[ldavidcooke]

Hey All,

Okay, the news is out. It has been determined that 55mya a combination of Axial Tilt and Orbital Eccentricity resulted in the Sub-Arctic meltdown exposing Permafrost; resulting in a spike in pCO2 and hence the end of the Ice Age... So, is it likely that it requires the change in axial tilt to cause pCO2 to spike...? Apparently not, in its place we could convert 100Gt of fossilized carbon to accomplish the same thing... So, what happens when you have, AGW, Permafrost meltdown, Axial Tilt and Orbital Eccentricity?

I'm sorry, if the axial/orbital variation is responsible for the exposure/meltdown of the permafrost then CO2 is only a marker and not a contributor. For one, in order to increase the warmth to get a pCO2 spike, the CO2 was not a contributor in the first place.

If CO2 were a primary contributor and the peak Arctic temperature reached the estimated 14C avg. max. above current ambient peak, then no more then 1/3 to 1/2 or 4.5-7 deg. C of that value was related to CO2. This est. pCO2ppm/deg.C value is terribly below current sensitivity estimates, as it is est. the pCO2 values exceeded 1600ppm at this time.

Given these values we would be looking at a value of 228ppm/deg.C to reach the 14 deg.C value seen in the Arctic. With an equivalent of @460ppm/deg.C in the temperate zone to achieve the est. 6deg.C spike seen there. This averages out to @17% of the current sensitivity est. globally.

So which is it, CO2 driving GW or planetary physics... So far the AGW camp seems pretty secure in their theories, so what of the geologists, if their data is correct then this would seem to be a major upset in the making...

As Andy pointed out 2ya in the Climate D&A Forum we are about 200 years into the 100ky planetary physics caused peak avg. temperature. Given that and the CO2 spike we are seeing would seem to suggest that the current abnormalities in our climate could be natural variation... Your Opinion...?

[Bazmundo]

Planetary Physics... which is why I normally stay quiet on such threads.

[StephenS]

Assuming this refers to the same research, the BBC has a different take: 'CO2 drove end to last ice age':

http://www.bbc.co.uk...onment-17611404

[Peter H]

ldavidcooke, on 04 April 2012 - 22:11, said:

Hey All,

Okay, the news is out. It has been determined that 55mya a combination of Axial Tilt and Orbital Eccentricity resulted in the Sub-Arctic meltdown exposing Permafrost; resulting in a spike in pCO2 and hence the end of the Ice Age... So, is it likely that it requires the change in axial tilt to cause pCO2 to spike...? Apparently not, in its place we could convert 100Gt of fossilized carbon to accomplish the same thing... So, what happens when you have, AGW, Permafrost meltdown, Axial Tilt and Orbital Eccentricity?

I'm sorry, if the axial/orbital variation is responsible for the exposure/meltdown of the permafrost then CO2 is only a marker and not a contributor. For one, in order to increase the warmth to get a pCO2 spike, the CO2 was not a contributor in the first place.

If CO2 were a primary contributor and the peak Arctic temperature reached the estimated 14C avg. max. above current ambient peak, then no more then 1/3 to 1/2 or 4.5-7 deg. C of that value was related to CO2. This est. pCO2ppm/deg.C value is terribly below current sensitivity estimates, as it is est. the pCO2 values exceeded 1600ppm at this time.

Given these values we would be looking at a value of 228ppm/deg.C to reach the 14 deg.C value seen in the Arctic. With an equivalent of @460ppm/deg.C in the temperate zone to achieve the est. 6deg.C spike seen there. This averages out to @17% of the current sensitivity est. globally.

So which is it, CO2 driving GW or planetary physics... So far the AGW camp seems pretty secure in their theories, so what of the geologists, if their data is correct then this would seem to be a major upset in the making...

As Andy pointed out 2ya in the Climate D&A Forum we are about 200 years into the 100ky planetary physics caused peak avg. temperature. Given that and the CO2 spike we are seeing would seem to suggest that the current abnormalities in our climate could be natural variation... Your Opinion...?

