Global warming is not caused by CO2

  • #126
Andrew Mason
Science Advisor
Homework Helper
7,610
356
That's, right they don't. But the keyword is emission altitude. (sorry short in time right now)Mind that if the incoming radiation is worth a blackbody temperature of -18C then at radiation equilibrium, the outgoing emission must originate from the same temperature range. No?
Not exactly. If outward radiation from any part of the surface or of the atmosphere is not absorbed on its way out, it will leave the earth. If it is aborbed, it will be re-radiated and 50% of it will be radiated back toward the earth. If above certain level the atmosphere did not contain any molecules that could absorb outward radiation and below that level the molecules absorbed ALL the radiation coming from below, the temperature of the atmosphere at that level would be the blackbody temperature of the earth. But the atmosphere is not like that.

Radiation emission orginates from all different levels at all different temperature ranges. Generally, the atmosphere is at thermal and radiation equilibrium at all altitudes.

The radiation distribution (the graph of intensity of radiation as a function of frequency) as seen from space will be the Planck curve corresponding to the blackbody temperature of the earth. That never changes (unless the emissivity of the earth changes, which is a function of the earth's albedo). What changes is the altitude in the atmosphere where the temperature matches the earth's blackbody temperature. As the atmosphere warms, the altitude at which the air matches the blackbody temperature of the earth increases.



AM
 
Last edited:
  • #127
4,465
72
As the atmosphere warms, the altitude at which the air matches the blackbody temperature of the earth increases.
Or the cloud cover and density increases, due to the accelleration in the water cycle, reducing the insolation, reducing the temperature, remember Pallé et al (posted earlier).

albedo-temp.GIF


The albedo variation is digitized from Pallé et al 2006, (fig2) variation in %. The global temperature variation in tenths of degrees in in top graph is from the file http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt [Broken] issued by the Hadley Met office in the UK

Given that in the Stefan Boltzman law for grey body a variation of 10% in albedo as we see here amounts to about 2.5 degrees in temperature, instead of about 0.5 degrees. Hence, it appears that there is a significant negative feedback somewhere, suppressing a larger variation.
Edit: erratum 1% changed into 10%
 
Last edited by a moderator:
  • #128
4,465
72
Please close this conspiracy thread.
Wouldn,t you think that this would require some substantiation. Please go carefully over the thread and find evidence of conspiracy first.
 
  • #129
vanesch
Staff Emeritus
Science Advisor
Gold Member
5,028
16
Please close this conspiracy thread.
I don't see a conspiracy here. There is no discussion of how the mean vile powerful Dr. Mad and the rich industrials to his boots and corrupt politicians are manipulating the minds of the innocent. There is a discussion of what scientific evidence there actually is that CO2 is the main cause of global warming, and what other plausible mechanisms could compete with that.

I myself have a few questions concerning the scientific *certainty* some display about the fact that CO2 is the main cause of a dramatic heating. I'm not putting into question its plausibility, but I'm putting into question its scientific certainty - meaning that there is a proof that is such, that any other mechanism would by necessity also violate some laws of physics. If that scientific case would be *beyond the slightest bit of reasonable doubt*, and if no other thinkable mechanism could be proposed challenging it without at the same time, say, challenging energy conservation or the second law of thermodynamics, and if it were a namecalling thread, then yes, this would be a conspiracy thread. But simply asking in a critical way of what exactly is the proof beyond doubt that CO2 is the sole, main origin of dramatic heating is, I would think, legitimate, no ?
Confronting the actual scientific case to a challenging critical question is all we could hope to promote, no ? Only better understanding can result from this.
 
  • #130
vanesch
Staff Emeritus
Science Advisor
Gold Member
5,028
16
vanesch has seen no benefit from fossil fuel use in the fall in 14C body radiation from 10,000 to 7,000 disintegrations/sec since 1969. He uses radiation hormesis to make his argument.
That was a half joke of course, I don't need hormesis. I was just pointing out that if you go for one hypothesis, you can also go for another one, and arrive at a different conclusion.

