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.
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