Solubility of CO2 in Water vs. Greenhouse Effect?

[peadar1987]

I appreciate your ability to admit you are wrong (rather than what others seem to do, which is confuse the issue until it is unclear what we are debating anymore )

Relative humidity is rarely 100% (indicating saturated water vapor content in the air for a given temperature), so the air could usually acquire more water vapor. The only time relative humidity approaches 100% is at night when the air is cooling. When the air is warming, the water vapor content does not keep up with saturation levels.

Yes, but it will even itself out over the course of a few days. If you pump water vapour into the air, you will increase the humidity for the rest of the day, but come nightfall, the temperature drop will push the reset button. Doesn't matter if there is 2%, 5%, or 10% water vapour in the air, once the temperature drops it will condense out. The geological processes that sequester carbon don't work like this

[AngelLestat]

I appreciate your ability to admit you are wrong (rather than what others seem to do, which is confuse the issue until it is unclear what we are debating anymore )

I guess I can do it too, but how to be sure? I never wrong.. XD

No comment regarding single-pane vs. double-pane windows?

With air in the middle?

Edited August 7, 2015 by AngelLestat

[arkie87]

I guess I can do it too, but how to be sure? I never wrong.. XD

In all seriousness, i wasnt trying to imply you were wrong about anything. I am just speaking from experience in the forums. If you call someone out on something about which they are 100% wrong, they will rarely outright admit it or rescind their original comment. They either wont respond to that part, or they will continue to argue and bring up tangents until you dont care anymore.

With air in the middle?

Yes. Trapped air is one of the best insulators.

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Yes, but it will even itself out over the course of a few days. If you pump water vapour into the air, you will increase the humidity for the rest of the day, but come nightfall, the temperature drop will push the reset button. Doesn't matter if there is 2%, 5%, or 10% water vapour in the air, once the temperature drops it will condense out. The geological processes that sequester carbon don't work like this

Yes, I agree. CO2 doesnt condense out of the air. But its effects on water vapor might be reset each night, no? (It's effects to raise temperature directly wont be reset, however).

Not sure what you mean by 2%, 5%, or 10%? Are you referring relative humidity or humidity ratio? Water vapor only condenses out of air if temperature drops below dew point, and as i said previously, relative humidity is very rarely 100% during the day.

Edited August 7, 2015 by arkie87

[peadar1987]

Yes, I agree. CO2 doesnt condense out of the air. But its effects on water vapor might be reset each night, no? (It's effects to raise temperature directly wont be reset, however).

But the CO2 raising the temperature directly does have an effect on the water vapour. Higher temperature leads to more water vapour in the air.

Not sure what you mean by 2%, 5%, or 10%? Are you referring relative humidity or humidity ratio? Water vapor only condenses out of air if temperature drops below dew point, and as i said previously, relative humidity is very rarely 100% during the day.

I was referring to a mass fraction, actually.

Humidity reaches 100% in clouds all the time (and we get plenty of them in Scotland!). Try telling someone who has lived a lifetime in northwestern Europe that water only very rarely condenses out of the atmosphere during the day!

[YNM]

I urge you, to look at this two data :

V NOTE : read this right to left V

http://www.globalwarmingart.com/images/7/76/Phanerozoic_Carbon_Dioxide.png

http://www.globalwarmingart.com/images/d/d3/Carbon_Dioxide_400kyr_Rev.png

Yeah, it becomes a problem once the levels of CO2, as recovered from recent past (read : less than 0.1% of a billion year, least are few tens of generations) carbonate data, and the current data, are far different. Earth did have a higher temperature in the long past, but humans aren't used to this, I suppose. AFAIK, one thing that a human is good at, is changing their surrounding environment to suit their needs - why not on this one as well ?

I'm not sure what your point is? You didnt address my comment at all.

These data are over two different time scales, so of course they dont have to agree. And they have no bearing on our discussion of whether or not as temperature goes up, CO2 concentration in atmosphere should go up or down.

We already know how temperature pretty much goes up and down along with CO2 concentration. You don't need to have a title in geology to know that there's a large probability that this also happens in much further past, which data is also available. Mind that the 0 point of the graph represent 26 deg C, here's one source (all you need to do is clicking an unknown part, like Antarctica, to know the global average).

Yeah, they're of different timescales - but the later is an inset of the first, for the leftmost portion of the first graph. Combine with my linked graph, and you'll see a super-strong correlation between temperature and CO2 concentration. Unless you want your average August summer days to be 40 deg C, I'm sure you will think of how to keep the Earth's temperature the way it is now.

[GeneralVeers]

Yes, CO2 radiates heat up and down, but since the energy is radiated back into the atmosphere from the ground, the next effect is to lose energy to space (since space isnt giving it back).

Though, that is a good point, that even though opacity might approach 100%, there is still a finite layer in the upper atmosphere that is radiating heat into space. I wonder what the limit is i.e. what the maximum effective opacity can be, given that a layer at the end of the atmosphere will always be radiating heat: some back to the atmosphere and some to space?