What is true however, is that there is no indication of any health effect of small doses, and that the linear no threshold model is just that: a model. It has the property of being the severest model for small dose variations, and that's why it is adopted in health physics: one wants to err on the safe side. But again, there are no serious scientific indications that small doses do have effects.

Now, even if the LNT model turns out to be correct, it means that its effect is in the noise. If we can't measure it, it means that the global effects are unimportant, compared to other causes. According to this model, the average natural background radiation should cause about 0.6% of deadly cancers. Compare that to the real incidence of cancer deaths (something between 13-20%), and you see that it is a negligible effect.

BTW, I didn't find any reference to C-14 in the articles you cited.

The dose burden of C-14 as compared to the total natural background radiation, and even to the medical doses we are subject to, is rather small.

Concerning the coal pollution and victims, here's a link,
http://www.sierraclub.org/cleanair/factsheets/power.asp [Broken]

but I agree that this is not a peer-reviewed thing at all.

There is also http://www.hsph.harvard.edu/news/press-releases/archives/2002-releases/press10172002.html [Broken]

Something more official from the WHO:
http://www.who.int/entity/quantifying_ehimpacts/countryprofilesebd.xls

(41 000 yearly victims of air pollution in the USA).

However, I would also like to see some more substantiated material concerning this.
 
Last edited by a moderator:
  • #131
4,465
72
I don't see a conspiracy here. There is no discussion of how the mean vile powerful Dr. Mad and the rich industrials to his boots and corrupt politicians are manipulating the minds of the innocent.
How subtle. If one wonders whether or not this is happening, perhaps include "enron" in the google searches.

But looking back at the thread. I still don't see any evidence presented that singles out CO2 to cause the recent global warming at the end of the former century and I see no evidence that CO2 was the reason for any temperature fluctuation in the past.
 
  • #132
Andrew Mason
Science Advisor
Homework Helper
7,610
356
...I'm not putting into question its plausibility, but I'm putting into question its scientific certainty - meaning that there is a proof that is such, that any other mechanism would by necessity also violate some laws of physics. If that scientific case would be *beyond the slightest bit of reasonable doubt*, and if no other thinkable mechanism could be proposed challenging it without at the same time, say, challenging energy conservation or the second law of thermodynamics, and if it were a namecalling thread, then yes, this would be a conspiracy thread. But simply asking in a critical way of what exactly is the proof beyond doubt that CO2 is the sole, main origin of dramatic heating is, I would think, legitimate, no ?
Who is saying it is beyond all reasonable doubt? Even climate scientists admit that they do not fully understand all of the factors that affect the earth's climate.

All anyone is really saying is that increased CO2 and other IR asborbing gases will result in more heat radiating from the surface being trapped in the atmosphere AND that we are putting more CO2 and other IR absorbing gases in the atmosphere. That will tend to cause the temperature of the earth surface and the atmosphere to rise. Whether there are other effects that will come into play that will reduce or nullify the heating effect of additional greenhouse gases, or that will accelerate the warming is a matter of ongoing study.

AM
 
  • #133
4,465
72
Who is saying it is beyond all reasonable doubt? Even climate scientists admit that they do not fully understand all of the factors that affect the earth's climate.

All anyone is really saying is that increased CO2 and other IR asborbing gases will result in more heat radiating from the surface being trapped in the atmosphere AND that we are putting more CO2 and other IR absorbing gases in the atmosphere. That will tend to cause the temperature of the earth surface and the atmosphere to rise. Whether there are other effects that will come into play that will reduce or nullify the heating effect of additional greenhouse gases, or that will accelerate the warming is a matter of ongoing study.

