In July last year, and after more than a year’s absence, NIWA got around to publishing another issue of their “flagship” publication, Water & Atmosphere. It’s an attractive magazine, but it contains some curious information which deserves comment.
First, we notice a helpful comment by NIWA Chief Executive, John Morgan:
NIWA has a responsibility as a Crown Research Institute to share the results of publicly-funded science.
Hmm. Morgan should compare that statement with the conclusion of the methane article in the same issue:
if any real solution [to agricultural emissions] is on the horizon it’s likely to be a closely kept secret.
The article has some gems:
methane levels have grown by 150 per cent since organised animal farming began in the early 1700s.
They tell us methane’s a problem
Was farming disorganised until the 18th century? That’s not what the history books say. So, global methane rose sharply many years before Capt Cook discovered New Zealand in 1769, and this was caused by ‘organising’ more livestock. This later caused global warming, which happened in NZ in 1944-57 and in the rest of the world in 1979-98.
Methane levels have continued to rise over the decades, growing fastest through the 1960s, ’70s and ’80s, before slowing down in the 1990s, levelling off in the early 2000s, and increasing again from 2007.
Note that they didn’t rise during the early 1800s when the world emerged from the Little Ice Age, or during the “warmest period on record” in the late 1990s. But they did rise during the cooling scare of the 1960s and ’70s. Methane concentration appears to be a good inverse indicator of warming.
Is methane a problem?
There is so little methane in the atmosphere that it was not detected there until 1948.
“This levelling has caused some to suggest that animals are not the problem. But with livestock accounting for only 15 percent of emissions, it’s more likely that the sources of the other 85 percent – like wetlands, which are susceptible to floods and drought – are responsible for the fluctuation”.
So why say that “organised animal farming” caused the fluctuation in the early 1700s?
The paper confirms that livestock farming is “carbon neutral” but says methane is 21 times more potent than CO2 at absorbing infrared rays and “it spends an average of nine years in the atmosphere before it is oxidised back into CO2.” After a few years of being Mr Hyde, methane reverts to being innocuous Dr Jekyll. All the methane emitted prior to 2001 is now CO2 and part of the current carbon cycle. But NIWA aggregates methane from NZ livestock since 1990 – a period twice as long as the life of the gas.
NIWA is continuing to manipulate the data and showing no sign of scientific objectivity.
ETS down on the farm, with methane
Some brief reflections on the operation of the ETS on the farm, courtesy of my friends, Neil and Esther, at Climate Realists.
Apparently MAF agree that “warming occurs in steady state situations because livestock cause CO2 to become CH4 and CH4 has a higher global warming potential.”
Nick Smith also agrees that the CO2 effect is just part of the carbon cycle, BUT converting it to methane means that the carbon atoms cause warming at 21 x CO2e for 9 years.
Surely, this isn’t advanced maths:
Year 2000: If I have a farm with 100 animals which emit one tonne per head pa, then my land is responsible for emitting 100 tonnes of CH4 (or 2100 tCO2e) in the current year [no different if measured per kg of milk solids or meat].
Methane stinks
Year 2009: Roll forward 9 years, and this year the atmosphere again receives 100 tonnes. But it also loses 100 tonnes (or 2100 tCO2e) through the oxidation of the CH4 I put up there in 2000. So the net CH4 emissions from my farm for this year = zero.
The Kyoto system focuses on timing. If I plant trees now, I’ll receive credits right away – but if I chop them down in 9 years, the credits are reversed. Then I’ll get credits again if I re-plant after that. You/they pay while your activities are still hurting/helping the atmosphere.
So does the inequity
Now let’s assume that my farm has enjoyed an 80% increase in production since 1990 (had to, because Roger Douglas took away all the props just before this), but has been ‘steady state’ since 2000. As shown above, my net emissions in 2009 are zero. The Kyoto regime punishes increases, not absolute amounts, so why should I be penalised?
Why is MAF going back to what I produced 20 years ago to calculate what penalty should be imposed? That ancient history has nothing to do with the amount of methane up there today. CO2 might last hundreds of years in the atmosphere (?), but CH4 is quite different – it’s all gone now!
Stinks.
Views: 233
A molecule of CH4 produces 7.2 times as much warming as the much-heavier molecule of CO2.
And a cubic metre of CH4 produces 7.2 times as much as a cubic metre of CO2.
But a GRAM (note: mass) of CO2 produces 21 times as much warming as a gram of CH4.
So which measure should we be concerned with?
MAF tells us that the warming is caused by INCREASING ATMOSPHERIC CONCENTRATIONS. So we don’t give a hoot how heavy it is. We want to know whether it will produce more parts per million in the atmosphere.
At present CH4 is only 1.8ppm in comparison with CO2 at about 390ppm. To produce 1ppm of CH4 would be a big deal – one-eighteenth increase. And that major effort will produce only 7.2 times as much warming as a trivial increase from 390 to 391ppm of CO2.
Australis, I agree that the warming from CH4 is negligible but 2 things:_
1) The #1 relevant heat characteristic (in my thermodynamics text books) is specific heat capacity which is kJ/kg K so mass is a factor and obviously we need to know the concentration but the key is – how much heat can it hold and on average, what proportion of the capacity is operative over time to re-emit radiation?
2) Downthread, myself, Andy, Jim, MostlyHarmless are trying to get to grips with GWP and it may be that the proportion in 1) is a factor called “radiative efficiency” but there’s still some work to do on this (and this is just my thinking at the moment and I may be wrong).
I hope you are following the comments downthread because you were first cab off the rank with some good brief points.
Whoever concocted the article on methane has never read History. Or Sience. ‘Organised’ farming is quite a few years older than three or four hundred years.
I would be interested to know about the instrumentation and methodology used to measure methane in the atmosphere prior to the 18th century.
If this is the best NIWA’s new ‘flagship magazine can come up with, taxpayers would seem entitled to ask for their money back.
Whoever concocted the article on methane has never read History. Or Sience. ‘Organised’ farming is quite a few years older than three or four hundred years.
I would be interested to know about the instrumentation and methodology used to measure methane in the atmosphere prior to the 18th century.
If this is the best NIWA’s new ‘flagship magazine can come up with, taxpayers would seem entitled to ask for their money back.
And sorry about my mis-spelling of ‘science’ in my previous comment.
Apparently, a good deal of “anthropogenic” methane emissions comes from rice paddies.
I do quite like the comment about modern farming. A quick internet search reveals some interesting facts from ancient Egypt.
For over 5000 years the farmers of Egypt created a civilization based on the union of the land and the Nile river. It was one of the earliest civilizations and it had a profound influence on the region.
[…]
Sheep, goats, cattle, pigs and geese were raised from earliest times and supplied milk, wool, meat, eggs, leather, skins, horn and fat. Even the dung had its uses. There is little evidence that mutton was consumed, while domesticated pigs were eaten at least since the beginning of the 4th millennium BCE
[..]
Some things haven’t changed though….
The administration was involved in everything the farmer did, from the assignment of the land to the collecting of the taxes. Before the harvest began, surveyors, scribes, supervisors and inspectors came to measured the size of the fields and estimated the quantity of grain. These officials fixed the tax the peasant had to give up to the royal treasury or the representative of one of the gods, among whom Amen had the vastest and best properties. Scribes trying to impress their pupils with the harshness of a peasant’s daily struggle for survival, may have slightly exaggerated the methods used by tax-collectors, but Egyptian officials were not noted for sparing the rod (nor have peasants ever shown an alacrity to part with the fruit of their labor)
What out for those scribes and inspectors!
