Retro 3D climate model applied to faint young sun paradox

faint_sun1From the AGU weekly highlights:

Evaluating solutions to the faint young Sun problem

During the Archean eon, between about 3.8 billion years ago and 2.5 billion years ago, the Sun was about 20 to 25 percent fainter than it is today. With less sunlight to warm the Earth, the oceans should have been frozen over, but geological evidence suggests that this was not the case.

Some proposed solutions to this problem, known as the faint young Sun problem, include an atmospheric composition with higher concentrations of greenhouse gases, higher atmospheric pressure, increased cloud droplet size, and changes in land distribution and Earth’s rotation rate.

Charnay et al. used a three-dimensional global climate model coupled to a dynamic ocean model to examine these possible solutions.

They find that an atmosphere that had 100 millibars of carbon dioxide and 2 millibars of methane 3.8 billion years ago, and 10 millibars of carbon dioxide and 2 millibars of methane 2.5 billion years ago—levels corresponding to 25 to 250 times the present level of carbon dioxide and 1000 times the present level of methane—would have made it possible for Earth to have had a temperate climate with a mean surface temperature between 10 and 20 degrees Celsius (50 and 68 degrees Fahrenheit), close to the current climate.

The authors suggest that these levels of greenhouse gases are consistent with geological data, making such an atmospheric composition a viable solution to the faint young Sun problem. Cloud feedbacks were also shown to prevent a full snowball Earth from developing during that time period. The authors find that some of the other potential solutions could have produced some warming during the Archean, but none individually produced enough warming to avoid widespread glaciation.

Source: Journal of Geophysical Research-Atmospheres, doi:10.1002/jgrd.50808, 2013 http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50808/abstract

 

Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM

[1] Different solutions have been proposed to solve the “faint young Sun problem,” defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1-D radiative convective models and did not account well for the clouds and ice-albedo feedback or the atmospheric and oceanic transport of energy. We apply a global climate model (GCM) to test the different solutions to the faint young Sun problem. We explore the effect of greenhouse gases (CO2 and CH4), atmospheric pressure, cloud droplet size, land distribution, and Earth’s rotation rate. We show that neglecting organic haze, 100 mbar of CO2 with 2 mbar of CH4 at 3.8 Ga and 10 mbar of CO2 with 2 mbar of CH4 at 2.5 Ga allow a temperate climate (mean surface temperature between 10°C and 20°C). Such amounts of greenhouse gases remain consistent with the geological data. Removing continents produces a warming lower than +4°C. The effect of rotation rate is even more limited. Larger droplets (radii of 17 μm versus 12 μm) and a doubling of the atmospheric pressure produce a similar warming of around +7°C. In our model, ice-free water belts can be maintained up to 25°N/S with less than 1 mbar of CO2 and no methane. An interesting cloud feedback appears above cold oceans, stopping the glaciation. Such a resistance against full glaciation tends to strongly mitigate the faint young Sun problem.

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GlynnMhor

“Cloud feedbacks were also shown to prevent a full snowball Earth…”
What assumptions were used for the cloud feedbacks, given that there is doubt as to the magnitude and even the sign of cloud effects?

phlogiston

Yet another climate model study in which the conclusion of the study is one of the model inputs.

milodonharlani
michael hart

I wonder how they modeled the effect of life on the carbon cycle 3.8 Billion years ago?
Nexxxt.

More meaningless talk to try to promote their soon to be obsolete AGW theroy.

thomasinga

Amazing that nobody is considering planetary migration as a factor, which could greatly vary the amount of radiation receives from even an cooler sun. Gravitational forces from other planets, even ones not currently counted in our existing solar system, could migrate the earth’s orbit by a very large degree. Consider the moon, at it’s formation ~4 billion years ago, it was 80-90% closer than its current oribt. Tidal forces alone likely were the sole cause of this migration. Not a stretch to think that that Earth was much closer to the sun in its early history.

F. Ross

Interesting study. Sounds plausible.
In a lighter vein … um
…the study results are due to humans back then, right? Right?

shenanigans24

Isn’t this just backcasting using a model that has already shown no ability to forecast? If the model is told CO2 drives the temperature with steady solar input, and we reduce the solar input then the model would have to react by increasing the CO2 to get the temperature wouldn’t it? Seems all this would say is the model behaves the way we told it to.
It’s like saying raindances bring rain, so by extrapolating the number of raindancers from the last rain shower we can prove the flood 100 years ago was caused by 1,000 raindancers. The rain dancing calculation is meaningless unless you have first proved raindancing causes rain. The CO2 calculation would seem the same until you can figure out what CO2 is doing to the temperature right now, which clearly nobody can.
I don’t know, maybe I’m way off. It just seems all these super hindcasting, forecasting results are nothing but mathematical masturbation. At some point you”re going to have to figure out what actually moves these temperatures, and models are not a shortcut for hardwork and patience.

milodonharlani

Their assumptions aren’t consistent with geologic data. Archean rocks show CO2 levels at most fifty times “pre-industrial” concentration. Some banded iron formations imply that the Archean atmosphere might have contained no more than about 900 ppm, just three times the presumed pre-industrial level.
Maybe their study addresses this conundrum. In any case, models whether 3D or 1D can’t be convincing.

