From the European Association of Geochemistry, a claim that looks to be little more than paleo-dowsing. Though, ya gotta love the silly claim that Earth would have hit a runaway greenhouse effect like Venus, had it not been for some mountains forming, sucking up all the CO2. Plus we’ve seen the Earth hit 5000PPM CO2 in the past, and it didn’t turn into Venus. This (Figure 1) from this post at the Met Office.
Of course it all just more model output, there’s no real earth science going on -all guesswork, no actual measurements.
How Earth avoided global warming, last time around
Geochemists have calculated a huge rise in atmospheric CO2 was only avoided by the formation of a vast mountain range in the middle of the ancient supercontinent, Pangea. This work is being presented to the Goldschmidt geochemistry conference in Sacramento, California.
Around 300 million years ago, plate tectonics caused the continents to aggregate into a giant supercontinent, known as “Pangea”. The sheer size of the continent meant that much of the land surface was far from the sea, and so the continent became increasingly arid due to lack of humidity. This aridity meant that rock weathering was reduced; normally, a reduction in rock weathering means that CO2 levels rise, yet in spite of this CO2 levels – which had been falling prior to the mountain formation- continued to drop, eventually undergoing the most significant drop in atmospheric CO2 of the last 500 million years. This phenomenon has remained unexplained, until now.
Now a group of French scientists from the CNRS in Toulouse have produced a model which seems to explain this contradiction. The period coincides with the rise of a vast series of mountains in the interior of Pangea, the “Hercynian” mountains”. These mountains arose in a wide belt, running from what is now the Appalachians, through to Ireland, South-Western England, through Paris and the Alps into Germany, and on further East.
According to team leader, Dr Yves Godderis (CNRS, Toulouse, France):
“The formation of these mountains meant that the rock weathering, which was threatening to slow to a walk through much of the supercontinent, was able to continue. The steep slopes of these Hercynian mountains produced physical erosion. Occurring in a humid equatorial environment, this physical erosion promoted rock weathering and removing CO2 from the atmosphere”.
He continued, “We believe that it is this which led to the dramatic drop in atmospheric levels of CO2. We estimate that if it hadn’t been for the formation of the Hercynian mountains, the atmospheric CO2 levels would have reached around 25 times the pre-industrial level, meaning that CO2 levels would have reached around 7000 ppm (parts per million). Let me put that into a present-day context; the current atmospheric CO2 levels are around 400 ppm, so this means that we would have seen CO2 rise to a level around 17 times current levels. This would obviously have had severe effects on the environment of that time. But the formation of the mountains in fact contributed to the greatest fall in atmospheric CO2 in the last 500 million years”.
The team believes that even if the mountains had not formed and CO2 levels rose sharply, this would not have led to a runaway greenhouse effect as happened on Venus, because the increasing temperatures would have led to rocks being ultimately weathered, heat compensating for the scarcity of water. Rock weathering would have removed CO2 from the atmosphere, thus stopping the rising temperatures.
“So it would eventually have been self-correcting” said Dr Godderis, “but there’s no doubt that this would have stalled Earth’s temperature at a high level for a long, long time. The world would look very different today if these mountains had not developed when they did.
This is a new model which explains some of the events in the 80 million years following the start of the Carboniferous period, and of course the ideas need to be confirmed before we can be sure that the model is completely accurate. The take-home message is that the factors affecting atmospheric CO2 over geological periods of time are complex, and our understanding is still evolving”.
In Cosmos episode 12, Carl Sagan’s protoge Neil dg Tyson uses the same switcheroo from a hellish Venus to what will happen on Earth if we don’t reduce man-made CO2. – all designed to scare the kiddies witless – “good one Neil” – NOT.
I made it about 6 minutes past that presentation in Cosmos and then closed the window to Hulu on my computer. I will never consider another word Tyson speaks again.
I really wish somebody would tear apart the lies presented in this latest Cosmos.
‘The take-home message is that the factors affecting atmospheric CO2 over geological periods of time are complex, and our understanding is still evolving”.’
The science isn’t settled?
“The team believes that even if the mountains had not formed and CO2 levels rose sharply, this would *not* have led to a runaway greenhouse effect as happened on Venus”.
“Understanding Still Evolving”. Precisely!
What I find interesting (and vaguely disturbing) is the apparent long term diminishing trend of CO2 in the Earth’s atmosphere. If I recall correctly, and please feel free to inform me otherwise if I’m mistaken, plants can start to run into problems with photosynthesis when CO2 falls below 150-170 ppm. Now, given that pre-industrial levels of CO2 were at 270(?) ppm, it seems to me that we weren’t too far away, geologically speaking, from some sort of REAL crisis and perhaps permanent mass extinction of the more complex life on Earth.
An idea which has occurred to me is that planetary eco-systems are something of a “biological battery”, where CO2 is the major organic fuel/component. Over deep time the CO2 is removed via organic/non organic means, eventually to a point of near depletion, making complex life non viable. Effectively the battery becomes discharged or in other words, “flat”!
Seems to be as good an explanation for the Fermi Paradox as any.