Brilliant Andy – very germane to our ‘modern civilisation’, which I have no doubt the Egyptians considered their civilisation.
The methane component is difficult to distinguish in LW infrared absorption spectra for earth’s atmosphere. The main methane absorption band at WN 1300 is largely overlapped (therefore masked) by water vapour. The oft-quoted “21 times” or “25 times” factor is the (virtually unexplained) so-called “global-warming potential” from the 2007 IPCC report. It is NOT a simple multiplier to apply to CO2 radiative forcing. The spectral curve at https://www.soils.org/images/publications/jeq/37/2/592fig1.jpeg shows the two bands with a circled 4 above them.
The claim in the 2007 IPCC report that methane (with two bands, one completely, and one partly overlapped by water vapour) has an effect about 1/3 that of CO2 yet has an atmospheric concentration of less that 1/200th that of CO2 is simply not plausible.
From http://en.wikipedia.org/wiki/Greenhouse_gas the diagram
http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png shows the absorption spectra of GHGs – methane barely figures.
Thanks, this is exactly the information I have been looking for.
I too have been looking for that 21* CO2 calculation and have yet to find it.
I have read from various sources that CH4 has a half life of 7 or 8 years in the atmosphere before oxiding to h2o and co2. These are long term issues. Taxing CH4 at 21-25 times co2 is ridiculous.
There is one other property of methane worth a mention. Unlike the other so called greenhouse gases it is not soluble in water. Therefore want goes into the atmosphere from rice paddies, cows or the Amazon rain forest only exits by way of breaking down into CO2 and H2O. The fact that atmopsheric levels have been reducing clearly means input is down.
The key factor to investigate, in my view, is this “21 CO2e” value. This is based on a “100 year equivalent”, whatever that means.
I think the Wikipedia article linked above has some references that date back to Houghton, which I will try to follow up.
It does seem that this 21 value is bandied around, in particular forming government policy worth billions of dollars, yet no one provides a source for this figure.
I should think it would at least be worth NZ Fed. Farmers spending some time looking into this.
A helpful climate scientist sends me this:
Page 211 of AR4 says.
Then he comments:
It is because of this that methane is a catastrophic anthropogenic global warming (CAGW) issue at all, since it does not come from storage as is the case with CO2.
Now I comment: If that helps, I’m glad. I’ve just unearthed a lot of material on the topic of CH4, and there are links above as well, so there’s a fair amount of reading to be done just on the science. After that’s been absorbed, we can tackle the approach of MAF and the MfE to agricultural emissions (unique in the world!). There are farmers around the place rather miffed they’ll soon have to pay for their animals’ intemperate belching damaging the climate.
Thanks Richard.
The link to your reference above is
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html#table-2-14
The RF calculations for the GWPs for CH4, N2O and halogen-containing well-mixed greenhouse gases employ the simplified formulas given in Ramaswamy et al.
This table on AR4 provides some information that doesn’t really corroborate the 21 times CO2e factor.
I am presumably missing something.
Table 2.14 of this link
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html#table-2-14
shows a radiative efficiency (meaning unknown to me) of the following:
CO2 1.4×10–5
CH4 3.7×10–4
(gives a ratio of 26.5:1 efficiency of CH4 to CO2)
However, table 2.1 of this link
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html#table-2-14
shows a radiative forcing of CO2 of 1.66 W/m2 compared to a forcing of CH4 of 0.48 W/m2
CO2 has a much greater radiative forcing that CH4 according to this table, yet the radiative efficiency is of the order 26:1 in the favour of CH4
What do these terms mean, anyone?
Saturation, Nonlinearity and Overlap
in the Radiative Efficiencies of Greenhouse Gases
http://www.sjsu.edu/faculty/watkins/radiativeff2.htm
This article attempts to explain the concepts of radiative efficiency and forcing. It asks a lot of questions on water vapour that we are familiar with.
Interesting article Andy. Both you and Bob have got me looking at the model physics in respect to CH4 and WV which are closely linked so I’ll point Bob to this comment rather than duplicate stuff. For your benefit Andy I can point you at some maths in the CAM5 Description that should send you into paroxysms of ecstasy.
First the article. Quoting:-
This: “presume that the level of water vapor in the atmosphere is a function of the global temperature and is therefore a derived effect” is incorrect for CAM5. The level of WV is derived from CH4 and the heat (warming) will be in proportion to that level as a result of “Choosing the (virtual) potential temperature” in the CAM5 model (more on that below).
Even so, the WV situation is very mysterious (observed levels), I’ve queried the PMSAC and Office of Climate Change but …….crickets…..
The CAM5 Description has this to say on CH4/WV (3### is line ID in the Desc):-
3574 Oxidation of CH4 is an important source of water vapor in the stratosphere, contributing 3575 about half of the ambient mixing ratio over much of the stratosphere. Although CH4 is not 3576 generally oxidized directly into water vapor, this is not a bad approximation, as shown by 3577 Le Texier et al. [1988]. In CAM 5.0, it is assumed that the water vapor (volume mixing ratio) 3578 source is twice the CH4 sink. This approach was also taken by Mote et al. [1993] for middle 3579 atmosphere studies with an earlier version of the CCM. This part of the water budget is of 3580 some importance in climate change studies, because the atmospheric CH4 concentrations have 3581 increased rapidly with time and this increase is projected to continue into the next century (e.g., 3582 Alcamo et al. [1995]) The representation of stratospheric water vapor in CAM 5.0 is necessar3583 ily crude, since there are few levels above the tropopause. However, the model is capable of 3584 capturing the main features of the CH4 and water distributions.
So the representation of WV (unless I’ve got this wrong) is rather different than the article suggests because we see in CAM5 Desc “Model Physics” the mass conservation law for WV (line 699) which includes “the mass mixing ratio (or specific humidity)” of WV (derived from CH4 levels), THEN we see “702 Choosing the (virtual) potential temperature as the thermodynamic variable, the first law 703 of thermodynamics”.
Note in this model method, CH4 is an extremely important input having a HUGE bearing on the output given that (in CAM5) WV (the most significant GHG) is derived from CH4.
CAM5 Description:-
http://www.cesm.ucar.edu/models/cesm1.0/cam/docs/description/cam5_desc.pdf
Back to the article. Quoting:-
“Radiative efficiency” could be a factor to reduce thermal heating effect compared to solar (LW vs SW), but I’m just guessing.
These parameters, factors, etc will turn up in the tables of parameters, constants etc in a model users guide along with options to scale the factors depending on the reqd simulation spec (ramping) but they will be instantaneous and not be in terms of lifetime (I think). I will have a look at CAM but I’m running out of time today. Meantime here’s the link to the CAM3 Guide (4 & 5 were incomplete drafts last time I looked):-
http://www.cesm.ucar.edu/models/atm-cam/docs/usersguide/usersguide.pdf
e.g.
Water vapor absorptivity/emissivity dataset
This is a lookup table for water vapor absorption. It is specified by setting the namelist variable, ABSEMS DATA. The default dataset provided with the dataset distribution can be found in CSMDATA/atm/cam2/rad/abs ems factors fastvx.052001.nc.
