A Note: Global Warming Threads

[adoucette]

And what KNOWN mechanism could cause the release of 50 BILLION TONS of Methane in a year?

I ask this because Methane is quite valuable nowadays and I'd think if there were sufficent stores of Methane in that quantitity that could be released that easily then we would be exploiting them commercially.

We aren't.

In fact I know they tried once (in Russia) and gave it up because there just wasn't that much Methane that could be recovered.

But 50 Gigatons of Natural Gas would be worth over 12 TRILLION dollars.

Doesn't add up.

Arthur

 

[billvon]

I ask this because Methane is quite valuable nowadays and I'd think if there were sufficent stores of Methane in that quantitity that could be released that easily then we would be exploiting them commercially.

?? Lots of oil wells flare off the extra methane if they do not have a way to get it to market.

 

[adoucette]

?? Lots of oil wells flare off the extra methane if they do not have a way to get it to market.

True, but then all that means is it just isn't than much methane.

For instance 1 ton of methane = ~50,000 cubic ft = ~$250 worth

So, one could easily flare off say 4 tons of methane a day at some distant well, or ~$1,000 worth, and that would still only be $365,000 worth of Gas per year and that might not pay for the capture/compression/transportation costs, and yet burning 200,000 cu ft of methane a day is quite the flaring operation.

But 50 gigatons of Natural Gas is over 12 Trillion dollars.
Nobody flares off millions of dollars of natural gas, let alone billions, let alone trillions.

Or maybe to put 50 GT of Natural Gas in perspective, that's well over 20 times as much as we use each year on a global basis.

Arthur

 

[Keln]

That over-simplified assessment was the reason for rejecting CO2 fluctuation as a major driver of ice age cycles, or cause of warming phases, back before WWII.

In the 1950s, a researcher with improved skills revisited the issue, and noticed that the decreasing absolute density in the thinning upper atmosphere was not accounted for in that description. A short history: .


Since then, the fact that -all else being equal - increasing the concentration of CO2 in the atmosphere will cause significant amounts of heat energy to be trapped, above what was trapped before, has been well understood.

And the various subsidiary effects (subsidiary however large), including the maintenance of an increase atmospheric capacity for water vapor, add their contributions.

I would like to see an explanation of the physics behind this. As far as I know, CO2 only absorbs in the 2.7, 4.3, and 15 uM range of IR (iirc). How does the placement of the CO2 (whether thin upper layer or lower layers) in the Earth's atmosphere change the absorption spectra of CO2?

And nothing is "trapped" by CO2. A small amount of IR within the aforementioned wavelengths that passes through the atmosphere, hits the Earth's surface, and of that, what isn't absorbed by the ground is reflected back up into the atmosphere. CO2, and other gasses, absorb some of it, and the rest goes back out into space. Eventually, that IR is remitted by the gasses that absorbed it, helping to warm the Earth. There are no "blankets". There is no "greenhouse".

So, it is only a question of physics. And in mathematical terms, if you have a relatively constant input of IR within specific wavelengths produced by the Sun and reflected from the Earth's surface, a constant absorption spectrum by CO2, and the only variable being CO2 concentration in the atmosphere, then you can calculate the maximum amount of CO2 that would absorb all available IR being reflected from the surface into the atmosphere. Beyond that level, your graph goes flat.

Without some unknown physics at work here, this is pretty clear-cut math. Now I am not denying that there very well could be some physics at work that we don't understand. If there is a real correlation between CO2 and absorption of IR beyond its known limits, then that is what should be studied.

But I never see any kind of attempt to look at that by those who are self-convinced that CO2 is the enemy. I very much suspect there are a lot of people who are being quite intellectually dishonest in these discussions. I'm a pretty objective person, and I only really care about the science behind it, not who or what is to blame...only the why. But I find myself always falling on the side of those who argue that AGW is hogwash.

So why is that?

 

[Keln]

Keln.
As demonstrated by the graph I posted, the CO2 absorption spectrum is far from being saturated, it still lies in the region of linear response, and will remain so until CO2 concentrations reach at least 3%

Could you provide the math and data with the graph? I've always considered graphs to be meaningless without the corresponding data.

 

[iceaura]

I would like to see an explanation of the physics behind this

The link I posted above features not only short summaries of the findings and arguments, but references to the original papers and dates of research, the names of the researchers playing key roles, and everything else you need, in chronological order.

I'm surprised you would be dealing in accusations of intellectual dishonesty, as you go on to do, without having checked out the major research efforts of the past half century.

