From the University of Colorado at Boulder a claim that computer modeling has solved the problem, with an atmosphere that is 20,000 parts per million of CO2 and 1,000 ppm of methane.
CU study shows how early Earth kept warm enough to support life
Scientists tackle faint young sun paradox with 3-D climate models
Solving the “faint young sun paradox” — explaining how early Earth was warm and habitable for life beginning more than 3 billion years ago even though the sun was 20 percent dimmer than today — may not be as difficult as believed, says a new University of Colorado Boulder study.
In fact, two CU-Boulder researchers say all that may have been required to sustain liquid water and primitive life on Earth during the Archean eon 2.8 billion years ago were reasonable atmospheric carbon dioxide amounts believed to be present at the time and perhaps a dash of methane. The key to the solution was the use of sophisticated three-dimensional climate models that were run for thousands of hours on CU’s Janus supercomputer, rather than crude, one-dimensional models used by almost all scientists attempting to solve the paradox, said doctoral student Eric Wolf, lead study author.
“It’s really not that hard in a three-dimensional climate model to get average surface temperatures during the Archean that are in fact moderate,” said Wolf, a doctoral student in CU-Boulder’s atmospheric and oceanic sciences department. “Our models indicate the Archean climate may have been similar to our present climate, perhaps a little cooler. Even if Earth was sliding in and out of glacial periods back then, there still would have been a large amount of liquid water in equatorial regions, just like today.”
Evolutionary biologists believe life arose on Earth as simple cells roughly 3.5 billion years ago, about a billion years after the planet is thought to have formed. Scientists have speculated the first life may have evolved in shallow tide pools, freshwater ponds, freshwater or deep-sea hydrothermal vents, or even arrived on objects from space.
A cover article by Wolf and Professor Brian Toon on the topic appears in the July issue of Astrobiology. The study was funded by two NASA grants and by the National Science Foundation, which supports CU-Boulder’s Janus supercomputer used for the study.
Scientists have been trying to solve the faint young sun paradox since 1972, when Cornell University scientist Carl Sagan — Toon’s doctoral adviser at the time — and colleague George Mullen broached the subject. Since then there have been many studies using 1-D climate models to try to solve the faint young sun paradox — with results ranging from a hot, tropical Earth to a “snowball Earth” with runaway glaciation — none of which have conclusively resolved the problem.
“In our opinion, the one-dimensional models of early Earth created by scientists to solve this paradox are too simple — they are essentially taking the early Earth and reducing it to a single column atmospheric profile,” said Toon. “One-dimensional models are simply too crude to give an accurate picture.”
Wolf and Toon used a general circulation model known as the Community Atmospheric Model version 3.0 developed by the National Center for Atmospheric Research in Boulder and which contains 3-D atmosphere, ocean, land, cloud and sea ice components. The two researchers also “tuned up” the model with a sophisticated radiative transfer component that allowed for the absorption, emission and scattering of solar energy and an accurate calculation of the greenhouse effect for the unusual atmosphere of early Earth, where there was no oxygen and no ozone, but lots of CO2 and possibly methane.
The simplest solution to the faint sun paradox, which duplicates Earth’s present climate, involves maintaining roughly 20,000 parts per million of the greenhouse gas CO2 and 1,000 ppm of methane in the ancient atmosphere some 2.8 billion years ago, said Wolf. While that may seem like a lot compared to today’s 400 ppm of CO2 in the atmosphere, geological studies of ancient soil samples support the idea that CO2 likely could have been that high during that time period. Methane is considered to be at least 20 times more powerful as a greenhouse gas than CO2 and could have played a significant role in warming the early Earth as well, said the CU researchers.
There are other reasons to believe that CO2 was much higher in the Archean, said Toon, who along with Wolf is associated with CU’s Laboratory for Atmospheric and Space Physics. The continental area of Earth was smaller back then so there was less weathering of the land and a lower release of minerals to the oceans. As a result there was a smaller conversion of CO2 to limestone in the ocean. Likewise, there were no “rooted” land plants in the Archean, which could have accelerated the weathering of the soils and indirectly lowered the atmospheric abundance of CO2, Toon said.
