From a University of Copenhagen News Release
First, read a primer on the Faint Sun Paradox here Normally, I wouldn’t use Wiki, but the article does include a reference to Nir Shaviv.
Lot’s of “mays and ifs” in this one. Our understanding is by proxy. In this article, unfortunately, life is made to be the culprit of the ice ages. Note the standard caveat at the end. Here is another primer, on Carbonyl Sulphide. Interestingly that primer says that:
This compound is found to catalyze the formation of peptides from amino acids. This finding is an extension of the Miller-Urey experiment and it is suggested that carbonyl sulfide played a significant role in the origin of life.
On the plus side, CO2 isn’t vilified here. – Anthony
The greenhouse gas that saved the world
Chemistry researchers uncover why the archean world was not frozen solid
When Planet Earth was just cooling down from its fiery creation, the sun was faint and young. So faint that it should not have been able to keep the oceans of earth from freezing. But fortunately for the creation of life, water was kept liquid on our young planet. For years scientists have debated what could have kept earth warm enough to prevent the oceans from freezing solid. Now a team of researchers from Tokyo Institute of Technology and University of Copenhagen’s Department of Chemistry have coaxed an explanation out of ancient rocks, as reported in this week’s issue of PNAS
A perfect greenhouse gas
– “The young sun was approximately 30 percent weaker than it is now, and the only way to prevent earth from turning into a massive snowball was a healthy helping of greenhouse gas,” Associate Professor Matthew S. Johnson of the Department of Chemistry explains. And he has found the most likely candidate for an archean atmospheric blanket. Carbonyl Sulphide: A product of the sulphur disgorged during millennia of volcanic activity.
– “Carbonyl Sulphide is and was the perfect greenhouse gas. Much better than Carbon Dioxide. We estimate that a blanket of Carbonyl Sulphide would have provided about 30 percent extra energy to the surface of the planet. And that would have compensated for what was lacking from the sun”, says Professor Johnson.
Strange distribution
To discover what could have helped the faint young sun warm early earth, Professor Johnson and his colleagues in Tokyo examined the ratio of sulphur isotopes in ancient rocks. And what they saw was a strange signal; A mix of isotopes that couldn’t very well have come from geological processes.
– “There is really no process in the rocky mantle of earth that would explain this distribution of isotopes. You would need something happening in the atmosphere,” says Johnson. The question was what. Painstaking experimentation helped them find a likely atmospheric process. By irradiating sulphur dioxide with different wavelengths of sunlight, they observed that sunlight passing through Carbonyl Sulphide gave them the wavelengths that produced the weird isotope mix.
– “Shielding by Carbonyl Sulphide is really a pretty obvious candidate once you think about it, but until we looked, everyone had missed it,” says Professor Johnson, and he continues.
– “What we found is really an archaic analogue to the current ozone layer. A layer that protects us from ultraviolet radiation. But unlike ozone, Carbonyl Sulphide would also have kept the planet warm. The only problem is: It didn’t stay warm”.
Life caused ice-age
As life emerged on earth it produced increasing amounts of oxygen. With an increasingly oxidizing atmosphere, the sulphur emitted by volcanoes was no longer converted to Carbonyl Sulphide. Instead it got converted to sulphate aerosols: A powerful climate coolant. Johnson and his co-workers created a Computer model of the ancient atmosphere. And the models in conjunction with laboratory experiments suggest that the fall in levels of Carbonyl Sulphide and rise of sulphate aerosols taken together would have been responsible for creating snowball earth, the planetwide ice-age hypothesised to have taken place near the end of the Archean eon 2500 million years ago. And the implications to Johnson are alarming:
– “Our research indicates that the distribution and composition of atmospheric gasses swung the planet from a state of life supporting warmth to a planet-wide ice-age spanning millions of years. I can think of no better reason to be extremely cautious about the amounts of greenhouse gasses we are currently emitting to the atmosphere”.