And then the sun grew brighter/stronger(near present levels) and in the Jurassic period some 170 million years ago when CO2 concentrations were near 2000 ppm why did the temperatures not have a run away rise to the upside and keep going? That is what AGW theory would suggest today if CO2 concentrations were to go to 2000 ppm ,let alone the 400 ppm they are making such a big deal over..
I wonder what their explanation would be for that? My answer is no explanation becaue the greenhouse gas/climate correlation does not work the way they are trying to convey.

bubbagyro

Radioisotope decay…

Latitude

The authors suggest that these levels of greenhouse gases…
I thought it was logarithmic

phodges

The orbit of the Earth was probably also different at the time.
This is something that is always neglected at the geologic timescale.
http://en.wikipedia.org/wiki/Stability_of_the_Solar_System

phodges

Fairly recent summary:
http://arxiv.org/abs/1209.5996
Is the Solar System Stable ?
Jacques Laskar
(Submitted on 26 Sep 2012)
Since the formulation of the problem by Newton, and during three centuries, astronomers and mathematicians have sought to demonstrate the stability of the Solar System. Thanks to the numerical experiments of the last two decades, we know now that the motion of the planets in the Solar System is chaotic, which prohibits any accurate prediction of their trajectories beyond a few tens of millions of years. The recent simulations even show that planetary collisions or ejections are possible on a period of less than 5 billion years, before the end of the life of the Sun.
Comments: 28 pages, 6 figures. Text of the Lecture given in the Poincar\’e S\’eminar, Paris, on June 2010, submitted
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Mathematical Physics (math-ph); Chaotic Dynamics (nlin.CD)
Cite as: arXiv:1209.5996 [astro-ph.EP]
(or arXiv:1209.5996v1 [astro-ph.EP] for this version)
Submission history
From: Jacques Laskar [view email]
[v1] Wed, 26 Sep 2012 16:34:34 GMT (1486kb,D)

MattS

Latitude,
“I thought it was logarithmic”
Yes it is, but the authors are talking about a 1 to 2 order of magnitude increase from current CO2 levels. That is going to make a noticeable difference even if the effect is logarithmic.

milodonharlani

Salvatore Del Prete says:
September 24, 2013 at 11:41 am
The Middle & Late Jurassic & Early Cretaceous are among the epochs most destructive to the CACA hypothesis.
http://www.geocraft.com/WVFossils/Carboniferous_climate.html
Paleo proxy data suggest that during the MJ, CO2 rose rapidly without affecting temperature, but just when the gas peaked in the LJ, temperature fell precipitously (possibly promoting the proliferation of feathered dinosaurs). Carbon dioxide dropped slowly & slightly during the LJ & EK, continuing to fall while temperature was rising toward its mid-Cretaceous high.
Other mid-Mesozoic CO2 reconstructions are even worse for the CACA case, when correlated with temperature.

Bill Illis

“… In our model, ice-free water belts can be maintained up to 25°N/S with less than 1 mbar of CO2 and no methane. An interesting cloud feedback appears above cold oceans, stopping the glaciation. Such a resistance against full glaciation tends to strongly mitigate the faint young Sun problem.”
I believe that says “less than 1000 ppm CO2 and no methane, cloud feedback stopped the glaciation at the tropics.”
In any event, a 25% less luminous Sun is entirely offset with a reduction in Albedo from today’s 30% to 5% at that period, (an unlikely number but any reduction would help).

Exactly, they are so full of it. Excellent link milodonharlani.