Another solution to achieving a habitable but slightly cooler climate under the faint sun conditions is for the Archean atmosphere to have contained roughly 15,000 to 20,000 ppm of CO2 and no methane, said Wolf. “Our results indicate that a weak version of the faint young sun paradox, requiring only that some portion of the planet’s surface maintain liquid water, may be resolved with moderate greenhouse gas inventories,” the authors wrote in Astrobiology.
“Even if half of Earth’s surface was below freezing back in the Archean and half was above freezing, it still would have constituted a habitable planet since at least 50 percent of the ocean would have remained open,” said Wolf. “Most scientists have not considered that there might have been a middle ground for the climate of the Archean.
“The leap from one-dimensional to three-dimensional models is an important step,” said Wolf. “Clouds and sea ice are critical factors in determining climate, but the one-dimensional models completely ignore them.”
Has the faint young sun paradox finally been solved? “I don’t want to be presumptuous here,” said Wolf. “But we show that the paradox is definitely not as challenging as was believed over the past 40 years. While we can’t say definitively what the atmosphere looked like back then without more geological evidence, it is certainly not a stretch at all with our model to get a warm early Earth that would have been hospitable to life.”
“The Janus supercomputer has been a tremendous addition to the campus, and this early Earth climate modeling project would have impossible without it,” said Toon. The researchers estimated the project required roughly 6,000 hours of supercomputer computation time, an effort equal to about 10 years on a home computer.
h/t to Dr. Leif Svalgaard
lsvalgaard says:
July 10, 2013 at 9:14 am
Barry Cullen says:
July 10, 2013 at 8:56 am
“What is the glucose eventually converted into?”
Plants! or some other photosynthesizing organism.
http://en.wikipedia.org/wiki/Decomposition :
“The chemical aspects of plant decomposition always involve the release of carbon dioxide.”
So eventually glucose becomes the CO2 that went into forming the glucose
>>>>>>>>>>>>>>>>>>>>>>
You forgot via the coal and oil we are now burning….
lsvalgaard, I think we are talking at cross purposes.
1. Ancient Earth had no life and no free oxygen in the atmosphere.
2. Life began as 1 celled bacteria without a nucleus in the oceans. (procaryotes)
3. procaryotes develop photosynthesis.
4. “…early primitive life (procaryote cells) modified our planet by converting CO2 and H2O to organic matter and releasing oxygen to the environment. As a consequence these organisms moved carbon from the atmosphere to the rocks (Figure 11) and broke down water molecules releasing oxygen to the ocean and eventually to the atmosphere….” – James D. Hays | Professor Emeritus | Columbia University (2004) link
If you disagree perhaps you should take it up with Dr. Hays, however we do know that thanks to life evolving on earth the amount of free oxygen increased and the amount of carbon dioxide decreased over time or are you suggesting the atmosphere has always been ~ 400ppm CO2, 20% O2, 78% N2, >1% Ar and other gases.
(For other WUWT readers Dr. Hays is the co-author with Imbrie, and Shackleton of the 1976 paper “Variations in the Earth’s orbit: Pacemaker of the ice ages.” Deep-sea cores, focusing primarily on a group of siliceous microfossils known as Radiolaria, and the history of climate change over the past three million years is his specialty.)
Jarryd Beck says:
July 10, 2013 at 4:21 pm
But the neutrinos didn’t match predictions did they. So someone came up with this untestable idea of them changing “flavours” so that the theory all worked again.
The change of flavors is tested and directly measured by looking at neutrinos from known sources [under the control of the experimenters] on the Earth so the observed flux is actually in good accordance with the theory: e.g. http://en.wikipedia.org/wiki/K2K_experiment
Gail Combs says:
July 10, 2013 at 5:39 pm
You forgot via the coal and oil we are now burning….
None of that was formed 3 billion years ago, which is the time frame of interest.
as you point out “limestone can also be a chemical sedimentary rock formed by the precipitation of calcium carbonate from lake or ocean water….” so is not produced by corals or shelled animals 3 billion years ago, as there weren’t any.
