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Thread: First temperature rises, then CO2

  1. #1 First temperature rises, then CO2 
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    Hey,

    A friend told me that they don't believe in global warming anymore because
    "if you look at geological history, what actually happens is that first temperature rises, then CO2 concentrations."

    Has anyone heard this before? Sounds farily irrelevant to me, but then I'm a layman .

    Any feedback would be great.

    Cheers.


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    You have not specified the level of temperature rise or, any time lag between the higher temp and the production of CO2.

    Without specific data, one logical scenario could be a rise in ambient temperature leading to conditions so dry that the propogation of fires (perhaps started by lightning) continue until the O2 level in the atmosphere drops to a level that can no longer sustain fire, thus the O2 consumed would be converted to CO2.

    I don't say this can or has happened I only say it seems plausible.

    Mind you, if the planet on fire isn't global warming what is?


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  4. #3 Re: First temperature rises, then CO2 
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    Quote Originally Posted by russell_c_cook
    Any feedback would be great.
    And there's your answer.

    In the past most warming wasn't initiated by Co2, but changes to amount and distribution of sunlight reaching the earth either by direct changes of the sun and astronomical forcing (look up Milankovich cycle)...aka the earth's wobble, degree of tilt, and orbit shape around the sun.

    There are two primary long term (scale hundreds to thousands of years) positive feedbacks that amplify climate: the amount of ice and snow reflecting sunlight and the amount of Co2 in the atmosphere. Somewhat obvious is when things warm, ice and snow area go down and thus the planet absorbs more sunlight and hence more warming.

    Natural CO2 balance is a bit more complex and mostly driven by our planet's ocean temperatures. When it's cold it can hold more CO2. When it's warmer it can hold less. Our best estimate are that it takes almost a thousand years for our oceans to completely flush and adjust to changes, which is coincidently about the amount of time of lag.

    So while past climate change has been initiated by astronomical forcing (or perhaps by direct solar change) followed by several positive feedbacks, any independent change to the long term feedbacks was always capable of changing changing. Enter humans and release of hundreds of millions of years of stored CO2.
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  6. #5 Re: First temperature rises, then CO2 
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    Quote Originally Posted by Lynx_Fox
    There are two primary long term (scale hundreds to thousands of years) positive feedbacks that amplify climate: the amount of ice and snow reflecting sunlight and the amount of Co2 in the atmosphere.

    Enter humans and release of hundreds of millions of years of stored CO2.
    The completely carbocentric scenario is politically and mediatically very strong, but quite impossible, for physical reasons, and for geological reasons.

    Yours is not so carbocentric, but not so released from the carbocentric dogma.

    For physical reason.
    Now, the two bands of absorptions of atmospheric CO2 are nearly saturated :



    And the CO2 content of the atmosphere has decreased all over the aging of the Earth.
    It has never been so low than now, in the Quaternary, an era with glaciations and polar ice caps.

    The CO2 atmospheric could begin to play a role in the climate if it continued to decrease severely. Maybe, after tens of millions years. Very long time after the extinction of the human species...

    The huge Marinoean glaciation came with a huge CO2 atmospheric content, in the Archean age. During the Vendian age, several (5) almost total glaciations occured, the Varanger is one of these. And the CO2 atmospheric was 16 to 20 times the actual. So total saturation of the absorption band : no sensitivity at all to the atmospheric CO2 abundance.

    For geological reasons, too :
    The big majority of CO2 fixed in the crust, is in the carbonates : calcite, aragonite, and dolomia. Carbon in organic fossilised matter, is only a small fraction of the carbon in the carbonates, and accessible fuels are only a very small fraction of the stocked organic matter.

    The CO2 is essential to photosynthesis. The aerial life of terrestrial vegetals is totally dependant of a minimum atmospheric CO2. Lots have disappeared as the atmospheric CO2 lowered.

    The scientists are in the hand of politicians, who hold the money, can threaten, blackmail, corrupt, who hold the careers...
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    The saturation argument is pretty common but was proven wrong nearly 70s years ago by the direct measurements of radiation in the stratosphere where air is dry and thus not anywhere radiation saturated with respect to Co2. Increased blocking of mid and upper atmosphere IR warms the entire column including where us primates live.