AM
One should take more factors into consideration, for one we have discussed convection and diurnal variation and putting more CO2 in the atmosphere also increases the outradiation into space. Which causes cooling again. Another factor that has not been discussed is the quantitative heat transportation and specific heat capacity of the out radiating atmosphere. Perhaps that Chiligar's increased convection rate also increases the energy flow to the average effective emission altitude, causing the increased 'trapped' heat to be vented out at comparable rates again. Just pondering about why all evidence suggest no detectable variation in temperature with variation in greenhouse gas concentration.
 
  • #134
104
0
That will tend to cause the temperature of the earth surface and the atmosphere to rise
Some years ago, three engineers were playing with their new toy: a computer. Instead of crashing cars, they were designing and testing a new structure with it. At a given moment, a crash of the current structure had still high damage on legs for rear passengers. Well, the T (inverted) junction between front and rear doors was to be reinforced, obviuosly. But one of them asked to retest it on the computer. At the end, they did it, even when it was obvious that the junction needed to be strengthened. But the computer told them the opposite: the junction needed to be weaker to allow a *correct* deformation to protect passenger's legs.

Given this real story and its moral:
* Are you sure that increasing CO2 will increase air temperature?
* Are you sure high albedo will increase earth temperature?
* Are you sure that CO2 increase is coming from higher rates of production and not from lower rates of sinking?
* Being water a high performing GHG, will more humidity feed an increase of temperature or will cloud formation imply a descend of temperature?

None of these questions should be considered obvious. And finding reasonable proof for any of them is a hard task.
 
  • #135
Andrew Mason
Science Advisor
Homework Helper
7,610
356
One should take more factors into consideration, for one we have discussed convection and diurnal variation and putting more CO2 in the atmosphere also increases the outradiation into space. Which causes cooling again.
This does not cause cooling. If the outradiation from the atmosphere increases, the temperature of the atmosphere must have increased. So, increased outradiation has to be associated with a temperature increase.

AM
 
  • #136
Andrew Mason
Science Advisor
Homework Helper
7,610
356
Given this real story and its moral:
* Are you sure that increasing CO2 will increase air temperature?
* Are you sure high albedo will increase earth temperature?
Increasing albedo will increase reflectivity of the earth and decrease the temperature of the earth.

* Are you sure that CO2 increase is coming from higher rates of production and not from lower rates of sinking?
What matters is whether there is a human cause of increased CO2.

* Being water a high performing GHG, will more humidity feed an increase of temperature or will cloud formation imply a descend of temperature?
We don't really know. What we do know is that increased atmospheric temperature will increase the vapour pressure of water and this will have an effect on climate.

AM
 
  • #137
49
0
Andrew Mason wrote “So I guess you can explain Venus' surface temperature without reference to CO2 content of its atmosphere.!?‘
Venus has a very hot surface and a complete cloud cover. The atmospheric pressure at its surface is 93 times that of Earth. A 1991 Magellan rocket recorded its atmospheric temperature; the recording stopped at 34 km altitude. http://www.datasync.com/~rsf1/vel/1918vpt.htm This figure extends its last recorded temperature to Venus’ surface using four lines to intersect at four surface temperatures reported later. The dry adiabatic lapse rate for Venus has been calculated by NASA to be 10.5 oK/km compared to 9.8 oK/km for Earth http://pds-atmospheres.nmsu.edu/education_and_outreach/encyclopedia/adiabatic_lapse_rate.htm
The difference is mediated by Venus’ slightly lower gravitational force and higher atmospheric mean molecular weight. The lines argue that Venus’ lower atmosphere is adiabatic, not heated by radiation. Venus’ temperature at 58 km altitude is 260 oK. This is the top of its sulfuric acid cloud. Below the cloud top, Venus’ temperature rises continuously to about 730 oK at the planet’s surface. Earth’s stratosphere has a peak temperature of 262 oK at 50 km mediated by ozone, but its temperature at 10 km is only 217 oK, rising to 298 oK at its surface. Venus’ outward radiation is determined by the temperature at its cloud top. 260 oK means 259.1 W/m2. The cloud reflects an albedo of 0.65 to lower the planet’s net downward solar radiation to 228.8 W/m2. The reduction in outward loss needed for radiation balance is 39.7 W/m2. The balancing temperature without a greenhouse effect would be 252 oK, 8 oK lower. Venus’ surface is ~730 oK because of its dense atmosphere. CO2 contributes 8 oK at the top. It is the massive nature of Venus’ atmosphere that acts adiabatically over a wide altitude range to make it so hot.
 
