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.
Arigato gozaimasu Leif Svalgaard San for sparing your time.
I still think it is a combination of things.
I hope Svensmark’s theory will be validated ( again? ) by CLOUD.
The crux of the paper quoted above does not seem to explain the conundrum.
So much to learn/discover. So little time meh?
But that’s just my uneducated dolt’s opinion.
Michael J. Dunn (12:45:14) :
Phillep Harding (12:02:13) :
Michael, your point to Phillip will be greatly magnified with the correct factors:
~580 Cal/g or ~2425 kJ/kg, not 1400 J/kg
~1 Cal/g/K or ~4.2 J/g/K, not 1 J/g/K
“”” Michael J. Dunn (12:45:14) :
Phillep Harding (12:02:13) :
“In South East Alaska and Iceland, cloudy weather is warmer than clear weather (all else equal). Where does the heat come from, if clouds are supposed to keep it from reaching the ground?” “””
Correct observation; but wrong question.
Why didn’t you ask; “Where do those clouds come from?”
I’ll rephrase your observation.
“In South East Alaska and Iceland, warmer weather is cloudier than colder weather (all else equal). Where does the cloud come from, if warmer surface temperatures are supposed to cause more water vapor in the atmosphere?”
Maybe the clouds are a direct result of the warmer (and more humid) surface conditions; rather than being the cause of those conditions.
I see the phenomenon on an almost daily basis (in California) dewey lawn and dew all over my parked car, but clear sky before sunup. As the sun rises and the day warms up, the mositure on my car and lawn all evaporates, and eventually clouds start to form at higher altitudes, and the hotter it seems to get at the surface during the day, the higher that newly forming cloud layer will be by sunset.
Another tail wagging the dog phenomenon.
There is weather, then there is climate, and then there is Geology!
OT. The DMI polar temperature shows a very large jump in temperature in the last few days and also a large discontinuity. Watts up with that?
“”” David Segesta (16:59:25) : “””
David these wild gyrations freaked me out last year.
Let me suggest that you go down the page a little and bring up some of the past year complete year plots, and all of a sudden it will become clear to you what a normal year looks like.
Which doesn’t mean the answer to you question isn’t of interest; but at least you will see that it isn’t too differnt from previous years.
My guess is this is the result of totally wild Nyquist sampling violations; and isn’t really what the arctic is doing at all. Also suggests it is weather rather than climate.
George
Leif Svalgaard (15:17:05) :
The amount of 18Oxygen in the zircons indicate that they were formed interacting with surface water.
The heavy oxygen isotope signature is a sign that the zircons formed in a cool wet sedimentary environment according the reference I read from NASA. However, zircons don’t crystallize in cool, wet sedimentary environments. They crystallize at depth in cooling magmas, not near the surface in sedimentary environments. What this means is that the zircons incorporated oxygen into their structures from sediments that had been subducted and melted at depth. This means that weathering of rock was occurring near or at the surface (turbidites) and being subducted. It does not mean that their were continental land masses present at this early stage of earth’s history. What it also means is that plate tectonics was working at a very early time. Much earlier than once thought.
As for the heavy oxygen isotopes, I’m not sure about that at the moment as I always thought that the early earth atmosphere didn’t have much in the way of oxygen. Must have come from the weathering of any existing rock.
I’m not so sure about this. I know that Lindzen and Rondanelli argued that the FYSP was resolvable by the Iris Effect:
http://www.agu.org/pubs/crossref/2010/2009JD012050.shtml
“”” Stephen Skinner (15:29:22) :
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.”
Water is not black. Oceans appear black because there is not much or no light coming back out. “””
Funny thing that; oceans appear black because there is not much or no light coming back out.
That is exactly the same argument that is offered as to why coal of tar, or flat black paint’s look black. Maybe they aren’t black either; it’s just that they look black, because not much or no light comes back out.
HP once made a very sensitive thermoplie sensor for broadband LWIR radiation. The achieved a surface which “wasn’t black” but “looked black”; it was actually gold; metallic ordinary gold. Well the surface was made up of zillions of tiny gold nano-partilcles; long before the term nano-technology ever was thought of.
And that labyrinthine nano surface looked as black as the ace of spades over the entire spectrum from UV out to 100 micorns and more; an almost perfect black absorbing surface. You might even be able to google up on an HP or maybe Agilent Technologies site; the original HP journal description of that sensor.
I really don’t have a good idea what Black means; other than some things “look black”, because not much or no light comes back from them.
The deep oceans are like that, because about 97% of at least solar spectrum radiation propagates into the water, and not much comes back out if the water is deep enough and clean enough.