From a University of Copenhagen News Release
h/t to Leif Svalgaard
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“Venus isn’t in runaway warming. It simply has a larger atmosphere.”
It isn’t now (fairly stable at 400 degrees), hence my use of past tense, but it’s generally accepted it experienced runaway warming at some point earlier, in which it rapidly warmed past the point where the oceans evaporated.
http://en.wikipedia.org/wiki/Atmosphere_of_Venus
Also, Venus’s amosphere is so dense mostly because there is nothing to remove carbon from the atmosphere. If you took out the CO2 from Venus’ atmosphere and made it a trace gas like here on Earth you would decrease its mass by 95%. It would still be thicker than Earth’s, but not by nearly as much.
Robert A Cook PE (11:13:02) :
Ive often wondered how much effect albedo has at high latitudes, Im assuming the optical depth of the atmosphere would reduce the shortwave that reaches the surface significantly? And the angle of the light id imagine would cause a higher percentage to be reflected out as short wave into space, (even off open water)…(im of the opinion sea ice has more to do with wind and currents)
But at lower latitudes i think it could be a significant factor.
The CO2 in Venus’ atmosphere does not explain its surface temperature.
The surface temperature is about 709K and solar energy and the greenhouse impact of the atmosphere can only explain about 309K. (I guess one could use 45C per doubling but that sounds a little unrealistic when Earth’s is only 1.5C to 3.0C per doubling and it has more initial solar energy to start with).
So, there is 400K missing – there is no candidate for what is causing this extra 400K other than atmospheric pressure – obviously, it is time to bring the “Gas Laws” into the climate equations.
Surface Temp = Solar Forcing + Greenhouse Forcing + Atmospheric Pressure/Gravitational Compression Forcing.
Bill Illis (17:01:51) : “obviously, it is time to bring the “Gas Laws” into the climate equations.”
That was the idea I think with having bars and bars of CO2 in the early Earth’s atmosphere to “solve” the faint young sun paradox. Doesn’t work on Earth, but Venus it might.
timetochooseagain,
If the greenhouse effect is 33C – if the surface temperature is 33C higher than it should be based on the solar energy alone, …
And if you do the math for 280 ppm in halvings (the opposite of doubling), there is only 11 halvings to get to effectively Zero.
If you assume 3.0C per doubling, then 11 halvings produces a ZeroC greenhouse effect (and the doubling value cannot be more than 3.0C – actually 3.2C is the accurate complete number). That would mean GHGs/CO2 is responsible for the entire greenhouse effect by also controlling 100% of the water vapour as well. Probably not true.
If you assume 1.5C per doubling, take away all the non-water-GHGs and you still have 16.5C left to explain.
The only candidates to explain the remaining half of the 33C extra surface temperature is:
– water vapour – it does not decline on a one-for-one basis as greenhouse theory assumes – it only declines at 50% of the rate the theory expects – the humidity data that is available indicates that water vapour is probably very stable – specific humidity should increase as the same relative rate as ln(CO2) has – but the data says that specific humidity has increased very marginally at lower atmospheric levels and declined at higher levels – so it is not responding as the theory indicates ; and/or the remaining 16.5C is explained through:
– atmospheric pressure contains latent heat.
Now temperatures do rise as pressure increases everywhere in the universe. The centre of the stars do not initiate fusion until the pressure and temperature inside builds to millions of degrees. The centre of Jupiter is 10,000K even though not a single photon of solar energy gets down there and there are no greenhouse gases – hydrogen and helium are not greenhouse gases? Venus is 400K hotter than it should be. The centre of the Earth is 5700K. There are “Gas Laws” that says pressure = heat so I don’t know why that is ignored.
What relevance does this have to a modern atmosphere?
I don’t think that the molecule would be stable in the presence of oxygen, for example.
Certainly, if Lovelock’s model of a self-regulating climate is correct, temperature has been regulated by life balancing out some of those factors under life’s control to keep the climate mostly stable, with only a few exceptions, over a couple of billion years. One of the inputs to that system is of course a greenhouse effect, of greater or lesser extent through time.