    The geological argument is also a poor one. The distant geological past is essentially a different solar system with a dimmer star, an earth with both different continents and ocean circulations. In the short term discussions of less than ten thousand years, comparisons with distant geology aren't strong arguments against current climate changes.
    --
    The scientists are in the hand of politicians, who hold the money, can threaten, blackmail, corrupt, who hold the careers...
    You're completely wrong but feel free to post your opinion in the political sub-forum. Here we will stick to the science.
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    The larger web site was posted higher in the thread, but here's an excellent short piece about the long ago disproved saturation argument; it explains the theory and the matching direct observations that confirm it. Direct observation of decreasing IR escaping in the Co2 bands as well as solid evidence of re-emission of those same wavelengths back towards the surface.

    http://www.skepticalscience.com/satu...termediate.htm
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    How's this for a brief summary?

    "In the historical record, the rise in CO2 concentrations has lagged the rise in average temperature. Therefore, some AGW skeptics claim that CO2 cannot be the cause of current global warming.

    The first thing to note here is that scientists to not use the historical record to provide evidence for present-day global warming.

    The reason for this trend is a positive feedback cycle. Firstly, changes in the Earth’s orbit would cause the initial change in temperature. In the case of warming, the warming of the ocean would result in the release of CO2.
    This obviously increases the atmospheric concentration of CO2, which in turn causes more warming. This positive feedback mechanism is what causes the shift to interglacials, as the variations in the Earth’s orbit are not sufficient to do this.

    In summary, rises in CO2 concentrations in the atmosphere do lag temperature rises, and this is explained by the above feedback mechanism. This does not provide evidence against modern-day AGW as climate scientists do not use these records to provide evidence for global warming."

    Also, two questions.

    1) What causes the feedback mechanism to stop? Is it when the oceans have released all of their CO2?
    2)Why does it take so long for the ocean to release its CO2?

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    It's not just oceans either. As the arctic tundra melts, lots of CO2 and CH4 is being released.

    It takes longer for the oceans, because it only undissolves from the surface, and some water in the oceans does not come close to the surface for centuries.
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    Lynx...

    What percentage of the earths land, do you think, is low enough in humidity, that a change in CO2 levels makes a difference?
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    Quote Originally Posted by Wild Cobra View Post
    Lynx...

    What percentage of the earths land, do you think, is low enough in humidity, that a change in CO2 levels makes a difference?
    This could be Water World, like in the Costner film, and Co2 rise would still lead to higher surface temperatures, because not very far up the atmosphere is much drier.
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    Quote Originally Posted by russell_c_cook View Post


    Also, two questions.

    1) What causes the feedback mechanism to stop? Is it when the oceans have released all of their CO2?
    2)Why does it take so long for the ocean to release its CO2?
    If I'm not mistaken, the thing that causes the feedback cycle to stop is that the Earth begins to radiate more heat away once it gets hotter. It's like how the burner on your stove radiates away more heat when it's hot than when it is cold. Once the Earth is hot enough to begin radiating heat away as fast as it absorbs heat from the Sun, the temperature stops increasing and the feedback cycle stops.

    Remember that no matter how much insulation the Earth has, it still can't keep building up heat forever. It has to start releasing it again at some point. The problem is that, if the new equilibrium temperature is higher than the old temperature was, the ocean levels will rise and stay risen. This day and age is not a good time to own ocean front property.
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    Quote Originally Posted by kojax View Post
    Quote Originally Posted by russell_c_cook View Post


    Also, two questions.

    1) What causes the feedback mechanism to stop? Is it when the oceans have released all of their CO2?
    2)Why does it take so long for the ocean to release its CO2?
    If I'm not mistaken, the thing that causes the feedback cycle to stop is that the Earth begins to radiate more heat away once it gets hotter.
    I believe this is an oversimplification. The Earth radiates heat to space from an effective radiating level which happens to be in the stratosphere. Adding CO2 pushes this level higher so that there is less blocking by CO2 above the effective radiating level and the energy balance can be maintained, but higher levels are colder so radiation is reduced. The level is determined by an equilibrium between lowering temperature and reducing blocking. What happens if and when the effective radiating level reaches the outer edge of the stratosphere where there is no blocking by CO2? The radiating level cannot rise any further so further additions of CO2 cannot be offset by increased radiation, and warming will continue and perhaps accelerate.

    There is probably a flaw (or three) in this argument. Anyone like to critique it?
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    Quote Originally Posted by Lynx_Fox View Post
    Quote Originally Posted by Wild Cobra View Post
    Lynx...

    What percentage of the earths land, do you think, is low enough in humidity, that a change in CO2 levels makes a difference?
    This could be Water World, like in the Costner film, and Co2 rise would still lead to higher surface temperatures, because not very far up the atmosphere is much drier.
    I disagree.