I would say that maximum opacity (to heat, anyway) would be rather low. Light is easy; near-100% opacity just by using a mirror. With heat it's not so easy, especially with a gas. Gases are always circulating, always moving heat from warmer to colder. The only good way to stop that process is with a solid object. The really good insulators, such as aerogel? A sleeping bag? Closed-cell sleeping pad for backpacking trips? What makes these good insulators of heat is that their internal structure consists of lots of tiny isolated air pockets. The pockets prevent circulation. But it takes a solid object to do that.

I dont see how circulation is relevant (or, more exactly, its effects would only be temporary).

Ever sleep in a bunk bed? The top bunk is almost always noticeably warmer than the bottom. Same deal in an office building with a high ceiling. That's why a greenhouse and a car interior get hot; because the low ceiling prevents hot air from doing what it wants to do--which is go up. If your greenhouse or your car had a ceiling a hundred miles up, the interiors at ground level would be nice and comfy. Except the greenhouse would probably violate local building codes, and the car would have a bit of a problem with tunnels.

Earth doesn't have a ceiling in its lower atmosphere. When warm air wants to go up, it goes up. Circulation moves heat up. Where it gets radiated into space.

If the atmosphere somehow compressed and heated up in the past, it should have cooled down already.

That's the reason I linked the Wikipedia article on Jupiter: it's a counterexample. Jupiter has not cooled down yet.

And the energy Jupiter is producing purely from pressure is considerable. Here's some extremely boring math: Earth is one-fifth as far away from the Sun as Jupiter is. One-fifth times one fifth is four percent. So per unit surface area, Jupiter gets four percent of the solar energy Earth does......BUT......Jupiter has more than a hundred times the surface area facing the Sun! Four percent times a hundred is four hundred percent. As I pointed out WITH A SOURCE, Jupiter is producing more heat from internal pressure than it's receiving from the Sun--and it's getting FOUR TIMES as much heat from the Sun than Earth is! That's a lot.

As a side, Jupiter is also under high pressure (much much higher than Venus)

Not true. At Jupiter's "surface" (which is a poorly-defined semi-liquid state), the pressure is only about ten atmospheres. A lot, but only one-ninth of Venus' surface pressure. Go deeper down into Jupiter, to its core, and the pressure is believed to be about 200 gigapascals. Which is only slightly higher than the pressure in EARTH's core.

Conclusions from all the above: the heat being produced by pressure--it its interior to some degree, but more importantly in the atmosphere at the surface--are a significant factor that cannot be ignored.

I think i've heard of that before. The reason this effect is still significant is because its cyclical

The cycle is not what causes the heat. It's the pressure itself. The planet's interior is simply oscillating around the stable point. Which helps answer one of your other questions further down. (Your argument that pressure doesn't increase temperature is a direct contradiction of the Ideal Gas Law. I'm not buying it.)

I wonder if K-H mechanism could explain long term variations in the Sun's power, that Milankovitch cycles cannot explain....

Almost certainly. It's the same mechanism that causes some variable stars to be variable: fusion in the star's core produces heat which causes the star to expand, which reduces the core pressure, which reduces the rate of fusion, which causes the star to cool, which causes the star to contract, which increases the pressure in the core, which accelerates fusion in the core. Like a pendulum swinging back and forth across its center point, a star that gets knocked away from the resting point by whatever means will end up oscillating around its equilibrium point instead of being a boring normal star like all the other stars.

Both are greenhouse gases, they let more heat pass, but they reflect the heat that tries to escape from earth

Wrong. Greenhouse gases don't know which way is in or out; they reflect equally in all directions. It's estimated Earth's atmosphere reflects about thirty percent of the Sun's energy back into space before it ever hits the surface. That's the only reason the Earth's surface doesn't reach the boiling point of water during the day (the Moon, with no atmosphere, does!)

The second problem is: people are just plain stubborn.

Which is far more true of global warming deniers than accepters, in my subjective experience. Case in point: the "Global warming stopped in 1997" brigade.

In my subjective experience, it's far more true of global warming accepters than deniers. By the way--they're not calling it "global warming" any more. Ever since the warming trend (allegedly) stopped and the wheels fell off their wagon, they've been trying to rebrand it as "climate change". So you're not allowed to say "global warm--"

EEP! Sorry. Almost slipped there.

Edited August 8, 2015 by WedgeAntilles

[AngelLestat]

In all seriousness, i wasnt trying to imply you were wrong about anything. I am just speaking from experience in the forums. If you call someone out on something about which they are 100% wrong, they will rarely outright admit it or rescind their original comment. They either wont respond to that part, or they will continue to argue and bring up tangents until you dont care anymore.

Yeah I know, I just wanted to throw a joke, something I can not always do in English

About being wrong, yeah I am many times, I accept it if I notice, I dont see any shame in that. We learn in all discussions, being wrong or being right.. the outcome is always the same, we learn something new each time. We just need to be care to not spread our errors to others, because if nobody notice it, then we all leave that discussion being wrong and thinking that we know.