In an early pre biological ocean; the water, might have been much more transparent than it is today. Phyto and zoo planktons do a lot of light absorption; and maybe there are also microbial critters that do too.
Without the atmospheric blue light scattering, I’m quite sure that from outer space, we might regard earth as the black planet, rather than the blue planet.
Leif Svalgaard (14:36:05) :
Carla (13:19:52) :
And what kind of interstellar medium would the sun have been embedded in then. Very hot, hot, medium, cool or cold would you say..?
Probably didn’t matter because of the strong solar wind blowing everything away.
~
So you say.
I’m picturing a hotter interstellar medium, very possibly flowing in the same direction of travel as the solar system. Maybe even shorter solar cycles here there Leif.
Unlike today where the interstellar cloud the solar system is embedded in, is traveling in the “opposite direction.” (we have a head wind)
Not to mention again, (but I like it) that indications are we are in the transition zone between the LIC local interstellar cloud and G cloud.
And lest we forget, haha the G cloud is faster, cooler and denser than the previous LIC cloud.
If the interstellar medium is hot, it would affect the entire system. Direction of travel changes in either or all also would.
Way too many missing pieces.
They said one of their assumptions was that the condensations nuclei sources were inadequate to provide large rain drops.
So when did some one invent the first volcano? Seems like todays volcanos are know to generate at least some nuclei that would be associated with rain.
The continental drift shows there has been no loss or gain of water on this planet since back to when water was finally settled.
This planet was also rotating much faster then today and orbited closer to the sun.
gkai (12:28:22) :
Also, Venus should be studied more, because obviously it did not turn out the same way for our planet sister…Why? At what point did it diverge?
—-
REPLY: Good topic to mention! I’ve repeatedly heard breathless climatologists compare Venus’s “runaway greenhouse effect” to what might happen on Earth.
However, Venus’ atmosphere is totally different from Earth. It is about 96% carbon dioxide, and the clouds are sulfuric acid, not water vapor! I believe Dr. Lindzen has spoken about the misuse of the comparison of the two planetary systems in lectures.
Talk about comparing apples to oranges….if Earth ever did encounter a runaway greenhouse effect resembling that of Venus, all life would be reduced to molecules.
Oceans also have a much denser density then land and is more dense the deeper you go. This effects heat exchange.
Leif Svalgaard (12:36:52) :
gkai (12:28:22) :
just by chance because both the greenhouse and albedo are independent from solar output
For the Svensmark enthusiasts: the early solar wind was 100-1000 times a vigorous back then so few galactic cosmic rays would have made it to the Earth, so no low clouds [and higher albedo] due to them…
Yes I had noticed that Svensmark cosmic ray theory works well very early in Earth’s history. Of course, it is still speculative as you are right to point out. Nevertheless Svensmark’s theories are currently being tested at CERN and, at least on this front, we should get some confirmation of the validity or otherwise of this cosmic ray hypothesis.
On the contrary, it does indicate the presence of a continental crust and plate tectonics.
Paul Hildebrandt (17:27:02) :
As for the heavy oxygen isotopes, I’m not sure about that at the moment as I always thought that the early earth atmosphere didn’t have much in the way of oxygen.
The 18O enrichment comes from evaporation of water where the lighter 16O preferentially evaporates leaving water with more 18O.
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.
This is interesting stuff. Obviously, at some early point, the Earth’s surface was predominantly water-covered. Thus the oceans of that time would have occupied something like 1.43 times as much area as today’s oceans (the Earth is not expanding or contracting. Maybe it has contracted a little since, say, 5 BY ago, when the interior was hotter than today; see below).
It is likely that plate tectonics initiated somewhere in the vicinity of 4.5 to 4.0 billion years ago. At that time the interior of the earth was hot compared to today, as a result of core formation and radioactivity (half or more the initial complement of U238 is now gone, only about a tenth the U235 remains, and technetium and much thorium is completely gone). Volcanism would have been prolific, and the mantle must have been relatively active probably resulting in spreading rifts galore. At some point, numerous little island arcs must have formed over subducting slabs of crustal material.
Still this had to have been a chaotic affair. Large meteorites were still smashing the Earth’s surface, affecting earth, sea and atmosphere. A lot of energy was being imparted into the Earth’s oceans by the Earth and by cosmological effects.