    The majority of the CO2 effect on the IR spectra it captures is already done. It's wavelengths that get past the CO2 and H2O that continue on, and don't care if CO2 or H2O is present in the upper atmosphere.
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    Quote Originally Posted by Wild Cobra View Post

    I disagree.

    The majority of the CO2 effect on the IR spectra it captures is already done. It's wavelengths that get past the CO2 and H2O that continue on, and don't care if CO2 or H2O is present in the upper atmosphere.
    You should, because I'm not even talking about the upper atmosphere. Water vapor content drops off dramatically in a just a few km above the surface, by 10km the atmosphere energy balance switches from convectively driven to radiation driven and has less than 10% if the water vapor it held near the surface--this is still in the lower atmosphere. Being saturated doesn't mean nothing gets through, it means they are captured and re-radiated; there's also constant spectral broadening in the lower dense atmosphere allowing significant amounts of IR to radiative on the margins of the spectral absorption line (none are sharp in the lower atmosphere). Above that 10km level, Co2 is not saturated, nor overlaping with water vapor; any additional Co2 will capture what ever made it that high and reradiate half of it back towards the surface. As Bunbury already eluded, this lowers the outgoing radiation from the planet and creates an overall energy imbalance that can only be compensated for by raising the temperature of the entire column including the lower atmosphere where we live.

    The saturation argument was put to rest nearly 70 years ago and is proven wrong both experimentally and empirically.
    If you want to get into the meat of it you could start with the original paper from 1952.
    http://journals.ametsoc.org/doi/pdf/...DOR>2.0.CO%3B2

    Skeptical science and several other web sites try to put this into laymans terms better than I have.
    Last edited by Lynx_Fox; August 3rd, 2011 at 02:13 AM.
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    Quote Originally Posted by Lynx_Fox View Post
    Quote Originally Posted by Wild Cobra View Post

    I disagree.

    The majority of the CO2 effect on the IR spectra it captures is already done. It's wavelengths that get past the CO2 and H2O that continue on, and don't care if CO2 or H2O is present in the upper atmosphere.
    You should, because I'm not even talking about the upper atmosphere. Water vapor content drops off dramatically in a just a few km above the surface, by 10km the atmosphere energy balance switches from convectively driven to radiation driven and has less than 10% if the water vapor it held near the surface--this is still in the lower atmosphere. Being saturated doesn't mean nothing gets through, it means they are captured and re-radiated; there's also constant spectral broadening in the lower dense atmosphere allowing significant amounts of IR to radiative on the margins of the spectral absorption line (none are sharp in the lower atmosphere). Above that 10km level, Co2 is not saturated, nor overlaping with water vapor; any additional Co2 will capture what ever made it that high and reradiate half of it back towards the surface. As Bunbury already eluded, this lowers the outgoing radiation from the planet and creates an overall energy imbalance that can only be compensated for by raising the temperature of the entire column including the lower atmosphere where we live.

    The saturation argument was put to rest nearly 70 years ago and is proven wrong both experimentally and empirically.
    If you want to get into the meat of it you could start with the original paper from 1952.
    http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1952)009<0001%3AOTPDOR>2.0.CO%3B2

    Skeptical science and several other web sites try to put this into laymans terms better than I have.
    Yes, I understand about the H2O stopping at about 10 km. My point was different, in that the energy also is very reduced at the spectra trapped by CO2 above that area.
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    Quote Originally Posted by Wild Cobra View Post
    Yes, I understand about the H2O stopping at about 10 km.
    I probably confused you a bit between Co2 and H2O and I actually overestimated the amount at 10%. You asked about water vapor at first so I'd address that again. More than half of water vapor is below 1.5km; 95% below 5km; 98% below 12km. Due to global circulation patterns these would be roughly the same even if the entire planet were covered in surface water. The continental areas where precipitable water (a measure of column water vapor) are only noticeably drier in the lee side of large mountain ranges or land massive very far from water. Over the subtropics there's prevailing subsidence (sinking) and dry air regardless of sea or land below. (See image). Over the poles there's so little water vapor that IR isn't saturated even with respect to water vapor.
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    Quote Originally Posted by Lynx_Fox View Post
    Quote Originally Posted by Wild Cobra View Post
    Yes, I understand about the H2O stopping at about 10 km.
    I probably confused you a bit between Co2 and H2O and I actually overestimated the amount at 10%. You asked about water vapor at first so I'd address that again. More than half of water vapor is below 1.5km; 95% below 5km; 98% below 12km. Due to global circulation patterns these would be roughly the same even if the entire planet were covered in surface water. The continental areas where precipitable water (a measure of column water vapor) are only noticeably drier in the lee side of large mountain ranges or land massive very far from water. Over the subtropics there's prevailing subsidence (sinking) and dry air regardless of sea or land below. (See image). Over the poles there's so little water vapor that IR isn't saturated even with respect to water vapor.
    Yes, it's only the polar areas that really make any difference with CO2, but because of the temperature, it is pretty insignificant. the IR emitted from clean snow and is is pretty small in the scheme of things. Brings us back to Black Carbon on Ice in my opinion.

