 |
|
Gas escaping from ocean floor may drive global warming
July 20, 2006(Santa Barbara, Calif.) - Gas escaping from the ocean floor may provide some answers to understanding historical global warming cycles and provide information on current climate changes, according to a team of scientists at the University of California, Santa Barbara. The findings are reported in the July 20 on-line version of the scientific journal, Global Biogeochemical Cycles.
Remarkable and unexpected support for this idea occurred when divers and scientists from UC Santa Barbara observed and videotaped a massive blowout of methane from the ocean floor. It happened in an area of gas and oil seepage coming out of small volcanoes in the ocean floor of the Santa Barbara channel -- called Shane Seep -- near an area known as the Coal Oil Point seep field. The blowout sounded like a freight train, according to the divers.
Atmospheric methane is at least 20 times more potent than carbon dioxide and is the most abundant organic compound in the atmosphere, according to the study's authors, all from UC Santa Barbara.
"Other people have reported this type of methane blowout, but no one has ever checked the numbers until now," said Ira Leifer, lead author and an associate researcher with UCSB's Marine Science Institute. "Ours is the first set of numbers associated with a seep blowout." Leifer was in a research boat on the surface at the time of the blowouts.
Aside from underwater measurements, a nearby meteorological station measured the methane "cloud" that emerged as being approximately 5,000 cubic feet, or equal to the volume of the entire first floor of a two-bedroom house. The research team also had a small plane in place, flown by the California Department of Conservation, shooting video of the event from the air.
Leifer explained that when this type of blowout event occurs, virtually all the gas from the seeps escapes into the atmosphere, unlike the emission of small bubbles from the ocean floor, which partially, or mostly, dissolve in the ocean water. Transporting this methane to the atmosphere affects climate, according to the researchers. The methane blowout that the UCSB team witnessed reached the sea surface 60 feet above in just seven seconds. This was clear because the divers injected green food dye into the rising bubble plume.
Co-author Bruce Luyendyk, professor of marine geophysics and geological sciences, explained that, to understand the significance of this event (which occurred in 2002), the UCSB research team turned to a numerical, bubble-propagation model. With the model, they estimated methane loss to the ocean during the upward travel of the bubble plume.
The results showed that for this shallow seep, loss would have been approximately one percent. Virtually all the methane, 99 percent of it, was transported to the atmosphere from this shallow seep during the blowout. Next, the scientists used the model to estimate methane loss for a similar size blowout at much greater depth, 250 meters. Again, the model results showed that almost all the methane would be transported up to the atmosphere.
Over geologic time scales, global climate has cycled between warmer, interglacial periods and cooler, glacial periods. Many aspects of the forces underlying these dramatic changes remain unknown. Looking at past changes is highly relevant to understanding future climate changes, particularly given the large increase in atmospheric greenhouse gas concentrations in the atmosphere due to historically recent human activities such as burning fossil fuels.
One hypothesis, called the "Clathrate Gun" hypothesis, developed by James Kennett, professor of geological sciences at UCSB, proposes that past shifts from glacial to interglacial periods were caused by a massive decomposition of the marine methane hydrate deposits.
Methane hydrate is a form of water ice that contains a large amount of methane within its crystal structure, called a clathrate hydrate. According to Kennett's hypothesis, climatic destabilization would cause a sharp increase in atmospheric methane -- thereby initiating a feedback cycle of abrupt atmospheric warming. This process may threaten the current climate, according to the researchers. Warmer ocean temperatures from current global climate change is likely to release methane currently trapped in vast hydrate deposits on the continental shelves. However, consumption of methane by microbes in the deep sea prevents methane gas released from hydrates from reaching the ocean surface and affecting the atmosphere.
Bubbles provide a highly efficient mechanism for transporting methane and have been observed rising from many different hydrate deposits around the world. If these bubbles escape singly, most or all of their methane would dissolve into the deep-sea and never reach the atmosphere. If instead, they escape in a dense bubble plume, or in catastrophic blowout plumes, such as the one studied by UCSB researchers, then much of the methane could reach the atmosphere. Blowout seepage could explain how methane from hydrates could reach the atmosphere, abruptly triggering global warming.