William Astley says:
July 10, 2013 at 4:44 pm
“there is no robust evidence of a widespread link between the cosmic ray flux and clouds”
The paper you quote and thoughtful keep at your site is a hand waving attempt to counter direct observational evidence that solar magnetic cycle changes modulate planetary cloud.
The paper examines the so-called evidence and finds it wanting.
Janice Moore says:
July 10, 2013 at 5:22 pm
As several comments above show, nevertheless, your coldly terse, dismissive, communication style, is quite frustrating for many of us
I answer questions to the best of my ability, but do not refrain from dismissing some of the sheer nonsense that is sometimes peddled here, and can understand the frustration that causes for the ‘know-it-alls’, but so be it. I know of no other ways to deal with them. Perhaps you could suggest some.
William Astley says:
July 10, 2013 at 4:44 pm
The paper you quote is a hand waving attempt to counter direct observational evidence that solar magnetic cycle changes modulate planetary cloud.
From the paper: “At present, two long-term independent global satellite cloud datasets are available (ISCCP and MODIS). Although the differences between them are considerable, neither shows evidence of a solar-cloud link at either long or short timescales. Furthermore, reports of observed correlations between solar activity and cloud over the 1983–1995 period are attributed to the chance agreement between solar changes and artificially induced cloud trends.”
So there is no credible observational evidence that solar activity [or the lack thereof] modulates cloud cover. Accept it and move on.
Konrad wins the internet for today….
Konrad says:
July 9, 2013 at 7:50 pm
Is this computer model study a genuine attempt to explain the faint sun paradox or just another sorry attempt to promote the idea that adding radiative gases to the atmosphere will reduce the atmospheres radiative cooling ability? Sadly I suspect the latter.
If solar radiation reaching the earth was indeed 30% lower 3 billion years ago, the faint sun paradox is more reasonably explained by the following factors –
1. Higher atmospheric pressures.
2. Reduced albedo.
3. Higher volcanic activity.
4. Different planetary rotation speed.
The empirical experiment for factor 1 is simple to conduct. (note – climate scientists may need Mum or Dad to help with the scissors) The question is what effect would higher gas pressures have on atmospheric temperatures for an atmosphere in conductive contact with a planets surface heated by solar radiation?
– Build two identical insulated tall pressure chambers
– in the base of each chamber place water coils of thin aluminium tube with input and output through the walls of the chamber.
– place temperature sensors (optical preferred) at several heights within each chamber.
– fill both chambers with dry nitrogen. ( chamber A to 1 bar, chamber B to 2 bar)
– run cooling water through the water coils of both chambers until gas temperatures are equalised.
– now run 90C water at equal flow rates through the water coils in both chambers.
– observe that the gas temperature in chamber B rises fastest.
– now alternate heating and cooling water flows to simulate diurnal cycle.
– using the temperature sensor highest in each chamber observe that chamber B maintains the highest gas temperature.
The authors of this radiative greenhouse effect “study” should immediately relocate it, not to where the sun shines 30% less but to where it does not shine at all.
Pat Sez:
“Why, then, is it a surprise that they find several thousand ppm of CO2 will, with a dollop of methane, warm the archaic climate? That conclusion is built into the model as an a priori condition. All they needed to do was find the levels of GHGs they needed to get the answer they want.”
This is the problem with models that include feedbacks: you HAVE to model, a priori, where the turning point is. Such as: with increased solar radiation, you get increased planetary heat but for the responding cloud cover which ameliorates the relation – a negative feedback. If you can fairly accurately posit ONE feedback, you might be OK in the short term.
Otherwise, you basically are in the boat of the problems with a linear model: first, we know that linear relations of any kind (linear, log, etc.) simply work to explain and predict over a limited range, PLUS, we know if one coefficient is a bit off, which it is certain to be, given measurement theory (X measured = X actual + error, and there is always error since all msmt is inherently a model), your model will have limits beyond which it does not apply/work (outside of tautologies, such as converting degrees F to degrees C), so if one feedback is WRONG by 0.1%, your model is, eventually, running WAY off.
Add a second feedback: your accuracy problem has just MULTIPLIED.