Still, in today’s Earth, chunks of terrane dating 4.0+ BY might amount to 1 percent of the 43% that is dry land (mainly in Greenland and Northwest Territories; can’t recall any others that age offhand). By 3.5 BY there are more significant chunks – parts of South Africa and Zimbabwe, maybe some Australia. By 2.7 BY there are substantial areas – much of Ontario, Quebec, Northwest Territories, Western Australia, Western Africa and Congo, Fenno-Scandia, Siberia, and India (and these are metamorphic ages; the absolute ages of these rocks could be older). And so forth. The Earth incrementally adds continental crust, and manages to aggregate all the little chunks formed here and there into bigger and bigger cratons as time goes on.
We can map to some extent the Earth’s crustal changes. Information in the rocks themselves sheds some light on other systems, like atmospheric composition, temperatures and so forth. But we’ll never concretely know much about the early evolution of the hydrosphere and the atmosphere, or of life itself, although we should increasingly be able to make good guesses.
It’s fun stuff, subject to much arm waving. But the key thing is, regardless how much chaos and radioactivity and kinetic energy and so on, the Earth has supported the proliferation of life of a certain kind from early on (the first algal mats preserved are something like 3.5 BY). From about 600 MY ago, no matter what Nature threw at the Earth, life has survived and further proliferated. Earth has maintained – regardless of the state of the Sun, whether or not massive bodies are slamming into us, volcanism on scales we’ve never witnessed, ice ages galore, etc. – a haven for life. The great “global warming” scare is purely bullshit in the face of this history.
But science that helps us understand the evolution of this magnificent world and universe is good. Thank you Stanford and thank you Anthony for bringing it to our attention.
One other aspect that should be considered is that the oceans were not, in fact, blue in the early Earth. They were likely a slight red color until all the iron and other metals were dissipated out by the rise of oxygen.
The atmosphere would also have had more combustible gases like methane until oxygen became more prevalent. The Ozone layer did not develop until oxygen levels were high enough so more UV and X-ray radiation reached the surface (and the Sun was more active at these wavelengths in its early history).
The first snowball earth episodes that we know about did not occur until after the rise of oxygen 2.8 billion years ago.
Uh oh! Dr. Richard Alley isn’t going to like this…see
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml
“There is no geologic evidence in these rocks for really high concentrations of a greenhouse gas like carbon dioxide”
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. Given the potent effect of methane as a greenhouse gas, would this not go a long way explaining faint sun problem?
Jim F (19:15:35) :
By 3.5 BY there are more significant chunks – parts of South Africa and Zimbabwe, maybe some Australia. By 2.7 BY there are substantial areas – much of Ontario, Quebec, Northwest Territories, Western Australia, Western Africa and Congo, Fenno-Scandia, Siberia, and India (and these are metamorphic ages; the absolute ages of these rocks could be older).
And the Sun was still faint then. Not 35%, but 25-15%, so the problem is still there.
Bill Illis (19:28:52) :
(and the Sun was more active at these wavelengths in its early history).
Today. Mars is losing its atmosphere to the solar wind. With a 100-1000 times stronger solar wind, even the Earth would have been scoured.
And they call us “deniers”
From the paper.
=> There is little consensus on when the first continents emerged, or the rate of growth since continental nucleation.
=> There is no simple relationship between the mass of continental material extracted from the mantle and the surface area of exposed land….
=> We have chosen to use the present-day area/volume relationship (Fig. 2a), which probably overestimates the continental area, and in consequence, the albedo for the early Earth.
=> Because the timing and rate of growth of the Earth’s continents is a matter of debate, we have included a scenario in which the surface area occupied by continents is constant over geologic time as one end-member in our model
So, a fairly ad hoc solution to the young faint sun paradox, and so there is still a lot more work to be done to have any real confidence that this describes historical reality.
D. Patterson (18:54:19) :
Paul Hildebrandt (17:27:02) :
It does not mean that their were continental land masses present at this early stage of earth’s history.
On the contrary, it does indicate the presence of a continental crust and plate tectonics.
I never said that plate tectonics were not occurring at that later date (read my post at 17:27:02), in fact, I said in that post that the presence of zircons that old with a heavy oxygen isotope signature indicates plate tectonic activity. However, there is still no evidence of any continental crust, just sedimentary processes which could be tidal action on near surface granites brought there by tectonic activity or by zircons caught up in volcanic activity in which the rock was pulverized explosively during contact with ocean water. The latter process would provide the necessary interaction with “surface” water.
Leif Svalgaard (18:55:14) :
Paul Hildebrandt (17:27:02) :
As for the heavy oxygen isotopes, I’m not sure about that at the moment as I always thought that the early earth atmosphere didn’t have much in the way of oxygen.
The 18O enrichment comes from evaporation of water where the lighter 16O preferentially evaporates leaving water with more 18O.
Thanks, that makes sense.