Yes. Trapped air is one of the best insulators.

Ok, I read again your last answer, now I understand better your question.

Correct me if I am wrong, you think that only 1 glass is enoght to reflect all the low frequencies as IR, so 2 or more glass layers only work to improve the isolation by conductive heat but not to reflect extra IR?

Transparent plastics or glass, depending its spectral characteristics, may block lets said a 10% of visible light and 60% of IR.

Visible light also carry energy/heat, the difference that the red color carry more heat, and IR (which is invisible to our eyes) carry even more heat.

So if we add many layers like the ones I mention in my example, taken the light blocked by the first layer, then the remaning light is blocked again by a 10% of visible light and a 60% of IR (so in theory is impossible to reach 100% light blocked not matter how many layers we add)

Even if I add 15 layers, it will still reaching a big % of visible light and a small % of Infrared.

That is why my experiment to put a thermometer inside many plastic layers with air between, is valid to reach high temperatures (maybe 90c to 150c) in the same way as Venus does.

Here one example for different glass windows:

Ever sleep in a bunk bed? The top bunk is almost always noticeably warmer than the bottom. Same deal in an office building with a high ceiling. That's why a greenhouse and a car interior get hot; because the low ceiling prevents hot air from doing what it wants to do--which is go up. If your greenhouse or your car had a ceiling a hundred miles up, the interiors at ground level would be nice and comfy.

Earth doesn't have a ceiling in its lower atmosphere. When warm air wants to go up, it goes up. Circulation moves heat up. Where it gets radiated into space.

you even bother to try to understand or check what arkie, peadar and I explain you?

Yeah hot air rise.. You got that right, but why then temperature decrease if altitude increase?

Because the air expand, to do it needs to push the other air around, it needs energy so release heat. Its gaining potential energy, so it lose heat and kinetic, when goes down, it lose potential energy and gains heat. But pressure or gravity by it self is not a source of energy/heat.

And the atmosphere does not escape to space, it has a ceiling limited by gravity!

The only heat that goes out is radiation.

And the energy Jupiter is producing purely from pressure is considerable. Here's some extremely boring math: Earth is one-fifth as far away from the Sun as Jupiter is. One-fifth times one fifth is four percent. So per unit surface area, Jupiter gets four percent of the solar energy Earth does......BUT......Jupiter has more than a hundred times the surface area facing the Sun! Four percent times a hundred is four hundred percent. As I pointed out WITH A SOURCE, Jupiter is producing more heat from internal pressure than it's receiving from the Sun--and it's getting FOUR TIMES as much heat from the Sun than Earth is! That's a lot.

Again.. try to speak with property.. Pressure in this case is not a source of energy, neither gravity.

The only energy here is potential energy. Once the gas shrinks, produce heat, but never will expand again, never. This process takes time because when it shrinks, produce heat, this produce a counter force which stop the shrinks, until this heat is radiated to space, then it shrinks again.

The cycle is not what causes the heat. It's the pressure itself. The planet's interior is simply oscillating around the stable point. Which helps answer one of your other questions further down. (Your argument that pressure doesn't increase temperature is a direct contradiction of the Ideal Gas Law. I'm not buying it.)

Ok.. hold that thought then.. lets see the opinion of your thermodynamics teacher.

Wrong. Greenhouse gases don't know which way is in or out; they reflect equally in all directions. It's estimated Earth's atmosphere reflects about thirty percent of the Sun's energy back into space before it ever hits the surface. That's the only reason the Earth's surface doesn't reach the boiling point of water during the day (the Moon, with no atmosphere, does!)

... but the incomming radiation from the sun has not the same spectrum than when bounce on the ground or against the atmosphere.

When it bounce does it at long wave IR, when it comes from the sun does it with UV, Visible light and high IR frequencies.

Which greenhouse gases are not very good blocking... But when it tries to go out with a longer wave, then it gets blocked. Because that is what a greenhouse gas does! It block low IR frequencies.. Take a look to the venus energy budget graphic, 16000w/m2 leaves the ground, and only 163 w/m2 goes out.

But from the incoming sun radiation, from 653 w/m2. 163 achieve to pass, which mostly is bloqued by sulfuric acid, not greenhouse gases.

So if you were right, from those 653 w/m2, only 0.1 would achieve to pass.

see also my answer to arkie, it will help you to understand.

Edited August 9, 2015 by AngelLestat

[GeneralVeers]

you even bother to try to understand or check what arkie, peadar and I explain you?

If you're going to take that tone with me, and assume the reason I disagree with you is due to a failure of comprehension? Then, no. There's no point in bothering.

Never assume that all rational people are going to come to the same conclusions you have. Because the scientific community is chock full of people, with really long strings of consonants after their names, who disagree on everything from atomic theory to zoology.

[arkie87]

But the CO2 raising the temperature directly does have an effect on the water vapour. Higher temperature leads to more water vapour in the air.

Yes, I admit that. But the extra water vapor in the air can be removed each day at night, when it cools down and dew point is reached.