The only way a feedback model can be used to explain something as genuinely complicated as the atmosphere is to have some governing “feedback,” or check, ruling over all processes, that by intent or discipline keeps a system running within some bounds, or beyond bounds when approved.
Is the atmosphere like this naturally? Maybe.
Can it be modeled? Yes. But you have to have some aspect of the model that governs some aspect or aspects of the model to never let some parameter exceed some level.
You could model the forces that can govern the acceleration of an automobile. But at some limit, heat or wind resistance or gravity will limit acceleration beyond some point. You can’t ‘model’ bigger cylinders, better alloys, lower friction bearings, and lower drag indefinitely.
Nature is the limiter.
We know sports cars pretty well, and this is obvious. However, we don’t know atmospheric modeling well, and so anything is possible. But we have to use common sense: models have limits, and a model of a system as long-standing as our atmosphere will necessarily include some highest-level governor that keeps everything within some range, without running away thus far, anywhere.
If you take the present as an end-point with a wrong model, the mistakes have to be dedicated to the past to have the past back-cast (vs. forecast) be the prelude to the present.
This is why I expect to see radical, surprising, and improbable back-casts of the early atmosphere.
Correspondingly, I don’t have much trust in forecasts of the atmosphere – if they go off-track a little in the short-run, they are sure to be wildly off-track in the long-run. **Unless they include some distinct overall governor bounding all the other parameters.**
As for me and my house, we know this governor.
“‘As for me and my house’, we know this governor.” [The Last Democrat — are you STILL one? Why??]
I do, too. And…. at some level of consciousness, so does nearly everyone…. (well, they know OF that governor, at least)… “For since the [beginning] of the world [“this governor”]’s invisible qualities — … eternal power and divine nature — have been clearly seen, being understood from what has been made … .” [Romans 1:20]
Dear Dr. Stalgaard,
With every step of our lives,
we enter into the middle of some story
which we are certain to misunderstand.
[G. K. Chesterton]
Over your long and distinguished career, I have the feeling that you have been sorely tried by some real “know it alls.” Your patience with such people is, thus, understandably, shot. I may be wrong, but, it may make you (and understandably!) a little extra sensitive to those you perceive to be know-it-alls, here. I guess my only suggestion would be to try to carefully consider whether or not a given commenter is, indeed, a presumptuous “know it all,” or merely someone sincerely but awkwardly trying to get at the truth.
If you are doing your best, that is all one can ask.
And, of course, with the REAL know-it-alls (and we get some real winners, here on WUWT, don’t we? LAUGH-OUT-LOUD), give it to ’em with both barrels!
And, for my part, I will try to not be extra-sensitive to what I perceive to be rude treatment (something I am, I will admit, over-sensitive to, thanks to some lovely people in my life “story”) by you of others. After all, it is, really, none of my business is it? Thank you for not telling me to mind mine.
Your impertinent friend in the “cheap seats” (R. Sowell),
Janice
Lessee; O2 is about 20% of today’s atmosphere. All O2 is still around because it was actively dissociated from CO2 by plants, and any removed by combustion or other reaction has been replaced.. Therefore at least 30% (accounting for the extra atom of Carbon) of the atmosphere by weight must have been CO2. That’s 200,000 ppm.
Sorry, meant to say “nearly 30%” and “that’s almost 300,000 ppm”.
(Those are a little high, because C is about 3/8 of the weight of CO2, not 50%, but you get the idea.)
Gail Combs says:
July 10, 2013 at 6:56 am
Phil. says: @ur momisugly July 9, 2013 at 9:20 pm
…..Photosynthesis converts H2O into O2 not CO2!
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Is that what they are teaching in school these days?
I certainly hope so Gail!
Photosystem II is the first step in photosynthesis and involves the ‘water splitting’ reaction which produces H+ ions and O2 as a waste product. This ability to use water as a source of electrons is believed to have evolved about 3 billion years ago.
In modern cyanobacteria CO2 is used to synthesize simple sugars using the energetic molecules produced by the upstream reactions of Photosystems I & II.
I would not be surprised – No teacher, but every textbook, left behind
The equation for photosynthesis is
6CO2 + 12H2O + light → C6H12O6 + 6O2 + 6H2O
So all of the CO2 and half the H2O is converted into glucose and O2.
