Paleocene Eocene Thermal Maximum: filling an ocean?

[Andre]

Recently another study is about to fuel the climate scare:

http://www.terradaily.com/reports/G...rojected_By_Ancient_Carbon_Emissions_999.html

That Paleocene Eocene Thermal Maximum was something completely different. The most likely explanation, that is, the explanation for the most enigmatic features is wrapped up in those odd last three words of the threads title. More later.

 

[Andre]

These recent studies show some imposibilities which appear to be the key to the solution of the problem. How do you get fresh water duckweed and tropical algea into the arctic?

 

[Andre]

So what are the main features of the PETM apart from the tropical algea and duckweed at the North Pole?

The main evidence is indeed in the oceans. Gigantic isotope jumps in the proxies, a red clay layer in the oceans named Elmo, etc. etc.

One of the most remarkable features of the PETM is its uniqueness. Nothing but really nothing in the geologic history resembles it at all. Given that, it appears evident that recurring events llike alleged greenhouse - ice house state changes on Earth would not suffice to explain it. That's why the greenhouse hype explanation is gibberish. Why is there only one PETM? Why not several at each high CO2 spike in the last so many 100 millions years ago? Actually the atmospheric CO2 was quite low already around the PETM.

No, to explain a unique feature you require unique causes.

One unique feature on geologic time scales is the continental drift due to plate tectonics. The topography of Earth is always unique as the continents drift around seemingly at random.

Would that help?

 

[Skyhunter]

One unique feature on geologic time scales is the continental drift due to plate tectonics. The topography of Earth is always unique as the continents drift around seemingly at random.

Would that help?

Not at all, since continental drift is not random, and takes place over millions of years, not thousands.

 

[Andre]

Okay I ment to say that a certain location of the continents is unique in the time. Next year the world map is wrong, some continents have moved a quarter of an inch or something.

An impression of the plate tectonics is animated here (source wikipedia) and each snapshot is unique.

Meaning that somewhere in a unique setting of the continents something unique has happened.

 

[Andre]

Now here is http://www.uwgb.edu/dutchs/graphic0/platetec/050my94.gif to get some inspiration.

So, How do you get tropical algae at the north pole?

 

[Andre]

Nobody? Can't say that I did not give it a chance, Not interesting? Ridiculous? No idea what's up?

Anyway, here is the abstract of the paper I'm working on, prio 2, the Mammoths go first:

Andre et al, (2006) Understanding the Paleocene Eocene Thermal Maximum, a reconstruction

Keywords Paleocene Eocene Thermal Maximum clathrate Pangea PETM

Abstract

The Paleocene Eocene Thermal Maximum is characterized by enigmatic proxy evidence suggesting warm climates, and, as inferred by numerous publications, massive marine methane hydrate (clathrate) destabilization events. The recent discovery of a near-tropical Arctic ocean however requires a review of existing hypotheses, including greenhouse forcing, to check for the trigger and the cause of events of the PETM.

Here we propose that alternately the same proxy evidence, in toto, could have been caused by another mechanism. After the breakup of the Pangaea supercontinent some 200 million years ago, North America moved in a semicircle clockwise towards the north, hinging around the Greenland - Svalbard area until Alaska and Beringia made contact. Thus the Arctic Sea became isolated and no longer had contact with open oceans. Then the evaporation of the Arctic inner sea exceeded accumulation for a prolonged period causing a significant sea level lowering in comparison with the rest of the oceans. Furthermore, the tectonic movements of the plates may have enlarged the Arctic basin as North America continued to move progressively to the southwest, lowering sea level iin the Arctic basin further.


At the start of the Eocene, 55 Ma ago, the Turgai Strait, splitting Siberia from North to South may have connected the virtually empty Arctic basin and the near-tropical Tethys sea, resulting in an Arctic basin which would have started to fill rapidly with the warm surface water of the Tethys sea, not only transporting alien biota towards the Arctic but also warming up the area. The resulting abrupt sea level drop of some 15-30 meters in a very short time would have caused a secular destabilization of the marine methane hydrates, which would then explain the remaining proxy evidence pertaining to isotope excursions and the Elmo. Hence the empty-Arctic-basin-hypothesis appears to be backed by the evidence, challenging the case for the Palaeocene Eocene Thermal Maximum to be explained primarily as an enhanced Greenhouse forcing scenario.