This paper
Greenhouse Warming Potentials from the Infrared
Spectroscopy of Atmospheric Gases
Matthew J. Elrod
provides some methodology used to calculate GWP’s for methane etc.
Apparently this can be done with Excel.
http://alpha.chem.umb.edu/chemistry/ch361/spring2006/greenhouse%20warming%20potential.pdf
The logic in this paper is daft. Quoting:-
OK we’ll let this go, “Intercepts” would be a better word than “traps” but just quibbling. Then it gets silly,
The energy is lost to space eventually by dissipation, convection, collision, re-emission etc. Yes the gas has a “warming potential”, “forcing capacity” and a “specific heat capacity” but these are maximums and the maximum potential is not operative 100% of the time and neither is capacity.
The energy is not “trapped’, this is proven empirically day in day out. Meanwhile what’s the WV “warming potential”, “forcing capacity”, “specific heat capacity” and what is the concentration? Studiously avoided by this paper but Miskolczi has quite a lot to say about it. Any “warming potential” that the minor GHGs have is easily offset by WV variation (but that’s top-secret at the moment).
These dipsticks cannot conceive how overwhelming is the modulating effect that the enormous quantity of the planet’s water (with its top-shelf heat capacity) that is circulating in the hydrological cycle has on planetary heat transfer. Conversely, what was the key substance that facilitated the Ice Age? Our climatic modulator exists in three states: solid, liquid and vapour, but minor GHG concentrations are only one of eight important factors thought to be the cause of a proliferation of the solid variety 20,000 years ago – the sun is a component of three. So just as solar heat and water is a powerful combination, water and the absence of solar heat is an extremely adverse combination.
Even an introductory text like “Applied Heat, An introduction to thermodynamics” by Roger Kinskey alerts a student to the shear power of heated water vapour and the industrial uses of superheated steam but that’s only 400 pages. My “Steam” text, an engineering epistle by Read and Renshaw, is over 1100 pages; that really gets down to the business of harnessing the power of H2O + heat.
Consider railway steam engines (still providing good service in places like India and China). If you need grunt, you use heat, WATER and pressure – hey presto – power! You don’t use air with high concentrations of CO2, CH4 etc.
Similarly, microwave ovens are ubiquitous (solar SW analogy) but try finding a LW oven (GHG analogy) that can actually cook anything.
“Global warming potential”? Get real.
/Rant
Should have said “You don’t use [dry] air with high concentrations of CO2, CH4 etc.”
Accuracy got lost in the “heat” of the moment (Ha!).
Aside from the issues around the theory itself, what I am trying to establish is how to calculate this “Global Warming Potential” using the methodology that they describe. They state that GWP is a function of atmospheric residency time and radiative forcing. Yet RF for methane is less than for CO2, and residency is significantly less than CO2. How, then, does this result in a GWP for methane that is 21 times for CO2?
They reference a worked example in Excel, which I have yet to find. Otherwise, I’ll just have to calculate it myself, when I get time.
Andy, I’ve placed a constructive (I hope) answer in a new thread header, this one’s too skinny.
https://www.climateconversation.org.nz/2011/06/methane-mthane-methinks-it-stinks/#comment-59548
It’s only a step along the way to defining the detail of the 21x construct, that’s still to be tracked down (or have I missed it) but I’ve tried to flesh out the “warming” process. As you can probably guess from the comment, I think it’s conceptually wrong from a thermodynamic perspective and I’m not very enthusiastic about actually using the factor in calcs but I’ll try to do my bit to resolve the mystery of the 21x factor.
I might go looking in AR4…….(sighs, grimaces, rolls eyes)
Jim Mck has already done the AR4 legwork (yaayyy), I,m sure you’ll see his comment but if not it’s here:-
https://www.climateconversation.org.nz/2011/06/methane-mthane-methinks-it-stinks/#comment-59549
Andy, CH4 may be more efficient than CO2 but both will be less efficient than solar in terms of thermal heating effect or put another way, who cares about re-radiation if that radiation doesn’t do any heating beyond the normal GHG effect?
I’m guessing that the efficiency factor is a quick and dirty way of apportioning a heating effect to GHGs probably in respect to solar or perhaps the thermal spectrum that will cause excitation (heating, temperature and re-emission) in the most particles. CH4 is probably more efficient than WV in that respect but because there is so little of it, who cares?
The 21x factor is a lifetime quantity unrelated to an instantaneous flux efficiency factor (I linked to the explanation a few posts ago and can drag it out but I don’t have much time at present).
Then the question arises, what gets heated? The heat retention of CH4 is totally insignificant (we’ve covered this previously using specific heat capacity) and once capacity is reached, the molecule re-emits but what does that heat? The only particles that will be heated are those that absorb at the wavelength of re-emission from CH4 (atmosphere, land or ocean) but WV (the major GHG) is already being heated by convection so how much difference will the CH4 re-radiation make to WV? Very little I suspect.
This leads to the forcing. I might be wrong but I think the 0.48 W/m2 CH4 forcing is the residual flux at the surface of the earth after any atmospheric effects and that flux will only heat those particles with compatible absorption characteristics. As with CO2, CH4 (and WV) LW re-emission has next to no effect on the ocean and there will be limited land material that will be heated.
But do those forcings and efficiencies translate to real-world measurable effects? e.g.:-
Where is the elevated heating attributed to GHGs being detected?
1) Atmosphere (No tropospheric hot-spot)
2) Land (None over the last decade)
3) Ocean (Out of the game)
A null hypothesis for AGW therefore.
To put the 0.48 W/m2 CH4 “forcing” into some perspective, the DLR flux measured at Darwin 2003 varied between 310 and 500 W/m2.
http://scienceofdoom.files.wordpress.com/2010/08/dlr-darwin-2003-499px.png?w=499&h=230
But govt boneheads want to include animal emissions in the ETS in spite of the complete insignificance of methane warming (and that’s if there really is any).
Occam’s razor anyone?
I am wrong on the forcing, it is actually:-
Radiative forcing: The relative effectiveness of greenhouse gases to restrict long-wave radiation from escaping back into space. For a particular greenhouse gas, radiative forcing is measured as the change in average net radiation (in watts per square meter) at the top of the troposphere, and depends on the wavelength at which the gas absorbs the radiation, the strength of absorption per molecule, and the concentration of the gas.
This puts me in a tizzy because now I have no idea how to compare the DLR flux of an individual GHG with total DLR flux.
I see where my confusion arose. Once you have RF you can (supposedly) determine temperature at the earth’s surface if you have climate sensitivity (CS) but the RF flux is TOA.
Radiative forcing is the change in the energy input to the Earth’s climate system over some period of time due to some external change. It is measured in watts per square meter (W/m²). It is a useful concept and leads to the definition of the climate sensitivity parameter λ, i.e.,
λ = ΔTs/ΔF
where ΔTs is the change in the Earth’s global mean surface temperature and ΔF is the radiative forcing.
Fair to say though, that alarmist values of CS are BS.
I agree, and they should look at the “298 CO2e” for nitrous oxide while they are about it.
Andy (continuing from up-thread), here’s the paper and entire comment from the Rachel Stewart comments that alludes (dimly) to the 21x factor.
