arkie87

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. Mass fraction is humidity ratio (or is at least related). I was talking about near land. Yes, as air rises, it cools and reaches dew point (i.e. 100% humidity). - - - Updated - - - I am still confused what you are saying. You posted this on page 4: 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... - - - Updated - - - 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. 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. 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. 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! 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! - - - Updated - - - 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...

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. Yes. Trapped air is one of the best insulators. - - - Updated - - - 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.

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. I can agree with that

They dont have to find a source that effects temperature and CO2. Temperature change by itself effects CO2! As mentioned above, this is a requirement of the theory of how CO2 affects global temperature via its positive feedback mechanism. Please explain this effect. Why should objects which are hotter absorb more radiative heat? This isnt how it would work. Cp does not change significantly. What causes the thermal inertia is the latent heat of the water vapor. Going from 30C air at 80% relative humidity down to 20C at 100% humidity, requires removal of water vapor thereby releasing latent heat in addition to sensible heat. The effective "Cp" over this range is about 2.8 J/kg-K But if CO2 by itself isnt enough to cause a significant greenhouse (everyone suggests it works via positive feedback loop with water), then the stability and quick residence time of water vapor matters. Adding more CO2 might increase the amount of water vapor. But the water vapor cycle is so stable and self-correcting (negative feedback) that it might not matter. - - - Updated - - - 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.

Sorry. I thought this was for earth, not Venus. My bad. No comment regarding single-pane vs. double-pane windows?

Dont forget about the dependence of solubility on pressure. Just 10 meters down, is twice the pressure. http://www.engineeringtoolbox.com/air-solubility-water-d_639.html EDIT: i guess that effect doesnt matter, since there is no way concentration can diffuse against the gradient

Your figure is quite poor. 0 reflected by surface? 0 latent heat? 0 thermals? Where are these numbers even from? I agree, all that matters in the end of outgoing radiation from upper atmosphere, but the point is, that even if lower atmosphere were completely opaque, upper atmosphere wouldnt cool wayyyy down, since convection from surface and lower atmosphere would keep it warm. Maybe this example will make sense: it's like the difference between being in a car with energy efficient double-pane (high R-value) windows, and single-pane windows. Yes, both windows will trap nearly all the IR radiation emanating from the hot air and surfaces inside the car. However, the single-pane window car will still be cooler, since hot inner surface of the windows can conduct more effectively to the outside surface, where it can then be radiated. And while the radiation that the surface abosrbs is only a small portion of total incoming flux from the sun, its effect isnt as small. Convection acts to improve the temprature uniformity between surface and atmospheric layers than what it would be without convection. It is all about thermal resistance. And while the thermal resistance from surface to upper atmosphere might be very large via radiation due to the opacity of the lower atmosphere, the convective thermal resistance is much smaller. That is the point. Ok, I can agree with that. Though i do think that when assessing climate trends, long term trends (1k, 10k, 100k years) are more important than 100 year trends, so ice core data might still be more useful than all the data we can collect in one lifetime.

Why would anyone pay to read dvd's, when you can just download VLC for free? What is microsoft thinking?

If i understand WedgeAntilles correctly, he is suggesting that convection undermines the radiation blanket caused by greenhouse gases i.e. while radiation cannot penetrate the atmosphere from the surface, convection can and does (indeed, it does as warm humid air rises to form clouds). Thus, while the upper atmosphere which radiates to space is insulated from surface radiation, it is not insulated from the surface by means of convection. So your example of the car is not apropos, since convection is not blocked here. If i understand you correctly, you are saying that the graph is unreliable to draw any conclusions, let alone as evidence of the greenhouse effect?

I am confused by your response: solubility of water goes down with temperature, making CO2 come out of the ocean and enter the atmosphere, thereby raising CO2 ppm with temperature. Thus, the graph would still look as is, no? This effect occurs according to everyone, and global warming in the past actually depended on this effect according to the original paper to create a positive feedback loop, so i dont see how an informed person can dispute it...

