Formation of coal almost turned our planet into a snowball

coal
Credit: Grant Wilson/public domain

While burning coal today causes Earth to overheat, about 300 million years ago, the formation of coal brought the planet close to global glaciation. For the first time, scientists show the massive effect in a study to be published in the Proceedings of the National Academy of Sciences.

When trees in vast forests died during the Carboniferous and Permian periods, the (CO2) they absorbed from the atmosphere while growing was buried; the plants' debris over time formed most of the that today is used as fossil fuel. Consequently, the CO2 concentration in the atmosphere dropped drastically and Earth cooled down to such a degree that it narrowly escaped what scientists call a "snowball state."

"It is quite an irony that forming the coal that today is a major factor for dangerous global warming once almost led to global glaciation," says author Georg Feulner from the Potsdam Institute for Climate Impact Research. "However, this illustrates the enormous dimension of the coal issue. The amount of CO2 stored in Earth's was once big enough to push our climate out of balance. When released by burning the coal, the CO2 is again destabilizing the Earth system."

The study examines the sensitivity of the climate in a specific period of Earth's deep past by using a large ensemble of computer simulations. While some of the changes in temperature at that time can clearly be attributed to how our planet's axis was tilted and the way it circled the sun, the study reveals the substantial influence of CO2 concentrations. Estimates based on ancient soils and fossil leaves show that they fluctuated widely and at some point sank to about 100 parts CO2 per million parts of all gases in the atmosphere, and possibly even lower. The model simulations now reveal that global glaciation occurs below 40 parts per million.

Today, CO2 levels in the atmosphere have reached more than 400 parts per million. Carbon dioxide acts as a greenhouse gas. The sun warms Earth's surface, but most of the heat radiated by the surface escapes into space; CO2 and other greenhouse gases hinder part of this heat from escaping, hence warming the planet.

"We should definitely keep CO2 levels in the atmosphere below 450 parts per million to keep our climate stable, and ideally much lower than that. Raising the amount of beyond that limit means pushing ourselves out of the safe operating space of Earth," says Feulner. "Earth's past teaches us that periods of rapid warming were often associated with . This shows that a stable climate is something to appreciate and protect."


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More information: Formation of most of our coal brought Earth close to global glaciation, Proceedings of the National Academy of Sciences (2017).
www.pnas.org/cgi/doi/10.1073/pnas.1712062114
Citation: Formation of coal almost turned our planet into a snowball (2017, October 9) retrieved 21 May 2019 from https://phys.org/news/2017-10-formation-coal-planet-snowball.html
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Oct 09, 2017
The paper is claiming that due to a lack of co2 the earth almost reached a tipping point of total glaciation. Now people are claiming the too much co2 will create the opposite tipping point. Both views fail to recognise the fact that there are negative feedback loops that prevent the earth from reaching these permanent extremes. If this was not the fact then the earth would be at one of these extremes right now as do all unstable systems.

Oct 09, 2017
BTW Please excuse the very poor grammar. I did not edit the statement in the allotted 3 minutes.

Oct 09, 2017
Now if they were claiming that a biological oscillation was occurring I might consider that plausible. How about this scenario. BTW this would also prove the temperature effects of co2.

It starts when the plants consume all of the available co2 creating a cooling that kills them. Biological production of co2 ceases and all biomass is converted into fossil fuels during the ensuing ice age.

Then, internal sources of co2 such as volcanoes and gas vents continue to pump co2 into the atmosphere but with no plant life to absorb the co2 it accumulates in the atmosphere until the ice melts and plant life can again absorb it and continue the cycle.

At least that is a cycle the requires no tipping points.


Oct 09, 2017
The only real problem with the theory and the above paper for that matter is that the cooling precedes the lowering of co2 levels in the historical records.

Oct 09, 2017
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Oct 09, 2017
I don't know about the C14 concentration found in some coal, but couldn't there be pockets of "New coal" that still have detectable amounts of C14 left? Does it fall under experimental error? The interplay between CO2 concentrations and plant life is a dynamic one as this link demonstrations so visually;
https://earth.nul...3,38.788

Assume @MR166 is correct and there was a cooling prior to a coal layer's creation, then the cooling would be the suspect in the plant's die-off. Globally that would imply a rapid cooling like that caused from Volcanoes. Or super volcanoes that last for 1000s of years in an eruption.


Oct 09, 2017
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Oct 09, 2017
@howhot, not much C14 left after a few hundred million years (and that's how long ago those coal deposits were laid down). C14 is only useful for at absolute most 100,000 years or so, and is commonly used for materials less than 60,000 years old.

Oct 09, 2017
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Oct 09, 2017
Got any links to any of these "numerous studies," @Chris_Spam?