I was referring to a mass fraction, actually.

Mass fraction is humidity ratio (or is at least related).

Humidity reaches 100% in clouds all the time (and we get plenty of them in Scotland!). Try telling someone who has lived a lifetime in northwestern Europe that water only very rarely condenses out of the atmosphere during the day!

I was talking about near land. Yes, as air rises, it cools and reaches dew point (i.e. 100% humidity).

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We already know how temperature pretty much goes up and down along with CO2 concentration. You don't need to have a title in geology to know that there's a large probability that this also happens in much further past, which data is also available. Mind that the 0 point of the graph represent 26 deg C, here's one source (all you need to do is clicking an unknown part, like Antarctica, to know the global average).

Yeah, they're of different timescales - but the later is an inset of the first, for the leftmost portion of the first graph. Combine with my linked graph, and you'll see a super-strong correlation between temperature and CO2 concentration. Unless you want your average August summer days to be 40 deg C, I'm sure you will think of how to keep the Earth's temperature the way it is now.

I am still confused what you are saying. You posted this on page 4:

Anyway, if we could get back on topic: is there any particular reason that those famous graphs of CO2 vs Temperature automatically indicate greenhouse effect, rather than just solubility of CO2 in water?

My main point is: if the greenhouse effect didnt exist, the graph would look the same (due to solubility), no? Thus, is it not a bad graph to show?

No at all. Solubility, if any, actually goes down when it's hotter, plummeting to full vaporization (no solubility, in turn, making gas out of it) at boiling point. They won't look the same at all : we are recording air temperature. Had air consist of matter that doesn't absorb EM at all the Earth would be devoid of life, and Venus would actually be the women paradise. Rock planets did cools down, but at that time it's mostly nothing but super-thin atmosphere much like Moon or Mercury, that even don't count to be called an atmosphere as we know, feel, live, and breath with it.

There, you try to correct my logic that CO2 and temperature shouldnt be correlated since solubility of water goes down, even though the fact that solubility of CO2 in water goes down, results in CO2 concentrations in the air going UP...

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Ever sleep in a bunk bed? The top bunk is almost always noticeably warmer than the bottom. Same deal in an office building with a high ceiling. That's why a greenhouse and a car interior get hot; because the low ceiling prevents hot air from doing what it wants to do--which is go up. If your greenhouse or your car had a ceiling a hundred miles up, the interiors at ground level would be nice and comfy. Except the greenhouse would probably violate local building codes, and the car would have a bit of a problem with tunnels.

You ignored my second half of the response. What i was trying to say here is that convection alone cannot cool anything long term, since the heat is still retained on the planet. Only radiation to space can.

Earth doesn't have a ceiling in its lower atmosphere. When warm air wants to go up, it goes up. Circulation moves heat up. Where it gets radiated into space.

Bolded part my addition. I hope it is clear now.

In case its not: I was basically confused how convection could cool anything long term since the heat is retained on the planet. But you are claiming convection heats up the atmosphere, which radiates to space, so it is plausible.

That's the reason I linked the Wikipedia article on Jupiter: it's a counterexample. Jupiter has not cooled down yet.

And the energy Jupiter is producing purely from pressure is considerable. Here's some extremely boring math: Earth is one-fifth as far away from the Sun as Jupiter is. One-fifth times one fifth is four percent. So per unit surface area, Jupiter gets four percent of the solar energy Earth does......BUT......Jupiter has more than a hundred times the surface area facing the Sun! Four percent times a hundred is four hundred percent. As I pointed out WITH A SOURCE, Jupiter is producing more heat from internal pressure than it's receiving from the Sun--and it's getting FOUR TIMES as much heat from the Sun than Earth is! That's a lot.

The fact that it hasnt cooled down yet is due to the mechanism. The planet is basically constantly contracting, but the potential energy released from contraction (falling itno the gravity well) causes it to heat up, which slows contraction and makes the planet warmer than it should be.

However, this ISNT happening on Venus (find me a source that says it is) since Venus has a rocky core. And even if it was in the past, Venus is much smaller than jupiter, so it will cool orders of magnitude faster.

Not true. At Jupiter's "surface" (which is a poorly-defined semi-liquid state), the pressure is only about ten atmospheres. A lot, but only one-ninth of Venus' surface pressure. Go deeper down into Jupiter, to its core, and the pressure is believed to be about 200 gigapascals. Which is only slightly higher than the pressure in EARTH's core.

The "surface" of jupiter is arbitrary. A simple google search for "pressure on jupiter" returns:

"Jupiter has the largest planetary atmosphere in the Solar System, spanning over 5,000 km (3,107 mi) in altitude. As Jupiter has no surface, the base of its atmosphere is usually considered to be the point at which atmospheric pressure is equal to 1 MPa (10 bar), or ten times surface pressure on Earth."

So basically, they decided to define the surface based on a pressure rather than define the pressure at the surface based on the surface... This should seem arbitrary to you. The pressure gets wayyyyy above Venus the deeper you go.... and its still a whole lot colder!