Last edited by a moderator:
  • #138
vanesch
Staff Emeritus
Science Advisor
Gold Member
5,028
16
Who is saying it is beyond all reasonable doubt? Even climate scientists admit that they do not fully understand all of the factors that affect the earth's climate.

All anyone is really saying is that increased CO2 and other IR asborbing gases will result in more heat radiating from the surface being trapped in the atmosphere AND that we are putting more CO2 and other IR absorbing gases in the atmosphere. That will tend to cause the temperature of the earth surface and the atmosphere to rise. Whether there are other effects that will come into play that will reduce or nullify the heating effect of additional greenhouse gases, or that will accelerate the warming is a matter of ongoing study.

AM
Ah. Well, that's also the statement I subscribe to. I would even add that "there are indications that it is possible that these effects are amplified through feedback and could potentially lead to much stronger heating than just the optical effect of the greenhouse gasses". But that's not really what is said everywhere in scientific circles, and it is certainly not the impression you get when you read the IPCC summary reports. There the tone is more that it is now "scientifically established" that there is going to be a strong heating, and the only thing that is left is an uncertainty of how much: 90% chance between 1.5 and 6 degrees, with a most probable value of 3 K.
 
  • #139
vanesch
Staff Emeritus
Science Advisor
Gold Member
5,028
16
This does not cause cooling. If the outradiation from the atmosphere increases, the temperature of the atmosphere must have increased. So, increased outradiation has to be associated with a temperature increase.
Yes, of upper layers in the atmosphere. The point is that convection can change the temperature profile of the atmosphere, and depending on that profile, you have a different radiative balance. That is the same as changing the resistivities in a resistive chain, will change the potential distribution along that chain, and will also change the overall current, for the same overall potential difference.
 
  • #140
104
0
Increasing albedo will increase reflectivity of the earth and decrease the temperature of the earth.
Ok. And low albedo will increase temperature? Sure?

What matters is whether there is a human cause of increased CO2.
The origin of CO2 matters if CO2 plays a role on climate change. But again, increase of CO2 is due to increased sources (human cause) or due to low sinking?

We don't really know. What we do know is that increased atmospheric temperature will increase the vapour pressure of water and this will have an effect on climate.
And referring water vapour, then we should clarify this first, shouldn't we?
 
  • #141
104
0
This does not cause cooling. If the outradiation from the atmosphere increases, the temperature of the atmosphere must have increased. So, increased outradiation has to be associated with a temperature increase.

AM
Consider an oven at a given inside temperature. Outoor temperature won't change significantly due to the oven. Between inner and outer walls will exist an stationary temperature gradient as thermal energy flows from the hotter inside to the cooler outside. The thicker the wall, the smaller the gradient, and less heat will be lost.
Now, inside the hard wall or even the vacuum wall (Dewar's flask) you have a coil with some fluid that goes from inside surface to outside surface and comes back on a closed loop. A pump keeps the fluid moving.
For sure you'll have increased the heat flow as you transport the hot fluid in contact with inner surface directly to the outer surface, were it will radiate and transfer far more heat as it will be much hotter than the wall would have been if heat was to travel due to temperature gradient through the wall.
 
  • #142
baywax
Gold Member
1,940
1
Just found this article... they're calling these Brown Clouds a mask for Global Warming because of their reflectivity creating a cooling affect(?)

"Imagine for a moment a three-kilometer-thick band of soot, particles, a cocktail of chemicals that stretches from the Arabic Peninsula to Asia," Achim Steiner, UN undersecretary general and executive director of the program, said during a news conference on the findings.