And in mathematical terms, if you have a relatively constant input of IR within specific wavelengths produced by the Sun and reflected from the Earth's surface, a constant absorption spectrum by CO2, and the only variable being CO2 concentration in the atmosphere, then you can calculate the maximum amount of CO2 that would absorb all available IR being reflected from the surface into the atmosphere.

The absolute density of CO2 available to trap otherwise radiating infrared varies with altitude - assuming well-mixed air, it's a constant fraction of a decreasing whole. Some loss of infrared radiation to space takes place through the upper atmosphere, which is thin. The lower "layers" of CO2, considered as individual slices or sections of atmosphere in preparation for taking limits etc, re-emit absorbed infrared radiation in all directions, half generally downwards ("trapped") and half generally upwards. Once you have noticed that, you will realize that the image of an impervious layer of CO2 already trapping all the infrared that it can, close to the ground, needs more careful explication.

The more detailed and precise wavelength analysis Trippy refers to is another matter, and a further problem with the by now long-discarded presumption that adding more CO2 would simply be redundant in its heat trapping effects.

 

[Keln]

The link I posted above features not only short summaries of the findings and arguments, but references to the original papers and dates of research, the names of the researchers playing key roles, and everything else you need, in chronological order.

I'm surprised you would be dealing in accusations of intellectual dishonesty, as you go on to do, without having checked out the major research efforts of the past half century.

Yes, I looked at your link, and didn't see much that I haven't seen before. I saw nothing that explains how CO2 starts absorbing wavelengths of IR that it normally doesn't, just graphs. Suddenly, the more CO2 available causes CO2 to assume completely different properties on a molecular level? How convenient that explanation is, with no data to back it up. And no, graphs are not data. Graphs are formed from data. Graphs without the hard data are pretty drawings that mean absolutely nothing. Correlation is not explanation. Why is the explanation, and I have yet to see it. I want the why. I don't want to "win an argument"...just understand how a process happens that is claimed to happen. And if that claim has no explanation, then I will ignore it.

One must wonder why Mars, with its 95+% CO2 atmosphere isn't a "greenhouse" abound with melted polar icecaps.

 

[arfa brane]

I'm inclined to agree with Arthur, actually.

That's ok. I'm kind of wondering why you seem to be agreeing with me as well:

About the only thing that I can offer to this at this point is that several authors have expressed concerns that the amount of methane reaching the atmosphere from the arctic (and tundra) may be up to five times larger than what people have been modelling it as.

My point was simply that recent literature suggests that more Methane may be being released faster from the Tundra and arctic shelf than had been anticipated.

I thought that was more or less what I was saying. Whereas adoucette appeared to be saying methane release from the Arctic doesn't show up on satellite images, there is no significant annual release--why did the researchers use sonar to detect large bubbles of methane? Why didn't they use satellite data?

 

[Billy T]

I may be able to say a few words to give some non-mathematical understanding or “feeling” about IR in molecular absorption band trying to escape from Earth surface, but problem is quite complex and only a math model gives the full story. Two basic physical laws are very important to understand: (1) no substance in thermal equilibrium can radiate more than a black body can at the same temperature and wave length. (2) A strong absorber at some specified wave length also approximates the radiation of a black body at that wave length and same temperature. A third physical fact, closely related to the laws of adiabatic cooling as a large volume of gas expands, is that generally speaking the air temperature decrease with altitude. (The decrease is often called the adiabatic lapse rate.) A fourth fact is that the atmospheric concentrations of molecules decreases with altitude and the fraction that is of heavier molecules does so more rapidly than lighter molecules

A very useful concept, is the “Optical Depth” OD, which is usually defined as the thickness required to attenuate a beam by a factor of (1/e). In gases the OD is strongly dependent upon wavelengths, if molecules have IR absorption bands close to the wavelength of concern. It also decreases if there are aerosols (solids or liquids) in the beam, but I will assume for this discussion that there are none. (no dust particles, fogs or clouds, etc.). I.e. all scattering of energy from the beam will be neglected, but absorption with re-radiation of the absorbed energy is not considered to be “scattering” and is quite important as the re-radiation has the same chance of reversing the energy flow as continuing it in the beam’s original direction. All directions of re-radiated energy / photons are equal probable. This, BTW contrasts sharply with true scattering (Compton scattering) in which the initial photon did not disappear by being absorbed. True scattering is strongly biased to be “forward scattering” with little “recoil energy” transferred to the scatter.