(Your argument that pressure doesn't increase temperature is a direct contradiction of the Ideal Gas Law. I'm not buying it.)

P = rho* R * T

If P increases, T increases if rho is constant. But rho is not constant!!! P is constant (since it is determined by the weight of the atmosphere above it only) and rho changes to compensate!

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Yeah I know, I just wanted to throw a joke, something I can not always do in English

About being wrong, yeah I am many times, I accept it if I notice, I dont see any shame in that. We learn in all discussions, being wrong or being right.. the outcome is always the same, we learn something new each time. We just need to be care to not spread our errors to others, because if nobody notice it, then we all leave that discussion being wrong and thinking that we know.

Ok, I read again your last answer, now I understand better your question.

Correct me if I am wrong, you think that only 1 glass is enoght to reflect all the low frequencies as IR, so 2 or more glass layers only work to improve the isolation by conductive heat but not to reflect extra IR?

Transparent plastics or glass, depending its spectral characteristics, may block lets said a 10% of visible light and 60% of IR.

Visible light also carry energy/heat, the difference that the red color carry more heat, and IR (which is invisible to our eyes) carry even more heat.

So if we add many layers like the ones I mention in my example, taken the light blocked by the first layer, then the remaning light is blocked again by a 10% of visible light and a 60% of IR (so in theory is impossible to reach 100% light blocked not matter how many layers we add)

Even if I add 15 layers, it will still reaching a big % of visible light and a small % of Infrared.

That is why my experiment to put a thermometer inside many plastic layers with air between, is valid to reach high temperatures (maybe 90c to 150c) in the same way as Venus does.

Here one example for different glass windows:

http://www.commercialwindows.org/images/Lowe_Spectrum.jpg

Ok, so 1 glass pane might not be enough depending on thickness, but that is really beside the point... if we present the glass is completely opaque, then the point still stands with 1 vs 2 panes of glass...

Edited August 9, 2015 by arkie87

[YNM]

We already know how temperature pretty much goes up and down along with CO2 concentration. You don't need to have a title in geology to know that there's a large probability that this also happens in much further past, which data is also available. Mind that the 0 point of the graph represent 26 deg C, here's one source (all you need to do is clicking an unknown part, like Antarctica, to know the global average).

Yeah, they're of different timescales - but the later is an inset of the first, for the leftmost portion of the first graph. Combine with my linked graph, and you'll see a super-strong correlation between temperature and CO2 concentration. Unless you want your average August summer days to be 40 deg C, I'm sure you will think of how to keep the Earth's temperature the way it is now.

I am still confused what you are saying. You posted this on page 4:

Anyway, if we could get back on topic: is there any particular reason that those famous graphs of CO2 vs Temperature automatically indicate greenhouse effect, rather than just solubility of CO2 in water?

My main point is: if the greenhouse effect didnt exist, the graph would look the same (due to solubility), no? Thus, is it not a bad graph to show?

No at all. Solubility, if any, actually goes down when it's hotter, plummeting to full vaporization (no solubility, in turn, making gas out of it) at boiling point. They won't look the same at all : we are recording air temperature. Had air consist of matter that doesn't absorb EM at all the Earth would be devoid of life, and Venus would actually be the women paradise. Rock planets did cools down, but at that time it's mostly nothing but super-thin atmosphere much like Moon or Mercury, that even don't count to be called an atmosphere as we know, feel, live, and breath with it.

There, you try to correct my logic that CO2 and temperature shouldnt be correlated since solubility of water goes down, even though the fact that solubility of CO2 in water goes down, results in CO2 concentrations in the air going UP...

Well... for one point, I do not care why it have to go up and down. The answer are various - you need a title in geology for this one, which I don't have either. For example, during 300 Mya, plants are booming up, taking almost all CO2 from air. Then, around 200 Mya, somehow plants are drying up, or totally gone. Then it gradually gets down to the point of Ice Age, and the condition we start before industrial revolution. So, you see, solubility can't be the only answer and regulator - you need an actual study of each case to know why it goes that way particularly, and not blaming at solely one answer. The world is a unique one, and you need to study everything to understand that uniqueness. But, what I care, is that we stay at the condition we're born with, not with some past conditions where we don't even lived yet.

[peadar1987]

That's the reason I linked the Wikipedia article on Jupiter: it's a counterexample. Jupiter has not cooled down yet.

And the energy Jupiter is producing purely from pressure is considerable. Here's some extremely boring math: Earth is one-fifth as far away from the Sun as Jupiter is. One-fifth times one fifth is four percent. So per unit surface area, Jupiter gets four percent of the solar energy Earth does......BUT......Jupiter has more than a hundred times the surface area facing the Sun! Four percent times a hundred is four hundred percent. As I pointed out WITH A SOURCE, Jupiter is producing more heat from internal pressure than it's receiving from the Sun--and it's getting FOUR TIMES as much heat from the Sun than Earth is! That's a lot.