"All of this points to an even greater and urgent need to look at emissions across the planet, because this is where the stories are linked in terms of greenhouse emissions and particle emissions and the impact that they're having on our global climate," he said.

The brown clouds have darkened 13 cities in Asia, including Beijing, Shanghai, Bangkok, Cairo, Mumbai, New Delhi and Tehran, "dimming" sunlight in some places by as much as 25 per cent.

The brown clouds, produced by the burning of fossil fuels, wood and plants, form particles like black carbon and soot that absorb sunlight and warm the air, enhancing the greenhouse effect.

Scientists, however, said the brown clouds also "mask" the warming impacts of climate change by an average of 40 per cent because they contain particles that reflect sunlight and cool the earth's surface.
http://ca.news.yahoo.com/s/cbc/081113/world/technology_brown_clouds_1 [Broken]

Yetch.
 
Last edited by a moderator:
  • #143
366
0
This thread offends people of reason, and should be locked.
 
  • #144
Andrew Mason
Science Advisor
Homework Helper
7,610
356
Yes, of upper layers in the atmosphere. The point is that convection can change the temperature profile of the atmosphere, and depending on that profile, you have a different radiative balance. That is the same as changing the resistivities in a resistive chain, will change the potential distribution along that chain, and will also change the overall current, for the same overall potential difference.
Certainly convection changes the temperature profile of the atmosphere. It moves heat from the surface to higher up in the atmosphere and reduces the temperature gradient. But convection exists now. It is not caused by the air absorbing IR radiation from the surface. It is caused by air being warmed by contact with the surface. It also does not change the radiative balance. That is determined by the amount of solar energy absorbed by the earth. That changes only with a change in the earth's emissivity.

My original question was: how does an increase in CO2 increase convection? Or, looking at it another way, how does adding CO2 to the atmosphere increase convection beyond what adding the same amount of nitrogen or oxygen to the air?

AM
 
  • #145
Andrew Mason
Science Advisor
Homework Helper
7,610
356
Consider an oven at a given inside temperature. Outoor temperature won't change significantly due to the oven. Between inner and outer walls will exist an stationary temperature gradient as thermal energy flows from the hotter inside to the cooler outside. The thicker the wall, the smaller the gradient, and less heat will be lost.
Now, inside the hard wall or even the vacuum wall (Dewar's flask) you have a coil with some fluid that goes from inside surface to outside surface and comes back on a closed loop. A pump keeps the fluid moving.
For sure you'll have increased the heat flow as you transport the hot fluid in contact with inner surface directly to the outer surface, were it will radiate and transfer far more heat as it will be much hotter than the wall would have been if heat was to travel due to temperature gradient through the wall.
I don't follow your analogy. If the energy supplied to the interior of the oven is constant and if the temperature is constant, the amount of energy being removed from the oven has to equal the amount of energy being supplied to the interior of the oven. If you increase the rate at which heat energy is removed, the temperature of the oven will reduce until the rate at which heat is removed exactly equals the rate at which energy is being supplied to the interior of the oven (ie. exactly the same rate as before).

Similarly, the energy which the earth radiates is determined not by the nature or motion of the atmosphere (assuming there is no change in reflectivity/emissivity), but by the amount of radiation incident upon the earth (ignoring the heat emerging from the interior of the earth). The total amount of radiation emanating from the earth is completely independent of convection occurring in the atmosphere or the oceans for that matter. The rate at which energy is radiated from the earth has to be exactly equal the insolation: the rate of radiation energy incident upon it. If this is not the case, the earth's temperature would self-adjust until the incoming radiation matched the outgoing radiation.

So increased convection cannot increase the amount of radiation emanating from the earth.