That's how you get tropical algae at the North Pole

 

[Andre]

Now you could think that this is nonsense, however:

Ernst SR , E Guasti, C Dupuis, RP Speijer 2006 Environmental perturbation in the southern Tethys across the Paleocene/Eocene boundary (Dababiya, Egypt): Foraminiferal and clay mineral records Marine Micropaleontology Volume 60, Issue 1 , 27 June 2006, Pages 89-111

Abstract
Foraminiferal and clay mineral records were studied in the upper Paleocene to lower Eocene Dababiya section (Egypt). This section hosts the GSSP for the Paleocene/Eocene boundary and as such provides an expanded and relatively continuous record across the Paleocene/Eocene Thermal Maximum (PETM). Deposition of illite–smectite clay minerals is interpreted as a result of warm and arid conditions in the southern Tethys during the latest Paleocene. Benthic foraminiferal assemblages are indicative of seasonal variation of oxygen and food levels at the seafloor. A sea-level fall occurred in the latest Paleocene, followed by a rise in the earliest Eocene...etc

 

[billiards]

#Interesting, haven't had the time to look into all your refernces, but agree about the continent positions. Not sure but I think some major ocean stuff might have been going on.

Go back to the mid Eocene and I think it is thought that a passage was open between north and south america, there is also some recent evidence that suggests an ice age at this time. Now I don't know all the evidence but presumably if (as someone I know who is just about to publish this suggests) this passage opened up in the Mid-Eocene, it would have been closed in the Early Eocene.

This would have encouraged western boundary currents (similar to the Gulf Stream) to form, which would have carried more warmth to the poles and helped melt the ice caps. I definitely think the position of the continents was important.

However I do not believe that any of this impedes on the validity of the greenhouse gases as a mechanism for global warming (take a look at Venus if you wann see what greenhouse gases can really do). Coupled with the fact that there is no evidence to suggest that the present-day continent arrangement is any less/more conducive to global warming than it was in the early eocene, I remain sceptical about those that use this kind of research to justify their climate/political views.

 

[Andre]

(take a look at Venus if you wann see what greenhouse gases can really do).

Take a look at Mars, with blackbody temperature about the same as the actual temperature, to see what greenhouse gasses fail to do. However the case of Venus is probably utterly, completely different, when looking at all its features simulanously.

Have a look here:

http://www.bautforum.com/showthread.php?t=10879

I remain sceptical about those that use this kind of research to justify their climate/political views.

You realize that you are insulting me and disdaining the scientific process for a bunch of fallacies. Here are observations, ideas to explain them and evidence to support that. What on Earth has that to do with climate/political views?

 

[billiards]

I'm not trying to insult you. But if you're using your research to convince people that greenhouse gases aren't important then you're clearly politically motivated. The two mechanisms are not mutually exclusive.

Your research is important but it is not as far reaching as you'd like to think, it certainly does not show that greenhouse gases are not important in raising global temps. In fact you insult me by suggesting that my ideas are "hype" and a bunch of scientific "fallacies". Perhaps you should be a little less sensationalist with your work, and try not to jump to such provokative and thoughtless conclusions.

 

[Andre]

But if you're using your research to convince people that greenhouse gases aren't important then you're clearly politically motivated.

Right there, you're doing it again. Most definitely not. Being indifferent towards global warming, my research started off with investigating the mass murder on the Mammoths in 1999 with the sole objective to find out whodunnit.

We solved that: here

but in the process we also found out that the very basis of AGW, the interpretation of the ice cores and other isotope proxies got refuted in the process. I'll post that eventually. You may want to know that my first thought was: "oops this is terrible" but noticing the remorseless hatred campaign against anybody who had the guts to challenge anything, my sentiment has reversed 180 degrees.

 

[billiards]

Andre, I am interested in what you have to say, but I am not sure exactly what it is that you are saying. I've clicked around as much as can be expected of any ordinary person, in an attempt to see what it is you are arguing. Perhaps it is time to sum up briefly your lines of evidence, and then clearly state your conclusions in one concise post.

I have some issues with what I think you're saying but I need further clarification before I will comment.

