Carbon Dioxide: Our Salvation from a Future Ice Age?

The greenhouse effect is real and has a temperature control mechanism, based on water availability in the soil.

[Oh great, another wacko with his own pet theory. Try http://en.wikipedia.org/wiki/Global_warming -W]

Our atmosphere is opaque to infrared rays. We can prove this by measuring the attenuation directly into the atmosphere.
The infrared atmospheric's absoção is a differential phenomenon.
The attempt to reduce CO2 emissions is totally useless for controlling the temperature of the earth. Only affect the economic balance of the signatory countries of the kyoto protocol

It is not so clear that we would have avoided entering a glacial (ie, an ice age in popular teminology) in the near term without anthropogenic emissions of CO2. It is clear, of course, that at pre-industrial levels, we would not enter a glacial; but without anthropogenic emissions from pasturing, the farming of rice, and land clearance, pre-industrial CO2 levels would have been 240-260 ppmv. At the lower end of that range, it is possible that a new glacial would initiate.

Any comments?

[This is the Ruddiman-type stuff? But I'm not at all sure that is a majority view -W]

"If Franzén and his team are right, the big chill is now under way, and is only just being held off by increasing human carbon emissions - perhaps explaining why temperatures have been merely flat for the last 15 years or so, rather than descending."

...

"Naturally this theory runs counter to the global warming scenario as presented by many other scientists and most of the media"

http://www.theregister.co.uk/2012/11/09/peat_ice_age_coming_only_co2_ca…

*barf*

1) When an argument is misframed from the start, it is hard to fix, although David Archer's "The Long Thaw" is a good place to start. This one has the general problem that the terms "ice age" "glacial" and "inter-glacial" are really not very well defined, and the former two are often used interchangeably.

WIkipedia says

'Within the ice ages (or at least within the current one), more temperate and more severe periods occur. The colder periods are called glacial periods, the warmer periods interglacials, such as the Eemian Stage.'

Suppose we had perfect records that gave us ice extent and global temperature. I would suspect that all would agree that the dates of a) and b) occurred during a glacial period, and dates c) and d) during an inter-glacial:
a) Minimum global temperature
b) Maximum global ice coverage
c) Maximum global average temperature
d) Minimum global ice coverage
(And a) and b) need not be the same, nor c) and d)).
although those still leave periods of calculation vague.

But *when* do glacials and interglacials transition?
Is this based on temperature, or ice coverage? Does the asymmetry (faster going up in temperature) matter?
Do we need another state in between?

In practice, temperatures rise with jiggles from cold to hot, then take much longer to return to cold, and to some extent the terms glacial and interglacial are fuzzy.

2) Whatever "our" interglacial (The Holocene) is, I think research accumulating over the last 10 years shows:

a) The Holocene doesn't resemble past interglacials, when properly aligned. The CO2/CH4 trends are way off.

b) Humans did it, first starting with deforestration (+CO2), agriculture, rice+livestock (CH4) thousands of years ago.

See special issue of The Holocene, specifically the Ruddiman, Kutzbach, Vavrus (2011)
The graphs on p866-867 show caloric summer insolation departures at 65degN for current and previous interglaciations and then the data for CO2 and CH4 changes with same alignment. The Holocene is different.

Fig 6 on p.871 compares the Holocene with the average of previous 6 deglaciations. From that chart, Holocene without humans would have CO2 ~250ppm, with SD ~20. We were right on the average CO2 curve into ~6,000BP, then increasingly went high.

p,877:

'The best-justified alignment of stages 11 and 1 indicates that the current interglaciation should have ended ~2000 years ago (or could end in the near future). In summary, the land-use, d13CO2 and stage 11 arguments that supposedly falsified the early anthropogenic hypothesis have all now been countered by new evidence that supports a strong early role by humans.'

