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 The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

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: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>