Peer reviewed journals only please.

Oct 09, 2017
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Oct 09, 2017
@Chris_Spam, the paper doesn't say what you claim it does. It says that coal gets contaminated by bacteria and fungus. It doesn't say the coal is 50kyr old or less. So you lied.

And that's one paper. Where are these "numerous studies?"

So, got any more, that are not about bacterial and fungal contamination of coal used as a reference material to test mass spectrometers?

Oct 09, 2017
@MR166 Of *course* there are feedback loops that keep the climate stable, normally. But they are not infinitely powerful. When they are overwhelmed you have a tipping point. Think of a buffer solution in water. The pH is stable to the addition of acid or base -- up to a point. Once you add enough acid and the pH will suddenly plummet.

Climate systems are complex, and you cannot deduce their behavior by reason alone, as if it were some philosophical problem. Understanding complex systems requires Science, not simply argument.

Oct 10, 2017
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Oct 10, 2017
Here's a model for you, @Chris_Spam:

E = mc²

Care to show us how inaccurate that one is?

Meanwhile, LOL, Hogan is a science fiction writer.

On Earth.

Oct 10, 2017
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Oct 10, 2017
"It is very easy for the modeller to produce the predestined outcome before the model can be run. This is a common flaw in mathematical modelling. A model is not real. Models are not evidence. Models with simulations, projections and predictions prove nothing. All a model shows is something about the model itself and the modellers, normally their limitations. As the Talmud states: 'We do not see things as they are. We see them as we are.'"

- Ian Plimer, Heaven and Earth: Global Warming - The Missing Science

I see we have "The Chris Reeve Show" going on in here.....
yada, yada, yada....

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Oct 10, 2017
So you're now claiming you gave me a paper that you don't believe is reliable, in order to prove that coal is 50,000 years old like you claimed.

Do I have that right?

Snicker.

BTW, where's the rest of the "numerous studies?"

Oct 10, 2017
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Oct 10, 2017
Mind you, coal is radioactive as it is because it contains uranium and thorium from erosion sources. This is why burning coal, and storing the coal ashes is an issue in general.

Take a geiger counter to a lump of coal. It ticks.Common coal in the US has a uranium concentration of about 1-4 ppm. Add a similiar amount for thorium. Coal in shale formations may contain up to 900 ppm - black shale rich with carbon from plant remains is also rich in heavy elements because the sedimentation process works like gold panning: the lighter sands are more easily washed away. Shale is also where you tend to find the fossils

To say that there's no cosmic ray sources to activate carbon into C14 under the ground, therefore it shouldn't exist after millions of years, is missing the blinking obvious: nearly everything in the ground is radioactive, and induces radioactivity in other elements, and this background noise is the main reason why radiocarbon dating doesn't work beyond 50,000 years

Oct 10, 2017
Wow, I mean that's not even a well-designed spambot.

Oct 10, 2017
A good reference for the point comes ironically through a creationist website:

http://www.talkor...c14.html

The case is that physicists want to use petroleum products for scintillation media in order to detect solar neutrinos colliding with it, but if the hydrocarbon liquid contains C14 it will give off beta radiation which is noise for the detectors, so they want to find a source of fossil fuels with the least amount of C14. In quote:

In the course of this work, they've discovered that fossil fuels vary widely in 14C content. Some have no detectable 14C; some have quite a lot of 14C. Apparently it correlates best with the content of the natural radioactivity of the rocks surrounding the fossil fuels, particularly the neutron- and alpha-particle-emitting isotopes of the uranium-thorium series. Dr. Gove and his colleagues told me they think the evidence so far demonstrates that 14C in coal and other fossil fuels is derived entirely from new production

Oct 10, 2017
I think I'll let @Eikka's and @PTTG's posts stand.

@Eikka, nice one, gave you 5s for the uranium/thorium C14 sources. The original paper @Chris_Spam posted mentioned this as well and discussed using paleo-graphite as an index material. It's apparent we'd need paleo-graphite that wasn't close to C14 generating actinides for this use.

Oct 10, 2017
Nice, Chris. Mnemonic Meme masturbation....
I guess this is how you can also stem the inevitable tide of arthritis...
Try playing a guitar or something - it's less annoying to the rest of us on the internet....


Oct 14, 2017
Hay Chris, did you decide to unleash some AI based quotation machine or something on us? That's pretty low dude. However, now that I have your attention, how old is coal? Is there young coal and old coal? As a coal man, which is better? Inquiring minds want to know.

Oct 26, 2017
So, Chris_Bot, do you want old coal or young coal in your stocking this year?

Oct 26, 2017
I gave Eikka a five for using creationist, good and ironically together, as they should be.

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