The CO2 problem is an insulation not an insolation problem. If the CO2 concentration of the atmosphere increases, more of the outward IR radiation from the surface is absorbed by the atmosphere and half of that is reradiated back to the surface. This means the surface has to heat up in order to balance outward and total inward radiation. Although the total radiation from the earth does not change, the temperature at the surface of the earth has to increase.

AM
 
Last edited:
  • #146
vanesch
Staff Emeritus
Science Advisor
Gold Member
5,028
16
My original question was: how does an increase in CO2 increase convection? Or, looking at it another way, how does adding CO2 to the atmosphere increase convection beyond what adding the same amount of nitrogen or oxygen to the air?
I have no idea how CO2 can influence convection all by itself. But what is true is that an increased CO2 content will increase the "opacity" of the atmosphere to IR, and hence as such redistribute absorbed and emitted power fluxes. This can have an influence on the temperature distribution in the atmosphere, which by itself is responsible for the drive behind convection.

But that is not the main point. IMO, the main point is that convection is a negative feedback mechanism (independent of whether there is CO2 or not) for radiative forcing of the surface, in that if the radiative forcing increases, then the surface temperature will also increase, and this will drive more convection, which will allow for a larger heat flux to transit through the atmosphere than when no such convection were present.

You are of course right that the total outward flux must equal the inward solar flux that is not reflected directly as visible light (albedo). So the total outward IR flux is fixed (at fixed albedo), and this, independent of what is the composition, and what are the heat transport mechanisms in the atmosphere. At least in a simple 1D model.

So we know (for fixed albedo) what is going to be the outward radiant IR flux. However, what we are interested in, is the total temperature gradient in the atmosphere needed to obtain that IR radiant flux. This net flux is everywhere going to be the same, at every point in the atmosphere. It will of course be composed of different partial fluxes: a radiant upward flux, a radiant downward flux, heat convection, and heat conduction. But the total balance, at every point in the atmosphere, must equal the same, fixed, outward IR flux. As such, the atmosphere (and even the vacuum) act as a kind of "resistor" in which a radiant flux is driven by temperature differences. For the "vacuum", that "resistor" is simply given by the black body formula: for a certain temperature (difference: with the CMB, but that's neglegible), we have a certain outward radiant flux. The atmosphere adds "resistance" to this: we need a bigger temperature difference to obtain the same radiant flux. That extra resistance is the greenhouse effect. It is due to the partial absorption and re-emission of IR radiation by layers of the atmosphere, which cause also a downward IR flux, and hence we need a higher upward flux to compensate, and arrive at the same net outward flux.

As such, we can think of heat to "make its way" through the atmosphere, and needing an extra "delta-T" each time it crosses a layer of atmosphere. The more the atmosphere absorbs, the more delta-T there is, and that's the basis of the extra greenhouse effect due to greenhouse gasses.

Also, these "delta-T"s will influence the temperature differences in the atmosphere itself.

So radiatively speaking, heat gets emitted from the earth surface, is radiated a bit upward, then a bit downward, then a bit upward again, etc... and makes its way all the way up to the highest layers, where it is eventually emitted in space. The sum of all these final contributions must make up the fixed outward radiant flux. The more opaque the atmosphere, the "more difficult" this outward way is, and the higher the overall delta-T that establishes it. Hence, heating of the surface. Each atmospheric layer is a thermal resistor that increases a bit more the overall thermal resistance of this atmosphere.

But here's my point about convection: if there is a "second way" by which heat can be transported upward through the atmosphere, then it "shunts" part of those resistors. Heat can then, by this second way, reach the higher layers more easily than just by radiation from layer to layer, with each time a partial down radiation. And as such, it will lower the delta-T as compared when there were no such convection.

And now here's my point about feedback. If we look at the purely optical effect of increasing CO2 content of the atmosphere, as calculated by MODTRAN, without altering in any other way 1) the rest of the composition of the atmosphere and 2) any convection or whatever, then we find that for a doubling of the CO2 content, we need to increase the surface temperature by about 0.8K in order to restore the same outward IR flux as before (which, we agree upon, is fixed by the solar influx, and albedo).

