A Note: Global Warming Threads

[arfa brane]

The fact that CH4 is not increasing in the atmosphere since the 90s suggests strongly that the atmosphere is in equilibrium with CH4 and your fears are not warrented.

You posted this, and it isn't true. Are you trolling?

Then you posted this:

CH4 levels in the atmosphere are stable and have been since the 90s.

Wrong. Methane output from the Siberian tundra has increased significantly in the last 5-7 years.

If you want to find some actual evidence that Methane is INCREASING then post it.

Done, you appeared to ignore it completely, I'll assume because you have no answer.

Otherwise, CH4 continues to be LESS and LESS of a percent of the GHG forcing.

Oops, WRONG again.

You haven't backed this up with any scientific data, have you? Methane IS increasing in the atmosphere, the Arctic IS warming, the IPCC got this wrong. Therefore, their 100-year assessment IS based on faulty data.

Your assessment of the IPCC report is faulty as well--you have what's known as "misplaced optimism"; that you've now resorted to bland denial suggests you really don't understand the debate.

 

[Trippy]

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%

 

[adoucette]

You posted this, and it isn't true. Are you trolling?

Direct atmospheric measurement of atmospheric methane has been possible since the late 1970s and its concentration rose from 1.52 ppmv in 1978 by around 1 percent per year to 1990, since when there has been little sustained increase. The current atmospheric concentration is approximately 1.77 ppmv, and there is no scientific consensus on why methane has not risen much since around 1990.

Wrong. Methane output from the Siberian tundra has increased significantly in the last 5-7 years.

Maybe it has, though you've produced nothing to support that assertion in terms of actual quantity of methane in relation to the current gloabal emissions of Methane.
On the otherhand, satellite mapping shows the vast majority of methane actually comes from much lower latitudes, central Eurasia, the Middle East, India, Northern Africa, Southern US etc.

This picture, taken in July in 2004 (when melting of permafrost should be going on) clearly shows that there is no significant outgassing of Methane from the Siberian tundra

http://www.sciencephoto.com/images/download_lo_res.html?id=690600022

Done, you appeared to ignore it completely, I'll assume because you have no answer.
Oops, WRONG again.

What?

You've done nothing, while I've been quite open with my sources of actual data.

The long-term growth rate of methane has declined steadily over the past 20 years, from about 15 ppb per year in the mid-1980s to about zero over the past six years. The reason for the decline is uncertain, but possibly involves a reduction or stabilisation in methane release from the oil and gas industry, as methane is now considered a valuable resource; in the 1960s, unwanted methane was commonly either burnt (flaring) or released under high pressure (venting). A worldwide trend to minimise leaks from natural gas reticulation networks, particularly in the former Soviet Union, might also have contributed to the trend.

As well as showing a long-term decline, the methane growth rate shows significant variability, the causes of which remain elusive. The growth rate was anomalously large in 1991 and 1998. The 1991 anomaly was followed by a drop in growth rate, which has been linked to the Pinatubo eruption in 1991, either by impacting on the chemical destruction of methane in the atmosphere or by suppressing methane emissions from wetlands. The 1998 anomaly was caused by tropical biomass burning.

http://www.environment.gov.au/soe/2006/publications/commentaries/atmosphere/climate-change.html

You haven't backed this up with any scientific data, have you?

Actually I have

http://www.esrl.noaa.gov/gmd/aggi/

See the chart on percent of forcing related to CH4

From that Chart I derived these figures:

CH4 continues to be LESS and LESS of a percent of the GHG forcing.

In 1979 CH4 represented 25% of the GHG forcing
in 1989 CH4 was 22%
in 1999 Ch4 was 20%
in 2009 CH4 was 18%

Methane IS increasing in the atmosphere, the Arctic IS warming, the IPCC got this wrong. Therefore, their 100-year assessment IS based on faulty data.

Methane did go up a bit recently, which has been acknowleded, but still the level of methane in the atmosphere is at or below all of the scenarios in the latest IPCC report (closest is the B1 scenario), but most of the IPCC scenarios actually project a Methane increase of ~20ppb for the next 40 years at least. The A2 senario projects ~doubling of methane by the end of the century.

Your assessment of the IPCC report is faulty as well--you have what's known as "misplaced optimism"; that you've now resorted to bland denial suggests you really don't understand the debate.