Thus, these first-ever quantitative measurements of a seep blowout and the results from the numerical model demonstrate a mechanism by which methane released from hydrates can reach the atmosphere. Studies of seabed seep features suggest such events are common in the area of the Coal Oil Point seep field and very likely occur elsewhere.
The authors explain that these results show that an important piece of the global climate puzzle may be explained by understanding bubble-plume processes during blowout events. The next important step is to measure the frequency and magnitude of these events. The UCSB seep group is working toward this goal through the development of a long-term, seep observatory in active seep areas.
University of California-Santa Barbara
"Other people have reported this type of methane blowout, but no one has ever checked the numbers until now," said Ira Leifer, lead author and an associate researcher with UCSB's Marine Science Institute. "Ours is the first set of numbers associated with a seep blowout." Leifer was in a research boat on the surface at the time of the blowouts.
Aside from underwater measurements, a nearby meteorological station measured the methane "cloud" that emerged as being approximately 5,000 cubic feet, or equal to the volume of the entire first floor of a two-bedroom house. The research team also had a small plane in place, flown by the California Department of Conservation, shooting video of the event from the air.
Leifer explained that when this type of blowout event occurs, virtually all the gas from the seeps escapes into the atmosphere, unlike the emission of small bubbles from the ocean floor, which partially, or mostly, dissolve in the ocean water. Transporting this methane to the atmosphere affects climate, according to the researchers. The methane blowout that the UCSB team witnessed reached the sea surface 60 feet above in just seven seconds. This was clear because the divers injected green food dye into the rising bubble plume.
Co-author Bruce Luyendyk, professor of marine geophysics and geological sciences, explained that, to understand the significance of this event (which occurred in 2002), the UCSB research team turned to a numerical, bubble-propagation model. With the model, they estimated methane loss to the ocean during the upward travel of the bubble plume.
The results showed that for this shallow seep, loss would have been approximately one percent. Virtually all the methane, 99 percent of it, was transported to the atmosphere from this shallow seep during the blowout. Next, the scientists used the model to estimate methane loss for a similar size blowout at much greater depth, 250 meters. Again, the model results showed that almost all the methane would be transported up to the atmosphere.
Over geologic time scales, global climate has cycled between warmer, interglacial periods and cooler, glacial periods. Many aspects of the forces underlying these dramatic changes remain unknown. Looking at past changes is highly relevant to understanding future climate changes, particularly given the large increase in atmospheric greenhouse gas concentrations in the atmosphere due to historically recent human activities such as burning fossil fuels.
One hypothesis, called the "Clathrate Gun" hypothesis, developed by James Kennett, professor of geological sciences at UCSB, proposes that past shifts from glacial to interglacial periods were caused by a massive decomposition of the marine methane hydrate deposits.
Methane hydrate is a form of water ice that contains a large amount of methane within its crystal structure, called a clathrate hydrate. According to Kennett's hypothesis, climatic destabilization would cause a sharp increase in atmospheric methane -- thereby initiating a feedback cycle of abrupt atmospheric warming. This process may threaten the current climate, according to the researchers. Warmer ocean temperatures from current global climate change is likely to release methane currently trapped in vast hydrate deposits on the continental shelves. However, consumption of methane by microbes in the deep sea prevents methane gas released from hydrates from reaching the ocean surface and affecting the atmosphere.
Bubbles provide a highly efficient mechanism for transporting methane and have been observed rising from many different hydrate deposits around the world. If these bubbles escape singly, most or all of their methane would dissolve into the deep-sea and never reach the atmosphere. If instead, they escape in a dense bubble plume, or in catastrophic blowout plumes, such as the one studied by UCSB researchers, then much of the methane could reach the atmosphere. Blowout seepage could explain how methane from hydrates could reach the atmosphere, abruptly triggering global warming.