I'm not sure what research you refer to, Dave? 55Mya or the end of the last ice age or both?

For me, it's as near to a science fact that the rise in CO2 is our doing as is possible. I'm also as convinced CO2 is a ghg with the properties science says it has. So, if the warming atm isn't to do with that it's a massive coincidence is it?

This post has been edited by Peter H: 05 April 2012 - 07:11

[John Mason]

There is a bit of confusion in this thread because there are two new papers in Nature; WUWT is running on the interglacials one whilst CP is running on the PETM one which LDC is writing about.

I've received a copy of the latter this morning. It is well worth reading. What it suggests is that hyperthermals within an already hot climate (Hothouse) are triggered at CO2 levels of >900 ppm by favourable points in long-term orbital cycles: in combination these serve to massively destabilise permafrost. There are several differences between Earth now and in the run-up to the PETM, the most obvious being that in the latter there were no polar ice-caps. However, when one considers the current goings-on in the Arctic (and a massive field research effort is underway to try to get a full understanding of this), the paper comes at an interesting time. Skeptical Science will have a post out on this paper in the near future. What I can say is that known feedbacks within the carbon cycle could easily account for a progressive build-up of atmospheric CO2 and CH4 and then once the threshold is passed the permafrost feedback kicks in on a simply gigantic scale, although typically hyperthermals are geologically brief, because the extra warmth and atmospheric moisture brings about a very enhanced rate of silicate mineral weathering, which acts as a huge CO2 drawdown, returning things to "normal".

Think of it as a reboot of the biosphere: it might be like a Windows 7 machine crashing and then rebooting to Windows 3.1 i.e. the basics will all be there but the details will be completely different.

Cheers - John

[John Mason]

Links to the abstracts:

DeConto et al (PETM): http://www.nature.co...ature10929.html

Shakun et al (deglaciation): http://www.nature.co...ature10915.html

I see The Guardian has gotten the two mixed-up as well

Cheers - John

[Peter H]

Right, I've got a better idea what we're talking about

[ldavidcooke]

Hey Peter and Stephen,

As to the current participation of CO2 in the last 50 years of temperature rise it is very likely that a combination of contributors of which CO2 makes up roughly 25% of the change in the Earths heat flow pattern, from primarily radiative to advective, is not in contention. Current CO2 levels and climate sensitivity experts seem to suggest that the relationship between atmospheric CO2 and the GAT are considered a fixed ratio. I suspect this may be one of the issues of contention that acts to seperate the experts, which to me is ridiculous. Why is it that everything must stay the same in a dynamic, changing enviornment is beyond me...

As to the article that Stephen brought up there is too much controversy to put much credit in that proposal as with the Earth covered to nearly 1/3 more ice cover then in the last 1000 years, it is unlikely Permafrost nor a Methane Hydrate release was likely to have occured. Hence, it is unlikely there could have been a natural 100ppm CO2 spike in the global atmosphere 11-17kya that drove the warm up or the massive ice melt at the time. Though there is evidence of both a carbon spike near the Y-D anomally and about 1000 years later or after the ice sheet was already in remission.

Peter, as you noted John did clarify things rather well, I was unaware of the more recent theory of the Ice Age recovery; however, for the release of 100ppm of CO2 would be reliant on the combustion of 30Gt of carbon within a short period of time, the only possible source could have been the decomposition of the organics trapped under the ice sheet. The result would have been a dramatic CO2 spike; however, it would have followed the already rising air temperature, not preceeded it.

[ldavidcooke]

Hey John,

There in lies a question, for to reach 900ppm before Permafrost melt in an already warm world would suggest there had to be a natural event that got the CO2 levels to that point in the first place. The Deccan Traps seems a logical choice... However, to get to the point that a large amount of organics were trapped in the Permafrost in the first place suggests that there had to be significant flora development.

This paper also seems to suggest the content of the Permafrost captured carbon as it appears to be the difference in about 900ppm and roughly 1600ppm. Given this data, it would seem to suggest that either the 900ppm or the 1600ppm are potentially in error if we are seeing current Permafrost exposure at @ 400ppm, given that planetary physics can achieve an equivalent warming.