—————————————————————————————————————————–
Greenhouse Warming Strengths of the Key Gases and Fuel Effect on Fossil Carbon Intensity:-
http://www.treepower.org/globalwarming/CO2-EPRI-EvanHughes.pdf
Quoting:
“In Table 5-1, different timeframes, as well as the four different gases, are shown because
the non-CO2 gases gradually are converted into CO2 over the years and will eventually
be at the same strength as CO2, but not until well beyond the timeframes of interest here.
In order to assess emission controls applied to different gases on a common basis for
global warming purposes, the emissions of the different greenhouse gases are normalized
to a common basis by expressing them as equivalent CO2 emissions. On a mass basis, and for a 100-year timeframe, methane (CH4) absorbs 21 times as much of the earth’s outgoing infrared radiation as carbon dioxide (CO2). Therefore, we say that the mass of the equivalent CO2 emission is 21x the mass of the methane put into the landfill gas energy system. In this section of the report the costs of greenhouse gas reduction will be
expressed and compared on the basis of dollars per metric ton (tonne) of elemental
carbon ($/tonne C), based on the absorbing strength when that carbon atom is in a CO2
molecule–the “CO2 equivalent.” When methane is the fuel, the carbon atom is in a CH4 molecule. Hence, the factor per unit of energy will be less than the 21x. Here we use a factor of only 7.64, which is 21 x (16/44). The 16/44 is because each molecule of
methane has a mass of 16, molecular weight, and goes into one atom of carbon in a
carbon dioxide molecule of weight 44.”
So what?
If we take the Specific Heat Capacity of CO2 as 0.819 (kJ/kgK) at 275 K.
http://www.engineeringtoolbox.com/carbon-dioxide-d_974.html
Methane holds 2.7 times more heat
http://www.engineeringtoolbox.com/methane-d_980.html
Water vapour holds 2.27 times more heat
http://www.engineeringtoolbox.com/water-vapor-d_979.html
Adjusting for atmospheric composition and setting CO2 at 1
Methane is 0.01 relative to CO2
Water vapour is 157.6 relative to CO2 (using 2.5% atm composition) which is 15,764 times greater atm heat capacity than methane.at 275 K.
http://geography.about.com/od/physicalgeography/qt/atmcomposition.htm
—————————————————————————————————————————–
So (according to Hughes) the 21x factor “normalized warming strength” is on a mass/time basis but it is not used when methane is a fuel, in that case 7.64x is the factor.
But in Elrod, “the radiative forcing capacity is the amount of energy per unit area per unit time” – a x-sectional area/time basis.
The Elrod molecule x-sectional area calc is only the first step in determining the “warming strength” of the molecule, the next step is the Hughes mass calc because the incoming radiative energy excites the entire molecule, the temperature rises, some energy is retained in the form of heat and an increasing amount is re-emitted as temperature rises. At a specific threshold, the molecule does not retain any more heat (it has reached its specific heat capacity) and all the incoming LW radiation energy is re-emitted as LW radiation energy (to escape to space, to earth’s surface, to other atm molecules that absorb at that wavelength and so on) and thus the energy is dissipated. NB, the radiative intercept/re-emit process is instantaneous.
Therefore “warming strength” has only one component – the retained heat (the re-emitted energy is surplus).
Now the time component kicks in. IF the molecule is continually replenished with incoming radiative energy, the continually retained heat (at the specific heat capacity) will continually emit for the lifetime of the molecule – THIS is the maximum potential “warming strength” (actually it’s just dissipated solar energy but I digress). In the real world this simply does not happen, day/night cycles, seasons, random interception, all ensure that it doesn’t.
[Note also (a mere side issue), that temperature rise causes radiative “forcing” contrary to IPCC RF methodology that has radiative forcing causing temperature rise – Duh!]
My bone of contention is that neither Hughes nor Elrod (apart from the fact they are contradictory) address the most important GHG characteristic – specific heat capacity (as in my duplicated comment above). Instead, it’s “the emissions of the different greenhouse gases” (from Hughes) that are supposedly more important along with molecular weights and x-sectional areas. Why don’t they use thermodynamic characteristics for heat calculations as heat engineers do?
The main kiwifruit season is winding down so I might be able to apply myself to this and other issues a bit more from now on (once the dust settles in my cranial cavities – some of the above may not be as accurate as it should be, no doubt Huub will point that out if he’s lurking).
http://www.grida.no/climate/ipcc_tar/wg1/pdf/TAR-06.pdf
I have trawled through this reference over the weekend and the devil is very much in the detail. The Global Warming Potential GWP calculation needs some close investigation. It is essentially the ratio of the perceived effect of addition to the atmosphere of a gas, say CH4 with the effect of the eqivalent addition of the reference gas (CO2).
To be a little more precise it is the result of dividing the sum of the perceived annual impacts of the measure gas by the sum of the perceived annual impacts of the same amount of CO2. (page385 – 6.2)
The “impacts” then are the product of the gases radiative efficiency and the time the gas stays about. The radiative efficiencies are 0.01548 for CO2 (page 386) and 0.00037 for CH4 (table page 388).
The IPCC in its wisdom looks at the time in atmosphere differently for CO2 than it does with the other gases (page 385). The time in atmosphere of a pulse of CO2 is taken from the Bern model of the carbon cycle and assumes 70-80% of anthropogenic emissions are removed from the atmosphere pretty much straight away. For the other gases theoretical constructions of time in atmosphere are calculated – 12 years for CH4. So the GWP of 21 for CH4 results from dividing the sum of 12 years of small impacts of CH4 by a very much smaller number for CO2. This is smoke and mirrors.
The additional pulse of CO2 doesn’t disappear as the calculation implies it just circulates for a very long time in the biosphere. Methane is of course also part of the carbon cycle and it is relevant to note that for the period that the atom of C is tied up in CH4 it has a much lower radiative efficiency than when it becomes CO2.
The IPCC is pulling the wool over our eyes and it is evident from the way they present their tables (page 388) that they know they are. No one else is particularly interested in GWP numbers because it is only some farmers from the antipodes who are stupid enough to include them in their taxation system.
Jim, many thanks for your analysis.
I was imagining that something like this to be the case. The idea that you can base the GWP on an assumption that CO2 has virtually zero residency in the atmosphere, and at the same time, claim that it will be in the atmosphere for “hundreds of years” (or whatever the IPCC claim) is dishonest in the extreme.
I’m glad you’re onto it Jim, I’ve had my wires crossed.
Ramaswamy et al., 2001 is Chapter 6 of TAR “The Scientific Basis” – not AR4 “The Physical Science Basis”. I didn’t read my own link carefully enough and went trawling for “Radiative Forcing of Climate Change” (what you have linked to) in AR4 Chapter 6 but didn’t find it, found “Palaeoclimate” instead, got thoroughly confused, pointed Andy at the wrong set of references (sorry Andy), gave up.
Now I can take up from this comment again (thanks Jim)
——————————————————————————————————————————
—————————————————————————————————————————–
I do some dumb things due to working long exhausting hours during kiwifruit main season packing and the above is just one of those.
Now that I’m looking at the right Chapter 6 I should make progress and mysteries like “21x”, “simplified yet still valid expression for CH4″ and “radiative efficiency” should become clear………….(“should” said in hopeful tones, I really want to see the definitions).