I don't believe my assessment of the IPCC report is faulty and I can't recall you making a single link to a single source besides Wiki (notoriously unreliable for contentious issues like Global Warming), yet I've quoted heavily from the IPCC, NOAA, GISS, CISRO etc, so I'd say it's you who needs to do a little research.

Arthur

 

[arfa brane]

Here are a couple of "interesting" links;


Arctic Sea Belching Tons of Methane
Ocean permafrost an overlooked greenhouse gas source, study says

http://news.nationalgeographic.com/news/2010/03/100304-methane-global-warming-permafrost-oceans/


Science: Methane Gas Release from Arctic Permafrost is Far Larger Than Expected

The sea surface above the East Siberian Arctic Shelf is full of ice and bubbles. Sonar is the only way to detect the vast clouds of methane bubbles rising from the seafloor.

 

[Trippy]

Predicted methane emission on the East Siberian shelf

Methane emissions from different ecosystem structures of the subarctic tundra in Western Siberia during midsummer and during the thawing period

Methane emission was measured using a static chamber method at seven different ecosystem structures of the subarctic tundra on the Yamal Peninsula (West Siberian Lowlands, Russia) in August 1995 (midsummer) and June 1996 (spring thaw). The results obtained represent one of the most extensive data sets available for Siberian tundra and confirm the significance of this area as an important source of atmospheric methane. Mean midsummer emission rates (4.24–195.3 mg CH4 m−2 d−1) were higher than mean rates reported for wetlands between 65–70°N in Alaska, Sweden and Russia. The highest emission rates were measured in a lake terrestrialization mire which was always flooded, the lowest rates at a dry site in a polygonal mire. Mean emission rates during spring thaw ranged from 0.16 to 56.2 mg CH4 m−2 d−1. These rates increased at 4 out of 5 sites from 2.4–15.1 mg CH4 m−2 d−1 at the beginning of the measuring period to 24.2–156 mg CH4 m−2 d−1 at the end...

...In addition to the direct influence of temperature on methanogenesis, the indirect effect on soil thawing was apparent. Increasing thawing depth was positively correlated with methane emission...

...Methane emission exceeded the calculated methane production in spring, suggesting that accumulated methane from the previous year was also released. The results show that considerable methane emission occurs even in the spring without an active vegetation cover and without plant-mediated methane transport...

Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf

...Here, we show that more than 5000 at-sea observations of dissolved methane demonstrates that greater than 80% of ESAS bottom waters and greater than 50% of surface waters are supersaturated with methane regarding to the atmosphere. The current atmospheric venting flux, which is composed of a diffusive component and a gradual ebullition component, is on par with previous estimates of methane venting from the entire World Ocean. Leakage of methane through shallow ESAS waters needs to be considered in interactions between the biogeosphere and a warming Arctic climate...

Methane flux in grassy marshlands near Kolyma River, north-eastern Siberia

Horsetail grassland emitted the highest amount of methane, 165.5 mg CH4/m2/d, while diverse-sedge grassland emitted less methane, i.e., −1.9 mg CH4/m2/d. Methane flux positively increased with electric conductivity (EC), water depth, thaw depth, and soil humidity. Of those, EC was strongly correlated to methane emission (Spearman's rank correlation, r2=0.630). The difference in methane flux between horsetail grassland and sedge-dominated grassland suggested that the morphological characteristics of vascular plants were important on methane transport, probably because vascular plants, such as horsetail, that developed aerenchyma and intercellular gas space promoted methane transport from soil to air while mosses do not.

The large proportion of the estimated winter fluxes compared to the annual fluxes

• The large proportion of the estimated winter fluxes compared to the annual fluxes
highlights the importance of the cold season to the annual GHG budget of the tundra
and the necessity to adequately study and quantify the fluxes during these periods.
• Including CO2 flux data [8], the overall carbon balance of the tundra during the
period July 2003 - July 2004 was -17.4 g C m-2. Considering the global warming
potential of methane compared to carbon dioxide, the GHG balance of the tundra in
units of CO2-C equivalents was +32 g Cequiv m-2. Thus, although the methane
emission had only a small influence on the tundra’s capacity as a carbon sink, it
turned the tundra into an effective source of greenhouse gases.

Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming

Extrapolation of these fluxes indicates that thaw lakes in North Siberia emit 3.8 teragrams of methane per year, which increases present estimates of methane emissions from northern wetlands (< 6–40 teragrams per year; refs 1, 2, 4–6) by between 10 and 63 per cent. We find that thawing permafrost along lake margins accounts for most of the methane released from the lakes, and estimate that an expansion of thaw lakes between 1974 and 2000, which was concurrent with regional warming, increased methane emissions in our study region by 58 per cent.

Hmmm, oh and...

Yes Arthur, you're absolutely right, average atmospheric methane leveled off between 2000 and 2005, however, between 2005 and 2009 they again increased.

 

[Trippy]

Here are a couple of "interesting" links;


Arctic Sea Belching Tons of Methane
Ocean permafrost an overlooked greenhouse gas source, study says

http://news.nationalgeographic.com/news/2010/03/100304-methane-global-warming-permafrost-oceans/

I'm inclined to agree with Arthur, actually.

 

[Billy T]

post 438: I said that you said that the effect wasn't any more important than reflected moonlight.... Arthur

But I did not, and never would say: "the effect wasn't any more important than reflected moonlight!!!!! You put those silly words in my mouth. You should apologize for misquoting me, not continue to try to justify misquoting me.

I said I thought the contribution of CH4 was small enough to be neglected COMPARED TO THE ERRORS* IN OTHER FACTORS, which were included in the IPCC report so CH4’s effect was probably neglected in IPCC's report. (That guess of mine, was wrong as I soon admitted.)

I made no comparison to moon light, not that it was the same as moonlight, nor that it was less than moon light. I.e. I never said what you falsely claimed I did. - That is misquoting. Wiggle all you like, instead of saying you are sorry for misquoting me, but the truth is you did misquote me – You put silly words in my mouth. You owe me an apology.
--------------------
*I discussed one of those “other errors” in some detail here:

There are many uncertainties, even in their present models, much less what they are assuming about the future. I will just mention one:

How large is the ocean surface? It is across that air ocean interface that the CO2 released is mainly removed. It is at least twice as large as that one would infer by looking at a map of the oceans. This is because there are waves and "zillions" of small and tiny bubbles - why "white cap" waves are white.

The net rate of transfer of CO2 from the air into the ocean water depends, essentially directly, upon the the pressure of the CO2 in the gas phase, (and several other factors) but in tiny bubbles, due to their surface tension that pressure can be much more than atmospheric. Furthermore, if the bubbles are meters deep in the ocean, the gas pressure inside the larger bubble is also greater than atmospheric and in some cases the concentration of CO2 in the water (diffusing back across the interface) may be less than at the surface, so this also increases the net rate of transfer of CO2 into the water.

The IPCC is of course aware of these complications, but no one knows with accuracy how large the effective sink for CO2 the ocean is. Why some researchers with POV that global heating by CO2 is not serious can conclude that the ocean sink is large enough to absorb all the CO2 that man is releasing, but only needs times as there is a lag. etc.

I mentioned moonlight only to make obvious that some factors should be neglected. I did not compare the size of the effect of CH4 to the effect of moonlight, and certainly never said the silly words you claim I did. I.e. I never said that CH4’s effect “wasn't any more important than reflected moonlight.”
I don’t want you putting silly words in my mouth. – Apologize!

 

[Billy T]

The third section of quotes in post 445 includes:
“morphological characteristics of vascular plants were important on methane transport, probably because vascular plants, such as horsetail, that developed aerenchyma and intercellular gas space promoted methane transport from soil to air while mosses do not.” And “Horsetail grassland emitted the highest amount of methane, 165.5 mg CH4/m2/d, while diverse-sedge grassland emitted less methane, i.e., −1.9 mg CH4/m2/d.”
I.e. CH4 release rates may be accelerated by factor (165.5 /1.9) = 87 fold if more “straw like” grasses replace mosses and lichens; But it may be saying that the Horsetail grassland emit CH4, whereas the moss like areas actually absorb 1.9 mg CH4/m2/d, which would be much worse change with a vegetation change.

That, with facts below from post 424, probably explains why methane release rate doubled in first year after fire burned an area in Alaska.