    What's your view with the record days above 100 degrees in parts of the nation? What is it now, 33 days in parts of Texas? I'm sure this is something many in the AGW crowd is salivating over as evidence. I see it differently though. I see it as being less latent heat, so there is more direct heat. That doesn't men the heat energy is the atmosphere is greater than normal, in fact, it can be less. Thoughts?
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    Quote Originally Posted by Wild Cobra View Post
    Yes, it's only the polar areas that really make any difference with CO2, but because of the temperature, it is pretty insignificant. the IR emitted from clean snow and is is pretty small in the scheme of things. Brings us back to Black Carbon on Ice in my opinion.
    Way to mix up and confuse several issues. Clean snow is nearly a perfect emitter of IR. You asked about effect of water surfaces--I answered. Increasing Co2 effects temperature everywhere; a bit more at the poles because there's less overlap with lower atmospheric water vapor; this is really old science.

    What's your view with the record days above 100 degrees in parts of the nation? What is it now, 33 days in parts of Texas? I'm sure this is something many in the AGW crowd is salivating over as evidence. I see it differently though. I see it as being less latent heat, so there is more direct heat. That doesn't men the heat energy is the atmosphere is greater than normal, in fact, it can be less. Thoughts?
    Few AGW scientist are salivating about it because it's a weather event not a climate event. There might be some attempts to assign attributions, and if you did so for this event, you might conclude that without increased Co2 you perhaps would have 33 days over 98 instead of a 100--or something similar.

    Drought areas, due to lack of available water vapor to evaporate or form dew, are subject to larger temperature swings.
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    Quote Originally Posted by Lynx_Fox View Post
    Way to mix up and confuse several issues. Clean snow is nearly a perfect emitter of IR. You asked about effect of water surfaces--I answered. Increasing Co2 effects temperature everywhere; a bit more at the poles because there's less overlap with lower atmospheric water vapor; this is really old science.
    Yes, however, it reflects something like 90% if the incoming solar radiationn first. Not only is the incidental angle rather shallow, but you cannot emit IR from energy that is reflected rather than absorbed energy.
    Few AGW scientist are salivating about it because it's a weather event not a climate event. There might be some attempts to assign attributions, and if you did so for this event, you might conclude that without increased Co2 you perhaps would have 33 days over 98 instead of a 100--or something similar.

    Drought areas, due to lack of available water vapor to evaporate or form dew, are subject to larger temperature swings.
    Well, it doesn't change my mind. I don't think the CO2 makes that much difference at all. Maybe about 0.5 F at best.

    Seriously though. If some of the energy that is maintaining these 100+ temperatures went to the latent heat in the atmospheric water, how much lower might the temperature be? I mean, if there was more water in the atmosphere...
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    Quote Originally Posted by Wild Cobra View Post
    Well, it doesn't change my mind. I don't think the CO2 makes that much difference at all. Maybe about 0.5 F at best.
    We passed that point above preindustrial about several decades ago.

    But perhaps we should take your opinion on this better than the actually agencies which study this extensively and all predict at least an order of magnitude more effect.
    The UK (HADCRU) climatologist (the conservative ones who don't extrapolate the polar observations) temperature predicted changes with business are usual Co2 emissions:


    The US (NASA) climate temperature predicted changes with business as usually over a bit of a different timeline and color scheme (and dated):
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    Quote Originally Posted by Bunbury View Post
    Quote Originally Posted by kojax View Post
    Quote Originally Posted by russell_c_cook View Post


    Also, two questions.

    1) What causes the feedback mechanism to stop? Is it when the oceans have released all of their CO2?
    2)Why does it take so long for the ocean to release its CO2?
    If I'm not mistaken, the thing that causes the feedback cycle to stop is that the Earth begins to radiate more heat away once it gets hotter.
    I believe this is an oversimplification. The Earth radiates heat to space from an effective radiating level which happens to be in the stratosphere. Adding CO2 pushes this level higher so that there is less blocking by CO2 above the effective radiating level and the energy balance can be maintained, but higher levels are colder so radiation is reduced.
    The main reason that layer is cold is because the air is more spread out, which makes it able to radiate heat better.