Many thanks for your contribution Jim, I’m as appreciative as Andy is
“simplified yet still valid expression for CH4″ was found by Andy in this comment
——————————————————————————————————————————
—————————————————————————————————————————–
See:- Table 3. Simplified expressions used in IPCC [1990] (Table 2.2).
There’s an expression for N2O too Jim.
The Myhre paper can be accessed here:-
http://folk.uio.no/gunnarmy/paper/myhre_grl98.pdf
Thanks Andy,
If you don’t mind I would like to expand the issue onto N2O, because not only is the denominator of the GWP bogus in this case, so is the numerator
The IPCC have calculated the lifetime of N2O from the time that it theoretically takes to get destroyed in the stratosphere – 114 years. (page 252). This may or not be correct. But here is no mention in the IPCC statements that N2O is soluble in water. In fact it has very similar solubility to CO2 in water. As with CO2 there is about 40,000 times more of it dissolved in the oceans than free in the atmosphere. The fact that the histories for atmospheric concentration of NO2 and CO2 mimic each other albeit that NO2 is parts per billion should have given them a bit of a clue.
The simple physics has to mean that there is an equivalent temperature driven flux between tropics and cold water regions for N2O as there is for CO2. The longevity of N2O therefore has to be very similar to CO2. Adjusting for their radiative efficiencies the GWP for N2O should be about 0.3 not 296. How’s that for a margin of error.
Thanks Richard,
I am presuming the term radiative forcing is pretty much the same as radiative efficiency. Someone please tell if it is not.
It seems to me the Mryre paper is tinkering with the Radiative efficiency/forcing numbers. The big driver of GWP is not the forcing number it is lifetime of gases.
If I am off the planet here please someone let me know.
I am presuming the term radiative forcing is pretty much the same as radiative efficiency. Someone please tell if it is not.
Jim – they are not the same, but I think your analysis is good and we need to press on with this as I feel this is a fairly major issue.
Unfortunately, mother nature has intervened in ChCh and we are on battery power tonight. Will be in touch
Jim, some simple definitions for now (I’m wrong on forcing elsewhere in comments so I’ll have to backtrack and repair the damage).
Radiation efficiency: At a given frequency, the ratio of the power radiated to the total power supplied to the radiator. [Note: this may not be the “radiative” efficiency of the IPCC]
Radiative forcing: The relative effectiveness of greenhouse gases to restrict long-wave radiation from escaping back into space. For a particular greenhouse gas, radiative forcing is measured as the change in average net radiation (in watts per square meter) at the top of the troposphere, and depends on the wavelength at which the gas absorbs the radiation, the strength of absorption per molecule, and the concentration of the gas.
Calculating the global-warming potential
http://en.wikipedia.org/wiki/Global-warming_potential
All the calcs are here (GWP & RF) except radiative efficiency.
Quoting:-
There is no hot-link for “radiative efficiency” in that paragraph – I’ll keep looking.
William Connelly must have been busy because we see this for water vapour:-
“Its concentration in the atmosphere mainly depends on air temperature” ? The CAM5 model derives WV from CH4 levels, but I digress.
This article (h/t Andy): “Saturation, Nonlinearity and Overlap in the Radiative Efficiencies of Greenhouse Gases”, disagrees with Wikipedia:-
And
Looks like I’ll have to mount a “diligent search”.
At the same site, the author writes on the role of water, in liquid and vapour forms, on the climate and paints a rather different picture than “There is no possibility to directly influence atmospheric water vapour concentration” [William Connelly ?]
Hi Richard,
I do like the idea of calculating the GWP of water. GWP is of course not an absolute measure it is measured relative to the “Reference Gas” CO2. The calculation should be straight forward abeit with an error range attached.
Our problem is essentially political. We need to get the message across that the GWP is a crazy and completely flawed construct and it is ridiculous to use it as the basis for our taxation system.
The major driver of GWP as produced by IPCC and illustrated above is time in system not the radiative properties of the gases.
Jim, I am still trying to get my head around your calculations. (In between earthquakes).
the reference value of CO2 GWP assumes an almost zero residency for most anthropogenic CO2 – is this correct? Do you have some references here? Thanks, Andy
Yep, we have to become expert in this “crazy and completely flawed construct” (unfortunately) and be able to apply it to water vapour (WV).
I agree Jim, that the really dodgy multiplier is decay, residency or “time in system”. You seem to have already covered much of that ground so I suggest that you keep on becoming expert in that area ahead of us because it will help those of us in catch-up mode to have a “go to” guy.
For me though (and probably Andy too), I need to know the basis of all the factors employed (Where did they originate? What paper? Are they valid? etc) and how to apply the expressions, formulae, factors, efficiencies etc i.e. the fundamentals.
Andy has a PhD, a couple of degrees, at least one of which is mathematics so I will defer to him when the going gets tough mathematically (I can only really get the gist of complex calculus but I muddle along). My interest is the physics and thermodynamics (among other things) with a grounding in engineering science (heat, heat transfer, power, work, energy and electricity) at Int NZCE (Mech) level which is now diploma level. Your background Jim? Not that it matters which field or whether you have academic quals – a diversity of skills is a team strength; investigative research curiosity seems be a useful attribute I find in this pursuit.
Given my focus which includes radiation energy, I’m still getting my head around the IPCC’s “radiative efficiency” (RE?) which seems to be a odds with what one would expect such an efficiency factor to be (the conventional definition I gave up-thread). Interpretation:- the IPCC makes stuff up instead of using conventional physics.
Case in point. I inserted “specific heat capacity” into the Chap 6 pdf search box and got “no matches were found” (Huh?). How can they be generating screeds on atm heat, warming, emittance etc without recourse to the very characteristic that is fundamental to all of that and especially over the residency of the gas?
A tip. We need to be VERY careful with units and state when necessary e.g.
Radiative efficiency of CO2 from Chap 6, 6.12.2 is 0.01548 Wm−2 ppmv−1.
Radiative efficiency of CH4 from Chap 6, Table 6.7 is 3.7×10−4 Wm−2 ppb−1
Note that these two values are NOT directly comparable as they stand in those units. As I said, I’m still getting to grips with this IPCC efficiency factor and I don’t understand it at all yet (someone chip in if you do).
Aside, I stumbled upon 6.11.2.2 “Cosmic rays and clouds” in Chap 6 while scrolling back and forth between tables looking for GWP and RE values (why don’t they put all related data in the same place?).
Quoting:-
Not any more, that will have to revised for AR5 now that proof has arrived.
And:-
Duh! It’s a Solar Wind Modulated Cosmic Ray Flux hypothesis i.e. the solar variability (in this case) is a modulator – not a forcing, in terms of “Cosmic rays and clouds”. Cloudiness varies as per the hypothesis, albedo changes, insolation changes, OHC and GAT changes. It’s not about whether “cloud cover responds to solar variability”.
Hi Andy,
The paper referred to above doesn’t give the absolute number. Page 386 para three refers to the carbon cycle and the removal function for CO2. Chapter 3 which seems to be saying that half of the anthrogenic emmisions (pulse) is directly absorbed.
In fact every effort is made not to mention the particular time frame for CO2 although you may be able to calculate it from the 20/100/500 yr AGWP numbers for CO2 given on page 386. This is a bit beyond me and I am relying on hints in Chapter 3, a quick look at the Bern Cycle and reverse engineering the lifetime.
