 |
|
Climate change and atmospheric circulation will make for uneven ozone recovery
April 13, 2009Earth's ozone layer should eventually recover from the unintended destruction brought on by the use of chlorofluorocarbons (CFCs) and similar ozone-depleting chemicals in the 20th century. But new research by NASA scientists suggests the ozone layer of the future is unlikely to look much like the past because greenhouse gases are changing the dynamics of the atmosphere.
Previous studies have shown that while the buildup of greenhouse gases makes it warmer in troposphere - the level of atmosphere from Earth's surface up to 10 kilometers (6 miles) altitude - it actually cools the upper stratosphere - between 30 to 50 kilometers high (18 to 31 miles). This cooling slows the chemical reactions that deplete ozone in the upper stratosphere and allows natural ozone production in that region to outpace destruction by CFCs.
But the accumulation of greenhouse gases also changes the circulation of stratospheric air masses from the tropics to the poles, NASA scientists note. In Earth's middle latitudes, that means ozone is likely to "over-recover," growing to concentrations higher than they were before the mass production of CFCs. In the tropics, stratospheric circulation changes could prevent the ozone layer from fully recovering.
"Most studies of ozone and global change have focused on cooling in the upper stratosphere," said Feng Li, an atmospheric scientist at the Goddard Earth Sciences and Technology Center at the University of Maryland Baltimore County, Baltimore, Md. and lead author of the study. "But we find circulation is just as important. It's not one process or the other, but both."
The findings are based on a detailed computer model that includes atmospheric chemical effects, wind changes, and solar radiation changes. Li's experiment is part of an ongoing international effort organized by the United Nations Environment Programme's Scientific Assessment Panel to assess the state of the ozone layer. Li and colleagues published their analysis in March in the journal Atmospheric Chemistry and Physics.
Working with Richard Stolarski and Paul Newman of NASA's Goddard Space Flight Center, Greenbelt, Md., Li adapted the Goddard Earth Observing System Chemistry-Climate Model (GEOS-CCM) to examine how climate change will affect ozone recovery. The team inserted past measurements and future projections of ozone-depleting substances and greenhouse gases into the model. Then the model projected how ozone, the overall chemistry, and the dynamics of the stratosphere would change through the year 2100.
"In the real world, we have observed statistically significant turnaround in ozone depletion, which can be attributed to the banning of ozone-depleting substances," said Richard Stolarski, an atmospheric chemist at Goddard and a co-author of the study. "But making that connection is complicated by the response of ozone to greenhouse gases."
The researchers found that greenhouse gases alter a natural circulation pattern that influences ozone distribution. Brewer-Dobson circulation is like a pump to the stratosphere, moving ozone from the lower parts of the atmosphere, into the upper stratosphere over the tropics. Air masses then flow north or south through the stratosphere, away from the tropics toward the poles.
In Li's experiment, this circulation pump accelerated to a rate where the ozone flowing upward and outward from the tropics created a surplus at middle latitudes. Though the concentration of chlorine and other ozone-depleting substances in the stratosphere will not return to pre-1980 levels until 2060, the ozone layer over middle latitudes recovered to pre-1980 levels by 2025.
The Arctic - which is better connected to mid-latitude air masses than the Antarctic -- benefitted from the surplus in the northern hemisphere and from the overall decline of ozone-depleting substances to recover by 2025. Globally averaged ozone and Antarctic concentrations catch up by 2040, as natural atmospheric production of ozone resumes.
This recovery in the middle and polar latitudes has mixed consequences, Li noted. It might have some benefits, such as lower levels of ultraviolet radiation reaching the Earth's surface and correspondingly lower rates of skin cancer. On the other hand, it could have unintended effects, such as increasing ozone levels in the troposphere, the layer of atmosphere at Earth's surface. The model also shows a continuing ozone deficit in the stratosphere over the tropics. In fact, when the model run ended at year 2100, the ozone layer over the tropics still showed no signs of recovery.