Barry Cullen

Reading the replies to a recent Willis Post I came to the realization how the earth maintained >273k temperature ca. 2.5 Byrs ago. Since the earth was receiving significantly less TSI, gravity was unchanged, and the atmospheric pressure had dropped to somewhere in the range of 50 – 100 bar by bleeding off into space then, any storms topped out at much lower elevations resulting in radiating significantly less energy back into space. With a higher pressure the adiabatic lapse rate had to be significantly greater than 10k/1000 M.
BTW – based on the present rate of atmosphere loss on Mars the atmospheric pressure had to be similar to Earth’s shortly after formation. That is 200 – 250 bar.

milodonharlani

phodges says:
September 24, 2013 at 11:50 am
Same goes for climatic effects of Earth’s rotation rate & the proximity of the Moon.
There have also been studies of the effects on life forms or lack thereof on the composition of the atmosphere & cloudiness.
The causes of the paradox may be many, but IMO among them are atmospheric density & composition, even without considering CO2 & CH4. Science cannot say with any precision how long it took H2 to escape to space or be consumed by organisms. If it lingered well into the Archean to any meaningful degree, then an atmosphere with twice as much N2 as now (ie, about twice as dense as at present) could produce ammonia & other hydrogen-nitrogen compounds, however short-lived, that would act as GHGs. The recent fossil raindrop study suggests that the Archean atmosphere was no more than about twice as dense as now.

GH05T

I love it when they use one faith-based theory to prove another. If the empirical evidence doesn’t support the Faint Young Sun theory, maybe the theory of stellar evolution is flawed. It’s not like anyone has ever seen one kind of star turn into a different type of star over the course of billions of years. We just observed different types of stars and imparted our own human need for order and categorization upon them.
Of course Stellar evolution may be correct and it’s the geological evidence that’s being misinterpreted. Maybe the calculation for the age of the strata is flawed. So much of what gets called science these days is nothing more than assumption stacked on assumption.

Paul

They forgot to mention that the earth was probably much more volcanic and with a hotter more radioactive core. Undersea volcanoes released enough heat to keep the seas much warmer making the atmosphere hot and humid. The atmosphere being much thicker would trap in the heat much better than the thin of atmosphere today. That is why carbon dioxide makes no difference to climate now. If you have a thick duvet on your bed in winter you will be cosy and warm but if you have a thin sheet you will be cold. Over billions of years the solar wind has stripped away some of earths atmosphere making it easier for heat to escape.

JimS

I can understand what a problem a dimmer Sun would mean. It seems that the Sun smartened up fast enough.

Carrick

Of course this is a model result, and may be false:

During the Archean eon, between about 3.8 billion years ago and 2.5 billion years ago, the Sun was about 20 to 25 percent fainter than it is today.

I don’t personally view evolutionary stellar models as being particularly more robust than climate models. One of the big unknowns is the rotational profile of the interior of the Sun. If you assume a constant rotation with depth, it is true this leads to the result that the Sun was about 25% less luminous 4-billion years ago, and then to an apparent paradox between observed Earth climate and solar luminosity.
If you assume a more rapid rotation of the interior, this leads to a much “flatter” luminosity curve with time than in a standard slowly rotating star. (See Tassoul’s excellent book on stellar rotation for an overview of this.)

Latitude

MattS says:
September 24, 2013 at 11:53 am
Yes it is, but the authors are talking about a 1 to 2 order of magnitude increase from current CO2 levels. That is going to make a noticeable difference even if the effect is logarithmic.
==================
It shouldn’t….once the bands are saturated…party’s over

Spartacus

For a geologist, this is almost a non-sense discussion. The earth’s crust was not even completely formed and it was thinner than today, granites were very scarce. Basalt and other basic rocks were dominant. The Earth behaved, until the end of the Archean, as a giant heat ball. Even the oceans were not as we know them today but a “soup” (heat ocean), were the life took the first steps. Not even massive continents, as we have today, existed. Oceans covered almost the majority of the earth’s surface, allowing a very good resilience to any temperature drop. It would be better if the authors of these alike articles could read a little about the work of geologists that study this period.

phlogiston

I go with negative feedbacks based on water and life and Lovelock’s daisyworld.

Billy Liar

Now they’ve explained the Archean period for earth perhaps they could go on to explain why Mars had oceans 3.8Bn years ago too.

Bryan A

@Salvatore Del Prete says:
September 24, 2013 at 11:41 am
During the time period of approx. 170my ago (Jurassic) Continental Drift was in full swing. The area that is now at the bottom of the Atlantic Ocean, The Volcanic Rift zone where the plates are spreading, was a heavily volcanically active zone and was largely responsible for the majority of the atmospheric CO2 concentration at the time. But the Mid Atlantic Rift Zone, prior to being submerged beneath the ocean was a volcanic ridge. In addition to CO2, there was other gasses like SO2, and various particulate matter like Ash clouds that would have acted as a negative feedback thereby moderating the effect of the volcanic CO2 and Mega Fauna induced CH4.

mkelly

If CH4 is a fossil fuel as they claim where did it come from way back then. Not many things around to make fossil fuel out of.

milodonharlani

Spartacus says:
September 24, 2013 at 12:29 pm
Excellent points. Sagan missed a lot by not studying other sciences, as shown by the errors in his TV show. His first wife was even a biologist.
Even had Archean global average temperature been zero degrees C, much of the nearly worldwide ocean would have remained ice-free.

george e. smith

Excuse me sir, but if the oceans are looking like they want to freeze, don’t you have a sky with basically no clouds in it, so you would have a whole lot more of the incident solar energy, not being scattered or absorbed by clouds and water vapor.

