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. >> -- 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.