You’re implying that greenhouse effects are good, so that it is impossible for them to hurt us?
Very simplistic reasoning, IMO.
Water is good too, but it’s certainly possible to drown in it.
And compared to the slow ripples our climate system and biology are adapted to dealing with, our geologically instantaneous increase in CO2 and especially methane is coming at us like a vertical wall, moving a thousand miles an hour.
First, read a primer on the Faint Sun Paradox here Normally, I wouldn’t use Wiki, but the article does include a reference to Nir Shaviv.
Better squirrel away a copy while you can. (That is now my standard procedure if using a wiki article these days… One time too many a good article has been corrupted after pointers to it started adding up…)
– “The young sun was approximately 30 percent weaker than it is now, and the only way to prevent earth from turning into a massive snowball was a healthy helping of greenhouse gas,”
The ONLY way? REALLY?
How about a much larger sized lump of U in the mantel and core of the planet when it first formed providing a bunch of persistent heat? I seem to remember someone positing this (and pointing out that his model also predicted a fall off in vulcanism that we’ve (maybe) seen – but also predicted that the U would “run out” [really just run down to a low level] about now and that has implications for C recycle along with a host of other things that keep us alive like our mag field…)
Oh, and the theory also explains the excess energy from Jupiter as well. AND provides the “trigger” to get the sun started. Basically the guy posits that U was present in enough abundance to form a lump in the center of the sun to make a fission trigger; in the center of Jupiter enough to explain it’s excess energy for 4+ Billion years; and in the center of the earth enough to explain our warmth and vulcanism for 4+ billion years.
To discover what could have helped the faint young sun warm early earth, Professor Johnson and his colleagues in Tokyo examined the ratio of sulphur isotopes in ancient rocks. And what they saw was a strange signal; A mix of isotopes that couldn’t very well have come from geological processes.
Come again? Changing the sunshine filtering changes isotopic mix in sulphur? Something is missing in this explanation…
By irradiating sulphur dioxide with different wavelengths of sunlight, they observed that sunlight passing through Carbonyl Sulphide gave them the wavelengths that produced the weird isotope mix.
I still don’t get it. Sunshine filtered by Carbonyl Sulphide gives a wavelength that produces isotope mixes? It has to be some kind of isotopic separation via reaction catalysis or something other than “produced the weird isotope mix” directly.
Robert A Cook PE (09:11:47) :
Well, at least it goes up and down at the right times: I’m convinced that orbit perturbations influence ice ages, but the ice ages themselves seem to come “too fast” […] But what “tips” to cause 4000 feet of ice to cover Indiana, Illinois, and all of North and South Dakota, Michigan, Minnesota, and most of Canada?
Best explanation I’ve seen is:
http://www.sciencebits.com/ice-ages
By Nir J. Shaviv
Which explains the ice-epochs, then Milankovitch explains the glacial / interglacial pattern within the ice-epoch.
Bill Illis (12:22:29) : Some of the newer research on stellar evolution of metal-rich GV stars like our Sun indicate there is a period at the beginning
What’s a “GV” star? It’s been a while since I had the “Geology of the Solar System” class (it was way cool and covered stellar evolution) and I may have forgotten the acronym or?… We’re just a regular old 1 Solar Mass main sequence star, no?
Secondly, a 30% less luminous Sun does not translate into 30% less solar energy at Earth distance.
And if I remember correctly, some folks were still arguing over the potential for the planets to have wandered a bit in their orbits since formation (something about the gas giants maybe migrating outward?) Do we really know exactly what distance earth orbited at 4 billion years ago? The moon is drifting outward, and I thought some of the planets had wandered further out too? No?
deadwood (15:55:38) : We are now seeing how bad science can infect other disciplines. We now have greenhouse gasses being used to explain every climate fluctuation in all of geological history.