Put another way, human-induced CH4 (CO2) changes started departing from the "natural" curves ~4,000 (~6,000) years ago, and both were 1 SD *above* the average by ~1,000 (~2,000) years ago, which might have something to do with the MWP discussions elsewhere in this blog.
I.e., human increases in CO2/CH4 canceled the normal slow downward temperature drift from lower 65degN insolation.

c) The 1600AD CO2 drop into the LIA seems increasingly likely to have been, in part the 50Mperson die-off in Americas and the resulting massive reforestration. See Nevle, Bird, Dull, Ruddiman(2011).
Changes in solar insolation and increase in volcanoes likely helped, but this CO2 drop was *before* The Maunder Minimum (1645=1715).

d) We have no danger of another ice age. To retain the comfortable Holocene temperature range, I'd guess that starting in 1850, a slow increase from 280ppm to (350ppm?) would have easily canceled the usual slow downward temperature drift, which after all, depend on NH ice-albedo feedbacks. If we ever faced an Ice Age, and still had tech civilization, we could generate really fierce GHGs like SF6.

But that is not our problem.

e) In summary, for about 6,000 years, humans generated enough extra to CH4 and CO2 to keep the temperature in an unusually narrow range. We no longer have the problem of another glacial for many times longer than the existence of civilization. Ratcheting thermostat up every decade of course causes another problem and it isn't Ice Age.

Tom Curtis & John Mashey --- Exactly so. The is a fairly recent issue of The Holocene devoted entirely to this question. At least on of the papers will be found on W.F. Ruddiman's publications website.

Yes, that's the special issue of The Holocene that I linked to.

This is not a majority view yet.
But there has been much research since Bill first started on this, not just by him, but by an increasing number of other people. When the dust settles on this, I believe it will be a classic study in the way surprising new hypotheses get proposed, people push back, cause refinements, get other scientists interested. People reexamine old data in light of the new hypothesis, do new research.

This one hypothesis (or two really, the early anthropogenic CO2/Ch4 combination and the plague-driven CO2 shorter-term jiggles over last ~2,000 years) has the nice property of being understandable to the general public (unlike many).
It has been tricky, because the accumulating evidence is highly interdisciplinary, and I'd guess very few climate scientists (or anybody else) naturally read the breadth of journals in which key results have appeared. Not many read about archaeology of Chinese rice paddies, studies of ancient farming practices, and charcoal in the Amazon.
I think it will a majority opinion by 2015, so will have taken less than 20 years , unlike, say continental drift. There of course will be doubters, but anyone serious about this should at least go through the abstracts of that issue of The Holocene I mentioned.

Why is this important? One of the reasons for doing paleoclimate is to help the attribution problem, ie, how much variability is natural, and how much is human?
Bill's hypotheses bear both on long-term CO2/CH4 effects & feedbacks as well as shorter-term ones (suchs as the 1525-1600AD event). Better understanding isn't just interesting, but helps people refine the models.

look at the rhythms in the vostok ice core investigation and you understand that a new ice age is ahead of us, [Incivility redacted -W] you are totally unable to see the obvious and easy. agw is a fake and the ice age coming, for 100% sure

[How easy science is in Kai-world, all you have to do is look at a few graphs and extrapolate them forwards. It hardly deserves the name of science, really -W]

kai --- That not the way the cookie crumbles, I fear.

But Terra is still in the ice age which began 2.588 million years ago. Right now we are experiencing a long interglacial which will come to an end in about 100 thousand years. Then you'll have your glacial.

John Mashey --- The Ruddiman hypothesis lacks obviousness. There is a well respected trigger hypothesis for the 'sudden' (on geologic time scales) descent from an interglacial to a full stadial. The problem this time around is the orbital forcing is so small that there is no precedent in the (limited) data for a decent from such a small forcing.

So without a better physical model the discussion will go on for sometime to come. I don't see an early resolution myself.

aren't the co2 warnists here able to interpret a simple graph and do simple logical deductions?

Again, an original mis-frame takes work to recover from, and in this case, it is easy to conflate multiple inter-related hypotheses.

For better clarity to all this, I will unpack the 2 hypotheses I mentioned into 4, then add 2 more. Of these, I think 1-5 are no longer seriously inarguable.. #6 remains somewhat arguable.

#1 Deforestration and agriculture started changing CO2 off the natural path for this interglacial, starting about 6,000 BP.
Fig 6.A, p.872, Fig 2.B, p.867 in Ruddiman, Kutzbach and Vavrus, "Can natural or anthropogenic explanations of late-Holocene CO2 and CH4 increases be falsified?".