In February, researchers from Johns Hopkins University, Baltimore, teamed with Stolarski and other NASA scientists on a similar paper suggesting that increasing greenhouse gases would delay or even postpone the recovery of ozone levels in the lower stratosphere over some parts of the globe. Using the same model as Li, Stolarski, and Newman, the researchers found that the lower stratosphere over tropical and mid-southern latitudes might not return to pre-1980s levels of ozone for more than a century, if ever.
NASA/Goddard Space Flight Center
"Most studies of ozone and global change have focused on cooling in the upper stratosphere," said Feng Li, an atmospheric scientist at the Goddard Earth Sciences and Technology Center at the University of Maryland Baltimore County, Baltimore, Md. and lead author of the study. "But we find circulation is just as important. It's not one process or the other, but both."
The findings are based on a detailed computer model that includes atmospheric chemical effects, wind changes, and solar radiation changes. Li's experiment is part of an ongoing international effort organized by the United Nations Environment Programme's Scientific Assessment Panel to assess the state of the ozone layer. Li and colleagues published their analysis in March in the journal Atmospheric Chemistry and Physics.
Working with Richard Stolarski and Paul Newman of NASA's Goddard Space Flight Center, Greenbelt, Md., Li adapted the Goddard Earth Observing System Chemistry-Climate Model (GEOS-CCM) to examine how climate change will affect ozone recovery. The team inserted past measurements and future projections of ozone-depleting substances and greenhouse gases into the model. Then the model projected how ozone, the overall chemistry, and the dynamics of the stratosphere would change through the year 2100.
"In the real world, we have observed statistically significant turnaround in ozone depletion, which can be attributed to the banning of ozone-depleting substances," said Richard Stolarski, an atmospheric chemist at Goddard and a co-author of the study. "But making that connection is complicated by the response of ozone to greenhouse gases."
The researchers found that greenhouse gases alter a natural circulation pattern that influences ozone distribution. Brewer-Dobson circulation is like a pump to the stratosphere, moving ozone from the lower parts of the atmosphere, into the upper stratosphere over the tropics. Air masses then flow north or south through the stratosphere, away from the tropics toward the poles.
In Li's experiment, this circulation pump accelerated to a rate where the ozone flowing upward and outward from the tropics created a surplus at middle latitudes. Though the concentration of chlorine and other ozone-depleting substances in the stratosphere will not return to pre-1980 levels until 2060, the ozone layer over middle latitudes recovered to pre-1980 levels by 2025.
The Arctic - which is better connected to mid-latitude air masses than the Antarctic -- benefitted from the surplus in the northern hemisphere and from the overall decline of ozone-depleting substances to recover by 2025. Globally averaged ozone and Antarctic concentrations catch up by 2040, as natural atmospheric production of ozone resumes.
This recovery in the middle and polar latitudes has mixed consequences, Li noted. It might have some benefits, such as lower levels of ultraviolet radiation reaching the Earth's surface and correspondingly lower rates of skin cancer. On the other hand, it could have unintended effects, such as increasing ozone levels in the troposphere, the layer of atmosphere at Earth's surface. The model also shows a continuing ozone deficit in the stratosphere over the tropics. In fact, when the model run ended at year 2100, the ozone layer over the tropics still showed no signs of recovery.
In February, researchers from Johns Hopkins University, Baltimore, teamed with Stolarski and other NASA scientists on a similar paper suggesting that increasing greenhouse gases would delay or even postpone the recovery of ozone levels in the lower stratosphere over some parts of the globe. Using the same model as Li, Stolarski, and Newman, the researchers found that the lower stratosphere over tropical and mid-southern latitudes might not return to pre-1980s levels of ozone for more than a century, if ever.
NASA/Goddard Space Flight Center
Greenhouse Gases Current Events and Greenhouse Gases News RSSInteractions with aerosols boost warming potential of some gases
For decades, climate scientists have worked to identify and measure key substances -- notably greenhouse gases and aerosol particles -- that affect Earth's climate.
Report examines hidden costs of energy production and use
A new report from the National Research Council examines and, when possible, estimates "hidden" costs of energy production and use -- such as the damage air pollution imposes on human health -- that are not reflected in market prices of coal, oil, other energy sources, or the electricity and gasoline produced from them.