Jim
Hi Andy,
Now you have me worried.
100 yr AGWP for Co2 say .01548 x 100yrs x 45% average in atmosphere equals 0.69. Thats about what they say page 386
Then multiply by 23 to get AGWP for CH4 of 16.0 as per same ref.
But AGWP for CH4 by same method as above .00037×100 and say 100%( no loss in atmosphere) gives AGWP of 0.037.
More reading required. But I better go and do some work.
Jim
Jim, I don’t think you can insert .00037 in place of .01548. Please see my screed up-thread where I touched on this:-
https://www.climateconversation.org.nz/2011/06/methane-mthane-methinks-it-stinks/#comment-59786
Basically:
We need to be VERY careful with units and state when necessary e.g.
Radiative efficiency of CO2 from Chap 6, 6.12.2 is 0.01548 Wm−2 ppmv−1.
Radiative efficiency of CH4 from Chap 6, Table 6.7 is 3.7×10−4 Wm−2 ppb−1
Note that these two values are NOT directly comparable as they stand in those units. You seem to be 3 decimal places out in your calcs and I think this is explained by your interchange of a value in ppmv with a value in ppb.
Although given my “radiative efficiency” (RE) knowledge gap, I could be wildly wrong.
Thanks Richard,
Will check over all my workings tonight
Jim
Hi Richard & Andy
I feel pretty stupid missing the ppb against ppm and it throws most of my position out the window. But at least there is some learning. They – IPCC- don’t make it easy for the great unwashed to work things out from first principals.
Here are my revised numbers:
Radiative Life AGWP GWP
Efficiency 100yrs (relative to
Wm(-2) ppm (-1) Wm(-2) /yr/ppm(-1) CO2)
x 10(-3)
CO2 15.48 100 yrs 0.696 1
CH4 370 12 yrs 16.0 23
N2O 3100 114 yrs 206 296
Taking seemingly realistic assumptions about rates of decay I have to admit that these numbers do hang together and that my earlier analysis and rhetoric was wrong.
This still leaves one obvious direction for inquiry. How on earth can the radiative efficiency of two such similar molecules as CO2 and N2O be so remarkable different.
Beyond me I suspect.
I might have to revert to developing one of my earlier arguments – that N2O can never a be any more of a contributor to global warming than it is perceived to have been historically ie it is trivial and should be ignored – as every one else in the world has.
That didn’t come out very well the numbers are in order:
gas
Radiative efficiency (ppm)
Life
AGWP
GWP
Lot’s of learning Jim (you’re still way ahead of me) and believe me, I share your frustration with “IPCC science”.
I think your numbers still need tweaking though. CO2 at 0.01548 W/m²/ppmv should remain unchanged if you convert the the others to that basis That will throw everything out of whack again and I hope I’m not putting you crook (if you’ll pardon the vernacular).
Also I hope you don’t “revert to developing one of my earlier arguments” because I don’t think we are anywhere near resolving these RE, GWP and AGWP calcs or being able to apply them accurately and knowing the origins of the terms and parameters (the “first principles”). May I suggest that we have to go backward in order to move forward eventually.That way we will uncover flaws in the IPCC rationale, method and science if there are any (and I’m sure there are – specific heat to start with).
You’ve been the leader so far and there’s still aways to go so I hope you don’t move sideways from that position. Once we have developed a modicum of expertise we can always look at N20 but with the benefit of the knowledge and ability that we are acquiring in our present quest.
I’m tied up in a kiwifruit packhouse tomorrow at least but the main season is winding down and I will soon have time for this but with sporadic intrusions of work.
I’ve also had a response to an approach to the NZ Office of Climate Change that I will have take some time to chew on VERY carefully.
Rich
Thanks for your comments. I will try to write it our more clearly. I had it all to common units with a power adjustment but will put it back to common usage and try to set it our more clearly. I might have to cut and paste a chart. I will get back to it shortly. Good work on the radiative efficiencies.
Jim
The Astrophysicists compute “radiative efficiency” simply as per the definition I gave up-thread, that was:-
Radiation efficiency: At a given frequency, the ratio of the power radiated to the total power supplied to the radiator. [energy in : energy out]
I found myself reading (with an element of disbelief that I was) “DIRECT CALCULATION OF THE RADIATIVE EFFICIENCY OF AN ACCRETION DISK AROUND A BLACK HOLE”
http://arxiv.org/PS_cache/arxiv/pdf/0808/0808.3140v1.pdf
But I STILL can’t find a simple calculation of GHG radiative efficiency. I found these papers (using Bing because I’d run out of avenues using Google):-
“Identifying the Molecular Origin of Global Warming”
Partha P. Bera,‡,| Joseph S. Francisco,§ and Timothy J. Lee*,‡,!
NASA Ames Research Center, Space Science and Astrobiology DiVision, Moffett Field, California 94035, and
Department of Chemistry and Department of Earth and Atmospheric Sciences, Purdue UniVersity, West Lafayette, Indiana 47907-1393
2009
http://www.r744.com/files/news/Identifying%20the%20Molecular%20Origin%20of%20Global%20Warming%5B1%5D.pdf
And a follow-up paper:-
Design strategies to minimize the radiative efficiency of global warming molecules
Partha P. Bera,a Joseph S. Francisco,b1 and Timothy J. Leea1
2010
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889070/
But I’m no wiser to the IPCC GHG RE calculation – back to Chapter 6 and Myhre.
In the Black Hole paper, the efficiency ratio is expressed as a unitless ratio but “per unit rest-mass” e.g.
“…….we find that the efficiency with which this simulation generated light reaching infinity, averaged from 7000–15000M, was 0.151. This number is 6% greater than the NT figure, which is 0.143 after allowing for photon capture”
Two unitless radiative efficiency ratios, 0.151 and 0.143, elsewhere the ratios are stated as “per unit rest-mass”
I can’t remember ever seeing an efficiency ratio with units (I can only remember unitless factors). So how does the IPCC GHG RE ratio gain units of Wm−2 ?
I guess it’s not a ratio as per astrophysics (or mechanical and any other application of efficiency) – just an IPCC invention.
Eureka! I have it……well some of it anyway.
Inserting “radiative efficiency in the Chapter 6 search box yields this gem from the first find pg 385 6.12.1 Introduction, under the GWP expression (6.2):-
This says to me that:
a) It is NOT the conventional radiative efficiency ratio used in Astrophysics.
b) It IS just an incremental power supply (or output – not 100% sure which) of an additional kg of gas in the atm. This is only half of the astrophysics radiative efficiency (ratio of the power radiated to the total power supplied to the radiator) .
c) If it’s power radiated (re-emitted), it’s the numerator if an efficiency factor is calculated. If it’s power supplied (absorbed), it’s the denominator.
d) Given that a GHG “traps” radiation, I’m guessing that it’s the supplied power.
e) Given d), it is a measure of the amount of radiation that a kg of atm GHG gas absorbs which is in turn an aggregation of the total area of the spectroscopic absorption profile. Somewhere there are details of the determination of these values.
f) It says nothing of the manifestation and retention of heat (the warming – what it’s really all about). That is limited by the specific heat capacity of the gas which for CO2 at 275 K (2 ºC) is 0.819 kJ/kgK and for CH4 is 2.191 but the higher in the atm that the kg of gas is located the lower the temperature will be and the lower the specific heat capacity will be e.g. mid-troposphere temperature is currently in the order of -47 ºC (226 K) . At 225 K the SHC for CO2 is 0.763 and 2.121 for CH4. This is Joules – not Watts.