#2 Rice paddies, livestock and biomass burning started changing CH4 off the natural path about 4,000BP.
Fig 6.A, p.872, Fig 2.A, p.867

#3 Some of the jiggles in CO2 in last 2,000 years have been caused by human plagues and reforestration, with the most striking being th1 1525-1600AD event.
Fig 4, [860 in
Nele, Bird, Ruddiman and Dull, "Neotropical human–landscape interactions, fire, and atmospheric CO2 during European conquest ".

#4 Some of the jiggles in CH4 in the last 2,000 years have been caused by plagues and/or wars.
The previous Nevle cite bears on that, but in addition, there is:
Mitchell, Brook, Bowers, McConnell, Taylor, "Multidecadal variability of atmospheric methane, 1000–1800 C.E.", which says:

'Times of war and plague when large population losses could have reduced anthropogenic emissions are coincident with short periods of decreasing global methane concentrations. '

brief description of Sapart, et al:

C. J. Sapart, G. Monteil, M. Prokopiou, R. S. W. van de Wal, J. O. Kaplan, P. Sperlich, K. M. Krumhardt, C. van der Veen, S. Houweling, M. C. Krol, T. Blunier, T. Sowers, P. Martinerie, E. Witrant, D. Dahl-Jensen, T. Röckmann. Natural and anthropogenic variations in methane sources during the past two millennia. Nature, 2012; 490 (7418): 85 DOI: 10.1038/nature11461

That concludes (on p.87):

'On the other hand, we show in Fig. 3 that the long-term trend in CH4 mixing ratio—that is, the increase between 100 BC and AD 1800—is in very good agreement with reconstructed global anthropogenic land use. This suggests that human activities, including the expansion of rice agriculture26, played an important role in the observed long-term CH4 trend over the past two millennia.
Our new isotope data from air trapped in Greenland ice cores allow the reconstruction of variations in differentCH4 source categories over the past 2,100 years. The changes seen in our d13C ice core record cannot be explained without variability in biomass burning, which correlates qualitatively with the charcoal index and fire activity data.
In addition, we show that the reconstructed source variations are correlated with anthropogenic activities, in particular with long-term increases in agricultural emissions and with varying levels of biomass
burning during the period of the Roman empire and the Han dynasty, the MCA and the onset of the LIA. It is thus likely that human activity contributed to variations in CH4 emissions to the atmosphere long before pre-industrial times.

#5 We aren't going to have another glaciation for tens of thousands of years.
David Archer, The Long Thaw (2007), Chapter 12,
p.156

'If mankind ultimately burns 2000 Gton C (this is about the business-as-usual forecast for the coming century), then it looks as though climate will avoid glaciation in 50 millennia as well, waiting until the next period of cool summers 130 millennia from now.

If we burn all the coal reserves (5000 GTon C), the next glaciation would be 4000 millennia away.

The journal article is:
Archer, Ganopolski, A movable trigger: Fossil fuel CO2 and the onset of the next glaciation , i.e., the "trigger hypothesis" David B alludes to. The PDF says (p.5)

'It appears that the natural evolution of the next few thousand years is a close call whether to glaciate or not, an issue of subtle differences in models rather
than a fundamental difference between them.'

#6 Glaciation naturally would have already started (or would soon), but has been prevented only by humans.

William Ruddiman, Plows Plagues and Petroleum (2005), Chapter 10, argues that glaciation (modest perhaps) should have already started. p.104
<blockquote'Future runs...will likely strengthen our conclusion that at least a small glaciation is overdue in northeastern Canada.'
(Not all glaciations are equal, and circular orbits make for smaller ones at any given CO2 level.)

David Archer, The Long Thaw(2007),
pp.152-153:

'This is a case where a reliable forecast cannot be made with the tools at hand. It's too close to call. There is nothing in the orbital wobbles that suggests that an ice age is going to start next week. It could be that a new ice sheet would naturally start to form sometime in the next millennium or two, or it could be that nothing would have happened, even with the global warming, for tens of millennia.

