Dear Stephen, I think that the metamorphosis of ice covered Arctic Ocean to open water plays the decisive role in the hydroxyl-driven methane oxidation:
Lets just take a relatively moderate storm surge with the crest between 2-3 metres along Yakutian coast. While the wind propelled storm surge current advances, the reverse current on the bottom of storm surge (which drains the water back into ocean) pulls loose sediments and silt away along the water. This rapidly excavates and exposes methane clathrates to warm water. Furthermore, as East Siberian Sea is so shallow, storm surges can form on sideway directions as well which might be strong enough to disturb bottom mud. This explains entirely the observed rapid methane clathrate losses on East Siberian Sea seabed last autumn. The sea bed responds to warming far faster than terrestrial permafrost due to higher thermal inertia of sea water to air above land. The hydrodynamical factors played key role in excavating those 22,000 methane craters along Siberian sea bed, many of which are one kilometre wide, largest ones 750 km2. As storm surges and rising bottom currents excavate methane clathrates rapidly, the hydroxyl supply is unlikely to keep up with these. Temperatures surge, winds rise and erosion grows. As a result the hydroxyl radical disappears due to large surges of methane, just the same way carbon-14 isotope will get increasingly diluted the more CH4 and CO2 come from Eurasian and Arctic frozen soils and seabed. Stephen, thus the answer to your question must necessarily be: Yes, methane from the Arctic does not get oxidised as warming and storm surges driven supply of methane quickly overwhelms the supply of methane oxidising OH-. It is crucial to understand that wind driven storm surges drive the loss of methane clathrates, unlike a steady loss of methane ice, this occurs rather rapidly in pulses thus encapsulating most of methane in a hydroxyl-protected enviroment. Regards, Albert > Date: Tue, 5 Jun 2012 11:10:24 +0100 > From: [email protected] > To: [email protected] > CC: [email protected] > Subject: Re: [geo] 400 ppm and rising > > Mike > > Both diffusion and oxidation are involved. Are you saying that methane > released from the Arctic does not get oxidised? > > Stephen > > Emeritus Professor of Engineering Design > Institute for Energy Systems > School of Engineering > Mayfield Road > University of Edinburgh EH9 3JL > Scotland > Tel +44 131 650 5704 > Mobile 07795 203 195 > www.see.ed.ac.uk/~shs > > > On 04/06/2012 14:46, Mike MacCracken wrote: > > Hi Stephen--I think there is a simpler explanation, and that is that the > > planetary boundary layer is shallow due to the typical inversion, so CO2 > > tends to build up near the ground during the non-growing season. My guess is > > that the late summer values also tend to be a bit lower than Mauna Loa due > > to the CO2 being pulled out from a thinner layer (you see a much larger > > seasonal variation in high latitude CO2 than at Mauna Loa). > > > > Mike > > > > > > On 6/4/12 6:30 AM, "Stephen Salter"<[email protected]> wrote: > > > >> Hi All > >> > >> There are not many large coal-fired power stations in the Arctic and so > >> the question arises about where this extra CO2 in the Arctic has come > >> from. One possibility is that it is the product of methane > >> decomposition and would be in line with the report to this group from > >> Greg Rau of 22 May. > >> > >> We know that the atmosphere weighs about 5 E18 kilograms. If we know > >> the plan area represented by the observing stations and the decay rate > >> of methane to CO2 we could get an approximate figure for the mass of > >> methane causing the rise in CO2. We could then compare this with the > >> scary rate of methane increase reported by Semiletov and Shakhova. > >> > >> Stephen > >> > >> > >> Emeritus Professor of Engineering Design > >> Institute for Energy Systems > >> School of Engineering > >> Mayfield Road > >> University of Edinburgh EH9 3JL > >> Scotland > >> Tel +44 131 650 5704 > >> Mobile 07795 203 195 > >> www.see.ed.ac.uk/~shs > >> > >> > >> On 02/06/2012 17:41, Rau, Greg wrote: > >>> Greenhouse gas levels pass symbolic 400ppm CO2 milestone > >>> Monitoring stations in the Arctic detect