To aid understanding, I think it is best to start by postulating a radiation beam incident upon the high altitude from space and a wavelength for which the atmosphere is several ODs thick – For example In an IR absorption band of CO2. Even at the lower edge of this highest OD, the temperature will be below freezing. By definition, only (1/e) of the incident beam will reach the bottom of the highest OD. Most of it will be absorbed in CO2 molecules and half will be heading back towards space. However, there really is no IR beam from space. The point of postulating it, and now that it is vanishingly weak was to show that this upper OD was a "good absorber" and hence a "good radiator" at that IR wavelength, but the radiation by it cannot exceed that of a black body at that same cold temperature. I.e. the upper OD is not radiating much at that IR wavelength to space.

Since the postulated IR beam does not exist, most of the molecules absorbing IR in this top most OD are absorbing radiation coming from the OD, immediately below it, and it too is cold and near thermal equilibrium. Thus there is very little IR passing into the top most OD as the max radiation is limited by Planck’s T^4 limit and T is low. Also, radiation from the bottom of the next to highest OD only has a (1/e)^2 chance of making it into space without absorption, which will have a 50/50 change of re –radiating back towards Earth, if we neglect the fact that sometimes a "super elastic" collision (particles leave with more KE than the total they had before the collision) will occur before absorbed IR can be re-radiated again. This is increasing likely at lower altitudes and is part of process that establishes the temperature's altitude profile.

Likewise from the bottom of the third highest OD, the chance of direct escape is only (1/3)^3 but there the temperature is higher and the T^4 law may compensate by making many more IR photons “outbound” One must do the math, with the actual temperature and CO2 density structure profile to know from what OD the bulk of the IR radiation escaping Earth actually comes from. I am only trying to give you a feel for that fact that it cannot be from high up where it is too cold and CO2 concentrations are low, nor from too close to the surface as then the (1/e)^n makes direct escape very improbably (where n it the total number of ODs surface radiation must pass thru).

Briefly let’s consider what the change would be if the CO2 concentrations were doubled at all altitudes: All of the ODs would be, at least to “first order” half their former thickness in meters so there would be twice as many, say N = 2n of them. The direct escape from the surface is now much less probable only (1/e)^N and from the highest OD escaping radiation is also slightly reduced as its center is slightly higher, and colder. Note however, each OD has essentially the same number of CO2 atoms as before. But each OD radiates less to space, the lower ones drastically less, but here are twice as many of them. The net effect of this change is that mainly the bulk of the escaping IR radiation now comes from a higher altitude, but it is not much reduced by doubling the CO2 concentration,IF the original CO2 concentrations were large enough to make the atmosphere several OS thick. When the atmosphere is only one or less OD thick, then the reduction in escaping radiation is essentially linear in the CO2 concentration - doubling it will cut the escaping radiation in half, at that IR wave length with 1 OD or less thick atmosphere. For most visible wavelengths, but not harsh UV, the atmosphere is much less than 1 OD thick.

I hope the above give some “feeling” for what is going on, but again, only the complex radiative transfer models can tell the story accurately. The true story is also made more complex as very few photons travel straight towards space – almost all that escape have made, via absorption and re-radiation, a very much longer trip with lots of “sideways” random walks. One way to think of this is that all of the ODs are on average much thinner in altitude or “more opaque” than (1/e) if of the same thickness.

 

[iceaura]

I saw nothing that explains how CO2 starts absorbing wavelengths of IR that it normally doesn't, just graphs. Suddenly, the more CO2 available causes CO2 to assume completely different properties on a molecular level? How convenient that explanation is, with no data to back it up.
- - - -
I don't want to "win an argument"...just understand how a process happens that is claimed to happen. And if that claim has no explanation, then I will ignore it.

I can lead you to the stuff, I can't make you think. But you are no longer allowed to claim you haven't been linked to the evidence and arguments - fifty years' worth, with names and publications and dates and everything you need. If you choose to not even bother to check it out, that's your prerogative.

One must wonder why Mars, with its 95+% CO2 atmosphere isn't a "greenhouse" abound with melted polar icecaps.

No surface water, partly due to ist smaller size, partly to its greater distance from the sun, and probably other factors and other reasons.

The comment is puzzling: is there some reason you think that contradicts the people who are pointing to the likely effects of doubling the CO2 in Terra's atmosphere? Why would you think that?

 

[Keln]

No surface water, partly due to ist smaller size, partly to its greater distance from the sun, and probably other factors and other reasons.