I think his wording is slightly fuzzy, when seen in context of the rest of that chapter, i.e, "would naturally have started" is what he meant, I think. He mentions Ruddiman's book, (p.154), but some of those arguments have been contradicted by more recent analyses, as per The Holocene papers.

I think Archer and Ruddiman agree on #5 (that there won't be another deep glaciation for a long time, i.e., that human CO2 has moved the trigger far enough to guarantee no glaciation in near future. That is, human activity is sufficient to guarantee no near-term glaciation.

#6 is subtly different, and the disagreement is an argument within real science, and a good example. Here, the issue is whether or not we would have had glaciation without humans, that is, was human activity necessary to avoid glaciation near-term (or even a few thousands of years ago)?
Answering that requires knowing not only the exact trigger point, but the CO2 track that would have been followed naturally. Unlike 1-5, that's a close call, with the usual "more research is needed," but we may never know for sure. I do think the evidence is building that ~240-245ppm is the most likely range for "natural" CO2 about now.

Franzén doesn't just believe in a new ice age, in this article (In Swedish) he claims that we are headed for a new snowball Earth:
http://www.elbranschen.nu/content/view/1528/85/lang,english/
The initial picture says it all.

Franzén does research on peat and it is tempting as a researcher to try to explain the world in terms of your own specialty, that peats control the world´s climate.

"Headed towards and iceball state" may be plausible if someone qualifies it with "when." :-)

One always has to ask someone what they mean by "soon," as disciplines differ.

Here's a Google translation, best I've got (and some is strange), unless there is actual English version.

John, given that the sun is slowly emitting more and more light it seems to me that it will be harder and harder to reach a snowball state. It seems more plausible that we are headed towards a runaway greenhouse effect in a few hundred million years or so.

Thomas: again, timeframes matter.
The Earth is almost certainly headed for permanent ucevsll state in 5Byears or do.
The Earth is almost certainly headed towards a Warner climate than now over the next few hundred years, with a peak sometime after CO2 emissions turn down, and with oeak's height determined by human emissions and whether or not crucial tipping points.

Temperatures get determined by:
1) Continental configurations, which change very slowly.
2) CO2 levels, whose average changes fairly slowly,but in last few million years has slowly dropped., from weathering processes that slowly sequester CO2.
3) Milankovitch cycles,which don't seem to matter much except when the combination of 1) and 2) is just right to create the sensitive state in which 65N insulation changes plus postive feedbacks create glacial-interglacial swings.

Now, a cusory look at Franzel's article hints at serious confusion, but that does not mean everything in the article is wrong. But why worry about it? People like Archer and Ruddiman are fine scientists who know this turf well. Ruddiman is responsible for one of the reasonable hypotheses for cause of long-term cooling (50My), see this.

Again, reading a confused article tends to propagate it. It really helps to go back to well-written texts by true experts like Archer or Ruddiman and get a coherent story. Articles that mix confusion with OK material really don't help much.

John, I don't disagree with anything you write here, except I don't see any room for an "iceball Earth" in that description. I don't say it's impossible, but conditions have to be really extreme by now to get ice all the way down to the equator. I heard a talk by Pierrehumbert a decade or so ago, and as I remember he stated that even removing all CO2 from the atmosphere might not be enough.

Thomas: it would really help if you can provide some citations for your assertions.

The two issues are:
a) Solar luminance is expected to increase along main sequence at what rate over next few billions years? And how does that compare with the variation in the usual sunspot cycles? How much effect does that have in the next, say 100M years?

b) This graph needs explaining, that is, you need to explain why you think under natural circumstances, the natural CO2 draw down was going to flatten or reverse, and back it with some citations to peer-reviewed papers. I'll happily look at that.

Dear debaters.

Every theory discussed here is based on the hypothesis of the transparency of the atmosphere to infrared rays.
This hypothesis has been challenged in 1863 by Jhon Tyndall's Royal Institute of sciences London.
I realized a measure of attenuation of infrared rays directly into the atmosphere which confirmed the data presented by Tyndall and also showed that this attenuation is a phenomenon with differential character which creates conditions to understand the greenhouse effect and its mechanism of control.
So any discusse or any study that considers the transparent atmosphere is totally wrong.

