Early Earth stayed warm because its ocean absorbed more sunlight; greenhouse gases were not involved, Stanford researchers say. See more about the Faint sun paradox here. A video clip follows.
From a Stanford University News press release.
Researchers have long wondered why water on Earth was not frozen during the early days of the planet, when the sun emanated only 70 to 75 percent as much energy as it does today. Some theorize that high levels of greenhouse gases in the atmosphere, the same mechanism cited in global warming today, were key. But new research involving Stanford scientists has a different explanation: The oceans, much larger than today, absorbed enough heat from the sun to avoid turning into ice.
BY LOUIS BERGERON
Four billion years ago, our then stripling sun radiated only 70 to 75 percent as much energy as it does today. Other things on Earth being equal, with so little energy reaching the planet’s surface, all water on the planet should been have frozen. But ancient rocks hold ample evidence that the early Earth was awash in liquid water – a planetary ocean of it. So something must have compensated for the reduced solar output and kept Earth’s water wet.
To explain this apparent paradox, a popular theory holds there must have been higher concentrations of greenhouse gases in the atmosphere, most likely carbon dioxide, which would have helped retain a greater proportion of the solar energy that arrived.
But a team of earth scientists including researchers from Stanford have analyzed the mineral content of 3.8-billion-year-old marine rocks from Greenland and concluded otherwise.
“There is no geologic evidence in these rocks for really high concentrations of a greenhouse gas like carbon dioxide,” said Dennis Bird, professor of geological and environmental sciences.
Instead, the team proposes that the vast global ocean of early Earth absorbed a greater percentage of the incoming solar energy than today’s oceans, enough to ward off a frozen planet. Because the first landmasses that formed on Earth were small – mere islands in the planetary sea – a far greater proportion of the surface of was covered with water than today.
The study is detailed in a paper published in the April 1 issue of Nature. Bird and Norman Sleep, a professor of geophysics, are among the four authors. The lead author is Minik Rosing, a geology professor at the Natural History Museum of Denmark, University of Copenhagen, and a former Allan Cox Visiting Professor at Stanford’s School of Earth Sciences.
The crux of the theory is that because oceans are darker than continents, particularly before plants and soils covered landmasses, seas absorb more sunlight.
“It’s the same phenomenon you will experience if you drive to Wal-Mart on a hot day and step out of your car onto the asphalt,” Bird said. “It’s really hot walking across the blacktop until you get onto the white concrete sidewalk.”
Another key component of the theory is in the clouds. “Not all clouds are the same,” Bird said.
Clouds reflect sunlight back into space to a degree, cooling Earth, but how effective they are depends on the number of tiny particles available to serve as nuclei around which the water droplets can condense. An abundance of nuclei means more droplets of a smaller size, which makes for a denser cloud and a greater reflectivity, or albedo, on the part of the cloud.
Most nuclei today are generated by plants or algae and promote the formation of numerous small droplets. But plants and algae didn’t flourish until much later in Earth’s history, so their contribution of potential nuclei to the early atmosphere circa 4 billion years ago would have been minimal. The few nuclei that might have been available would likely have come from erosion of rock on the small, rare landmasses of the day and would have caused larger droplets that were essentially transparent to the solar energy that came in to Earth, according to Bird.
“We put together some models that demonstrate, with the slow continental growth and with a limited amount of clouds, you could keep water above freezing throughout geologic history,” Bird said.
“What this shows is that there is no faint early sun paradox,” said Sleep.
The modeling work was done with climate modeler Christian Bjerrum, a professor in the Department of Geography and Geology, University of Copenhagen, also a co-author of the Nature paper.
The rocks that the team analyzed are a type of marine sedimentary rock called a banded iron formation.
Video: These rocks, billions of years old, tell a new story about the evolution of early Earth, Stanford researchers say.
“Any rock carries a memory of the environment in which it formed,” Rosing said. “These ancient rocks that are about 3.8 billion years old, they actually carry a memory of the composition of the ocean and atmosphere at the time when they were deposited.”
Another constraint on early carbon dioxide levels came from life itself.
In the days before photosynthetic organisms spread across the globe, most life forms were methanogens, single-celled organisms that consumed hydrogen and carbon dioxide and produced methane as a digestive byproduct.
But to thrive, methanogens need a balanced diet. If the concentration of either of their foodstuffs veers too far below their preferred proportions, methanogens won’t survive. Their dietary restrictions, specifically the minimum concentration of hydrogen, provided another constraint on the concentration of carbon dioxide in the atmosphere, and it falls well below the level needed for a greenhouse effect sufficient to compensate for a weak early sun.
