Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ozone layer decline leveling off, according to new study

31.08.2005


A new global study involving long-term data from satellites and ground stations indicates Earth’s ozone layer, while still severely depleted following decades of thinning from industrial chemicals in the atmosphere, is no longer in decline.



Betsy Weatherhead, a researcher with the Cooperative Institute for Research in Environmental Sciences, a joint institute of the University of Colorado at Boulder and the National Oceanic and Atmospheric Administration and corresponding author of the study, said the team documented a leveling off of declining ozone levels between 1996 and 2002, and even measured small increases in some regions.

"The observed changes may be evidence of ozone improvement in the atmosphere," said Weatherhead. "But we will have to continue to monitor ozone levels for years to come before we can be confident."


It most likely will be decades before the ozone layer recovers, and it may never stabilize at the levels measured prior to the mid-1970s, when scientists discovered human-produced chlorine and bromine compounds could destroy ozone and deplete the ozone layer, Weatherhead said.

A paper on the subject involving researchers from CU-Boulder, NOAA, the University of Wisconsin Madison, the University of Chicago and the University of Illinois was published online Aug. 29 in the Journal of Geophysical Research.

The halt in the ozone decline follows the 1987 Montreal Protocol, an international agreement now ratified by more than 180 nations that established legally binding controls for nations on the production and consumption of halogen gases containing chlorine and bromine. Scientists say the primary source of ozone destruction is chlorofluorocarbons, or CFC’s, which once were commonly used in refrigeration, air conditioning, foam-blowing equipment and industrial cleaning.

The new statistical study focused on levels of total-column ozone – ozone existing between Earth’s surface and the top of the atmosphere. Total-column ozone is a primary blocker of UV radiation in the atmosphere.

The team analyzed data from a cadre of NASA and NOAA satellites as well as ground stations in North America, Europe, Hawaii, Australia and New Zealand.

About 90 percent of total-column ozone is found between 10 miles to 20 miles above Earth’s surface in the stratosphere, Weatherhead said. The ozone layer protects the planet from the harmful effects of UV radiation, including skin cancer and cataracts in humans and damaging effects on ecosystems.

Despite the new evidence for the beginnings of an ozone recovery, Mike Repacholi, The World Health Organization’s environmental health coordinator in Geneva, warned that precautions such as UV-blocking sunglasses and skin protection remain vital. "This study provides some very encouraging news," he said. "But the major cause of skin cancer is still human behavior, including tanning and sunburns that result from a lack of proper skin protection."

Ozone depletion has been most severe at the poles, with levels declining by as much as 40 percent on a seasonal basis, said Weatherhead. But there also has been as much as a 10 percent seasonal decline at mid-latitudes, the location of much of North America, South America and Europe.

Other anthropogenic changes to the atmosphere such as methane levels, water vapor and air temperatures will affect future ozone levels, which are naturally maintained by complex chemical processes sparking the continual creation, destruction and redistribution of ozone, said Weatherhead. "Even after all chlorine compounds are out of the system, it is unlikely that ozone levels will stabilize at the same levels."

Scientists warn a return to significantly higher atmospheric ozone levels may take up to 40 years. "Chemicals pumped into Earth’s atmosphere decades ago still are affecting ozone levels today," said Sherwood Roland of the University of California, Irvine, who shared the 1995 Nobel Prize in Chemistry with Paul Crutzen and Mario Molina for their work in identifying the CFC threat to the ozone layer. "This problem was a long time in the making, and because of the persistence of these chlorine compounds, there is no short-term fix."

Greg Reinsel, a UW Madison researcher and the lead author of the study, was one of the first scientists to quantify the ozone decline more than two decades ago. He died unexpectedly in May after completing the study.

Other co-authors include NOAA’s Alvin Miller, Lawrence Flynn and Ron Nagatani, George Tiao of the University of Chicago and Don Wuebbles of the University of Illinois.

Betsy Weatherhead | EurekAlert!
Further information:
http://www.srrb.noaa.gov/UV/
http://www.noaa.gov

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>