Tarcisio José D'Avila --- The situation with regard to infrared is rather subtle. A good starting read is "The Discovery of Global Warming" by Spencer Weart:
http://www.aip.org/history/climate/index.html
and then the technical details are very well done in Ray Pierrehumbert's "Principles of Planetary Climate"
http://geosci.uchicago.edu/~rtp1/PrinciplesPlanetaryClimate/index.html
(which will requite serious study and possibly some supplementary texts as well).

John Mashey --- Very nice summary of the anthropogenically avoided cold spell, potentially a glacial. Thank you.

@david b. benson: wrong: "anthropogenically avoided cold spell":

[Redacted; incivility -W]

david benson, it is difficult here to explain to you why you are wrong in assuming that humans are able to avoid a gacial. the talkmaster here does not like to hear the truth, nor is he willing to learn scientific facts.

mister connolley, it is really cumbersome to explain to you how natural science works. you as a computer programmer without formation in meteorology and geology behave as if you would be competent to discuss the non-existing impact of greenhouse gases on a potential prevention of a new glacial.

john mashey, do you have an explanation why your firm belief on the accuracy of your above assertions about a hot co2 world is not reflected in the disastrous copenhagen, cancun and durban climate alarmists meetings, which completely failed to produce any results except that the whole world laughed about the irrelevance of climate politics.

Dearest Kai

In keeping with Eli’s new policy, let the bunny point out that he and just about everyone else here takes umbrage of being told such a load of crap from a bullshit shill like you. We have no interest in talking to you or giving the appearance that anything you say or write has worth because it does not. Trying to talk with you is guaranteed to take ten points off the IQ of whomsoever tries it. However, telling you this repeatedly has its attractions.

Now you may think you can outlast Eli. Wrong again

Eli: you needBilly Madison, to help you learn: simply do not listen or read to things that make your dumber.

The days of USENET KILLFILEs were the good old days.

Richard Feynman took a sabbatical in Rio in the 1960s and taught at the University of Rio. He discovered that only 3 of his students could manage to think well enough to understand what he was talking about -- of the 3, 2 had gone to study in Europe and 1 was an autodidact -- the rest had been taught in the usual Brazilian way -- by rote memorization. Little has changed in the Brazilian method of teaching physics, math, or medicine since that time.

It's a mystery to me how anyone can look at a chart like this
http://en.wikipedia.org/wiki/File:Vostok_420ky_4curves_insolation.jpg
and deny that M cycles are running the show. CO2 is clearly the effect, and impotent as a forcing agent. --AGF

[No one does deny that the ice age cycles are paced by Milankovitch forcing.

No one who actually looks at the numbers denies that Milankovitch forcing isn't enough to cause the changes observed. There have to be feedbacks, and CO2 is the most obvious.

As a general principle, you can't do science just by looking at graphs, you have to read the words too and the calculations. Try reading http://scienceblogs.com/stoat/2007/03/12/yet-more-tco2-lags/, from Eric Wolff -W]

You can learn more from a glance at one good sea level chart than from 10 years of listening to NPR. This explanation of lag due to gas entrapment is mighty curious--I had long been under the impression that it was a matter of decades, not centuries, and millennia were out of the question. And one is left to explain the different behavior of CH4--is it trapped more readily? Vostok shows CO2 lagging T and T lagging CH4; how is this explained through gas entrapment? Rather, CO2 is absorbed by the ocean and turnover is roughly 800 years.

But these little lags are quite irrelevant to ice core interpretation: GHG's and T don't play games of team tag or leap frog through mutual self amplification--such behavior fundamentally defies the rules of signal processing. What controls CO2? It is quite absurd to have CO2 and T amplifying each other and maintaining any sort of equilibrium or cyclic behavior. Rather both are governed in tandem by ice sheet extension, which ice growth or recession is governed by M cycles, with lags of several millennia. And there is important feedback involved, that of albedo, which is of 2 orders of magnitude greater than GHG feedback.

