Ozone Hole Smallest on Record

James Marshall
October 22, 2019

The hole in the ozone layer above the Antarctic - once a powerful sign of the environment's woes - is the smallest it's been since it was first spotted in 1982, scientists from NASA and NOAA have reported this week.

The space and weather agencies use a combination of satellites - including NASA's Aura satellite, the NASA-NOAA Suomi National Polar-orbiting Partnership satellite and NOAA's Joint Polar Satellite System NOAA-20 satellite - to measure the dimensions of the ozone hole from space.

According to NASA and NOAA, the annual ozone hole - which consists of an area of heavily depleted ozone high in the stratosphere above Antarctica, between 11 and 40 kilometres above the surface - reached its peak extent of 10.1 million square kilometres on September 8 and then shrank to less than 6.3 million square kilomeres during the remainder of September and October.

"During years with normal weather conditions, the ozone hole typically grows to a maximum of about 8 million square miles", the agencies said in a news release.

"It's not a sign that atmospheric ozone is suddenly on a fast track to recovery", said Paul Newman, a scientist at NASA's Goddard Space Flight Center in a recent statement.

Chlorine in the air needs cold temperatures in the stratosphere to convert into a form of the chemical that eats ozone.

Instead, scientists attribute the relatively tiny ozone hole to unusually mild temperatures in that layer of the atmosphere.

The hole over the Antarctic forms during the Southern Hemisphere's late winter as the Sun's rays start to cause ozone-depleting reactions.

Ozone is a highly reactive molecule comprised of three oxygen atoms that occurs naturally in small amounts.

Similar weather patterns led to unusually small ozone holes in 1988 and 2002, they reported.

There is no identified connection between the occurrence of these unique patterns and changes in climate.

"It's a rare event that we are still trying to understand. If the warming hadn't happened, we would likely be looking at a much more typical ozone hole", said Strahan. Scientists release these balloon-borne sensors to measure the thickness of the protective ozone layer high up in the atmosphere.

The ozone is monitored by NASA and NOAA through a variety of instruments, including satellites and weather balloons.

About 12 miles up from the surface, temperatures were 29 degrees Fahrenheit warmer, making it the warmest year since observations began. In addition to keeping ozone depletion minimal, the weather systems responsible for the temperature shift reduced the jet stream around Antarctica from 161 miles per hour to 67.

This caused less clouds to form and air rich in ozone was actually brought up above the ozone hole.

According to NASA, the ozone above Antarctica is expected to return to its 1980 level around the year 2070.

The Montreal Protocol, a landmark global environmental treaty that went into effect in 1988, has successfully reduced CFC emissions worldwide.

The ozone hole should disappear and close over the next six weeks, according to NOAA.

Other reports by Click Lancashire

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