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 dont see how circulation is relevant (or, more exactly, its effects would only be temporary). The control volume is around the entire globe. If the energy isnt radiated to space, then it stays in the globe and will warm it. OR, is what you are saying that circulation warms the upper layer in the atmosphere, which increases the radiation temperature in the upper atmosphere, where the opacity is not 100%? Thus, even though the surface is radiatively insulated from the upper atmosphere due to greenhouse gasses, circulation can effectively bring heat up there, through the radiative "blanket". That makes sense. I dont know if anyone has quantified the strength though? I think i've heard of that before. The reason this effect is still significant is because its cyclical, so it is constantly being renewed. Venus does not undergo these contraction/expansions AFAIK, since it is a rockey planet (it seems like it only happens to stars/gaseous planets). As a side, Jupiter is also under high pressure (much much higher than Venus), but the temperature is obviously way below that of Venus, and it is closer to it's blackbody temperature. So pressure has nothing to do with temperature. The planets are cooling from formation. Earth's core is still molten. Eventually, it will freeze, the magnetic field will stop, and life on earth will end. Mars's magnetic field is gone already since its core is frozen. Its core is frozen since the planet is smaller, and therefore, cools more rapidly. If the atmosphere somehow compressed and heated up in the past, it should have cooled down already. It does not have nearly as much thermal mass as the planet does. Besides, based on the physics, its not possible for atmospheres to (permanently) compress/pressurize. The pressure is constant: the volume changes with temperature, not the pressure. I wonder if K-H mechanism could explain long term variations in the Sun's power, that Milankovitch cycles cannot explain.... - - - Updated - - - 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?

This is true for gasses in a constant volume: if you increase the temperature, you increase the pressure due to the reasons you mentioned. However, planets are not constant volumes; their atmospheres actually expand and contract as mean atmospheric temperature changes (see: Scale Height). When temperature increases, the atmosphere gets bigger, but the pressure on the surface stays the same. The pressure on the surface is ONLY dependent on the weight of the atmosphere above; not on temperature. While your statements regarding kinetic theory of gasses is true, it has nothing to do with the steady-state temperature of Venus. The steady-state temperature has to do ONLY with how much heat is absorbed by the planet vs. how much is emitted to space. The only fluxes that matter are those that cross the planetary control volume. These effects you describe would only be temporary. These gasses should have cooled down already, if they were only heated due to compression in the past. The very top of the atmosphere becomes/is a radiator, and as less and less of the surface heat reaches the top, less and less of the upper atmosphere remains a radiator, since it takes less and less distance to become opaque. Moist air also has more enthalpy, so it has more thermal mass. Not sure if you can isolate that affect. Greenhouse effect doesnt quite work the same way. It only insulates heat coming from cold sources (i.e. long wavelength light). Like glass: it is transparent to visible light but opaque to infrared. Gravity doesnt do any work. It takes no energy to keep a gas under pressure, just force. Gravity isnt actively doing work on anything or compressing anything to increase its temperature. - - - Updated - - - I was Ninja'ed

That's not how it works. I have a tank of 2000 psi nitrogen in my lab (~136 atmospheres in pressure). It is at room temperature. It is not as hot as venus just because it is under high pressure. If you compress a gas, it gets hot, sure. But it will cool down to its steady-state temperature. Venus's steady state temperature is hot, so that is caused by something else. In addition, one might think that the elevated pressures are caused by the high temperatures, but this is incorrect too. Pressure is caused by the weight of the atmosphere from the surface to space, and together, pressure and temperature cause density from ideal gas law. That is true, except that in our case, it radiates heat faster, but that heat is absorbed increasingly better by the atmosphere. So the fact that it gets hotter doesnt help, since the radiation does not escape the control volume of the planet. The planet should not stop heating up and the rate of heating up should accelerate as the atmosphere becomes more opaque to IR. The only way its possible to have negative feedback is if the wavelengths of the emitted radiation shifts significantly, which only occurs at really elevated temperatures.

ugghhh. this is exactly what i said i DIDNT want to happen... - - - Updated - - - Now if we could get this thread back on track... Yes, that would be my next point. If, for some reason im not seeing from this graph (or from other external evidence or simulations) we can show that the feedback mechanism is responsible, then i have two additional questions: (1) why does it reach a new steady state at only a few degrees higher temperature? i.e. what additional negative feedbacks exist that overpower the positive greenhouse effect? (2) why isnt it always followed (as you pointed out). Why dont small rapid increases in temperature always result in a departure from an ice age or vice versa?