It is quite hard work to keep a tidy mind. I find that I must fight constantly to keep the trash out… And the whole “greenhouse gas” meme is very trashy…
Sometimes we have to keep in mind that the words of Mark Twain, who said “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. “
I must dig out my old book of Mr. Mark Twain and read him again. Such a finely honed and tidy mind… A more suitable stone for sharpening ones wit a whit is not to be found.
timetochooseagain (17:37:51) :
srchuck (16:42:27) : Gore doesn’t have a doctorate. He flunked out of Divinity School, but he doesn’t get to call himself Doctor.
Hey, for a small fee he could… I can call myself a Doctor (I have a D.D. Doctorate of Divinity). I paid the extra when my friends requested their free “minister” ordinations (I think it was $20 extra?) and went for the full D.D. (with which one got a much nicer certificate…)
Kirby J. Hensley and the Universal Life Church:
http://en.wikipedia.org/wiki/Universal_Life_Church
But that was 30 years ago… it probably costs more now 😉
And yes, it is legal and means that I can perform marriages and officiate at funerals (along with other things). The fact that I happen to agree with some of the (very limited) “official” beliefs is strictly accidental 😉
Nogw (17:03:06) : You apparently have no clue what Shaviv’s idea was. There is no “diving in and out of the milky way like a dolphin” involved at all.
Yeah. We don’t “dive in and out” of the spiral arms, they are compression artifacts, more like the stop and go of cars in a traffic jam, causes by the changes of gravity as things bunch up and spread out. Oh, and while the two galaxies are merging, turns out we really are from The Milky Way – the story that we were the space aliens caught me too, but it isn’t correct.
E.M.Smith, CDP, DD, AB, BFD
Lucy Skywalker (02:34:27) : Now here’s a new idea. Suppose there was lots more atmosphere originally. Would that not support giant life-forms a lot more easily? Would not the atmosphere condition be much more like the present oceans which can support the vast life-forms of whales? What could drive the atmosphere off, in this case? Moon ejection or similar (sudden)? Solar wind (gradual)?
Or more prosaic: It didn’t leave.
Take a look at the mass of the banded iron formations (postulated to be from the removal from the atmosphere of O2) and the global carbonate rock deposits (postulated to be from CO2 scrubbing via the ocean).
There is one heck of a large mass of “stuff” that is supposed to have come out of the air. And if it came out, and what we have now is the residual, there was a lot more air in the past…
http://en.wikipedia.org/wiki/Banded_iron_formation
has: “The total amount of oxygen locked up in the banded iron beds is estimated to be perhaps twenty times the volume of oxygen present in the modern atmosphere”
As for the carbonates: Think marble, dolomite, White Cliffs of Dover, all the chalk they drilled though to get the Chunnel to France, limestone all over the place. I don’t know what the total is, but this article:
http://www.ingentaconnect.com/content/bsc/iar/2001/00000010/00000001/art00001
claims a rate of accumulation between 14.8 and 29.8 x 10e18 mol/ma (though it looks a bit tenuous to me…)
At any rate, pick a place on the planet and you are likely to find many meters thick layers of some carbonate or another somewhere nearby. Heck, even the Himalaya have sea shell deposits (as do the sediments in the Sierra Nevada), most of Florida is carbonate, the Karst deposits of the Southeast too, even the land that the Grand Canyon is cut through has shells in the sandstone.
So put all that carbonate into the air as CO2 (assuming in a very not newly formed world carbonates are not stable) and you get a pretty thick atmosphere.
That ought to have been “assuming a very HOT newly formed”…
“It isn’t now (fairly stable at 400 degrees), hence my use of past tense, but it’s generally accepted it experienced runaway warming at some point earlier, in which it rapidly warmed past the point where the oceans evaporated.”
I’m not sure I trust Wikipedia on anything to do with the greenhouse effect. I would, in any case, like more detail on this argument, because it doesn’t fit together for me yet.