Outrageous Ampersand

It’s all about erosion. The atmosphere has been eroding away for eons by the solar wind.
As the sun got brighter, the solar wind became more forceful, and eroded the atmosphere faster. This thinner atmosphere held less heat, and thus the increased radiation didn’t heat the planet much.

jono1066

Just create and filmed a mini solar system using electrostatically charged polystyrene granules and a fast rotating conducting core in my workshop, clearly showing eleptical orbits… anyone got a computer model so I can prove its real….

jono1066

thats “just created” (past tense)
sorry

Here is an interesting graphic for the percent composition of the earth’s atmosphere over 4.6 billion years.
http://www.scientificpsychic.com/etc/timeline/atmosphere-composition.html
I’m not sure i believe it entirely…. the overlap of H20 and CO2 does not leave room for the N2 at 3.8 Billion years. It also does not indicate the surface pressure and changes to it. But it is a generally well done graphic.

Billy Liar

mkelly says:
September 24, 2013 at 12:38 pm
If CH4 is a fossil fuel as they claim where did it come from way back then. Not many things around to make fossil fuel out of.
On Mars, Curiosity (the rover) is looking for CH4 because ‘it is the signature of life’. WUWT?
http://www.space.com/18333-mars-rover-curiosity-methane-measurements.html

DirkH

Yeah, use models that failed right after their invention in explaining today’s climate within a decade and use them to examine millions of years.
It’s the easy way to get the taxpayer’s dough. You can do it too!

mkelly

Billy Liar says:
September 24, 2013 at 1:14 pm
On Mars, Curiosity (the rover) is looking for CH4 because ‘it is the signature of life’. WUWT?
The problem with that idea is Titan. Where did it get life to make methane?

milodonharlani

mkelly says:
September 24, 2013 at 1:31 pm
Methane can be produced both abiotically & biotically, but on Earth, it’s mainly biological.
This prediction of methane loss on Titan is based upon a model, but with some observational data & basic chemistry behind it:
http://www.jpl.nasa.gov/news/news.php?release=2013-136

mkelly

milodonharlani says:
September 24, 2013 at 1:41 pm
mkelly says:
September 24, 2013 at 1:31 pm
Methane can be produced both abiotically & biotically, but on Earth, it’s mainly biological.
Yes I know. But you cannot claim you found proof of life on Mars just by finding CH4.

Berényi Péter

Do we know salinity of Archean seas? At 350 PSU (ten times more saline than present day oceans, equal to salinity of Dead Sea) freezing point is -35°C.
The process regulating salinity of seawater is not well understood. Amount of salts carried by rivers to sea is enough to reach 35 PSU (current average) in 10 million years (a small fraction of geologic time). In the Archean this process might have been dominated by deep ocean vents, sped up by a much higher geothermal gradient. At the same time there were less chance to form closed basins where salts are removed by evaporation/sedimentation, because less continental crust was available.
Anyway, it is possible to have liquid water well below 0°C.

MarkW

The sun is currently shrinking by millions of tons a day, both in the form of the solar wind and from fusing hydrogen into helium. As the sun grew lighter, the orbits of the planets expanded.
Doubt this will account for all of the difference, but it will handle some of it.

kadaka (KD Knoebel)

Compare to what is said about the Oxygen Crisis, aka the Great Oxygenation Event of 2.4 billion years ago:

Either way, the oxygen did eventually accumulate in the atmosphere, with two major consequences. First, it oxidized atmospheric methane (a strong greenhouse gas) to carbon dioxide (a weaker one) and water, triggering the Huronian glaciation. The latter may have been a full-blown, and possibly the longest ever, snowball Earth episode, lasting 300–400 million years.[7][8]

Above from the press release:

They find that an atmosphere that had 100 millibars of carbon dioxide and 2 millibars of methane 3.8 billion years ago, and 10 millibars of carbon dioxide and 2 millibars of methane 2.5 billion years ago—levels corresponding to 25 to 250 times the present level of carbon dioxide and 1000 times the present level of methane…