Oh, BTW, has anybody got any reliable figure/estimations regarding the quantity of CO2 generated by beer, sparkling wine, soft drinks etc.? Seriously…
[TO ANTHONY: I’d thought about broaching this idea a while ago but this post seemed an opportune time to do so. Thanks for all your effort.]
I was very much disappointed with NDT’s views on CO2. Even more disturbing is a short YouTube video in which he attempts to explain “climate” and “weather” using a dog on a leash. Simplistic and mis-leading.
I’ve given up on Cosmos.
They got the timing completely backwards here.
CO2 fell steadily from about 380 million years ago until it reached a low plateau starting about 320 million years ago lasting to 265 million years ago, getting down to about 350 ppm.
This happened before the formation of Pangea and the Central Pangean Mountains which started forming about 265 million years ago. CO2 started rising rapidly about 265 million years ago just as these mountains started forming.
The CO2 drawdown happened at least 100 million years before the mountain building phase. More in line with when Gondwana was over the south pole and the large glaciers of the Carboniferous formed here. Europe and North America were actually very flat at the time and were actually off-and-on flooded by the ocean during the low CO2 point. What often happens in cold ice age conditions (like the Carboniferous), CO2 levels are drawn down.
Overall, this study is just scientists who know nothing about the timelines but have a creepy fascination with the word “weathering” which many CO2 warming proponents also have.
Critical Zone and Carbon Cycle in the Deep Time by Yves Godderis
Abstract (Godderis Y, Donnadieu Y & Carretier S)
[My Bold]
The large scale spreading of vascular plants decreased the albedo of the continents, leading to a paradoxal climatic evolution in which an ample decrease in atmospheric CO2 over the course of the Devonian period might have occurred at roughly constant continental temperatures3. This study also emphasized the key role played by land plants on the continental hydrologic cycle.
http://goldschmidt.info/2014/uploads/abstracts/finalPDFs/817.pdf
In light of more CO2 equals higher temps, I would like to see an explanation for the roughly constant temperatures.
Don’t you just love these new fangled computer models. They can take arid environments and turn them into humid equatorial environments just by growing some mountains. No mention of how tall the mountains were… I wonder how many mountain passes the computer modelers programmed in.
Steep slopes of the Hercynian mountains… Steep? I suppose the model required steep mountains for some reason? The odd thing about steep mountains is that above certain altitudes, they tend to keep moisture as perennial snowcaps. Steep mountains with heights under the snowcap level look sort of funny if they’re mesa shaped.
Mountains on Earth have difficulty retaining steep slopes because gravity wins. Weathering is a complex process where the more complex the mineralization, the quicker the weathering. There are exceptions where large resistant granitic massifs are elevated. But whole mountain chains composed of massifs are about as believable as funny models.
Bill Illis says:
June 11, 2014 at 9:22 pm
How this study’s authors managed to ignore the Late Carboniferous (Pennsylvanian) glaciation needs explaining. Maybe they discuss it in the paper.
CO2 fell in the Pennsylvanian (323 to 299 Ma) because of a long, deep glaciation, which persisted into the Early Permian. Colder T meant more of the gas in the oceans & less in the air.
Previously (during the Mississippian, (359 to 323 Ma) it fell due to the then luxuriant growth of land plants, which made the eponymous Carboniferous coal beds, especially before the development of advanced fungi to help break down rotting vegetation.
Golly-Gee Mr.Wizard !! I always thought all that CO2 went into the coal beds & limestone deposits (and other carbonate bedrock) laid down during the Carboniferous age which was, curiously enough ~360 million years ago. Curiously enough, this coincides nicely with their graph’s descent from 2000+ ppm CO2 to low levels. Who would have thunk it ??
Let’s do an experiment and burn every lump of coal (think of all those bad-boys) & lime up every ounce of limestone and see what happens !! Dodge that ….
” Rock weathering would have removed CO2 from the atmosphere, thus stopping the rising temperatures.”
==============
Not a word in regards to salt water /heat capacity.
cnxtim said: “In Cosmos episode 12, Carl Sagan’s protoge Neil dg Tyson uses the same switcheroo from a hellish Venus to what will happen on Earth if we don’t reduce man-made CO2. – all designed to scare the kiddies witless – “good one Neil” – NOT.”
I haven’t even bothered. I am 30 but I remember my dad getting the cosmos series on VHS in the mid-90s. I was mesmerized. It had a huge effect on my understanding of the world and, to this day, I will go back and watch various little snippits.
The beauty of it: as it was put together in the late 70s (I believe), there wasn’t one mention of climate change. It was just science. It makes me sad to think what I would have missed out on if it hadn’t been produced when it was, before anything scientific had to have a CAGW-related footnote on every Godd**n release.
Our kids are being robbed and the villians won’t be satisfied until they have their souls. Oh, silly me. That’s right: ‘souls’ are religious, mystical fluff. How could I be so unscientific?!? They have now been replaced by the NRDC mission statement and offset by carbon credits.