“The conclusion from all this is that we can’t solve a faint sun paradox and also satisfy the geologic and metabolic constraints by having high carbon dioxide values,” Bird said.
But the theory of a lower Earthly albedo meets those constraints.
“The lower albedo counterbalanced the fainter sun and provided Earth with clement conditions without the need for dramatically higher concentrations of greenhouse gasses in the atmosphere,” Rosing said.
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Need to add to the previous post that some continental land masses may have been present at 4.4 Gya. However, if they existed, they were probably scattered microcontinents and islands.
Not convinced. More water (as stand-alone explanation) sounds highly implausible to me. Perhaps a combination of more atmospheric water plus more internally produced heat. I don’t even have a back-of-the-envelope calculation to cite but it strikes me as wilfully blind to formulate theories to explain an early warm earth without openly considering the possibility of dissipation of heat from a recently-accreted planet with massive internal dynamics.
Even today most of the earth (in terms of volume) is red-hot (though not quite as hot as Al Gore appears to think it is). In early geological times it was SO hot this kept spilling out of the core/mantle onto the surface through tectonic and volcanic activities. It strikes me as quite plausible that Earth’s INTERNAL heat sources were significant enough at the time to compensate for a lower solar energy output. It is also plausible (to me) that geothermal energy declined in its effect on the surface, through stabilization of the Earth’s crust, more-or-less in step with the increase in the sun’s heat-releasing dynamics.
Paradox … begone!
@Leif Svalgaard (20:09:54) :
“…And the Sun was still faint then. Not 35%, but 25-15%, so the problem is still there….”
I guess I’m missing something. What is “the problem”? My post was merely setting a context on the earth’s geological development. None of that was affected by the Sun’s luminosity.
You must be more specific about which of Earth’s multiple atmosphere’s you are discussing. The Earth has had multiple atmospheres with radically different compositions and characteristics.
Earth’s first atmosphere was derived from the same matter as the nebula from which the planet and the Sun were formed. Different sources have estimated this first atmosphere to be 105 or up to 250 atmospheres in mass. Hydrogen was the overwhelmingly dominant atmospheric gas, until the Sun’s solar wind and a likely collison with a planetary mass the size of Mars, sometimes called Theia, stripped away about five Lunar masses of Earth’s hydrogen, helium, methane, ammonia, and more.
After about the first 500 million years following the proposed impact event with Theia, forming the Moon, the much smaller remnant atmosphere became augmented by outgassing from vulcanism and by a relatively high rate of further cometary and asteroidal impacts. This became Earth’s second atmosphere. Some sources are in substantial disagreement about the composition of this second atmosphere.
The earlier view described the second atmosphere as being dominated by water vapor, carbon dioxide, nitrogen, and sulfates. In this view, after the water vapor condensed out of the atmosphere to create the hydrosphere, the composition of the atmosphere was 80% or 800,000ppm carbon dioxide, water vapor, and much smaller percentages of nitrogen, sulfates, and trace gas.
The Early Cool Earth view presented recently proposes a second atmosphere which is far cooler at much earlier time periods with only small concentrations of carbon dioxide.
Earth’s third atmosphere came into being when it became possible for oxygen to remain fre in the atmosphere. Previously, any small amounts of oxygen liberated into the atmosphere immediately reacted with iron and other substances in the rocks and oceans to form oxygen rich compounds. Eventually, these oxygen reactive substances in the environment became saturated with oxygen, so free oxygen began to accumulate in the atmosphere. This free atmospheric oxygen was poisonous to the anaerobic lifeforms inhabiting this increasingly oxygen enriched atmospheric environment. Taking advantage of the new opportunities, aerobic lifeforms developed and radically changed the composition of the atmosphere by increasing the oxygen in the atmosphere while removing carbon dioxide from the atmosphere and sequestering the carbon as carbonates in the lithosphere.
That statement appears to be arguable.
Jim F (21:23:36) :
I guess I’m missing something. What is “the problem”? My post was merely setting a context on the earth’s geological development. None of that was affected by the Sun’s luminosity.
I was just referring back to the original topic [Faint sun paradox etc]. No problem with your comment. You pointed out that substantial land existed 3.5-2.7 Gyr ago, and during that time the Sun was still more luminous than today, so the Faint Sun was still a problem if we have to assume all water to explain away the paradox.
It is good news that the ancient CO2 level proved not high. This fact will be able to change the narrow view on the relation between CO2 and temperture.