The comment is puzzling: is there some reason you think that contradicts the people who are pointing to the likely effects of doubling the CO2 in Terra's atmosphere? Why would you think that?

Well, Venus also has a mostly CO2 atmosphere...and no surface water that we know of (too hot!).

What's going on here? Are we being bilked?

And, Mars has no magnetosphere...it gets the full effect of Sol's radiation. Every wavelength, every particle...boom, on the surface.

So, why does Mars, with its obviously post-industrial, sentient life-form destroyed CO2 atmosphere have such cold weather? Sure, it's further from Sol than Earth, but come on...according to the AGW models, with that much CO2, it should be like, 1000 K on the surface. Like an Al Gore paradise or something. But it has polar ice caps...what's up with that?

I mean, because, according to your linkys, the more CO2 you have, the more of the IR spectrum CO2 can absorb. It is logarithmic! Exponential! Catastrophic! Mars should be only a little cooler than Venus.

Well, why is Venus so hot? AGW bubbas like to point to its CO2 atmosphere all of the time, resolutely ignoring the rather poignant Sulfuric Acid layer in its lower atmosphere. "Well its hot because it has so much CO2!" Well no...it is hot because it is closer to Sol, and it has a layer of gaseous sulfuric acid that leads to incredible warming.

Mars has no such layer. Earth has no such layer. Earth has, compared to other planets in the Sol system, trace amounts of CO2. So why is it inferred that CO2 is the culprit?

Let me put it like this...if AGW is real, I don't think CO2, based on what I have read from OBJECTIVE sources (IE. nobody related to or paid by the UN) is the culprit.

Far more other nefarious emissions are produced by man. Try the NOX line of gases for example. We may very well be heating the Earth to dangerous levels, but blaming CO2, based on what I have read, seems silly. We need to look at the other things we are spewing into the atmosphere. Unfortunately, this is not politically expedient, since the majority of those gases are easily scrubbed by relatively inexpensive engineering controls, and that is not really what control freaks are looking for.

 

[arfa brane]

So, why does Mars, with its obviously post-industrial, sentient life-form destroyed CO2 atmosphere have such cold weather? Sure, it's further from Sol than Earth, but come on...according to the AGW models, with that much CO2, it should be like, 1000 K on the surface.

Mars doesn't have cold weather except at the poles. The night/day temperatures also vary widely, from +100s of degrees C on the dayside, to about -100C on the nightside. The atmosphere of Mars is much thinner than Earth's. There isn't sufficient depth to the atmosphere to capture and store the amounts of solar energy the Earth's atmosphere does.

Well, why is Venus so hot? AGW bubbas like to point to its CO2 atmosphere all of the time, resolutely ignoring the rather poignant Sulfuric Acid layer in its lower atmosphere. "Well its hot because it has so much CO2!" Well no...it is hot because it is closer to Sol, and it has a layer of gaseous sulfuric acid that leads to incredible warming.

The CO2 in the Venusian atmosphere, and the proximity of the planet to the sun are the main reasons it got so hot, it has a significant amount of sulphates because of outgassing (over large geological periods), plus the gravity of Venus prevents the atmosphere from dissipating. The Martian atmosphere is thought to have been a lot denser and thicker a long time ago, but it lost most of it because it doesn't have the same mass as Venus, or the Earth, but it does receive the same kind, if not the same quantity, of radiation.

 

[Trippy]

And what KNOWN mechanism could cause the release of 50 BILLION TONS of Methane in a year?

I believe a Landslide was one of the considered mechanisms - we're not talking about a small movement here either, we're talking something comparable to the Hawiian slope collapses here, at least, as far as I recall.

By the way - you're cherry picking, because the paper also considers releases over a period of a decade. If you're interested I believe that the lead author of the first paper I linked to has published more than one paper on the matter,.

I ask this because Methane is quite valuable nowadays and I'd think if there were sufficent stores of Methane in that quantitity that could be released that easily then we would be exploiting them commercially.

You'd think so, wouldn't you, and yet you're seemingly choosing to ignore one cruicial link in the chain - dispersal.

We aren't.

In fact I know they tried once (in Russia) and gave it up because there just wasn't that much Methane that could be recovered.

But 50 Gigatons of Natural Gas would be worth over 12 TRILLION dollars.

Doesn't add up.