Not true. At Jupiter's "surface" (which is a poorly-defined semi-liquid state), the pressure is only about ten atmospheres. A lot, but only one-ninth of Venus' surface pressure. Go deeper down into Jupiter, to its core, and the pressure is believed to be about 200 gigapascals. Which is only slightly higher than the pressure in EARTH's core.

Conclusions from all the above: the heat being produced by pressure--it its interior to some degree, but more importantly in the atmosphere at the surface--are a significant factor that cannot be ignored.

The cycle is not what causes the heat. It's the pressure itself. The planet's interior is simply oscillating around the stable point. Which helps answer one of your other questions further down. (Your argument that pressure doesn't increase temperature is a direct contradiction of the Ideal Gas Law. I'm not buying it.)

Almost certainly. It's the same mechanism that causes some variable stars to be variable: fusion in the star's core produces heat which causes the star to expand, which reduces the core pressure, which reduces the rate of fusion, which causes the star to cool, which causes the star to contract, which increases the pressure in the core, which accelerates fusion in the core. Like a pendulum swinging back and forth across its center point, a star that gets knocked away from the resting point by whatever means will end up oscillating around its equilibrium point instead of being a boring normal star like all the other stars.

No, this really is not true. I am a postgraduate researcher in thermodynamics, I know what I'm talking about here. Pressure alone does not cause heating. Compression causes heating according to Charles' Law, oscillation about a mean point (As in Jupiter) causes heating by hysteresis, simply being under pressure does absolutely nothing.

Wrong. Greenhouse gases don't know which way is in or out; they reflect equally in all directions. It's estimated Earth's atmosphere reflects about thirty percent of the Sun's energy back into space before it ever hits the surface. That's the only reason the Earth's surface doesn't reach the boiling point of water during the day (the Moon, with no atmosphere, does!)

Also untrue. Greenhouse gases are more transparent to incident radiation, and less transparent to the reemitted radiation which is shifted towards the infrared end of the spectrum. They are better at keeping heat in than keeping it out.

In my subjective experience, it's far more true of global warming accepters than deniers. By the way--they're not calling it "global warming" any more. Ever since the warming trend (allegedly) stopped and the wheels fell off their wagon, they've been trying to rebrand it as "climate change". So you're not allowed to say "global warm--"

EEP! Sorry. Almost slipped there.

Complete fabrication: https://www.skepticalscience.com/climate-change-global-warming.htm

Both terms are in use, and have have been used at about the same ratio to each other in both scientific literature and mainstream publications.

If "climate change" is gaining some traction recently over "global warming", it's probably for the benefit of people who don't know the difference between winter and climate, and who don't understand that a global warming trend can result in things like increased precipitation.

[arkie87]

No, this really is not true. I am a postgraduate researcher in thermodynamics, I know what I'm talking about here. Pressure alone does not cause heating. Compression causes heating according to Charles' Law, oscillation about a mean point (As in Jupiter) causes heating by hysteresis, simply being under pressure does absolutely nothing.

I think the confusion is from ideal gas law. P = rho*R*T only shows that increasing temperature leads to an increase in pressure when density (or volume and mass) is constant. For planets, volume is not constant, and instead of pressure increasing when temperature changes, density and/or volume changes to compensate.

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Well... for one point, I do not care why it have to go up and down. The answer are various - you need a title in geology for this one, which I don't have either. For example, during 300 Mya, plants are booming up, taking almost all CO2 from air. Then, around 200 Mya, somehow plants are drying up, or totally gone. Then it gradually gets down to the point of Ice Age, and the condition we start before industrial revolution. So, you see, solubility can't be the only answer and regulator - you need an actual study of each case to know why it goes that way particularly, and not blaming at solely one answer. The world is a unique one, and you need to study everything to understand that uniqueness. But, what I care, is that we stay at the condition we're born with, not with some past conditions where we don't even lived yet.

I'm not talking about every case. I am just talking about that graph, since that graph has been used to show greenhouse effect. My only argument is that even if greenhouse effect magically didnt exist, the graph would look the same due to release of CO2 from ocean, due to solubility. Therefore, it is a bad graph to use to that end, since it doesnt isolate the greenhouse effect (or even necessarily show it). Please address that point...

Or are you agreeing, saying that the reasons CO2 has gone up and down in the past has been so variable, that one cannot use it to show greenhouse effect either?

Edited August 9, 2015 by arkie87

[YNM]

My point is more along the (somewhat) tight correlation between atmospheric CO2 levels and ground-level atmospheric temperature. Which is unfortunately called the greenhouse effect, a bad name indeed. (I mean, it's not like you can have more greenhouse for even hotter temp inside or less greenhouse the other way, not even more or less glass. A bad naming indeed)

EDIT: It's actually called greenhouse gas effect, so it makes sliightly more sense than just "greenhouse effect". They make it that the gases are acting much like the low glass roofs of a greenhouse.