So now all I have to do is find the science where the RE values were determined as per e), I suspect I will have to go back to the IPCC FAR.
Ye gads, this is painful.
Rather than go back to FAR, SAR, I’ll settle for the RE revisions detailed in Myhre et al 1998 that are determined by.LBL model, NBM model and BBM model. There’s enough there I think to get a good handle on how it was done and there’s probably some references at the bottom of the paper worth looking at.
Interesting that the original RE’s were overestimated by 15%.
Then it’s on to the GWP calculation with Jim.
The operative word there is “potential” i.e they are quoting all their data at maximum value but they ignore the limit of heat retention ability that a substance has and they don’t offer data that represents the dynamic nature of heat transfer (that’s why it’s called thermodynamics) over the altitude / temperature / pressure range – their data is static but where is their incremental kg of gas situated? .
From Lindzen and Choi (2011)
I suspect that GWP does the same. A very dodgy construct in my mind.
Back on line
The mathematics behind GWP’s, even without going into RE’s, is pretty rugged. In an attempt to deal with that I have tried to develop a test for reasonableness or as it turns out unreasonableness in the calculation of GWP’s.
refer http://tinyurl.com/5usypfp
I have looked at the absolute warming caused by an injection of CH4 over 100 years as calculated by IPCC. That warming was 43% of the warming that would have occurred (using the same IPCC assumptions) if that methane remained in the atmosphere over the 100 years time horizon and there were no secondary feedback effects. We know however that the half life of CH4 is about 9 years and secondary feedbacks (according to 6.6.2) add 73% to the direct impact. I would have expected from this that the warming over 100 years would be 15% (maybe19% if the CO2 generated by the oxidisation of CH4 is included) not 43% of the no loss scenario.
This indicates that the AGWP for CH4 and consequently the GWP is well overstated. It is noted (6.6) that the confidence margins in secondary effects is much wider that for direct ones. I think we know which side of the confidence intervals IPCC swings.
Please let me know if there holes in this analysis.
Jim
Jim, much as I would like to thrash this out fully i just can’t get to it due to another action I am pursuing in regard to key climate metrics for this century (projected vs observed) that I’ve challenged the MfE CC Office to make public. I think I can be more effective by concentrating on that.
This exercise has been an eye opener and we can pick it up again with the focus on CO2 now that the govt has announced the agricultural emissions will not be included in the ETS as planned.
Nice table but I can’t offer any critique.
This issue is also high on my to-do list. It might yet become an election issue in NZ.
Noted Richard, you are doing a great job – I thought though that agriculture was only delayed not excluded. The web sites certainly don’t say they are canned.
Continuing with the thread.
We are used to the GWP number of 23 for CH4 because that is the number that will used to tax us. However because CH4 only hangs round for 8 years the more interesting number is the 20 year time horizon number. Impacts beyond 20 years should be pretty negligible versus CO2 which has a much longer half.
The GWP for the 20 year time horizon has CH4 as 62 times as bad as CO2.
I have been researching why the GWPs of CH4 looks so anomalous. It turns out that the indirect impacts are supposedly about 3 times the direct impacts. You can get a feel of this from the reasonable test above.
This forced me into looking at the atmospheric chemistry behind this so called indirect impact. It turns out to revolve around the OH radical. This is the thing that oxidises methane and some other gases (not CO2). By greedily using up these radicals the ability of the atmosphere to cleans itself of other dirty gases (including CH4 itself) is diminished. I found out that only 8% of the OH radicals were used by CH4 before I came across this:
http://www.worldclimatereport.com/index.php/2011/01/11/oh-oh-redux-ii/
The paper referred to was first published in Science Magazine in January this year and seems to have gone unnoticed. It seems to me to be fundamental to the calculation of GWP’s. It turns out that the calculations produced 10 years ago of the level of destruction of OH radicals from emissions of CH4 have been grossly overstated. This then impacts the calculation of indirect impacts of CH4 and the GWP numbers.
Could be ask NIWA to redo their numbers?
Our friend Neil Henderson, at Climate Realists, tells me Key has been saying for some time that farming will be brought into the ETS in 2015, already pushed back from 2013. It was delayed months ago, not last week, and there’s certainly been no decision to exclude farming.
On the GWP of methane, I’m a few hours away from reposting Barry Brill’s Quadrant Online article from last month that gives further reason to ignore CH4 as a GHG. He in turn cites Dr Wilson Flood’s paper “The Methane Misconceptions” published in Energy and Environment (behind a paywall) in April. Let me know what you think of it. What you’ve discovered about CH4 and the hydroxide ion is fascinating.
We could certainly ask NIWA to reconstruct their GWPs; they’ve given in to us once already, but I think I know our chances of success…
Sorry, I shouldn’t leave that on a flippant note. It’s absolutely imperative that we continue to press NIWA and other scientific authorities to revisit decisions that now appear mistaken or unjustified.
I like Barry’s article. I had not picked up on the atomic weight multiplier. Normally when weights in the carbon cycle are discussed it is done in terms of CPg’s ie Petagrammes of the C component. I had not realised they had slipped that one through.
So we now have an artificial weight multiplier times an artificial multiplier of the indirect effects due to incorrect assessment of the OH radicals robustness.
Richard, before you republish you might get Barry to look at his comments about CH4 being washed out by rain. It is to all effects insoluble in water. That comment does not impact the rest of the piece.
Yes, the mistakes are piling up.
I’ll find out about the rain thing; thanks.
I’ve found the rainwater comment is in Flood’s paper. In describing GWP, he says:
I won’t spend any more time on it just now; if it’s good enough for the Aussie scientists, it’s good enough for me.
Just realised it’s ambiguous — the CSIRO web page is talking about all GHGs, only some of which are soluble in water. I’ll mention it to Barry. Thanks again.
Not wishing to be pedantic but the above refers to various gases. Methane is not one that is washed out. The BB article is specific to methane. But not an issue – the article is important.
Yes, I was slow to notice that. You’re not so much pedantic as accurate!
Another issue with regard to methane, and agricultural emissions in general, is this supposed unusual profile that NZ has because of its relative weighting of industrial CO2 to agricultural emissions.
I am wondering why Norway doesn’t apply this criteria also. Although its dairy industry is relatively small compared with NZ, Norway has 99% renewable energy (electricity generation – mostly hydro) compared with around 75% for NZ.
The cynical may say that the presence of Gro Harlem Brundtland, three times PM for Norway,and now Special Envoy on Climate Change for the United Nations Secretary-General Ban Ki-moon, may have some sway in the matter.
I can’t help feeling that the NZ dairy industry was sacrificed as part of a deal to keep NZ in the limelight at UN climate change talks.
These “public servants” are making these moves to keep their careers going, and represent neither the people of this country, nor the best interests of the environment.
We need to keep treating them with the contempt that they deserve.
I could not agree more Andy
In fact there is a good basis for an Official Information request. On how many occassions and at what cost have NZ officials attended climate change and ETS related conferences and meetings offshore?
The problem is that if they see the light and become doubters they are off the gravy train.