Maybe the reconstruction of Earth’s atmospheric history has changed since I last read about it, but as I recall, after Earth finished accreating it’s atmosphere was very like that of Venus. Then massive amounts of carbon dioxide were sequestered by the formation of carbonate rocks, mainly by reaction with calcium and magnesium ions in the oceans. So the reason Earth is not like Venus is because Earth had literaly oceans of water from very early on.
“Plus we’ve seen the Earth hit 5000PPM CO2 in the past, and it didn’t turn into Venus.”
Also, 5000ppm although larger than 400ppm is still not significant compared to 965,000ppm. as on Venus. If CO2 is that effective that small variations of between 300ppm to 5000ppm can have large temperature effects then 965,000ppm should have turned the surface of Venus molten?
Just asking.
“runaway greenhouse effect as happened on Venus” ?
Venus is a newcomer in the solar system and it is slowly cooling down and speeding down its rotation velocity. There is no runaway greenhouse effect on Venus.
Robertvd says:
June 12, 2014 at 12:25 am
“runaway greenhouse effect as happened on Venus” ?
“… and speeding down its rotation velocity. ”
Can it go any slower?
Venus, tropopause 70K above the surface, surface atmospheric pressure 92bar, insolation less than half that of earth due to very high albedo, (0.67) atmospheric lapse rate 10.2C/km surface temperature over 700K due to ADIABATIC COMPRESSION.
jiohnmarshall says:
“surface temperature over 700K due to ADIABATIC COMPRESSION”.
Sorry, but no, compression only heats a gas when pressure is increasing and energy is added to the system. Strange that this seems to be so difficult to understand.
It is true that the high temperature on Venus’ surface is due to the depth of the atmosphere and the lapse rate, but the temperature profile is due to convection.
‘Plus we’ve seen the Earth hit 5000PPM CO2 in the past, and it didn’t turn into Venus’, well even 300,000ppm! But if you research deep enough there is a reason for everything. Anyhow Venus is not the Earth, there are differences.
CO2 300,000 ppm but snowball Earth, followed by hot house Earth!
‘a puzzle called the faint sun paradox is explained by the warming effect of GHG, mostly co2…but if co2 fell it wouldn’t take much to tip the world into an ice age…a positive feedback leading to more cooling, more ice, more reflection, until nearly all the world was covered by ice…there is no way the Sun could melt all this ice,…but something did…because the Earth turned into a hothouse…geologists say the reason is very simple, the only part of the Earth not covered by ice was warm spots caused by volcanoes…but they did release gases..,co2 under normal conditions this would have reacted with rocks and rainfall and get washed out to sea…but in snowball Earth, there is no rain, no weathering…so the co2 just keeps building up…so you have high co2 levels with glaciers at the equator but this is a dynamic process, it doesn’t stay like this’.
Now see for yourself!
Mountain building takes place over many millions of years. CO2 climate sensitivity is so fast it takes place in a few years, allegedly.
There is no way this is a meaningful- if even honest- attempt to explain the past.
By the way, what is happening in Indonesia is a massive mountain building exercise.
And, as others have pointed out, calling Venus a ‘runaway greenhouse’ is a deceptive way to speak of Venus. And anyone asserting Earth could become Venus is being even more deceptive.
Stephen Skinner says:
“Also, 5000ppm although larger than 400ppm is still not significant compared to 965,000ppm. as on Venus. If CO2 is that effective that small variations of between 300ppm to 5000ppm can have large temperature effects then 965,000ppm should have turned the surface of Venus molten?”
Actually it is much worse than that. It isn’t the proportion but rather the total amount of CO2 that matters. Counted in “terran ppm” the amount of CO2 in Venus atmosphere is more than 65,000,000 ppm.
Stephen Skinner says:
June 12, 2014 at 12:28 am
“Can it go any slower?”
Apparently it is slowing down. Can’t find the link, but there was a rash of stories a few months ago about measurements of Venus showing an unexpected change in its rotation.
One of those things.
Of course the difference between Venus and Earth is very simple: we have water. Without water our atmosphere would be a roiling, toxic nightmare just like the one on Venus, though we obviously wouldn’t be around to worry about it.
tty above,
The venusian atmosphere is under continual compression. It is not stratified and isothermal but under continued convectgion. Surface winds are monumental.
The atmosphere is so thick it is debatable if any insolation actually makes the surface to heat it. It is all adiabatic.
Actually it is pretty meaningless trying to quantify weathering of past mountain chains, the reason being that today only the roots of the mountains are left, and we have no good way of judging how high they were. It is possible to roughly judge the amount of weathering by studying the amount of sediments laid down around the mountains. However on that score the Caledonian orogeny was a great deal larger than the Variscan, judging by the vast deposits of “old red sandstone” and equivalent sediments.
Also the balance of mechanical erosion vs. chemical weathering varies widely. Young and steep mountain chains are largely mechanically eroded, and the sediments contain quite fresh, unweathered materials. The chemical weathering becomes dominant later, when the mountains are already partly eroded and there is plenty of finer materials to weather (a big, solid lump of rock weathers vastly slower than gravel).