was still at levels we saw back in the year 2000.”
According to NASA, the annual ozone hole reached an average area coverage of 8.83 million square miles (22.9 square kilometers) in 2018, almost three times the size of the contiguous United States. It ranks 13th largest out of 40 years of NASA satellite observations. Nations of the world began phasing out the use of ozone-depleting substances in 1987 under an international treaty known as the Montreal Protocol.
Read more at NASA / Goddard Space Flight Center
Image: This time-lapse photo from Sept. 10, 2018, shows the flight path of an ozonesonde as it rises into the atmosphere over the South Pole from the Amundsen-Scott South Pole Station. Scientists release these balloon-borne sensors to measure the thickness of the protective ozone layer high up in the atmosphere. CREDITS: Robert Schwarz/University of Minnesota