No the CO2 is involved in the synthesis of sugars and has nothing to do with O2.
Janice Moore says:
July 10, 2013 at 9:31 pm
carefully consider whether or not a given commenter is, indeed, a presumptuous “know it all,”
That is easy, as we have only about half a dozen of them recurring in just about every thread, as you must have noticed.
There are two genuine ways to accurately test this, and climate models in general.
1. Build time-travel device. Go back in time, observe.
2. Construct two identical planets. Place them in counter-orbit, seed with intelligent beings. Allow one to progress naturally, maintain pre-industrial technology on the other. Observe and document conditions.
Anything other than one of these two is conjecture and to be taken with a grain of salt.
Brian H,
your conservation of O2 mass is missing teratons of
CaCO3 – Limestone
CaMg(CO3)2 – Dolomite
Al2Si2O5(OH)4 – Kaolinite
The components of Bauxite: gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH),
TiO2 – Anatase
The dozens of Phosphate minerals, such as
Ca5(PO4)3(F,Cl,OH) – Apatite Group
Fe2O3 – Hematite
Fe3O4 – Magnetite
(By no means is this an exhaustive list of oxygen containing minerals that form as part of a weathering or living process.)
Oxygen is a highly reactive element. Without plant life constantly replenishing it, almost all of it would be combined with other elements.
It is probably easier to track the carbon.
Then all you have to account for is the biomass of the biosphere, the burried total organic carbon in coals, petroleum, natural gas, and organic matter trapped in all shales. Then add in the limestones, dolomites, marbles.
The Archean spans 1.5 or 2.8 billion years (depending on your source), starting at the vague point where the hot Earth cooled enough to allow water to condense into oceans, continents emerged (or were completely submerged), plate tectonics began, and the first chemosynthetic lifeforms appeared (most plausibly at a hydrothermal vent).
Chemosynthetic archeae feed on either i) hydrogen sulfides + CO2, or ii) hydrocarbons (no CO2). Hydrocarbons are not evidence of archaic “bodies” – hydrocarbons are geochemical:
Photosynthetic life evolved from chemosynthetic life near the end of the Archean era, at around 3.5 billion years ago. When signs of photosynthetic activity became abundant in the proxy records, we drew a line in the sand and called it a new era.
So for BioBill and Gail Combs, you cannot point to hydrocarbon or limestone and call it evidence for photosynthesis (chemosynthesis produces limestone too). And for Brian H, you are very unlikely to find 30 percent oxygen during any of the subdivisions of the Archean era, because, as Leif has pointed out repeatedly, the oxygen producers weren’t around at the time in question (at least not in abundance.)
richard verney says:
July 10, 2013 at 5:09 pm
“I have often wondered why, if the solar system is the result of some gravitational collapse of a gas cloud, there are so many heavy atoms in the planets (that is the rocky planets as opposed to the gas giants). ”
The same proportion of heavy and light atoms were in the inner planet gas clouds as in the outer planetary clouds. The difference was, it was warmer in the inner solar system, most of the gases, especially hydrogen, moved rapidly and escaped the planet in early times. In contrast, it was cooler in the outer system, gases moved more slowly, were held more easily by the planetoid, and the outer planetoids grew more quickly. In addition, the outer planets had the
escaped gases from the inner system to draw on.
http://www.scientificamerican.com/article.cfm?id=how-planets-lose-their-atmospheres
That process is still going on, and over billions of years our planet would gradually become a barren rock if more drastic effects, like the sun vaporizing the earth did not happen sooner.
Levenspiel, Fitzgerald, and Petit also had a paper on the evolution of planetary atmospheres from a different perspective. Of course, this is the chemical engineering perspective and seems to step on the toes of the geologists and biologists. So it took nearly a decade to get the manuscript published by the ACS:
http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn.html
The genesis of the paper was Levenspiel trying to explain to his grandkids how dinosaurs were able to fly. He has the first part of the paper on his own web site:
http://levenspiel.com/octave/dinosaurs.htm
Hi Leif,
As always, I find your cogent and annotated scientific replies very informative. As to your “tone” I find that you display deferential patience, and provide information, to the merely ignorant while taking gentle jabs at those that arrogantly flaunt their misinformed opinions. If these characters persist in their misinformation you ramp up the disdain accordingly (and appropriately in my opinion).