400ppm of CO2 would seem to suggest the actual value of warming, as it relates to CO2 sensitivity. This warming would appear to be NMT 1/2 of current sensitivity estimates... So which is correct? Is the current warm up due entirely to CO2 or is it possible that planetary physics is inaccuately being attributed as CO2 warming?

[ldavidcooke]

Hey All,

Here is an even scarrier thought, if indeed that planetary physics does contribute to the current warming and the 100ky warming cycles are accurate then we are due for a plunge in the GAT within the next 500 years. Meaning anyone living to the north of the 35th parallel are in danger of becoming part of the pCO2 spike in 90ky. This then returns us to the question do we all become Snow Angels or do we burn in Tropical Hell...? (Who said there is no relationship between Science and Religion,.... )

[Bazmundo]

I don't think it's that scary, if you consider the appropriate orbital mechanisms as a number of metronomes and a resounding choral "tick" is required to trigger the bomb. You then still need the various oceanic, atmospheric and biological processes to have conspired to provide the fuel for the bomb. I'd venture that the required obliquity trend for warming has occurred more often than subjectively catastrophic warming has? I haven't drawn comparisons with Milankovitch cycles for this, but will do if I get time.

[ldavidcooke]

Chris Lloyd, on 05 April 2012 - 12:29, said:

Planetary physics of course

I seem to remember not so long ago, in another thread, asking about axial tilt and its effect on the previous positions of glacial fields.

I forget the responses; oh yes there weren't any

Hey Chris,

I think that what happened was that subject was not in-line with the thread at the time and Andy or Andre spawned a seperate thread to discuss it in depth in the Climate D&A Forum.

The conclusion was there was insufficient data at the time. What we do not know is how much warming we can attribute to planetary physics alone.

We also do not know what the effects would be. Granted it is probable that the GAT (global avg. temp.) would increase; but, how would it be manifested? Would the TSI change, no. Would the seasonal cycles change, more then likely. Would the radiational versus advectional heat flow change, initally; until the GAT were more evenly distributed. Would there be a change in the pCO2 levels, it depends on the character of the organics buried under the polar ice. Would the time frame for the changes occur within 50 years, no. How long would it take for the change to be noticed, about 6ky on average, after the peak or about 6kya. How much time does it take for the plunge in GAT to be manifest after the peak, this is a variable; the shortest time appears to be about 2ky, with a slight roll-off for about 1ky before dropping, the longest period appears to be the present period. So how long until the drop, that is what the latest research is attempting to figure out.

If planetary physics is equivalent to 450ppm of pCO2 it could be 25ky or better before we see a change, (5ky to eliminate all carbon combustion sources and 20ky for the atmospheric carbon to be sequestered in the ocean. (Providing no geo-engineering is employed and we keep using carbon based fuels. (Of course, that is if mankind is still alive...)))

[John Mason]

ldavidcooke, on 05 April 2012 - 11:32, said:

Hey John,

There in lies a question, for to reach 900ppm before Permafrost melt in an already warm world would suggest there had to be a natural event that got the CO2 levels to that point in the first place. The Deccan Traps seems a logical choice... However, to get to the point that a large amount of organics were trapped in the Permafrost in the first place suggests that there had to be significant flora development.

This paper also seems to suggest the content of the Permafrost captured carbon as it appears to be the difference in about 900ppm and roughly 1600ppm. Given this data, it would seem to suggest that either the 900ppm or the 1600ppm are potentially in error if we are seeing current Permafrost exposure at @ 400ppm, given that planetary physics can achieve an equivalent warming.

400ppm of CO2 would seem to suggest the actual value of warming, as it relates to CO2 sensitivity. This warming would appear to be NMT 1/2 of current sensitivity estimates... So which is correct? Is the current warm up due entirely to CO2 or is it possible that planetary physics is inaccuately being attributed as CO2 warming?

LDC - I shall send you the full paper tomorrow!