Sure, but how can you prove that from that graph? One could argue temperature is changing due to some unknown factor (or insolation + other unknown factors), or just that earth's temperature is a bit more complicated than we presently understand, and CO2 is just following temperature around due to solubility (and the fact that temperature raises first is good evidence that this occurs). I understand the mechanism, but i do not understand how anyone can say it is due to greenhouse and not just solubility (from that graph). - - - Updated - - - I understand the feedback mechanism. I do not understand how one can prove that is happening from that graph. Something else might be regulating temperature, and CO2 is just following temperature around.

Ok, thanks What am I to conclude from this graph? What are you trying to say?

I have said this in the OP. I dont think this addresses my question?

(Before I start, I just wanted to say that please be respectful in this forum; given the subject matter, I imagine it is quite easy to get frustrated and condescending and would like to request that those that do not feel they can be respectful kindly not enter the discussion; I am coming here with questions and want to learn). So, if this source is correct, then not only does mainstream science accept the idea that in the past 400,000 years, temperature changes happened before CO2, it actually requires it due to the proposed positive feedback mechanism. This video also helps explain it: If this is the case, then why is this graph repeatedly shown all the time as evidence of greenhouse effect? One could easily say, the reason they are correlated is due to solubility of CO2 in water. I understand it is possible to argue that the initial changes in solar insolation are not sufficient to cause the large jumps in temperature, thereby, requiring a positive feedback mechanism (perhaps greenhouse effect); however, this is not directly shown by the graph (it is a separate argument which requires separate proof), and it seems intellectually dishonest to show this graph as evidence that CO2 and temperature are correlated due to greenhouse effect. Am i missing something?

oops... i misread. Altitude not latitude... Yeah, that's probably why you only see antarctica data, since it goes back much longer.

Because Greenland is further south than the VOSTOK location? This is just due to MilanKovitch cycles, no? i.e. it can be accounted for... The second two examples can be accounted for, since those effects have been/can be easily quantified.

Thanks! It's a bit hard to tell if they are in sync or not. Certainly, overall, it seems like they warm in sync, but there is a lot of noise in the data. Maybe the northern data is tainted... or maybe its natural that the northern data varies by more, since it is surrounded by land, which has lower heat capacity.

It is my understanding that those graphs are only VOSTOK which is antarctic. Greenland cores would be fine too. I'm mostly interested to see if northern hemisphere and southern hemisphere warm up and cool down in phase or out of phase. If it is in phase, then TSI or greenhouse effect could be the cause (but not Milankovich cycles); If it is out of phase, than Milankovich cycles can be the cause (but not TSI or greenhouse).

Has anyone seen any source that compares the ice-core derived temperatures (and CO2) from Arctic vs. Antarctic sites for the past 400,000 years (like the famous graph that is often shown e.g. this?

To what are you responding? Is the mass of the reduced rain forests significant to account for the effect you are trying to explain (keeping in mind that more than half of all photosynthesis is done by algae)?

I dont think ive quoted any facts out of context. Please find an example. I dont see how you could tell my bias in the 9th post in this thread, when it was still talking about CO2 content? Is it biased to do preliminary first-order calculations to see if CO2 level increases can be manmade based on the sheer mass of CO2 we are releasing? Besides, i was searching for a correction (and i corrected myself). How does that indicate bias-- given that i corrected myself against a false "climate denier" argument? Incidentally, CO2 levels around 1960 were raising around 1 ppm/yr, and back then, we werent burning enough carbon to account for that (even if none of it was absorbed by the ocean, though the margin is quite slim). What the heck are you talking about? Before this thread, I've never engaged in any climate change debate on these threads (nor have I even seen one)... that is straight up made up? Are you confusing me with someone else? Besides, if you express opinions in previous threads about how global warming is manmade, does that give me a right to ridicule you so that other readers can be aware of it? What gives? - - - Updated - - - That is enough evidence for you? why do i get the sense you are afraid to disagree or ask too many questions out of fear of being bullied? When i was a kid, I heard the reasoning IndestructibleEVA gave as well. Why does one explanation preclude the other? What about the graphs that show it is a thing? Why should they be discounted?