Thus, these first-ever quantitative measurements of a seep blowout and the results from the numerical model demonstrate a mechanism by which methane released from hydrates can reach the atmosphere. Studies of seabed seep features suggest such events are common in the area of the Coal Oil Point seep field and very likely occur elsewhere.
The authors explain that these results show that an important piece of the global climate puzzle may be explained by understanding bubble-plume processes during blowout events. The next important step is to measure the frequency and magnitude of these events. The UCSB seep group is working toward this goal through the development of a long-term, seep observatory in active seep areas.
University of California-Santa Barbara
Global Warming Current Events and Global Warming News RSSPast climate of the northern Antarctic Peninsular informs global warming debate
The seriousness of current global warming is underlined by a reconstruction of climate at Maxwell Bay in the South Shetland Islands of the Antarctic Peninsula over approximately the last 14,000 years, which appears to show that the current warming and widespread loss of glacial ice are unprecedented.
Climate variability impacts the deep sea
Deep-sea ecosystems occupying 60% of the Earth's surface could be vulnerable to the effects of global warming warn scientists writing in the Proceedings of the National Academy of Sciences.
Interactions 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.
Volcanoes played pivotal role in ancient ice age, mass extinction
Researchers here have discovered the pivotal role that volcanoes played in a deadly ice age 450 million years ago. Perhaps ironically, these volcanoes first caused global warming -- by releasing massive amounts of carbon dioxide into the atmosphere. When they stopped erupting, Earth's climate was thrown off balance, and the ice age began.
Glacial melting may release pollutants in the environment
Those pristine-looking Alpine glaciers now melting as global warming sets in may explain the mysterious increase in persistent organic pollutants in sediment from certain lakes since the 1990s, despite decreased use of those compounds in pesticides, electric equipment, paints and other products.
Seismic Noise Unearths Lost Hurricanes
Seismologists have found a new way to piece together the history of hurricanes in the North Atlantic - by looking back through records of the planet's seismic noise. It's an entirely new way to tap into the rich trove of seismic records, and the strategy might help establish a link between global warming and the frequency or intensity of hurricanes.
As Greenland melts
Not that long ago - the blink of a geologic eye - global temperatures were so warm that ice on Greenland could have been hard to come by. Today, the largest island in the world is covered with ice 1.6 miles thick. Even so, Greenland has become a hot spot for climate scientists.
Television Has Less Effect on Education about Climate Change than Other Forms of Media
Worried about climate change and want to learn more? You probably aren't watching television then. A new study by George Mason University Communication Professor Xiaoquan Zhao suggests that watching television has no significant impact on viewers' knowledge about the issue of climate change. Reading newspapers and using the web, however, seem to contribute to people's knowledge about this issue.
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.
Growth versus global warming
Houses on stilts, small scale energy generation and recycling our dishwater are just some of the measures that are being proposed to prepare our cities for the effects of global warming.
