Additionally, methane does not undergo oxidation as it rises to the surface. It dissolves at is rises, then it is slowly oxidised by methylotrophs in its well-mixed state.
A On 7 March 2010 14:55, Mike MacCracken <[email protected]> wrote: > While I wholeheartedly agree that methane is a critical issue, it would > sure be nice if they got the facts right. > > Consider this paragraph: “*Dr. Shakhova said that undersea methane > ordinarily undergoes oxidation as it rises to the surface, where it is > released as carbon dioxide. But because water over the shelf is at most > about 50 meters deep, she said, the gas bubbles to the surface there as > methane. As a result, she said, atmospheric levels of methane over the > Arctic are 1.85 parts per million, almost three times as high as the global > average of 0.6 or 0.7 parts per million. Concentrations over the shelf are 2 > parts per million or higher.” > > *It is simply not the case that the concentration over much of the globe > is currently 0.6 or 0.7 parts per million. That may well have been the > preindustrial concentration that was being referred to, and if that is the > case, that correction is needed. Alternatively, they should report the > global average concentration as roughly 1.6 to 1.7 parts per million, as is > clearly shown in the global observations (see > http://instaar.colorado.edu/sil/images/ch4rug_490px.jpg ). > > Mike > > > > On 3/5/10 5:11 PM, "John Nissen" <[email protected]> wrote: > > > http://www.worldchanging.com/archives/011011.html > > *Methane Melt: The Most Important Story You Don't Follow* > > Alex Steffen <http://www.worldchanging.com/bios/alex.html> , 5 Mar 10 > > We've written before about the danger that climate change will lead to the > thawing and release of methane frozen on the ocean floor, and indeed the > worrisome news that some scientists were observing patches of Arctic sea > foaming with gas bubbles from "methane chimneys" rising from the sea floor < > http://www.worldchanging.com/archives/008702.html> . > > Now, researchers in Alaska have found a similar process underway < > http://www.nytimes.com/2010/03/05/science/earth/05methane.html?em> : > > * > Natalia Shakhova, a scientist at the university and a leader of the study, > said it was too soon to say whether the findings suggest that a dangerous > release of methane looms. In a telephone news conference, she said > researchers were only beginning to track the movement of this methane into > the atmosphere as the undersea permafrost that traps it degrades. > * > *But climate experts familiar with the new research reported in Friday’s > issue of the journal Science that even though it does not suggest imminent > climate catastrophe, it is important because of methane’s role as a > greenhouse gas. Although carbon dioxide is far more abundant and persistent > in the atmosphere, ton for ton atmospheric methane traps at least 25 times > as much heat.* > > *Until recently, undersea permafrost has been little studied, but work so > far shows it is already sending surprising amounts of methane into the > atmosphere, Dr. Shakhova and other researchers are finding.* > > *Last year, scientists from Britain and Germany reported that they had > detected plumes of methane rising from the Arctic seabed in the West > Spitsbergen area, north of Scandinavia. At the time, they said they had > begun their work hoping to gain data to predict future emissions and had not > expected to find evidence that the process was under way.* > > *It is “indispensable” to keep track of methane in the region, Martin > Heimann of the Max Planck Institute in Germany said in a commentary > accompanying the Science report. So far, Dr. Heimann wrote, methane > contributions from Arctic permafrost have been “negligible.” He added: “But > will this persist into the future under sustained warming trends? We do not > know.”* > > *In an e-mail message, Euan G. Nisbet of the University of London, an > expert on atmospheric methane, said the situation “needs to be watched > carefully.”* > > *Atmospheric concentrations of methane have more than doubled since > pre-industrial times, Dr. Heimann wrote. Most of it comes from human > activities including energy production, cattle raising and the cultivation > of rice. But about 40 percent is natural, including the decomposition of > organic materials in wetlands and frozen wetlands like permafrost.* > > *Dr. Shakhova said that permafrost in the East Siberian Arctic Shelf, peat > land that flooded as sea levels rose after the last ice age, is degrading in > part because runoff from rivers that feed the Arctic Ocean is warmer than in > the past.* > > *She estimated that annual methane emissions from the East Siberian Arctic > Shelf total about seven teragrams. (A teragram is 1.1 million tons.) By some > estimates, global methane emissions total about 500 teragrams a year.* > > *Dr. Shakhova said that undersea methane ordinarily undergoes oxidation as > it rises to the surface, where it is released as carbon dioxide. But because > water over the shelf is at most about 50 meters deep, she said, the gas > bubbles to the surface there as methane. As a result, she said, atmospheric > levels of methane over the Arctic are 1.85 parts per million, almost three > times as high as the global average of 0.6 or 0.7 parts per million. > Concentrations over the shelf are 2 parts per million or higher. > * > > > A huge release of one-frozen methane is (potentially) almost the definition > of a feedback loop <http://www.worldchanging.com/archives/010802.html> , > perhaps even a tipping point into runaway climate change. > > Luckily, we're not there yet. Scientists have been very clear to say that > while these field observations are surprising and disturbing, they do not > yet indicate a catastrophe. We need to wait for more data to figure out if > it's time to panic yet. > > In the meantime, we need to focus even more strongly on four solution > spaces: > > 1) Getting to a zero net emissions < > http://www.worldchanging.com/archives/007879.html> economy as quickly as > possible. It's very clear now that we can do this at a net gain for society, > with more (and more wide-spread) prosperity for most people, and that it's > largely the opposition of entrenched interests that's preventing us from > making huge strides forward: this needs to change. > > 2) Implementing climate-adaptive ecological restoration, safeguarding < > http://www.worldchanging.com/archives/004253.html> ecosystem services and > researching <http://www.worldchanging.com/archives/007126.html> soil > carbon sequestration < > http://www.worldchanging.com/local/canada/archives/008992.html> and other > practices that have multiple benefits while pulling greenhouse gasses from > the air. We need to be helping the planet's natural systems heal towards > resilience as much as we possibly can. > > 3) Engaging in a stronger and more realistic debate about geoengineering, > its limits and its politics < > http://www.worldchanging.com/archives/008364.html> , especially since news > of potential tipping points always accelerates calls for geoengineering > research, even deployment. Geoengineering's main use in the climate debate > at the moment is as a propaganda tool by those seeking to stall action on > emissions reduction <http://www.worldchanging.com/archives/009784.html> ; > that doesn't mean that we don't need to discuss what mega-scale answers > might be possible should we find tipping points sliding past more quickly > than we feared. > > 4) Building psychological resilience < > http://www.worldchanging.com/archives/007906.html> in the face of huge and > alarming planetary changes. News like this is disturbing. We need to find > ways, as a culture, as communities and as individuals, to understand > disturbing changes without losing our balance. Psychologically wrecked > people are no good to themselves, others or the planet. We need to promote > the capacity to be healthy and happy despite monumental challenges. > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<geoengineering%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