Arctic land and seas account for up to 25 percent of world's carbon sink
In a new study in the journal Ecological Monographs, ecologists estimate that Arctic lands and oceans are responsible for up to 25 percent of the global net sink of atmospheric carbon dioxide.
Tech researchers using nanotechnology in biofuel process to save money, environment
Dr. James Palmer, associate professor of chemical engineering at Louisiana Tech University, is collaborating with fellow professors Dr. Yuri Lvov, Dr. Dale Snow, and Dr. Hisham Hegab to capitalize on the environmental and financial benefits of "biofuels" by using nanotechnology to further improve the cellulosic ethanol processes.
Do dust particles curb climate change?
A knowledge gap exists in the area of climate research: for decades, scientists have been asking themselves whether, and to what extent man-made aerosols, that is, dust particles suspended in the atmosphere, enlarge the cloud cover and thus curb climate warming.
Arctic sea ice recovers slightly in 2009, remains on downward trend, says U. of Colorado report
Despite a slight recovery in summer Arctic sea ice in 2009 from record-setting low years in 2007 and 2008, the sea ice extent remains significantly below previous years and remains on a trend leading toward ice-free Arctic summers, according to the University of Colorado at Boulder's National Snow and Ice Data Center.
Water scarcity will create global security concerns
Water scarcity as a result of climate change will create far-reaching global security concerns, says Dr. Rajendra K. Pachauri, chair of the intergovernmental panel on climate change, a co-recipient of the 2007 Nobel Peace Prize.
Denver to Barcelona: Global cities and greenhouse gas emissions
Denver released the largest amount of greenhouse gases (GHG) and Barcelona the smallest amount in a new study documenting how differences in climate, population density and other factors affect GHG emissions in global cities.
Concentrating emissions
Researchers at MIT have shown the benefits of a new approach toward eliminating carbon-dioxide (CO2) emissions at coal-burning power plants.
Diamonds are a laser's best friend
Tomorrow's lasers may come with a bit of bling, thanks to a new technology that uses man-made diamonds to enhance the power and capabilities of lasers.
More Greenhouse Gases Current Events and Greenhouse Gases News Articles
 |
Greenhouse Gases (At Issue Series) by Ronnie D., Jr. Lankford (Editor) |
 |
Ecology: Understanding The Greenhouse Effect The environment emits and absorbs carbon dioxide and other gases as part of normal biological and geological processes. Man, however, as a result of his agricultural and industrial activities, is adding to the carbon dioxide level in the atmosphere at an alarming rate - especially since the industrial revolution. Scientists believe the resulting greenhouse effect can cause significant climatic changes if we don't step into action. In this episode of the Environment and Ecology Series, students learn about the greenhouse effect, its causes, its effects on global warming, and what scientists are doing about it. Includes animation and time-lapse photography, as well as suggestions for careers in this field of study. This product is manufactured on demand using DVD-R recordable media.... |
 |
Greenhouse Gases: Management, Reduction and Impact by Jonathan L. Ramseur (Editor), Larry Parker (Editor), Brent D. Yacobucci (Editor) Instituting policies to manage or reduce GHGs would likely impact different states differently. Understanding these differences may provide for a more informed debate regarding potential policy approaches. However, multiple factors play a role in determining impacts, including alternative design elements of a GHG emissions reduction program, the availability and relative cost of mitigation options, and the regulated entities' abilities to pass compliance costs on to consumers. Three primary variables drive a state's human-related greenhouse gas (GHG) emission levels: population, per capita income, and the GHG emissions intensity. GHG emissions intensity is a performance measure.In this book, GHG intensity is a measure of GHG emissions from sources within a state compared with a state's... |
 |
Hydrogen Fuel Cell Vehicles Starring: Amber Goetz Directed By: Chris Blakely, Rob Newell Also With: Chris Blakely (Producer), Chris Blakely (Writer), Rob Newell (Producer), Rob Newell (Writer) |
 |
Greenhouse Gas Carbon Dioxide Mitigation: Science and Technology by Martin M. Halmann (Author), Meyer Steinberg (Author) Any mention of the "greenhouse effect" tends to ignite controversy. While the rising atmospheric concentrations of greenhouse gases-especially carbon dioxide- are certainly among the most pressing issues today, theoretical and perceived consequences have been subject to conjecture and misinformation.That raging debate has obscured an important fact: scientists and engineers are hard at work on methods to reduce CO2 emissions, and devise practical methods for their remediation.Greenhouse Gas Carbon Dioxide Mitigation: Science and Technologysheds light on the most recent advancements, documented by two of the world's leading researchers on CO2.Aware of the complexity and still-unknown factors behind climatic change, the authors consider the need to make CO2 mitigation viable for both... |