Keep up the good work.
Lance
Is it not possible that the sun during its journey through the galaxy encounters other celestial bodies, eg a brown dwarf star, that could affect and even alter the position and mass of planets ?
Robertv says:
July 11, 2013 at 10:31 am
Is it not possible that the sun during its journey through the galaxy encounters other celestial bodies, eg a brown dwarf star, that could affect and even alter the position and mass of planets ?
Possible, but extremely unlikely and has not happened the last million years as it would have changed the timing of glaciations
stuart L says:
The earth is moving away from the sun at 15cm per year is that a factor?
If we assuming this was liner for billions of years.
we would be 4.5 x 10^10 km closer to the sun. the sun today is 1.496×10^8 km from the earth.
In other words it isn’t a liner number.
Either way you make a good point. We were much closer then we are today.
Ox AO says:
July 11, 2013 at 11:14 am
We were much closer then we are today.
No, that is not very likely [and certainly not ‘much’] :
http://www.leif.org/EOS/1306-3166-Faint-Sun.pdf
@Gary Young Hladik July 10, 12:14 pm
Gary, thanks for that reference. That piece of research has preoccupied me for the past 24 hours. I’d like to find holes in it because my bias/belief/working-hypothesis is that we had thicker atmospheres in the geologic past than today. 25 inch dragonfly wingspans beg for higher atmospheric pressure as well as higher O2 partial pressures than today.
But it seems like a good piece of work on first read. It details three closely spaced fossilized raindrop sites in an ash in southern Africa from 2800 Mya. The best avenue worth exploring is the hailstone alternative they weakly, IMHO, dismiss:
Well, hailstone divots would be deeper unless the atmosphere was thicker than anticipated. The reasoning seems a bit circular.
I’m also at a loss why they focus on rain-fall rates of 100 mm/hr — That’s a lot and if it lasted for any length of time would have destroyed the rain drops. I’ve been in aborted showers where there are big drops going ‘plop’ at my feet, but so few that sidewalk is never covered. This sparce type of shower would seem to be a requirement to preserve raindrop imprints.
Fig. S4 I think sets up a strawman where by raindrop size distributions and rainfall rates, from modern day atmospheric conditions is being used to limit the uncertainty in the Archean. What would these distributions be under a 10 bar atmosphere? How about CO2 saturated raindrops falling in a 10-bar CO2-CO-CH4 atmosphere? Again, it seems a bit circular to work with distributions that use the atmospheric pressure of present day to investigate the atmospheric pressure of yesteryear.
Hypothesis: Atmospheric pressures were zero at 4500 Mya after the Moon-forming impact occurred, gradually built up to 1-2 bar in the Archean 4000-2500 Mya, then builds up and range 4-20 bar in the Paleozoic and Mesozoic (600-65 Mya) to support large flying fauna, and drops off to 1 bar today.
@Greg Smith July 11, at 9:21 am
I liked the Levenspiel, Fitzgerald, and Petit ACS paper you linked. This spoke to my world-view. To me it seems highly improbable that atmospheric pressure has remained more or less constant at 1 bar for three billion years. But I doubt the 45-90 bar “Venusian” thickness as a possibility, too. The formation of our Moon and its existance, precludes that thick an atmosphere.
lsvalgaard
Interesting thank you
Lorenzo Iorio states the earth drift from the sun is measured at 1.5 cm yr but doesn’t seem to follow up on it’s implications. But he has a lot of good points… which leads to more questions.
Ox AO says:
July 11, 2013 at 1:31 pm
Lorenzo Iorio states the earth drift from the sun is measured at 1.5 cm yr
Actually, he does not. He says that the current limit of detectability is 1.5 cm/yr [so the actual change, if any, is smaller than that], not that that is the change, Furthermore a change of 510 cm/yr [dr/rr = 3.4 10(-11)] is required to use the change of distance as the explanation.