As for the mechanism to change the albedo, I like the idea of H.-W. Ou (“Possible Bounds on the Earth’s Surface Temperature: From the Perspective of a Conceptual Global-Mean Model,” J. Climate, 14, 2976-2988 (2001)). He demonstrated that changes in the amount of high clouds and low clouds can explain the faint sun paradox. His theory is based on the maximum entropy production theory (or non-equilibrium thermodynamics), which is not established well enough yet.
Anyway, the albedo appears essentially important in the global climate.
@frank (19:39:20) :
Thanks for posting that link. A very interesting and animated talk. It seems like a good update on a lot of work in the field of geology/geochemistry.
I have some doubts however about some of the conclusions. I was particularly intrigued by his segue of the lag in CO2 versus temperature in ice cores into credit card debt and interest payments. There it seems somehow that the chicken morphed into the egg, or vice versa. Not a very edifying answer.
However, he seems to pin a rise in T to ~3 degrees C to a “doubling” of CO2, as opposed to 4-12 degrees C supposed by some of his warmist compatriots. He should look at his t vs. co2 charts that he showed several times early in the talk; to get those temperatures it would take something like 2000 ppm CO2.
Overall, it seems from his comments that CO2 acts at the margin. Orbital issues, albedo changes and other things come first; CO2 can add to or subtract a bit from those changes.
I would welcome others’ comments on the video (which incidentally was flawless in its presentation on my computer).
If I had to venture a guess, Dennis Bird has the belt buckle?
Where did they get T subscript s?
What is the importance of the increasing gap between T subscript s and T subscript e?
Is that because of water vapor?
WOW! Thanx Anthony. It is easy to understand why this IS the best SCIENCE blog in the world. It’s the only place that I know of where I can get a university grade edumacation for free!
🙂
No, using the word “proved” is incorrect. It is a competing hypothesis, which has not yet undergone the trials required to become adopted as a theory. The prevailing viewof the evidence has heretofore found an atmosphere with an 80% or 800,000ppm composition of carbon dioxide. The early Cool Earth hypotheses dispute the earlier findings, and their cited evidence conflicts with the eralier evidence. It remains to be seen how this irreconcilable views and evidence can become reconciled or supplanted.
Supportive of high carbon dioxide:
Supportive of low carbon dioxide:
It remains to be seen which hypothesis will withstand further research and scrutiny.
You’re confusing the differences between the geographer’s definition of a continent as a major body of dry land or terrain surrounded by the oceans versus the geological and geomorphological definition of a continent as a continental crust or crustal plate.
At “4.4 Gya” sial continental plates such as those existing today did not yet exist. The process of refining the basalts to produce the first granitic crustal plates had not yet progressed far enough to create sial continental crust or crustal plates. That would occur during the next 800 million years and become ecognizable at about 3.8Gya. The proto-crust and proto-continental crust was much more mafic in its composition. The proto- continental crust was slightly less dense, being composed of an anorthositic like rock similar to those found in the Lunar highlands, than the subducting non-continental crust. Since the density differences were so much less, it was much easier to progressively subduct the sima proto-continental crust along with the sima non-continental crust, resulting in further refinement and separation of the silicon and aluminum compounds which would become the sial continental crust 800 million years later.
Note, it is not necessary for a hydrosphere to be present to create a sima or sial continental crust. Continental crust in this geological context only represents the differences in density substantial enough for the lighterweight crustal plate to override a heavierweight crustal plate. The lighterweight crustal plate then persists so long as it is not eroded away by a subducting plate at the prism, and it is not itself subducted by collision with another lighterweight continental crustal plate.
Add water and you can then describe the heavierweight sima crustal plate as oceanic crust versus the lighteweight sima or sial continental crustal plate. It’s the relative compositions of the crustal plates, their densities, and their tectonics which defines a continent in geological terms, not the geographer’s view of a dry land amidst the oceans.
Leif Svalgaard (21:42:13) :
The sun’s core held more energy and rotated faster. This in turn made the suns carona smaller.
For some farout reason, science believe suns and planets rotate forever while still using and loosing energy. Even Atomics need a material to be repentished to continue.
How about the Earth ıtself. The early Earth was a ball of fıre and nuclear fıssıon. Surely that early state was stıll ın the process of coolıng down, and radıtıng lots of energy.
.
Hmmm, I wonder if Newton’s law of motion is incorrect?
“In the absence of a net external force, a body either is at rest or moves with constant velocity. Newton ”
Rotation has density that is compressible and can hold energy that is slowly released. The object, planet, sun, etc. slows down naturally through the “unwinding of compressed mass” Being gases or material.