The temperature on the surface of Venus is a combination of an average altitude of emission to space about 50 km up, (due to a high-level tropopause and thick clouds above it) and an 8 C/km adiabatic lapse rate, giving a cloud-surface temperature difference of roughly 400 C. The main difference between our atmospheres is that on Earth the CO2 was locked away in carbonate rocks by plate tectonics, and fairly obviously wasn’t on Venus (or at least not permanently) because it’s currently free.
Why is a ‘runaway greenhouse’ from boiling oceans required to explain this? It is true that if there were ever oceans on Venus, they must have boiled at some point, and something must have caused the rising temperature and thickening atmosphere, but how can anyone tell what it was?
Stevo,
Shrug. I’ll tell you what I always tell people in these situations: don’t trust Wikipedia, trust the cites. It’s not really warmenist-friendly.
“This paper is an extension of previous work by Kasting and Ackerman (1986), who showed that CO2 increases alone would not trigger a runaway greenhouse.”
http://adsabs.harvard.edu/abs/1988Icar…74..472K
The main difference between our atmospheres is that on Earth the CO2 was locked away in carbonate rocks by plate tectonics, and fairly obviously wasn’t on Venus (or at least not permanently) because it’s currently free.
Exactly. This is why it’s a bit inexact to say Venus simply has a bigger atmosphere: most of that is carbon, which we have a similar amount of here.
Why is a ‘runaway greenhouse’ from boiling oceans required to explain this?
Because, as I understand it, lack of plate tectonics isn’t enough to explain how all that carbon ended up in the Venusian atmosphere. There is also a sublimation reaction at high temperatures that pulls CO2 out.
There’s been some talk it might someday be possible to cool Venus back to its primordial state. If we can block some percentage of the radiation it receives so it cools a bit, we could introduce some hardy engineered microbes to lock that carbon back into the ground and get some oxygen going, eventually making the place habitable for humans.
Stevo (11:28:12) :
Agreed, the fact that venus has 243 earth day, days, no magnetic field to speak of, slightly less mass etc, its not really comparing apples with apples.
I think our climate would be significantly different with just one of these factors, with all three, i dont think its unreasonable to speculate that the h2o would be stripped from our atmosphere relatively quickly, and with no means for sequestering co2 we would soon be in the same boat…
TallDave,
Generally, I don’t trust the cites either, but I take your point. 🙂
Thanks for the pointing out the paper, it clarifies a few issues, but I still have some questions about it.
The calculation seems based on the ideas around figure 7. The outgoing IR and net incoming solar fluxes at the top of the atmosphere are calculated assuming a solar constant of 1360 W/m^2 for various surface temperatures. They then effectively ask what you have to multiply the solar flux by to get it to balance the IR flux, and assert that this is the solar constant that would yield that temperature.
The problem is, I think that increasing the solar constant would increase the outgoing IR flux too. The problem is, they’re a bit skimpy on the details of how they calculated it, so I can’t tell.
They say that the reason the IR out approaches a constant 310 W/m^2 as temperature rises is that the moist convective atmosphere becomes thick enough to be totally opaque to IR, so the emission to space is unchanged by additional thickness of the layer. Agreed. But I would expect that this limit is going to be determined by the heat out approaching balance with the heat in. They use 1360 W/m^2 as the solar constant, which you can divide by 4 to get the average over a sphere, giving 340 W/m^2. I’m not sure why there’s a 10% difference here, but I strongly suspect that with some adjustments this is the basic origin of this number.
The net solar flux is essentially this same number reduced by the albedo, so the ratio of the two winds up being close to 1/(1-albedo), about 1.4.
Their ‘runaway’ greenhouse effect comes down to an assertion that a hot moist planet cannot lose heat faster than 310 W/m^2, so once the heat input exceeds this the temperature rockets up uncontrollably. (Note, not by positive feedback.) It’s only when the blackbody radiation from the surface gets into the visible part of the spectrum that it can start losing more heat again.
So what I want to know is where the 310 W/m^2 figure comes from, and why does it not change as the solar constant is increased?