Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Climate change may become major player in ozone loss

05.06.2002


While industrial products like chlorofluorocarbons are largely responsible for current ozone depletion, a NASA study finds that by the 2030s climate change may surpass chlorofluorocarbons (CFCs) as the main driver of overall ozone loss.



Drew Shindell, an atmospheric scientist from NASA’s Goddard Institute for Space Studies (GISS) and Columbia University, N.Y., finds that greenhouse gases like methane and carbon dioxide are changing the climate in many ways. Some of those effects include water vapor increases and temperature changes in the upper atmosphere, which may delay future ozone recovery over heavily populated areas.

Scientists have expected the ozone layer to recover as a result of international agreements to ban CFCs that destroy ozone. CFCs, once used in cooling systems and aerosols, can last for decades in the upper atmosphere, where they break down, react with ozone, and destroy it. They remain the major cause of present-day ozone depletion.


"It’s hard to tell if those great international agreements [to ban CFCs] work if we don’t understand the other big things that are going on in the stratosphere, such as increases in greenhouse gases and water vapor," Shindell said. The stratosphere is a dry atmospheric layer between 6 and 30 miles (9.7 and 48.3 kilometers) up where most ozone exists.

Ozone shields the planet’s surface from the Sun’s harmful ultraviolet radiation and makes life on Earth possible. The study examined the ozone layer over heavily populated areas around the equator and mid-latitudes where ozone thinning occurs, excluding the Polar regions, where ’ozone holes’ form.

Ozone thinning can occur when increased emissions of methane get transformed into water in the stratosphere. At high altitudes, water vapor can be broken down into molecules that destroy ozone.

Also, methane and carbon dioxide change our climate by trapping heat in the atmosphere before it can escape out to space. This greenhouse effect, much like the inside of a car with all the windows closed, heats the air within the lowest layer of the atmosphere, called the troposphere. Warming in the troposphere can alter atmospheric circulation and make the air wetter, since warmer air holds more water. Though complex and not well understood, there is evidence that water vapor can get wafted from the troposphere into the stratosphere by shifting air currents caused by climate change.

Climate change from greenhouse gases can also affect ozone by heating the lower stratosphere where most of the ozone exists. When the lower stratosphere heats, chemical reactions speed up, and ozone gets depleted.

The chemical and atmospheric processes in the lower stratosphere are complex, quite variable, and not well understood. Shindell focused his study largely on the upper stratosphere where processes are simpler and better understood, and then used those findings to make inferences about ozone in the lower stratosphere.

Computer model simulations were used to separate the different factors that contribute to ozone changes. According to the models, which contain some uncertainty, ozone levels are expected to reach their lowest point in recorded history by around 2006. Scientists hope that by banning CFCs, ozone will eventually return to healthier levels, like those that existed prior to 1979.

One simulation isolated the impacts of CFCs on ozone, and showed that as CFCs decline, by the year 2040 overall ozone makes close to a full recovery from current low levels. When CFCs, water vapor and temperature changes were all combined in a computer model, by 2040, overall ozone levels recovered only slightly from their current low point.

These computer simulations suggest that climate change from greenhouse gases may greatly slow any anticipated ozone recovery. Shindell said the effects of climate change need to be better accounted for as scientists and others try to track the success of international agreements, like the 1987 Montreal Protocol that banned CFCs.


The paper appears in the latest issue of the Journal of Geophysical Research - Atmospheres.

The study was supported by NASA’s Atmospheric Chemistry Modeling and Analysis Program, and a NASA Earth Observing System postdoctoral Fellowship. Some of the data used was obtained from the NASA Langley Research Center’s EOSDIS Distributed Active Archive Center.

Krishna Ramanujan | EurekAlert
Further information:
http://www.gsfc.nasa.gov/topstory/20020422greengas.html

More articles from Earth Sciences:

nachricht Predicting eruptions using satellites and math
28.06.2017 | Frontiers

nachricht NASA sees quick development of Hurricane Dora
27.06.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>