Edited August 9, 2015 by YNM

[AngelLestat]

My point is more along the (somewhat) tight correlation between atmospheric CO2 levels and ground-level atmospheric temperature. Which is unfortunately called the greenhouse effect, a bad name indeed. (I mean, it's not like you can have more greenhouse for even hotter temp inside or less greenhouse the other way, not even more or less glass. A bad naming indeed)

I dont follow you... why you mean?

[YNM]

@AngelLestat: corrected my original post. Also, I think people needs a good understanding first over how CO2 levels had, has, and will affect temperature levels, also vice versa, before going into global warming climate change ice melting yadda yadda yadda. I'm not a denier at all, I just want to make that statement clear.

Edited August 9, 2015 by YNM

[GeneralVeers]

No, this really is not true. I am a postgraduate researcher in thermodynamics, I know what I'm talking about here.

Then you're a postgrad who's making mistakes. Guess what, even Albert Einstein screwed up now and then (his Cosmological Constant? Big time science fail by one of the greatest minds ever born)

Pressure alone does not cause heating. Compression causes heating according to Charles' Law

And what causes compression, Einstein? PRESSURE.

Transitive relationship. A causes B, and B causes C. Therefore A causes C.

Pressure by itself causes heating.

Yes, folks, there's a bunch of stuff you wrote in other posts, which I didn't reply to. No, my silence does NOT constitute agreement, let's just be clear on that.

[KSK]

Then you're a postgrad who's making mistakes. Guess what, even Albert Einstein screwed up now and then (his Cosmological Constant? Big time science fail by one of the greatest minds ever born)

And what causes compression, Einstein? PRESSURE.

Transitive relationship. A causes B, and B causes C. Therefore A causes C.

Pressure by itself causes heating.

Yes, folks, there's a bunch of stuff you wrote in other posts, which I didn't reply to. No, my silence does NOT constitute agreement, let's just be clear on that.

How about quoting all of his reply before getting too snarky. Compression is a change in pressure, which yes, causes heating by Charles's law. However simply maintaining something at a fixed pressure does nothing to change temperature. Which is what Peadar said.

Edited August 9, 2015 by KSK

[GeneralVeers]

How about quoting all of his reply before getting too snarky.

Because I've seen how badly that ends--many, many times. The posts get longer and longer, and the process accelerates as ONE post gets quoted by SEVERAL other people, causing the original respondent to have exponentially increasing amounts of blabbermouthing to respond to. In a curious analog to real life, the thread eventually reaches a critical mass, collapses under its own weight, gets closed by a moderator, and is never seen again.

Compression is a change in pressure, which yes, causes heating by Charles's law.

Thank you. That's all I needed.

I said from the start that the heating caused by pressure is a temporary thing. Obviously a lot of people missed that part.

I had other stuff I was gonna reply to, but I'm putting that on hold for a while, so the above stuff gets a chance to sink in.

[arkie87]

@AngelLestat: corrected my original post. Also, I think people needs a good understanding first over how CO2 levels had, has, and will affect temperature levels, also vice versa, before going into global warming climate change ice melting yadda yadda yadda. I'm not a denier at all, I just want to make that statement clear.

Can agree with that!

- - - Updated - - -

Compression is a change in pressure, which yes, causes heating by Charles's law.

Thank you. That's all I needed.

Charles Law does not state that increasing pressure will increase temperature. It states that the ratio of temperature to volume will remain constant if pressure is held constant. More directly. Charles' Law states:

"When the pressure on a sample of a dry gas is held constant, the Kelvin temperature and the volume will be directly related."

Note that pressure must be held constant!

P*V=n*R*T

If T goes up, EITHER P or V can increase to compensate. If T is doubled, doubling V will prevent P from changing!

Similarly, if P increases, V can go down such that T can be held constant! Increasing pressure does NOT necessitate an increase in temperature!!!!!!!!

Compression is a change in pressure, which yes, causes heating by Charles's law.

Compression is a change in volume, not pressure (though sometimes pressure changes as well). You can compress a gas by cooling it at constant pressure (isobaric process)! Compression can also cause heating if done quickly/adiabatically.

Edited August 10, 2015 by arkie87

[GeneralVeers]

Charles Law does not state that increasing pressure will increase temperature.

It doesn't have to. That's what happens in the real world. When pressure is applied, temperature must ALWAYS increase, because the gas takes time to contract. Could be a second, could be a week. Regardless, V cannot change instantly, so temperature must go up.

Edited August 10, 2015 by WedgeAntilles

[arkie87]

It doesn't have to. That's what happens in the real world. When pressure is applied, temperature must ALWAYS increase, because the gas takes time to expand. Could be a second, could be a week. Regardless, V cannot change instantly, so temperature must go up.

I assume by expand, you meant contract, since you are applying pressure. The fact that temperature goes up in your real world experience has nothing to do with ideal gas law, it has to do with isentropic compression (since that is what it is).

