Geoff, again in short: the Mauna Loa data are mixed NH data, the mixing of CO2 in the NH atmosphere is very fast (a matter of days). Seasonal changes are relative fast changes, as well as for seawater surface temperature as for vegetation. Sea surface temperatures (and pH and plant life and CO2 levels/DIC) govern the local CO2 pressure (pCO2) in seawater. If the pCO2(water) is higher than pCO2(air), then we have a CO2 flow from water to air and reverse. This is a fast process and induces large continuous (warm to cold) and seasonal CO2 exchanges (about +90 GtC summer, -90 GtC winter), but the net change after one year is only about +/- 2 GtC (about 1 ppmv) change, due to year-to-year temperature differences. Without internal or external disturbances, the long-term trend is zero and the average yearly difference in pCO2 between seawater and atmosphere is zero too.
One-time pulses like volcanic eruptions and/or continuous emissions give extra CO2, which increases the pCO2 of the atmosphere in all seasons, which leads to an extra sink of about 4 GtC nowadays, about halve the emissions. The removal rate of that extra CO2 only depends on the average yearly difference in pCO2 between air and oceans (about 7 mbar nowadays), that doesn’t change the seasonal exchange that much (e.g. +88 GtC summer, -92 GtC winter), but the net effect is always a slow removal, no matter the source of the extra CO2.

I agree with John that the CO2 cycle is not of much interest here. There was and is a lot of discussion on the cycle/trend in the sceptics world (see e.g. http://www.climateaudit.org/?p=820 responses 41, 112, 120, 138,…), but that has no effect on the fate of SO2 (which is in average only 4 days). I am working on a comprehensive web page to give a detailed answer to the many questions which arise about the CO2 cycle.

The only link between CO2 and SO2/BC is the use of sulfur containing fossil fuels, mainly coal and oil. China data are of interest here and what is published is probably highly underestimated: use of any coal type (cheap, high sulfur), heavy oil (2-5% S!), scrubbers, even if installed, in many cases are bypassed,…

I’m sneaking up on SO2, to be On Thread, via a CO2 path. I understand that the rate of release of CO2 from different souces can be fast or slow and we can imagine short-term pulses. I’m more worried about removal than production. Just because a source produces CO2 fast, that does not mean it has to vamoose slow – or fast. Mental model – hand-pump up a bicycle tire that has a hole in it. No matter how fast you pulse, the decay will be determined by the size of the hole. I equate the rate of decay of Mauna Loa ripples each year with the size of the hole. What other mechanism do you propose to make the concentration fall so fast, especially if you feel that mixing would be fairly complete all that way to isolated Hawaii?

First we have to understand the dynamics of CO2 before we look at SO2, which is much more reactive with other substances.

#203 states and #201 assumes that there is a balance. But I think this is somewhat out of thread. We were considering sulphate emissions and carbon black. I think Steve would appreciate not discussing CO2 sinks and balances. So, I guess my question is “are there relevant factors in this carbon cycle, other than timing of the response that are relevant?” In paricular, on a small time span, can’t Ax+b be used and ignore the lesser or long-term effects of different or assumed carbon response rates relative to sulphate and black carbon emissions?

While Phil Jones has thus far refused to disclose the station data used in HadCRU3 despite several FOI requests, my guess is that the stations with post-1990 information in HadCRU3 will prove to be predominantly from places like Beijing, Shanghai, Lanzhou etc.

Anything yet on this?

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(FYI, PPP is purchasing power parity and MER is market exchange rates)

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Ferdinand, I was joking…. But good explanation of lowering the melting point of ice…

Geoff,

One need to make a separation in thinking about what happens with an individual CO2 molecule and what happens with total quantities of CO2 masses in the different compartiments.

Due to the huge seasonal flows from oceans to air and back (about 90 GtC) and from vegetation to atmosphere and back (about 60 GtC), about 25% of the air mass is renewed each year, which leads to a decay rate of about 5.2 years for small one-time pulses of individual molecules (like the 14C CO2 introduced by atmospheric nuclear bomb testing in the 1950-1960′s).
The introduction of extra CO2 by fossil fuel burning is a disturbance of a different type: higher total CO2 levels lead to increase of pCO2 in the atmosphere, where the difference between pCO2 of water and atmosphere will be less positive at places of high pCO2 in the oceans (the warm tropics) and more negative at the sink places (the cold high latitudes), which leads to less degassing at one side and more absorption of CO2 in the oceans at the other side. This is responsible for a large part of the difference between what is emitted and the measured increase of CO2 in the atmosphere. But that is only 3 +/- 2 GtC/year, far less than the seasonal exchange.
If for any reason the emissions should stop, in the first subsequent year the atmospheric pCO2 would be the same as in the previous year, leading to a drop of CO2 in the atmosphere (of about 3 GtC), because there is no addition anymore. The next years, the difference between ocean and atmospheric pCO2 will decrease, thus the absorption of the extra CO2 (30% or 250 GtC since the start of the industrial revolution) will slow down, in this case with a halve life time of 30-40 years.

Other, slower decay rates come into play too: the decay of longer-term CO2 storage in wood roots/trunks if CO2 levels drop, the exchange between ocean surface CO2 (responsible for most of the above decay rate of 30-40 years) and deepsea CO2, etc…

Thus all together: individual molecules have a short residence time, total CO2 mass above the pre-industrial equilibrium has a much longer residence time…

You have expressed your points most lucidly. Thank you.

On a related problem, you are more aware than I about the politics of carbon emissions trading worldwide. Australia is particularly affected because of the huge value of fossil fuel exports from here. Hypothetical: If I was a major carbon exporter and I wanted to trade, would there be enough offsets in the world to allow a scheme to work? Are we now in a world where major producers try to muscle their ways in to trade a rapidly-diminishing supply of candidates (nuclear power being an obvious exception)?

Or have clear heads delayed this rush in case the AGW theory is illusory?

There are already shonky schemes afoot. Some trade forest products. Overall, the CO2 sequestration of vegetation is proportional dominantly to the mass per unit area of growing vegetation. Long term sequestration only happens when currently barren or low-vegetation areas are replaced by (say) large trees, but that is a one-off effect once the land has been taken up. In looking further for land, one can foresee useful agriculture being displaced.

The tangled web has been woven. Now to recover from it.