In space, a body will still slow over time due to frictional forces such as specks of gases or mass. There is a great deal of dust debris in space.
The “paradox” might be explained by the fact that in the far past the Earth’s orbit was closer to the Sun. The Sun is loosing mass because, by ‘burning’ hydrogen, helium is formed + energy (whence mass loss). If the Sun’s mass is decreasing, the planets are slowly spiralling outward. The greater distance to the Sun might (almost exactly?) counterbalance the hotter Sun.
But don’t ask me details. I am not an astrophysicist.
“I thought it was well established that there was (very) large amounts of methane in the atmosphere until photosynthetic organisms built up oxygen levels about 2000 million years ago. ”
You can’t even trust scientists to count tree rings accurately but you expect to believe in the science of the planet billions of years ago from people more interested in their own ego than the truth?
Scientists find errors in hypothesis linking solar flares to global temperature
http://www.physorg.com/news189845962.html
Greenhouse? What Greenhouse?
When I was learning physics I was taught the usual theory about how a
greenhouse warmed. As a physics teacher in the 1970s, I also taught
my students the same theory. But despite it being in all the text
books the theory is wrong and has been known to be so for a hundred
years! 100 years ago, a simple experiment showed beyond doubt that
the greenhouse effect‘ has little to do with secondary IR radiation.
Yet no physics text books have ever bothered to correct the wrong
theory!
Note on the Theory of the Greenhouse
by Professor R. W. Wood, 1909.
THERE appears to be a widespread belief that the comparatively
high temperature produced within a closed space covered with glass,
and exposed to solar radiation, results from a transformation of
wave-length, that is, that the heat waves from the sun, which
are able to penetrate the glass, fall upon the walls of the
enclosure and raise its temperature: the heat energy is
re-emitted by the walls in the form of much longer waves,
which are unable to penetrate the glass, the greenhouse acting
as a radiation trap.
I have always felt some doubt as to whether this action played
any very large part in the elevation of temperature. It appeared
much more probable that the part played by the glass was the
prevention of the escape of the warm air heated by the ground
within the enclosure. If we open the doors of a greenhouse on
a cold and windy day, the trapping of radiation appears to lose
much of its efficacy. As a matter of fact I am of the opinion
that a greenhouse made of a glass transparent to waves of every
possible length would show a temperature nearly, if not quite,
as high as that observed in a glass house. The transparent
screen allows the solar radiation to warm the ground, and the
ground in turn warms the air, but only the limited amount
within the enclosure. In the ”open,• the ground is continually
brought into contact with cold air by convection currents.
To test the matter I constructed two enclosures of dead black
cardboard, one covered with a glass plate, the other with a
plate of rock-salt of equal thickness. The bulb of a thermometer
was inserted in each enclosure and the whole packed in cotton,
with the exception of the transparent plates which were exposed.
When exposed to sunlight the temperature rose gradually to 65°C,
the enclosure covered with the salt plate keeping a little
ahead of the other, owing to the fact that it transmitted the
longer waves from the sun, which were stopped by the glass.
In order to eliminate this action the sunlight was first
passed through a glass plate.
There was now scarcely a difference of one degree between the
temperatures of the two enclosures. The maximum temperature
reached was about 55°C. From what we know about the
distribution of energy in the spectrum of the radiation emitted
by a body at 55°C, it is clear that the rock-salt plate is
capable of transmitting practically all of it, while the glass
plate stops it entirely. This shows us that the loss of
temperature of the ground by radiation is very small in
comparison to the loss by convection, in other words that
we gain very little from the circumstance that the
radiation is trapped.
Is it therefore necessary to pay attention to trapped radiation
in deducing the temperature of a planet as affected by its
atmosphere? The solar rays penetrate the atmosphere, warm
the ground which in turn warms the atmosphere by contact
and by convection currents. The heat received is thus
stored up in the atmosphere, remaining there on account
of the very low radiating power of a gas. It seems to me
very doubtful if the atmosphere is warmed to any great extent
by absorbing the radiation from the ground, even under the
most favourable conditions.
I do not pretend to have gone very deeply into the matter,
and publish this note merely to draw attention to the fact
that trapped radiation appears to play but a very small part
in the actual cases with which we are familiar.
further comment by Philip Foster on the above:
This is why CO2 and H2O (along with O3, N2O and CH4) in
the atmosphere cannot cause warming. If they did we would
have access to unlimited energy for no cost! The very small
amount of radiated infrared from H2O and CO2 reaching the
ground cannot warm the ground as the temperature of these
gases is lower than the temperature of the ground – just
as hot coffee in a Vacuum flask does not start boiling!