Five times more partial pressure of CO₂ than CH₄, and it was the methane keeping the planet warm. Once the methane went away in the Oxygen Crisis, the Earth’s surface cooled to deep glaciation.
Conclusion: Carbon Dioxide is WEAK. At 25 times current concentrations it was insufficient to keep the planet warm. With mounting evidence the logarithmic greenhouse effect of CO₂ is saturated at current levels, we can clearly see the further expected increases are nothing to fear.
But as the planet is cooling and this interglacial altogether has been cooling as we slide back to planetary glaciation, we could use more methane. I’ll do my part to increase demand for cow-derived products. We also need more termites. We’ll let them eat The House That Gore Built.

Duster

mkelly says:
September 24, 2013 at 12:38 pm
If CH4 is a fossil fuel as they claim where did it come from way back then. Not many things around to make fossil fuel out of.

Methane occurs on all the outer gaseous planets, in traces on Mars, and in gaseous nebulae in deep, interstellar space as well . It is not necessarily a “fossil fuel” in the proper sense of the word “fossil.” Here on earth it can be, and mostly is. However during the era of planetary condensation, vast volumes of methane would have been pulled in, and that is one of the empirical realities that has been used to brace the argument for so-called “abiotic” oil. Merely because a molecule is an “organic” compound does not mean it was ever part of a living organism.
Probably more important to climate is the observation made by Phodges that the solar system is chaotic. The Lyupanov Time for the solar system is uncertain – the estimate I’ve read places it with two orders of magnitude. The important point though is that over at least a few tens of millions of years it simply is no longer possible to be certain about things like when the seasons occurred, or even if there were seasons. I have a geology text that states that there is no evidence of seasons during the paleo- and mesozoic. You don’t necessarily have to take that as a fact, but it does mean that even the origins of seasons is not fully understood – we know why but not when. That could very well account for things like dinosaurs within less than 10 degrees of the north pole, which leaves you wondering about whether plate tectonics may have a very long term effect on seasons by redistributing and creating continental mass and affecting the efficient redistribution of ocean water around the globe.
There’s a whole lot we don’t know, and models which simply use a random number generator to simulate our ignorance really can’t inform of us of anything.

Bryan A

mkelly says:
September 24, 2013 at 12:38 pm
If CH4 is a fossil fuel as they claim where did it come from way back then. Not many things around to make fossil fuel out of.
CH4 or Methane is a byproduct of digestion and given the size of the animals of the time, there were probably remarkable amounts of Gut Gasses. Not to mention the massive ammounts of off gassing from Dino Droppings

tty

It is hard to see how such a high concentration of CH4 could be maintained for such a long time. Even in an anoxic atmosphere surprisingly large quantities of H2O2 are formed photochemically and would oxidize the CH4, It would an enormous biological production to maintain it.

kadaka (KD Knoebel)

From MarkW on September 24, 2013 at 1:56 pm:

The sun is currently shrinking by millions of tons a day, both in the form of the solar wind and from fusing hydrogen into helium. As the sun grew lighter, the orbits of the planets expanded.

The mass of the Sun is 1.989×10^30 kilograms. It is 99.86% of the total mass of the solar system.
In the core, the Sun is fusing 620 million metric tons (6.2 x 10^11 kg) of hydrogen every second. The resulting elements however are staying around the core thus the Sun is not shrinking by that much mass per second.
The solar wind accounts for a mass loss of about 4 to 6 billion metric tons per hour. While this may sound impressive, only about 0.01% of the Sun’s total mass has been lost in total this way.
The fusing does not reduce the Sun’s mass, save the tiny bit released as energy by current exothermic fusion processes. The solar wind does not noticeably reduce the Sun’s mass.
In all but the most technical senses, the Sun is not shrinking, it has not gotten lighter.

klem

“Radioisotope decay…”
Exactly, the earth probably stayed warm because it produced it’s own heat.

Brad Weaver

Are you guys kidding me? Modeling something that MIGHT have happened 3.8 BILLION YEARS AGO???
What a waste of carbon (air breathers) and electrons (computer modeling)…
1.75 BILLION YEARS (latest estimated time left for life on Earth) from now, is someone going to say how accurate the warmistas were?
What is our “time-span” concern for the future? 500, or a thousand years? At what point do they call it quits and take a break?
Hasn’t humanity adjusted to its climatic environment, moving as needed, adapting to new foods and shelter, etc?
All this time and effort for some mystical “solution” that won’t alter climate change, and could get wiped out in the span of a few days by a large asteroid the size of a small building….very sad.