record levels of carbon dioxide, > >>> higher than ever above 'safe' 350ppm mark > >>> Associated Press > >>> guardian.co.uk, Friday 1 June 2012 07.50 EDT > >>> > >>> The Arctic Ocean with leads and cracks in the ice cover of north of > >>> Alaska. > >>> Photograph: Courtesy Eric Kort/Jet Propulsion Laboratory/NASA > >>> The world's air has reached what scientists call a troubling new milestone > >>> for carbon dioxide, the main global warming pollutant. > >>> > >>> Monitoring stations across the Arctic this spring are measuring more than > >>> 400 > >>> parts per million of the heat-trapping gas in the atmosphere. The number > >>> isn't quite a surprise, because it's been rising at an accelerating pace. > >>> > >>> Years ago, it passed the 350ppm mark that many scientists say is the > >>> highest > >>> safe level for carbon dioxide. It now stands globally at 395. > >>> > >>> So far, only the Arctic has reached that 400 level, but the rest of the > >>> world > >>> will follow soon. > >>> > >>> "The fact that it's 400 is significant," said Jim Butler, the global > >>> monitoring director at the National Oceanic and Atmospheric > >>> Administration's > >>> Earth System Research Lab. "It's just a reminder to everybody that we > >>> haven't > >>> fixed this, and we're still in trouble." > >>> > >>> "The news today, that some stations have measured concentrations above > >>> 400ppm > >>> in the atmosphere, is further evidence that the world's political leaders > >>> > >>> with a few honourable exceptions are failing catastrophically to address > >>> the climate crisis," former vice president Al Gore, the highest-profile > >>> campaigner against global warming, said in an email. "History will not > >>> understand or forgive them." > >>> > >>> Carbon dioxide is the chief greenhouse gas and stays in the atmosphere for > >>> 100 years. Some carbon dioxide is natural, mainly from decomposing dead > >>> plants and animals. Before the industrial age, levels were around 275 > >>> parts > >>> per million. > >>> > >>> For more than 60 years, readings have been in the 300s, except in urban > >>> areas, where levels are skewed. The burning of fossil fuels, such as coal > >>> for > >>> electricity and oil for gasoline, has caused the overwhelming bulk of the > >>> man-made increase in carbon in the air, scientists say. > >>> > >>> It's been at least 800,000 years probably more since Earth saw carbon > >>> dioxide levels in the 400s, Butler and other climate scientists said. > >>> > >>> Readings are coming in at 400 and higher all over the Arctic. They've been > >>> recorded in Alaska, Greenland, Norway, Iceland and even Mongolia. But > >>> levels > >>> change with the seasons and will drop a bit in the summer, when plants > >>> suck > >>> up carbon dioxide, NOAA scientists said. > >>> > >>> So the yearly average for those northern stations likely will be lower > >>> and so > >>> will the global number. > >>> > >>> "It's an important threshold," said the Carnegie Institution ecologist > >>> Chris > >>> Field, a scientist who helps lead the Nobel Prize-winning > >>> Intergovernmental > >>> Panel on Climate Change. "It is an indication that we're in a different > >>> world." > >>> > >>> Ronald Prinn, an atmospheric sciences professor at the Massachusetts > >>> Institute of Technology, said 400 is more a psychological milestone than a > >>> scientific one. We think in hundreds, and "we're poking our heads above > >>> 400," > >>> he said. > >>> > >>> Tans said the readings show how much the Earth's atmosphere and its > >>> climate > >>> are being affected by humans. Global carbon dioxide emissions from fossil > >>> fuels hit a record high of 34.8 billion tonnes in 2011, up 3.2%, the > >>> International Energy Agency announced last week. > >>> > >>> The agency said it's becoming unlikely that the world can achieve the > >>> European goal of limiting global warming to just 2 degrees based on > >>> increasing pollution and greenhouse gas levels. > >>> > > > > > > -- > The University of Edinburgh is a charitable body, registered in > Scotland, with registration number SC005336. > > -- > 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. > -- 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.