It's another study that reinforces what we know: i.e. the heat that comes in is like the element in the hot-water tank (the sun), but the thermostat is greenhouse gases (on a seriously wrong setting).If Mankind wants to reboot Earth to another version within a few decades, that is fine by me. But if you have offspring, that might be worth thinking about. I have long been horrified WRT how sociopathic humans living in this age are with respect to future generations........

Cheers - John

[ldavidcooke]

Bazmundo, on 05 April 2012 - 12:02, said:

I don't think it's that scary, if you consider the appropriate orbital mechanisms as a number of metronomes and a resounding choral "tick" is required to trigger the bomb. You then still need the various oceanic, atmospheric and biological processes to have conspired to provide the fuel for the bomb. I'd venture that the required obliquity trend for warming has occurred more often than subjectively catastrophic warming has? I haven't drawn comparisons with Milankovitch cycles for this, but will do if I get time.

Hey Baz,

Do you want an even more scary thought, it turns out the Y-D Ice Age (not the PETM) paper is based on, wait for it,... models.

Seems the NOAA team suggested that it is unlikely that the end of the last Ice Age could not be ended by any other mechanism then CO2. So they dug out a model; stuffed in the "global" proxies; "shook the can" and ran Petrobytes of, for all intents and purposes "garbage", through the CRAY super computer at Oak Ridge and are now holding millions of dollars ransom to maintain the "garbage" data.

Even though both SH and NH ice core MEASUREMENTS are in agreement that temperature leads CO2 and not as they have theorized in this paper... Sorry, since when do virtual or proxy based models have more clout that factual measures? Talk about the tail wagging the dog...

(Sorry, its just a rant, not to be mistaken as pointed at you... It is just you and John understand the science and I do not see how this paper can pass for science..., except to point out a basic problem with either the proxies or the models...)

[Paul Domaille]

I would say planetary physics should be your first port of call, somethimng I have harped on about for a while. With 4 Milankovich cycles of varying frequency and other cyclical effects coming intom play one has to take those into account asestablished theories before adding in theorised effects.

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[John Mason]

Dave, the key problem with the ice-cores is that the temperature data they provide are of course local, so the obvious problem is that they do not necessarily provide a complete picture of what occurred globally. This work has gone some way towards addressing that problem.

Cheers - John

[Bazmundo]

ldavidcooke, on 05 April 2012 - 20:42, said:

Hey Baz,

Do you want an even more scary thought, it turns out the Y-D Ice Age (not the PETM) paper is based on, wait for it,... models.

A simplified model would be my first thought, it's an easy way (though I don't fully condone 'easy ways') of finding a baseline or theoretical control. I'd start with an atmosphere-less rock (the Earth would be an average -15C at surface) and compute the necessary obliquity, nutation (by adding the moon), etc. The I'd start adding the atmosphere and oceans, running the model each time (I'd make sure cloud effects would get a look in, nudge-nudge-wink-wink) a parameter was added. At least if a simplified model of the atmosphere under orbital changes doesn't throw up any effects correlating to any one of the Milankovitch cycles, then I'd know where to invest money/effort in future?

I'm tempted to surmise that the mechanism could be orbital, and that a range of subsequent effects (aridity causing fires in biomass, permafrost melting, oceanic turnover causing methane release) are feedbacks that generate extreme effects. Though as far as historical climate extremes go, I'm more interested in the overall equation than finding one variable to blame over all others.

[John Mason]

Models are never perfect, but given that they are used for things like aircraft design and many people fly, is it the case that models are cherrypicked positively if they come up with what people want to hear (e.g. "this plane will not fall out of the sky")???

Cheers - John

[Andy Mayhew]

As far as this paper on CO2 and the end of the last ice age is concerned, all I see is that it shows:

a) that Antarctica ice cores do not provide a good global temp proxy since it turns out warming in Antarctica lagged behind that in the rest of the world

and

CO2 acts as a positive feedback in a warming world, regardless of the initial cause of warming.

However it does also dispell that strange myth that CO2 cannot cause warming because it lagged behind warming at the end of the last ice age (and the even more bizarre notion I've seen mentioned, that current CO2 rises are caused by previous temp rises ....).