Cheers

 

[Andre]

My priority right now is giving NERC something to think about here.

http://www.nerc.ac.uk/about/consult/debate/debate.aspx?did=1&pg=1

But that's all part one of the Popper philosophy, before trying new explanations, old ideas need to be falsified first.

A wrap up of post about the evidence for the last glacial transition is here:

http://home.wanadoo.nl/bijkerk/refuting%20the%20Greenland%20paleo%20thermometer.pdf

 

[billiards]

Unfortunately I can't currently read pdfs on this computer :(

I guess the obvious point is why do you think the presence of duckweed and tropical algae in the Arctic is a nail in the coffin for the theory of greenhouse gas induced global warming??

 

[Andre]

Perhaps try acrobat reader: http://www.acrobat-stop.com/index.asp?s=go-uk&a=acrobat&kw=acrobat

It's free.

The PDF is about the last glacial maximum, proving that isotopes are lousy paleothermometers. The PETM temperature is also mainly isotopes. The paper about the PETM is still WiP.

 

[billiards]

Perhaps if you could answer me more directly this would be a more interesting thread? It's nice to communicate with people and the references you give are great but they are no substitute for genuine discussion.

Remember: I am not a researcher in this field, I don't have the time to try to draw out all the information for myself. But as a student of geophysics I am interested, especially with your claim that greenhouse gases are not significant in global warming.

But I am confused because in one of the abstracts you cited earlier you mentioned how gas hydrates released beneath the frozen soil woulg have warmed the Earth - these are greenhouse gases... See what I mean about not understanding your argument?

 

[Andre]

Okay, there are many common features in terms of isotopes between the PETM 55 My and the Late Pleistocene. However the main difference is that the PETM happened only once, while the interglacials occur about every 100ky. On the latter we have orders of magnitude more data, yet it's very contradictory. My research however reveals that bluntly against the broad but sloppy consensus, there is very little if any evidnece that the isotope spikes in general are indicating temperature changes as in coming in and out of glacial periods.

Thus isotopes are very lousy paleothermometers, simply because manu more events can cause isotope jumps, especially seasonality of precipitation. But isotope evidence is widely used to identify the PETM as cold warm.

there is pretty strong evidence that the PETM is about massive release of oceanic methane hydrate, but what caused it? Warmth? Then the effect was aso GHG heating. Isn't there a whee bit circular reasoning in that. Chickens and eggs.

How about massive methane hydrate release caused by a sudden dramatic eustatic sea level fall, reducing the pressure on the hydrate, causing it to destabilize on a global scale? How do you do that? By filling the empty Arctic bassin? The isotope spikes associated with it are merely reactions on precipitation patterns, acidity changes, salinity changes, and other chemical interactions, not drectly related to warmth.

Have to think out of the box a little.

 

[billiards]

I consider that it is more likely that a meteorite impact caused the catastrophic release of methane leading to the thermal maximum, it just seems more likely, but there could be any number of mechanisms. Sea level rises could have flooded a lot of the biosphere causing it to rot and release gases?

Besides, this might be a unique event in our incomplete record (which has worse and worse resolution the further you go back in time), but it does not contradict anything I've heard about anthropogenic CO2 causing global warming. Our activity could be a trigger mechanism, no? Of course this hasn't happened before but that doesn't tell us anything because we haven't had industrial societies before.

 

[Andre]

But we have had hundreds of large meteorite impacts in the last 4,7 Ga of which a few dozens are recognized in the last 600Ma. Some may have left distinct effects. There is the antipode flood basalt volcanism hypothesis. This may have occurred with the K-T extinctintion, the Indian Deccan traps being antipode to the Chicxulub crater at 65 Ma. But, why wasn't there a catastrophic release of methane.

Possebly the same happened during the End Permian extinctions and the Siberian Trap flood basalt volcanism and possible impacts http://researchnews.osu.edu/archive/erthboom.htm

Hence not very unique

A rather big difference with this type of events is the subsequent extinctions. Instead, the PETM led to an explosion of biodiversity.

Another thing, after installing acrobat reader and reading my PDF file it should be clear that during the last glacial transition the large methane spikes did not lead to significant warming events, consequently there is no reason to expect something different then.

 

[billiards]

I've heard arguments that there was a catastrophic release of methane 65 Ma ago. But that's beside the point...