 |
TRASHED Trashed is a provocative investigation of one of the fastest growing industries in North America. The garbage business. The film examines a fundamental element of modern American culture...the disposal of what our society defines as "waste." It is an issue influenced by every American, most of whom never consider the consequences. Nor, it seems, the implications to our biosphere. At times humorous, but deeply poignant, "Trashed" examines the American waste stream fast approaching a half billion tons annually. What are the effects all this waste will have on already strained natural resources? Why is so much of it produced? While every American creates almost 5 pounds of it every day, who is affected most? And who wants America to make more? The film analyzes the causes and... |
 |
2009 Complete Guide to Carbon Sequestration Research, Carbon Capture and Storage Technologies to Fight Global Warming and Control Greenhouse Gases, Government Research Programs (CD-ROM) by U.S. Government (Author) This comprehensive electronic book on CD-ROM provides an up-to-date review of all aspects of carbon sequestration, carbon capture and storage technologies from the Federal Government! To retain fossil fuels as a viable world energy source, carbon capture and storage (CCS) technologies must play a central role. By cost-effectively capturing CO2 before it is emitted to the atmosphere and then permanently storing or sequestering it, fossil fuels can be used in a carbon constrained world and without constraining economic growth. Absent binding constraints, CO2 emissions in Organization for Economic Cooperation and Development (OECD) countries which include the United States, most of Europe, Australia, Korea, New Zealand and Japan are expected to increase at about 1.1 percent per year through... |
|
Carbon Offsets: Examining Their Role in Greenhouse Gas Reduction (Climate Change and Its Causes, Effects and Prediction) by Karen T. Morningstar (Editor) This book looks at carbon offsets which provide a way for individuals, businesses, and governments to address concerns about the impact of their greenhouse gas emissions on the earth's climate by paying others to undertake activities that reduce, avoid, or sequester greenhouse gases. A carbon offset can be defined as a measurable reduction of greenhouse gas emissions occurring elsewhere. For example, a U.S. manufacturer might offset its emissions by funding an external project that captures methane, a greenhouse gas emitted from agricultural sources and landfills. The emissions reduced, avoided, or sequestered by such projects are collectively termed carbon offsets, though they may involve different greenhouse gases. Carbon offsets are a potentially attractive option for those interested... | |
 |
Climate Technology Strategies 1: Controlling Greenhouse Gases. Policy and Technology Options (ZEW Economic Studies) by Pantelis Capros (Author), Leonidas Mantzos (Author), Patrick Criqui (Author), Nikolaos Kouvaritakis (Author), Antonio Soria Ramirez (Author), Leo Schrattenholzer (Author), E.Lakis Vouyoukas (Author) The book provides an integrated analysis of the implications for the energy system from adapting to meet climate change targets and analyses the role of improving energy technologies for the world and the EU markets. The first part of the book sets the stage for the analysis by presenting the European and World economic and energy outlook. The second part examines the policy options available for controlling greenhouse gases in the period to 2010. Over such a relatively short period, the role of technology lies mostly in making possible the more efficient use of energy. Finally, the third part of the volume examines the longer term role of technology in the context of a case study for the power generation sector. |
 |
The Potential of U.S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect by Ronald F. Follett (Editor), John M. Kimble (Editor), (Editor) Grazing lands represent the largest and most diverse land resource-taking up over half the earth's land surface. The large area grazing land occupies, its diversity of climates and soils, and the potential to improve its use and productivity all contribute to its importance for sequestering C and mitigating the greenhouse effect and other conditions brought about by climate change. The Potential of U.S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect gives you an in-depth look at this possibility. |
| © 2009 BrightSurf.com |