JPL press release:

NASA, NOAA Data Indicate Ozone Layer is Recovering

A new study using NASA and National Oceanic and Atmospheric Administration (NOAA) data finds consistent evidence that Earth's ozone layer is on the mend.

A team led by Dr. Eun-Su Yang of the Georgia Institute of Technology, Atlanta, analyzed 25 years of independent ozone observations at different altitudes in Earth's stratosphere, which lies between 10 and 50 kilometers (six and 31 miles) above the surface. The observations were gathered from balloons, ground-based instruments and NASA/NOAA satellites.

The stratosphere is Earth's second lowest atmospheric layer. It contains approximately 90 percent of all atmospheric ozone. The researchers concluded the Earth's protective ozone layer outside of the polar regions stopped thinning around 1997. Ozone in these areas declined steadily from 1979 to 1997.

The abundance of human-produced ozone-destroying gases such as chlorofluorocarbons peaked at about the same time (1993 in the lowest layer of the atmosphere, 1997 in the stratosphere). Such substances were phased out after the 1987 international Montreal Protocol was enacted.

To measure ozone at different altitudes in the stratosphere, the team combined data from balloons and independent ground-based observing networks with monthly averaged satellite data. The satellite data came from five independent NASA and NOAA instruments.

Measurements were compared with computer predictions of ozone recovery that considered actual measured variations in human-produced ozone-destroying chemicals. The calculations took into account other factors that can affect ozone levels, such as sunspot cycle behavior, seasonal changes and stratospheric wind patterns.

"These results confirm the Montreal Protocol and its amendments have succeeded in stopping the loss of ozone in the stratosphere," Yang said. "At the current recovery rate, the atmospheric modeling community's best estimates predict the global ozone layer could be restored to 1980 levels — the time that scientists first noticed the harmful effects human activities were having on atmospheric ozone — sometime in the middle of this century."

The researchers concluded approximately one half the observed ozone change was in the region of the stratosphere above 18 kilometers (11 miles) and the rest in the lowermost stratosphere from 10 to 18 kilometers (6 to 11 miles). The researchers attribute the ozone improvement above 18 kilometers almost entirely to the Montreal Protocol.
"Scientists expected the Montreal Protocol to be working in the middle and upper stratosphere and it is," said co-author Dr. Mike Newchurch of the University of Alabama in Huntsville. "The real surprise of our research was the degree of ozone recovery we found at lower altitudes, below the middle stratosphere. There, ozone is improving faster than we expected, and appears to be due to changes in atmospheric wind patterns, the causes of which are not yet well understood. Until the cause of the recent ozone increase in the lowermost stratosphere is better understood, making high-accuracy predictions of how the entire ozone layer will behave in the future will remain an elusive goal. Continued careful observation and modeling are required to understand how the ozone recovery process will evolve."

"Our study is unique because it measures changes in the ozone layer at all heights in the atmosphere, then compares the data with models as well as observations from other instruments that measure variations in the total amount of ozone in the atmosphere," said Dr. Ross Salawitch, a senior research scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Results are published in the Journal of Geophysical Research - Atmospheres. For information about NASA and agency programs, visit: http://www.nasa.gov/home .

Other media contacts: Chris Rink, NASA's Langley Research Center, Hampton, Va., 757-864-6786; Jane Sanders, Georgia Institute of Technology, 404-894-2214; Nina Stickles, Hampton University, Va., 757-727-5457; Anatta, NOAA, Boulder, Colo., 303-497-6288; Phil Gentry, University of Alabama, Huntsville, 256-824-6420; and Harvey Leifert, American Geophysical Union, Washington, 202-777-7507.

JPL is managed for NASA by the California Institute of Technology in Pasadena.

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This is good news since I now live near the darn hole. The only drawback is that ozone is a greenhouse gas. I wonder if in the future they will ease off on the chlorofluorocarbon ban as a temperature control measure?

Fix the ozone ...... increase the greenhouse effect.

Reduce particle emissions ..... decrease global dimming .... increase solinisation.

Aaahh that rollercoaster we call climate control.

Saw the movie/doco "Krakatoa". The eruption kept global climates down well into the 20th century.... and stunning sunsets for years.

Anyway I'm glad we seem to be repairing the ozone, 'specially as a fair skinned antipodean.

Isnt there an ozone hole in the northern hemisphere too?

Our planetary system naturally restores ozone in the stratosphere. The earth was hit by a solar storm on October 28, 2003 that destroyed around 75% of the ozone in Earth's middle atmosphere.
http://www.agu.org/pubs/crossref/200...GL021521.shtml
As a result the ozone hole was largest in 2003 at around 29 million kilometers.
The damage from this storm caused the United Nations weather organization to add 15 years to the ozone hole recovery rate, moving the recovery period out to 2065.
http://www.agu.org/pubs/crossref/200...GL021521.shtml

So just out of curiosity... how much data do we have for the last several thousand to several hundred thousand years to understand what is normal for the ozone layer...

I hope we can onvince upcoming industrial powers of the importance of some decent environmental care. No need to become tree huggers, but it wouldn't hurt to look at the lessons we learned. And if outside forces alter the planet much more than humans, at least we can plee innocence .

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