… "The key is that the soil is warming. It really doesn’t matter whether that happens gradually or dramatically, through fire.” As the warming of the soil increases, it favors the shrubs because they can more easily take root and then grow substantially faster in milder conditions, eventually “shading out” and outcompeting mosses and lichens. {Billy T notes: that with shrubs as fire fuel, instead of mosses and lichens, the next fires are larger. – a positive feedback system leading to more rapid permafrost melting.}

"burned an area ~40 miles long by 10 miles wide, or > 250,000 acres."
Adrian Rocha of The Ecosystems Center in Woods Hole, Mass., found that a year after the fire, severely burned tundra released nearly twice as much carbon into the air as unburned tundra absorbed. …" ...

It will be interesting to see if a decade after the burn, when these new plants are larger with deeper roots, the CH4 release rate has climbed to any factor even approaching an 87 fold increase.

SUMMARY: In any cases there certainly now is an increasing release of CH4 in arctic regions in part due to positive feedback factors, including vegetation changes following fires that clear large areas of mosses and lichens. None of these newly understood positive feedbacks was considered in the IPCC report and it is still unclear how important they may be.

 

[adoucette]

But I did not, and never would say: "the effect wasn't any more important than reflected moonlight!!!!! You put those silly words in my mouth. You should apologize for misquoting me, not continue to try to justify misquoting me.

Billy I always included the EXACT quote I was referencing, as I'll again do here:

If CH4 is included in the IPCC studies, then I am wrong to state it is not but given the extremely low levels, now and for 40 years, there is no need to have included it as the errors on more important aspects are much larger than its total effects* - I.e. I assumed that they knew that and would not bother to include it any more than the heating by reflected moon light needs to be included. ”

You can ARGUE about what you meant by those words, but they seem pretty clear to me: that you thought that CH4 effects could be ignored FOR THE SAME REASONS that they didn't need to include reflected moonlight.

Arthur

 

[adoucette]

Yes Arthur, you're absolutely right, average atmospheric methane leveled off between 2000 and 2005, however, between 2005 and 2009 they again increased.

I mentioned in several posts that it had "gone up a bit recently".

Still, since the increase in forcing for CH4 for the entire decade, between 2000 and 2009, is just .007 w/m2, I think the term essentially flat is still accurate.

http://www.esrl.noaa.gov/gmd/aggi/

And more importantly (to these assertions about the IPCC being wrong) is that the IPCC model assumptions of CH4 are still above the actual levels AND above the annual growth rates of CH4 (see previous IPCC charts), some of them decidedly so.

Arthur

 

[Trippy]

I mentioned in several posts that it had "gone up a bit recently".

Still, since the increase in forcing for CH4 for the entire decade, between 2000 and 2009, is just .007 w/m2, I think the term essentially flat is still accurate.

http://www.esrl.noaa.gov/gmd/aggi/

Most of which has been since 2005/2007 - seemingly an important point to note.

Similarly, I reckon it's probably also important to note that this behaviour paralells the behaviour seen elsewhere in the data set - periods of comparitively large change interspersed with periods of being relatively constant. Compare, for example, the period 1992-2000 to 2000-2009. I'll grant that the increases in the '90s were still bigger than what we've seen lately, however, broadly the behaviour of these two periods is very similar.

One of the things I found interesting was several authors have commented on the unexplained variability in the data set - for example, no one cane quite fathom why the eruption of Pinatubo seems to have had quite the profound effect that it did.

And more importantly (to these assertions about the IPCC being wrong) is that the IPCC model assumptions of CH4 are still above the actual levels AND above the annual growth rates of CH4 (see previous IPCC charts), some of them decidedly so.

Arthur

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.

 

[adoucette]

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.

Except that is not how the GCM models work.

They did the Economic/Social/Population forcasts to come up with the various Scenarios and those assumptions were used to generate forecasts of the various GHG growth over the next century and THOSE values are input into the GCMs. As far as amount of actual increase, if you cherry pick the endpoint to 2006, the year that it started to grow again, to 2010, you have about 30 ppb growth, yet all the A series scenarios were using a growth of over 80 ppb for the same time frame (~20 ppb per year untill ~2040).

As far as worrying about the Tundra, it's been warming in the Arctic since the mid 70s, so we have nearly 40 years of warming already demonstrated in the global CH4 levels. The reason it isn't having much impact is it freezes up every winter and only thaws just a bit further down each year.