When pressure is applied, temperature does not necessarily increase. Whether or not temperature increases depends on the compression mechanism. There are two types: isentropic and isothermal. Isentropic compression requires the process to be adiabatic (no heat lost) so the process must either be quick or the volume of gas well-insulated. Isothermal compression is either slow or not well insulated, and, as the name implies, is performed at constant temperature. In both processes, pressure goes up and volume goes down. In isentropic process, no heat is lost, so the temperature goes up as well; in isothermal case, some heat is lost so temperature remains the same. You can think of isothermal compression as such a slow compression that as you compress the gas slightly, its increase in temperature causes it to be cooled faster than compressing it causes it to heat up.

In the case of Kelvin-Helmholtz mechanism, it is actually relatively slow process, and the planet radiates the excess energy away, so it is actually closer to isothermal compression, since all the heat/temperature gained from compression, is released as heat instantly, since the compression is so slow....

[KSK]

I stand corrected - thank you arkie.

To Wedge. I take your point but in this case I think it's worth quoting things in full simply because thermodynamics is a science (perhaps more than any other) where there is a lot of room for confusion unless you set out your assumptions clearly. As arkie demonstrates very clearly!

[AngelLestat]

My point is more along the (somewhat) tight correlation between atmospheric CO2 levels and ground-level atmospheric temperature. Which is unfortunately called the greenhouse effect, a bad name indeed. (I mean, it's not like you can have more greenhouse for even hotter temp inside or less greenhouse the other way, not even more or less glass. A bad naming indeed)

EDIT: It's actually called greenhouse gas effect, so it makes sliightly more sense than just "greenhouse effect". They make it that the gases are acting much like the low glass roofs of a greenhouse.

I dont see any problem with the analogy of greenhouses and the effect co2 or different long IR blockers gases, you dont need to know thermodynamics to understand that inside a greenhouse the temperature is higher than outside, and its because the light/heat can enter, but not all can escape ..

The same that happens in the atmosphere. If it would be exactly the same with all its process, it would not be an analogy.

@AngelLestat: corrected my original post. Also, I think people needs a good understanding first over how CO2 levels had, has, and will affect temperature levels, also vice versa, before going into global warming climate change ice melting yadda yadda yadda. I'm not a denier at all, I just want to make that statement clear.

They already know that.. they know to the perfection what is the effect of co2 or other greenhouse gases on the heat trapped, they know how much time co2 last in the atmosphere; the hard part, is follow that new heat trapped in all its different energy forms in all its possible locations.

Is the same that the evolution theory, the process is know, now you need to find the evidence and path of each species family through time.

[peadar1987]

Classic researcher mistake. Get all caught up in advanced stuff and forget about Junior Cert physics. Of course Charles' Law is at a constant pressure. That said, the name of the law doesn't affect the content of the post, a change in pressure will tend to cause a change in temperature, a constantly high pressure will not mean that something is hot.

Venus' atmosphere will have been heated during its formation, but the mass of the atmosphere is orders of magnitude smaller than the planet itself. The surface of earth isn't a sea of molten rock because there have been billions of years for things to reach an equilibrium state.

Edited August 10, 2015 by peadar1987

[GeneralVeers]

I assume by expand, you meant contract

Sigh. Well, as I said a couple posts ago--even geniuses make mistakes. Previous post corrected.

Yes, as P goes up, you could reduce V in order to keep T constant. But real-world gases don't act that way. Apply pressure to a real gas, and both V will go down and T will go up.

When pressure is applied, temperature does not necessarily increase. Whether or not temperature increases depends on the compression mechanism. There are two types: isentropic and isothermal.

Both of which are ideal cases that can't actually happen.

Isentropic compression: no heat is lost. In real-world thermodynamics, that's impossible. There's no such thing as a perfect insulator; some heat must always be lost to the surroundings.

Isothermal: constant temperature. Yes, in theory V could go down in order to keep T constant. But that process can't happen instantly. It takes time. In the interval, T still goes up. Eventually T will then go back down as the system cools, but that also takes time. In some cases (one of which has a name that starts with the letter J......) the process takes a few billion years.

In the case of Kelvin-Helmholtz mechanism, it is actually relatively slow process, and the planet radiates the excess energy away, so it is actually closer to isothermal compression, since all the heat/temperature gained from compression, is released as heat instantly, since the compression is so slow....

"Kelvin-Helmholtz mechanism " is merely a fancy term for "expanding and contracting in a cycle". The mechanism can't actually produce any more heat than if the planet simply sat in the center of the cycle at the stable pressure point. Bottom line: the internal pressures within the planet Jupiter are retaining the heat that was created when the planet formed; the planet is cooling (and shrinking!) but it's a multibillion year process.

Alrightey, here's a puzzle for you: there's been a lot of talk about how it's a change in pressure that causes a change in temperature. So here's the puzzle: you've got your gas chamber full of gas, and a piston to compress it. You were saying the gas will only heat up if the volume goes down.

So what happens if the volume doesn't go down? You apply pressure to the piston, but the volume doesn't decrease. In real-world physics, for that to happen, something must push back against you when you push on the piston. Normally it's temperature; the gas heats up, which causes it to push harder against the compression. But if that doesn't happen......what else can? What else could possibly produce the force that prevents the compression from occurring?