More Global Warming Current Events and Global Warming News Articles
 |
Unstoppable Global Warming: Every 1,500 Years, Updated and Expanded Edition by S. Fred Singer (Author), Dennis T. Avery (Author) In this New York Times bestseller, authors Singer and Avery present the compelling concept that global temperatures have been rising mostly or entirely because of a natural cycle. Using historic data from two millennia of recorded history combined with natural physical records, the authors argue that the 1,500 year solar-driven cycle that has always controlled the earth's climate remains the driving force in the current warming trend. |
 |
Climate Confusion: How Global Warming Hysteria Leads to Bad Science, Pandering Politicians and Misguided Policies That Hurt the Poor by Roy W. Spencer (Author) The current frenzy over global warming has galvanized the public and cost taxpayers billons of dollars in federal expenditures for climate research. It has spawned Hollywood blockbusters and inspired major political movements. It has given a higher calling to celebrities and built a lucrative industry for scores of eager scientists. In short, ending climate change has become a national crusade. And yet, despite this dominant and sprawling campaign, the facts behind global warming remain as confounding as ever. In Climate Confusion, distinguished climatologist Dr. Roy Spencer observes that our obsession with global warming has only clouded the issue. Forsaking blindingly technical statistics and doomsday scenarios, Dr. Spencer explains in simple terms how the climate system... |
 |
Global Warming: The Complete Briefing by John Houghton (Author) John Houghton's market-leading textbook is now in full color and includes the latest IPCC findings, making it the definitive guide to climate change. Written for students across a wide range of disciplines, its simple, logical flow of ideas gives an invaluable grounding in the science and impacts of climate change and highlights the need for action on global warming. Is there evidence for climate changing due to human activities? How do we account for recent extremes of weather and climate? Can global electricity provision and transport ever be carbon free? Written by a leading figure at the forefront of action to confront humanity's most serious environmental problem, this undergraduate textbook comprehensively explores these and other issues, allowing students to think through the... |
 |
The Deniers: The World Renowned Scientists Who Stood Up Against Global Warming Hysteria, Political Persecution, and Fraud**And those who are too fearful to do so by Lawrence Solomon (Author) |
 |
Global Warming: A Scientific and Biblical Expose' of Climate Change Starring: Larry Vardiman, Calvin Beisner, Al Gore, Jason Lisle, Michael J. Oard Directed By: Jason Beaupied,Ben Wilt Javier Pena |
 |
The Real Global Warming Disaster: Is the Obsession with "Climate Change" Turning Out to Be the Most Costly Scientific Blunder in History? by Christopher Booker (Author) Booker focuses his attention on the mother of all environmental scares: global warming. This original book considers one of the most extraordinary scientific and political stories of our time: how in the 1980s a handful of scientists came to believe that mankind faced catastrophe from runaway global warming, and how today this has persuaded politicians to land us with what promises to be the biggest bill in history. Christopher Booker interweaves the science of global warming with that of its growing political consequences, showing how just when the politicians are threatening to change our Western way of life beyond recognition, the scientific evidence behind the global warming theory is being challenged like never before. The book exposes the myth that the global warming theory is... |
 |
Heaven and Earth: Global Warming, the Missing Science by Ian Plimer (Author) Climate, sea level, and ice sheets have always changed, and the changes observed today are less than those of the past. Climate changes are cyclical and are driven by the Earth's position in the galaxy, the sun, wobbles in the Earth's orbit, ocean currents, and plate tectonics. In previous times, atmospheric carbon dioxide was far higher than at present but did not drive climate change. No runaway greenhouse effect or acid oceans occurred during times of excessively high carbon dioxide. During past glaciations, carbon dioxide was higher than it is today. The non-scientific popular political view is that humans change climate. Do we have reason for concern about possible human-induced climate change? This book's 504 pages and over 2,300 references to peer-reviewed scientific... |
 |
The Politically Incorrect Guide to Global Warming (and Environmentalism) by Christopher C. Horner (Author) This latest installment in the P.I.G. series provides a provocative, entertaining, and well-documented expose of some of the most shamelessly politicized pseudo-science we are likely to see in our relatively cool lifetimes. |
 |
Global Warming: Understanding the Forecast by David Archer (Author) Global Warming: Understanding the Forecast is a comprehensive introduction to all aspects of global warming. Written in an accessible style, this important book examines the processes of climate change and climate stability, from the distant past to the distant future. Examining the greenhouse effect, the carbon cycle, and what the future may hold for global climate, this text draws on a wide range of disciplines, and summarizes not only scientific evidence, but also economic and policy issues, related to global warming. A companion web site at (http://understandingtheforecast.org) provides access to interactive computer models of the physics and chemistry behind the global warming forecast, which can be used to support suggested student projects included at the end of each... |
 |
Global Warming Is Uncool AA 5495, Asphalt, XX-Large by HiveTees |
| © 2009 BrightSurf.com |