    No matter what you do, each individual molecule only radiates as fast as it absorbs.

    The level is determined by an equilibrium between lowering temperature and reducing blocking. What happens if and when the effective radiating level reaches the outer edge of the stratosphere where there is no blocking by CO2? The radiating level cannot rise any further so further additions of CO2 cannot be offset by increased radiation, and warming will continue and perhaps accelerate.

    There is probably a flaw (or three) in this argument. Anyone like to critique it?
    I was talking about how the H2O cycle stops. As more water evaporates, more heat is trapped, which causes more water to evaporate, ... etc... but that ends when the increase in heat radiated away due to being at a higher temperature catches up with the decrease in heat radiated away caused by the additional H2O. The two things climb at different speeds, so one is bound to overtake the other eventually.

    For the most part, CO2 levels only increase if people burn hydrocarbons. That's what starts the H2O feedback process.

    Quote Originally Posted by Wild Cobra View Post
    ..

    Yes, it's only the polar areas that really make any difference with CO2, but because of the temperature, it is pretty insignificant. the IR emitted from clean snow and is is pretty small in the scheme of things. Brings us back to Black Carbon on Ice in my opinion.

    What's your view with the record days above 100 degrees in parts of the nation? What is it now, 33 days in parts of Texas? I'm sure this is something many in the AGW crowd is salivating over as evidence. I see it differently though. I see it as being less latent heat, so there is more direct heat. That doesn't men the heat energy is the atmosphere is greater than normal, in fact, it can be less. Thoughts?
    I'm pretty sure that if it was just the ice absorbing heat, then we'd have global cooling instead of global warming, because the melting ice absorbs heat from the surrounding area. Water levels would still rise, but world wide temperatures would probably drop for the time being, at least until the process ends.

    I could be wrong about that. Ice is still one of those mysteries I'm trying to understand, but that's how Ice cellars worked in the days before refridgeration. Melting ice kept the whole cellar cool.
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    Quote Originally Posted by cobra
    Seriously though. If some of the energy that is maintaining these 100+ temperatures went to the latent heat in the atmospheric water, how much lower might the temperature be? I mean, if there was more water in the atmosphere...
    The humidity just north of the Texas drought set records - Minnesota had several days of dew points in the 80s. Tropical island stuff. The temps stayed under 100.
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    I was wondering if bsides greenhouse gases, byproducts like dust and smog particles stay in the atmosphere, causing sunlight to be blocked, may result in Earth being cooled instead? Is there any basis for this?
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    Quote Originally Posted by miwashi View Post
    I was wondering if bsides greenhouse gases, byproducts like dust and smog particles stay in the atmosphere, causing sunlight to be blocked, may result in Earth being cooled instead? Is there any basis for this?
    Ssssh, do not be silly. Big brains know that CO2 and ONLY CO2 are important factors here, silence heretic! Also ignore natural sources of CO2, only from combustion is this gas harmful! Go now and sin no more!
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    Quote Originally Posted by miwashi View Post
    I was wondering if bsides greenhouse gases, byproducts like dust and smog particles stay in the atmosphere, causing sunlight to be blocked, may result in Earth being cooled instead? Is there any basis for this?
    Yes there is. Sometimes that effect is called global dimming and has been getting added to the climate models for the past ten to fifteen years. It's also more complext, in that while over the globe it might be blocking, and hence masking some of the warming effects from Co2, it also might be warming snow covered regions by darkening their surfaces as it precipitates (and settles) out of the air. Here's a quick story about the effects: nsf.gov - National Science Foundation (NSF) News - "Brown Cloud" Particulate Pollution Amplifies Global Warming - US National Science Foundation (NSF)

    Quote Originally Posted by The Finger Prince
    Ssssh, do not be silly. Big brains know that CO2 and ONLY CO2 are important factors here, silence heretic!
    No climatologist think Co2 is the only effect.
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    Thank you, that was informative!
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    With regard to plant CO2 absorption, I was wondering, will increasing atmospheric CO2 concentrations benefit carbon gain during times of extreme high temperatures of around 40-41 degrees celsius? At around what temperature will CO2 assimilation begin to fall off? And from this, would temperate or tropical plants benefit most from carbon gain during elevated CO2 periods?
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