Now, if you take it that the atmospheric composition also changes concerning water vapor, and you keep fixed relative humidity (instead of fixed total water vapor), which means that you suppose that at the surface, the wet surface will keep a similar equilibrium as the ratio between partial vapor pressure and temperature in the equilibrium case, but without more cloud formation or convection or anything, then you have, IMO, the maximal possible positive feedback from water vapor. MODTRAN then calculates that you need about 1.5 K surface temperature increase for a CO2 doubling, and the increase in water vapor (due to 1.5 K temperature increase) to have again the same outward IR flux. One would expect the right answer to be somewhere between the two. More water vapor probably means more cloud formation and so on (which increase albedo), but that effect is difficult to quantify. Water vapor is also lighter than air, so this might increase convection (what happens in a cooling tower). This might also decrease the effect of water vapor. Water will not evaporate more than given by the partial pressure equilibrium, so this case is the maximal water vapor feedback. So, without taking into account clouds or convection, according to MODTRAN, a CO2 doubling should result in a surface temperature increase between 0.8K and 1.5K.

Now, convection is a negative feedback which should reduce this needed temperature increase of the surface. I have no idea by how much, but I haven't seen any treatment of this.

But the IPCC talk about an average value of 3 K for CO2 doubling, in an interval of 1.5K to 6K. So there needs to be an extra positive feedback, which is not water vapor, and which is capable to bring this 0.8K to 1.5 K interval or smaller to the 1.5 K to 6 K interval. However, those mechanisms are not really explained. This is where I still have my question marks.
 
Last edited:
  • #147
4,465
72
My original question was: how does an increase in CO2 increase convection?
Wasn't it mentioned that the Infra red radiative interaction starts in the lowest layers of the atmosphere, at the Earth surface, the primary source of the IR. With more CO2 the lower layers get warmer faster increasing the convection rate.

Also, since the convection is adiabatic it also shows that balancing the temperatures between air parcels by radiation is not a predominant process.
 
  • #148
wolram
Gold Member
4,267
557
This thread offends people of reason, and should be locked.

People of reason should state their reasons why the thread should be locked.
 
  • Like
Likes heckler73
  • #149
104
0
I don't follow your analogy.
Heat is transferred from inside to the outside through a medium. If the medium is solid, heat is transferred by contact and radiatively layer by layer, creating a T gradient. The greater the gradient the higher the heat flow. But with convection in place, high temperature layers will radiate directly half of its energy to the outside, while in a situation with no convection, lower, high temperature layers will radiate half of its energy to upper layers. So not all of the energy is radiated outwards as upper layers will re-radiate inwards part of the energy


So increased convection cannot increase the amount of radiation emanating from the earth.
It is generally assumed that the temperature decreases at a rate around 2ºC every 300m o 1000 feet. This is the standard atmosphere, based on an standard gradient. But advection and convection have a great impact on this gradient, modifying energy transfer.
 
  • #150
mheslep
Gold Member
311
728
...But the IPCC talk about an average value of 3 K for CO2 doubling, in an interval of 1.5K to 6K. So there needs to be an extra positive feedback, which is not water vapor, and which is capable to bring this 0.8K to 1.5 K interval or smaller to the 1.5 K to 6 K interval. However, those mechanisms are not really explained. This is where I still have my question marks.
Off the top of my head they cite surface albedo changes from ice cover losses as one of the other feedbacks.
 

Related Threads on Global warming is not caused by CO2

  • Last Post
2
Replies
35
Views
19K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
18
Views
3K
  • Last Post
Replies
6
Views
6K
  • Poll
  • Last Post
2
Replies
36
Views
15K
  • Last Post
4
Replies
88
Views
15K
  • Last Post
Replies
4
Views
8K
  • Last Post
3
Replies
66
Views
14K
Replies
2
Views
6K
  • Last Post
3
Replies
54
Views
9K
Top