[You just made that up. No, the albedo forcing isn't two orders of magnitude larger than CO2 forcing. I appreciate you "need" CO2 forcing to be small, for your views to make any sense, but that doesn't mean you can invent things -W]

So, on a millennial scale CO2 tracks T because they respond in tandem to ice sheet extension; on a secular scale they don't correspond at all because CO2 is such a feeble agent of climate forcing. --AGF

"[You just made that up. No, the albedo forcing isn't two orders of magnitude larger than CO2 forcing. I appreciate you "need" CO2 forcing to be small, for your views to make any sense, but that doesn't mean you can invent things -W]"

I made that up??? June insolation varies by 100W/m^2 at 65N (24hr average) over the long term. Albedo varies from near 0 to near 1 depending on the presence or lack of ice--and forest. Insolation on a clear summer noon is near 1000W at the surface. CO2 IR is who knows what? 1 or 2 W, theoretically--it has yet to be measured. I made that up?? --AGF

[Yes, you made it up. We could go into the details, I suppose, but I sense you're not really interested. How about you start with some proper references? -W]

I sense you are in no way capable of going into the details. If you want something easier, why don't you go back to this preferential capturing of CH4 over CO2? (Your lag explanation was bogus, and your background is not sufficient to be aware of it.) I appreciate your need to appeal to authority when you're stumped, but why don't you just stay out of the arena if you're a novice? --AGF

[Now you're trolling, which is dull. Drop the "background" stuff, you sound like Kai.

As to "preferential capturing of CH4 over CO2" I've no idea what you're talking about. Refs? -W]

I thought the wiki graph explained it all--didn't you look? The lag doesn't apply to methane. Why not? Or do you not accept that T lags CH4? --AGF

[What are you on about? You can't see a lag as small as 800 years in that pic, and you certainly can't see any difference between CO2 and CH4 lags in that pic. You're just making stuff up. Can you point to any scientific papers that actually support that you're saying, or is this just your own brilliant pet theory? -W]

This is passing strange--a few posts back you sent me to a site that claimed a CO2 capturing time of several millennia, which should be easily visible in a big graph. If you prefer raw data I'll see what I can dig up. --AGF

[The graph is 400 kyr in 800-ish pixels, which is 500 y per pixel. You certainly won't see an 800 year lag in that.

"which should be easily visible in a big graph" - well, you can either see it, or you can't. Somewhat earlier you were claiming that something or another was obvious. Now I've asked you exactly what, its suddenly not very obvious at all.

I'd prefer you to point me to a real scientific paper. If this fascinating effect you claim to be able to see is genuine, it would be pretty weird for you and only you to have noticed it. OTOH, if you can see it clearly in the raw data, then I'll be happy to be shown it -W]

Wiki's Vostok chart at 130-120ky has CO2 lag T and CH4 by a good 20 or 30 pixels. Granted, J65N insolation drops 80W, but that's the point: how can CO2 amplification compete with that? CO2 lingers 10ky on top of the 5k or so already incorporated into the calibration, and its feeble input does nothing to prevent the ice age.

[But you can't call that a lag - the CO2 and T graphs clearly have different shapes. "lag" is where the same thing happens, but later in time. CO2 and T have a maximum at the same time, to within the accuracy of the graph.

However, looking at the graph I now understand your "CO2 is orders of magnitude smaller than albedo" error - you're comparing insolation, in one month, at one latitude, with global CO2. Which you can't do -W]

T is a rough measure of global albedo, and between insolation and albedo feedback GHG significance is wishful thinking. 80% of the last half million years have been much colder than now, and it's really too bad all our CO2 can't save us from the average climate. --AGF

Wrong. What melts the ice? Nothing averaged globally, but local conditions at the edge of the ice--in the temperate latitudes. The extra 100W TOA starts it, and the albedo feedback keeps it going. The albedo feedback is stronger than the original forcing, not like weak CO2. --AGF

agfosterjr --- Study Ray Pierrehumbert's "Principles of Planetary Climate"
http://geosci.uchicago.edu/~rtp1/PrinciplesPlanetaryClimate/index.html
through chapter 6 and then inform us wherein the error lies and whose it is.

Thank you.

guys, i am fed up with cold temperatures. it would be much more convenient with 5 degrees celsius more in winter time

[Have you considered moving house? -W]

D B Benson: You may either mail me a copy or you may summarize whatever points he makes which you think will gainsay mine. --AGF