By suggesting that it can is to break one of the laws of
thermodynamics (Kevin Trenberth seems to have have done this:
http://www.cgd.ucar.edu/cas/abstracts/files/kevin1997_1.html
The only role they can play is like that of a glass plate
as opposed to a rock-salt plate as described by
Prof. Wood above: namely to slightly inhibit the
warming of the ground. But as they cannot trap
the convecting air (unlike solid glass in a greenhouse)
all comparisons with a greenhouse effect‘ are invalid.
Leif Svalgaard (18:55:14) :
Carla (17:39:40) :
Way too many missing pieces.
Which means that you cannot just jump to the conclusion you like since there is no specific evidence for it.
~
Women, go figure, it always has and always will be, LOCATION, LOCATION, LOCATION. Our variable star is variable because of LOCATION within the galaxy it resides, orbits. Anytime the LOCATION CHANGES, so does the star.
Men, go figure, always dancing around LOCATION, some even think CO2 is everything. lol
And if at the time (young star) was nearer a star forming region, it would be hotter, with much faster winds, and varying densities surrounding said young star..
IMHO you can’t separate the star from its environment and expect to..
D. Patterson (00:22:00) :
Paul Hildebrandt (20:42:32) :
Need to add to the previous post that some continental land masses may have been present at 4.4 Gya. However, if they existed, they were probably scattered microcontinents and islands.
You’re confusing the differences between the geographer’s definition of a continent as a major body of dry land or terrain surrounded by the oceans versus the geological and geomorphological definition of a continent as a continental crust or crustal plate.
I’m not confusing anything. Hawaii is an island, yet it is not sialic. As I stated above, if they existed, they were probably scattered and few in number. The fact that zircons of that age have not been found in their native environment argues against microcontinents. However, that does not mean that they did not exist. We just haven’t found any or they haven’t surfaced due to the stable nature of the Archean cratons.
At “4.4 Gya” sial continental plates such as those existing today did not yet exist. The process of refining the basalts to produce the first granitic crustal plates had not yet progressed far enough to create sial continental crust or crustal plates.
If plate tectonic processes were ongoing at 4.4 Gya, would not partial melting of basaltic crust create calc-alkaline (sialic) melts? Furthermore, because the geothermal gradient at this early time in earth’s history was so steep, the basaltic crustal rocks would not have fully dehydrated before melting. Therefore, melting would occur at much shallower depths than present day melting. The time for these calc-alkaline magmas to reach the surface can take as little as 100,000 years. So, yes; 100 million years is more than enough time for calc-alkaline magmas to be formed and migrate to the surface.
D. Patterson (21:29:51) : Thanks for the info. I was of course referring to the atmosphere between ~4.5 to 2 billion years before present. Seems that there is still a lot of different opinions about. I have seen some comparisons to Titan, and some like your suggestion of lots of CO2 (and above with little). Looks like there is still a lot to be discovered/researched in this area, even if the oxygen history is much better understood.
The Group W think that without taking in to account the VARIABLEs of the sun’s orbital parameters..that most of what they read here is conjecture, including jumping to conclusion. So much time spent on the orbital parameters of planets and yet when it comes to the suns, ah oh well???
The Who, “Eminence Front.”
Jim F,
You’re most welcome for the link, and thank you for your analysis, which I agree with entirely. As an engineer, I don’t “respect” science that has to be contorted to explain similar phenomena over varying time scales, which I see a lot of in Dr. Alley’s presentation. Case in point is that while he attributes orbital cycles as the primary cause of the periodic glaciation, he invokes CO2 as a main driver between cycle endpoints. In my mind, this ignores basic physical effects like the inverse relationship between CO2’s solubility in water with temperature (Henry’s Law), and also appears to disregard the logical principals of Occam’s razor.
Carla (05:46:25) :
Our variable star is variable because of LOCATION within the galaxy it resides, orbits.
No, the LOCATION has nothing to do with it.
Carla (07:07:16) :
The Group W think that without taking in to account the VARIABLEs of the sun’s orbital parameters.
What you think does not make it so. The easiest to delude is oneself.
Leif Svalgaard (08:01:54) :
Carla (07:07:16) :
The Group W think that without taking in to account the VARIABLEs of the sun’s orbital parameters.
What you think does not make it so. The easiest to delude is oneself.
~
Geesh Leif, “Pour Some Sugar..” one lump or twooooo?
Maybe now that I’m delusional I should go back on my meds.
Whoaa here Group W says, “But your not on meds, Carla.”
Well now that I’m having some delusion maybe I should start? lol