Jim
I think the reason CH4 is more radiative than CO2 is because there’s very little of it in the atmosphere. As you know, radiative forcing reduces logarithmically with volume.
The suggestion that up to 80% of anthropogenic CO2 fails to enter the atmosphere is at odds with a major paper produced at Bristol U last year. I think the ratio is usually close to 50%.
My reading of the FAR on “secondary effects” of CH4 was that the subject has barely been studied, and the figures were mainly one author’s guesswork. CH4 was visited with the GWP of O3 that MIGHT have been oxidised if only CH4 hadn’t eaten the scarce hydroxyls.
If hydroxyls are not scarce, as seems to be the confident finding of the current paper you cite, then the 03-related indirect effects don’t exist, and the GWP comes come down by about two-thirds.
I think it would be extremely useful if you could write this up as a semi-scientific paper, explaining all the steps and arriving at a conclusion as to the probable GWP of CH4 on the basis of current knowledge. That paper could then be used as the basis of questions to NIWA, MAF, etc.
According to Wikipedia:
For example, the 20 year GWP of methane is 56, which means if the same weights of methane and carbon dioxide were introduced into the atmosphere, that methane will trap 56 times more heat than the carbon dioxide over the next 20 years.
So they compare weight for weight.
Yet later, they say:
The GWP depends on the following factors:
1. the absorption of infrared radiation by a given species
2 the spectral location of its absorbing wavelengths
3 the atmospheric lifetime of the species
http://en.wikipedia.org/wiki/Global-warming_potential
From what I can see, all three points here show metrics that are less than the equivalent for CO2. I need to work through the spreadsheet example that I linked somewhere above to see where the calculation is getting the high number. The equation is quite clear from what I can see.
I’ve found the spreadsheet from Matthew Elrod that calculates GWP here
http://www.chem.hope.edu/~elrod/mathcad/gwp.xls
The original paper is here
http://alpha.chem.umb.edu/chemistry/ch361/spring2006/greenhouse%20warming%20potential.pdf
I’ll try to look into this tonight
Andy, I have not read the article yet, but note the spread sheet is for CF3CH2F. Is there one available for CH4.
JIm, I haven’t found one, but a cursory read of the article suggests that you can apply the same spreadsheet to methane, by plugging in the radiative values in the appropriate column,
Andy, yes I can see how it can be used in part although dont have all the imputs required to do a full analysis. I can see where the life time feeds in. Table one of the article has GWP 20 years of 37 for CH4 but a lifetime of 15 years. Bring the lifetime back to 7.5 years will bring the number down to 23 the number we have from other sources of the direct GWP for CH4 over 20 years (cf 62 IPCC total number). The analysis they are using does not include any indirect impacts.
Can’t quite get my head around whether the weight versus moles is an issue or not.
Hi Andy,
I just spent some time on the spreadsheet. Once I had unbundled it a bit I have found it quite useful. The sensitivity to lifetime assumptions becomes clear. I have ignored the narrow band forcing calc because we don’t have the equivalent for either CO2 or CH4, however substituting RF’s for their forcing numbers (it is only the ratio after all that flows through) you get a working model that seems consistent.
It has focused me to find out what lifetime means to IPCC. Half life, lifetime and effective life are all used pretty randomly in the literature. The model gives the relationship between lifetime and effective life. But I am not sure whether lifetime always means half life
JIm,
Have you managed to recreate the 21 times GWP figure from the spreadsheet? If so, I’d be really interested to see the results. I can give you my email address if you want,
Cheers
Andy
Good point. I have been playing with 20 year time horizon numbers and the they looked consistent. I will have a bit more of a play and email them via richard
Methane Mythology
Written by Joel Kauffman, guest post | August 15 2011
Editor’s note: Please feel free to link to, or copy and paste. Joel Kauffman gives his permission for any type of cross-posting with proper attribution.
http://climatechangedispatch.com/temperate-facts/co2-and-gw-primers/methane-mythology
The greenhouse gas theory says that emission of infrared radiation from the Earth is absorbed by certain gases in the atmosphere, which heats them up. For this to happen, the wavelengths emitted by the Earth, a broad swath peaking at 20 microns, can only be absorbed by a gas with a broad swath peaking at 20 µ microns (from 3-30 µ).Here the champion absorber is water vapor. A minor absorption peak of carbon dioxide at 13 µ absorbs, but its major peak at 4 µ does not. The major peak of methane (Link 12) at 3 µ (3000 cm-1) is too far away from Earth’s emission to matter, but its smaller absorption at 8 µ (1300 cm –1) might absorb a little.
How much might this matter? In Figure 7 of the review:“Climate Change Reexamined” (Link 13) you can see an infrared spectrum of humid air.
Look near 3 µ or 3000 cm-1 for the major infrared peak of methane. Do you see any of it?
There is none.
This means that at its level of only 1.8 ppm in air, methane is not a significant absorber.
This means it cannot be an active “greenhouse gas”.
This is good science.
Interesting article, and full of links, thanks
Owen McShane picks up the story here
At present rates the atmospheric methane concentration would need 360 years to double. Methane levels are not rising rapidly and present no conceivable threat of any kind.
The amount of methane in the atmosphere is increasing by a mere 14 million tonnes (0.014 gigatonnes) per annum . Only a small fraction of this will be due to farm animals and one is led to the conclusion that research into methane emissions from this latter source is wasteful of resources since the amount is insignificant when compared with the total mass of the atmosphere which is approximately 4.5 million gigatonnes.
http://breakingviewsnz.blogspot.com/2011/08/owen-mcshane-what-is-it-with-bovine.html
Aydin et al 2011 linked here (haven’t read it myself):-
http://www.c3headlines.com/2011/08/scientists-confirm-that-settled-science-prediction-about-a-greenhouse-gas-proves-to-be-robustly-wron.html
“Recent data from NSF-funded research in both Greenland and Antarctica demonstrate that fossil-fuel related emissions of both methane and ethane, two of the most abundant hydrocarbons in the atmosphere, declined at the end of the twentieth century…causes of the decline in methane emission rates to the atmosphere have been puzzling scientists for some time. This new study shows that a change in human activities may have played a key role in the recent leveling off of methane, which, being a potent greenhouse gas contributes to global temperatures…”
And send money for more research.
BTW, the NZCSC NZT7 review gets space at C3 Headlines and Tom Nelson
Global Warming Doesn’t Do New Zealand – No Material Warming Over Last 100 Years
http://www.c3headlines.com/2011/08/global-warming-doesnt-do-new-zealand-no-material-warming-over-last-100-years.html
Fascinating article.
I just checked the model. Radiative Efficiency and GWP have a simple linear relationship.
If RE is 5 times over stated so is GWP. This might be the simplest line of attack.
There’s quite an interesting comment thread on Robin Grieve’s
farmcarbon.co.nz website
http://www.farmcarbon.co.nz/index.php/2009/02/the-methane-cycle/
In particular, the rather long comment from Michael Russel (comment number 1) has some interesting observations on the methane cycle.
The Global Warming Permafrost Tipping Point: Scientists Discover Permafrost Thawing Not Happening
The IPCC scientists and global warming alarmists predicted that increasing CO2 emissions would lead to a catastrophic permafrost tipping point, unleashing gigatons of methane gas – they were wrong…….
>>>>>>>
http://www.c3headlines.com/2012/02/the-global-warming-permafrost-tipping-point.html