Why is anthropogenic CO2 not important in global warming?! I am yet to receive a satisfactory, direct answer.

 

[Andre]

We could echo that as follows:

Why is anthropogenic CO2 important in global warming?! I am yet to receive a satisfactory, direct answer.

I'm about to answer your version of the question in the NERC discussions here: post 237

http://www.nerc.ac.uk/about/consult/debate/debate.aspx?did=1&pg=1

 

[billiards]

No! That shows nothing... you keep referring back to this case study with the mammoths, but you seem unwilling to specify exactly how or why this demonstrates that CO2 is unimportant (apart from your own (lack of?) politics which I am not interested in).

Elaborate, explain it to me like I am a kid.

As for reflecting the question back, "why is anthropogenig CO2 important?". I would argue (fairly standardly) that CO2 is a greenhouse gas, we may only contribute about 3% of the world's total CO2 output but considering that the Earth may well be warming naturally anyway (it might not be we don't know) this addition of CO2 could be disastrous. It is as simple as that - it's a greenhouse gas!

The effect of a 3% increase could (is currently?) trigger the ice caps to melt, sea levels to rise, changing ocean circulation. The response time will also be quite slow, and the recovery time even longer so the full effects of our damage still haven't been fealt and will not be fixable even if we found a way to cool things back down. If deep water formation mechanisms shut down and heat is concentrated in the upper surface we would see significant temp rises much greater than just the greenhouse mechanism predicts.

So why is CO2 not important!?

 

[Andre]

http://www.nerc.ac.uk/about/consult/debate/debate.aspx?did=1&pg=2

#228 was intended to answer the question if anthropogenic addition of CO2 into the atmosphere "matters" for climate. However I was jumping too quickly. Some elaboration is required.

In #41 I said that calculation of doubling CO2 for a blackbody without feedbacks would be 0.7K initially and 1.2K at thermal equilibrium, to be reached millenniums later. This should not worry anybody, doubling alleged pre-industrial 280ppm is still a long way and there is probably not enough fossil fuel around to get that value doubled again.

However there is the question of feedbacks, positive or negative which makes that number useless. It could be only 0,1 K/2xCO2, it could be 5 K/2xCO2. Now we can try and model all we want, but the complex chaos of climate requires empirical observations for temperature adaptation to various levels of greenhouse gasses. Therefore we look at Mars, Venus, the Jurassic, the Palaeocene Eocene Thermal Maximum, the Pleistocene ice ages, the Holocene Thermal Maximum, the Medieval Warm Period. I try to demonstrate that the interpretation of many details may require some revision and that there is no support for any "positive feedback". There is also the notion of flickering climates with flipping point of no return, which is based on the Dansgaard Oeschger events from the Greenland isotopes. I have shown that the interpretation of those isotopes is incorrect, it's mostly about strong variation in summer precipitation and little about temperatures.

So, what then, caused the warming of the past part of the former century? For that I refer to #39 in which I refer to the albedo measurements of Pallé et al 2006 and the correlation with temperature. This would have lead to a theoretical 2.7 K variation in temperature but the real increase was only ~0.5 K showing a robust negative feedback, which answers the question. Negative feedback ensures that there is no reason to assume that increase in CO2 has significant effects on climate

post #247

Several posts have discussed the greenhouse effect qualitatively, how about a few numbers. Without an atmosphere and with the same reflectivity of 30% Earth would have an average temperature of -18C. Instead the average temperature is some +15C (not really but ok). So the difference is explained as greenhouse gas forcing of which 5-25% is due to CO2 depending on the source, the rest mainly water vapour. We are on the logarithmic relationship between concentration and radiation absorption. So if we assume a baseline of 1 ppmv CO2 we get to 360 ppmv after some 8,5 doublings. So if we assume that CO2 controls the water vapour for 100% as feedback, the increase in temp for doubling CO2 would be about 33/8,5 is about 3,9 degrees/2xCO2. Close to the high end forecast of IPCC (why do we need those billions to get that calculated?). Anyway, this is very unrealistic. Without a trace of positive feedback, and assuming neutral feedback or a gain factor of 1, the actual figure would be anywhere near 0,2 - 1 degree per doubling for the 5-25% range of the effect of CO2, that is, if that 33 degrees is indeed greenhouse effect.