Arthur

Only if you only consider part of the picture.
Consider how many km[sup]2[/sup] that 50GT is spread over.
Messoyhaka Gas field - while they weren't tapping the clathrates, data suggests the clathrates may have been contributing to production. Currently supplying Norilsk.
Malik Hydrate gas field - Researchers have successfully extracted a continuous stream of Methane.
http://www.nnsl.com/northern-news-services/stories/papers/mar31_08ma.html
Another part of the picture you're ignoring - for mining the deposits to be econmically viable the energy provided by the methane has to be worth more than the energy used to extract it, and remember, we're talking about having to melt Ice here (although in Malik they did it by depressurization, which cost substantially less energy).
MH21 hope to be successfully mining Japanese Methane clathrates in the next 5 years following the work that was done in Malik.
China has invested 800 Million Yuan for the investigation of mining clathrate deposits in Qinghai province over the next 10 years.
And there have been investigations into tapping the deposits in the gulf as well.

But again, we come back to the point that because they're there, and because there's large quantities there doesn't make it economically viable to extract it.

 

[Trippy]

Could you provide the math and data with the graph? I've always considered graphs to be meaningless without the corresponding data.

Provided in subsequent posts - Arthur linked to the source paper, and I quoted extensively the text associated with the graph.

 

[Trippy]

That's ok. I'm kind of wondering why you seem to be agreeing with me as well:

I thought that was more or less what I was saying. Whereas adoucette appeared to be saying methane release from the Arctic doesn't show up on satellite images, there is no significant annual release--why did the researchers use sonar to detect large bubbles of methane? Why didn't they use satellite data?

Because you're making wrong assumptions about what I'm agreeing with him on - in this case, your lack of research.

 

[Trippy]

AIRS 2006-2009 annual mean upper troposphere(359Hpa) methane concentration(ppm). Data source:http://daac.gsfc.nasa.gov/giovanni/

 

[Keln]

Mars doesn't have cold weather except at the poles. The atmosphere of Mars is much thinner than Earth's. There isn't sufficient depth to the atmosphere to capture and store the amounts of solar energy the Earth's atmosphere does.

The CO2 in the Venusian atmosphere, and the proximity of the planet to the sun are the main reasons it got so hot, it has a significant amount of sulphates because of outgassing (over large geological periods), plus the gravity of Venus prevents the atmosphere from dissipating. The Martian atmosphere is thought to have been a lot denser and thicker a long time ago, but it lost most of it because it doesn't have the same mass as Venus, or the Earth, but it does receive the same kind, if not the same quantity, of radiation.

So you are saying the major contributor to the warming of Venus is not gaseous Sulfuric acid?

I mean...because the data...you know, that inconvenient thingy composed of numbers...says otherwise.

I mean...even though the mostly Nitrous atmosphere of Earth is warmed mostly by water vapor clouds...Venus' mostly CO2 atmosphere couldn't be mostly warmed by clouds of Sulfuric Acid. Right?

 

[adoucette]

Only if you only consider part of the picture.
Consider how many km[sup]2[/sup] that 50GT is spread over.

When you are talking about 12 Trillion Dollars worth of Methane I think you need to be a bit more specific about what the issue is, because with a Trillion dollars to work with you can dig up a LOT of seabed and still make a return equal to over 10 times your investment.

Arthur

 

[Keln]

AIRS 2006-2009 annual mean upper troposphere(359Hpa) methane concentration(ppm). Data source:http://daac.gsfc.nasa.gov/giovanni/

Well, I guess that throws the whole "cattle contributes to atmospheric methane" thing out the window, since South America, being the largest cattle exporter has a very low Methane level.

Makes me want to eat a hamburger!

 

[Trippy]

When you are talking about 12 Trillion Dollars worth of Methane I think you need to be a bit more specific about what the issue is, because with a Trillion dollars to work with you can dig up a LOT of seabed and still make a return equal to over 10 times your investment.

Arthur

Still, you're only considering part of the picture, and I've been as specific as I need to be.

Let's see. The west Siberian permafrost is 1 million square km, and 25m deep.
This means that if the 50GT is spread evenly, each cubic meter of permafrost, which weighs in at 2000kg, there is 2kg of Methane. This figure gets even lower if you also consider the east siberian permafrost, and the deposits on the continental shelf.

But as I've already said:
http://money.cnn.com/2010/03/09/news/economy/nat_gas_crystals/index.htm

Collett said in the Arctic, the cheapest place to extract this gas, costs vary. It can be just as expensive as it is now to produce conventional natural gas, to twice that amount. Going offshore gets even more expensive.