The methane in our atmoshere is almost entirely generated in the Northern Hemisphere, almost exclusively of terrestrial origin, mostly during the summer and far more is released in the mid latitudes than the high latitudes.

Arthur

 

[Billy T]

... you thought that CH4 effects could be ignored FOR THE SAME REASONS that they didn't need to include reflected moonlight. ...
Arthur

That is correct. I thought and said the CH4 effect was probably not as important as the errors in larger effects. Certainly that is true of moon or star light also; however, that does not say or imply the words you put in my mouth, which were:
"the effect wasn't any more important than reflected moonlight"

While I did falsely believe that the CH4 effect was less than the errors in IPCC's included effects, I certainly knew it was much more important than moonlight, at least 10,000 times larger, I would guess. In fact my guess that it probably need not be included is wrong -It is very important and is included, but not with the larger rate of release values now known.

Thus you falsely put silly word in my mouth by claiming I said CH4 was no more important than moonlight.

Since you will not say you are sorry for miss quoting me, I guess I will be forced to put some silly words in your mouth, by misquoting you.

 

[Trippy]

Except that is not how the GCM models work.

Didn't say it was.

As far as worrying about the Tundra, it's been warming in the Arctic since the mid 70s, so we have nearly 40 years of warming already demonstrated in the global CH4 levels. The reason it isn't having much impact is it freezes up every winter and only thaws just a bit further down each year.

The methane in our atmoshere is almost entirely generated in the Northern Hemisphere, almost exclusively of terrestrial origin, mostly during the summer and far more is released in the mid latitudes than the high latitudes.

Arthur

I'm not actually disputing any of this.
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.

 

[Trippy]

That is correct. I thought and said the CH4 effect was probably not as important as the errors in larger effects. Certainly that is true of moon or star light also; however, that does not say or imply the words you put in my mouth, which were:
"the effect wasn't any more important than reflected moonlight"

While I did falsely believe that the CH4 effect was less than the errors in IPCC's included effects, I certainly knew it was much more important than moonlight, at least 10,000 times larger, I would guess.

Thus you falsely put silly word in my mouth by claiming I said CH4 was no more important than moonlight.

Since you will not say you are sorry for miss quoting me, I guess I will be forced to put some silly words in your mouth, by misquoting you.

I'm sorry Billy, I'm going to have to agree with Arthur on this one as well.

Irrespective of whether you meant it that way or not, it does kind of come accross that way.

 

[adoucette]

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.

That may be possible, but you have to put it in perspective that they haven't been releasing much to begin with.

Looking at that animated gif, that the HOT spots for Methane is an area, in the summer that runs from China over to North Africa and upwards into much of Southern Europe, while the oceans are a sink and there is a lot less activity as you progress upwards towards the higher latitudes.

Arthur

 

[Trippy]

That may be possible, but you have to put it in perspective that they haven't been releasing much to begin with.

Looking at that animated gif, that the HOT spots for Methane is an area, in the summer that runs from China over to North Africa and upwards into much of Southern Europe, while the oceans are a sink and there is a lot less activity as you progress upwards towards the higher latitudes.

Arthur

Again, I'm not actually disputing any of this, and the perspective is pretty much self evident.

The interest in the Tundra is the (estimated) 50GT store of Methane locked in the permafrost, which evidence suggests has in the past been released on time scales potentially short as one year.

 

[Trippy]

Oh, and there are some rather interesting frames in that animation, but I'm not sure if I have the software installed to inspect or extract them.

 

[adoucette]

The interest in the Tundra is the (estimated) 50GT store of Methane locked in the permafrost, which evidence suggests has in the past been released on time scales potentially short as one year.

Released in 1 year.

What evidence would that be?

 

[Trippy]

Released in 1 year.

What evidence would that be?

I don't have the information at my fingers tips just now, and about 5 minutes before I have to go to work, but one of the papers I linked to (the first I think) examines various release scenarios (ramging from 1year to 10 years), and the clathrate gun hypothesis considered timescales as short as several decades (And yes, I'm aware that several aspects of the Clathrate Gun Hypothesis are disputed - including its role in the end of the last ice age).

Actually I mis-spoke. The store is 1400GT with 50GT 'poised for release at any time'.
But IIRC this is through a variety of mechanisms.