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Thread: Contributions to sea level rise in worst case scenario

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    Contributions to sea level rise in worst case scenario

    Say global warming continues until all geological carbon fuel is burned and the feedbacks run around, making the tropics uninhabitable and melting all the glacial ice, and finally heating up the oceans.
    IIRC, ice melt will raise sea level 60 or 70 meters.
    HOWEVER, the oceans will also rise from thermal expansion of the sea water. How much will this contribute?
    How long will the rise take?

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    World's largest volcanic range may lurk beneath Antarctic ice
    Does not answer your question, but it's a lovely new addition to worst case scenario.
    Scientists found 91 previously unknown volcanoes, ranging in height from 100 to 3850 metres. The peaks are concentrated in a region known as the West Antarctic Rift System, spanning 3,500 kilometres from Antarctica's Ross Ice Shelf to the Antarctic Peninsula.

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    CO2, shoggoths--now this...

    On a serious note--it is easy to imagine Antarctica as nothing but a flat plain with some mountains--with nothing but ice. But it is a continent--with varied terrain like any other--we just can't see it.
    Last edited by publiusr; 2017-Aug-25 at 10:07 PM.

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    Hey Tom, here's one for you.

    Don't you know that that *dropping* sea levels are also caused by global warming?

    https://phys.org/news/2017-08-caspia...peratures.html
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    Quote Originally Posted by BigDon View Post
    Hey Tom, here's one for you.

    Don't you know that that *dropping* sea levels are also caused by global warming?

    https://phys.org/news/2017-08-caspia...peratures.html
    First sentence from the linked article (I added the bold):
    Earth's largest inland body of water has been slowly evaporating for the past two decades due to rising temperatures associated with climate change, a new study finds.
    Unless the Caspian Sea is fed by melting glaciers or a melting ice cap, it seems completely unsurprising to me that if the temperature is higher, there would be more evaporation and water levels would drop.

    However, the "not fed by melting glaciers or a melting ice cap" criteria would not apply globally to the oceans.
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    Glacial cliffs of over 100 meters seem to collapse quickly when they hit the sea: New science suggests the ocean could rise more — and faster — than we thought
    Pretty little piece of work, and on the drowned reefs too.

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    Quote Originally Posted by Tom Mazanec View Post
    Say global warming continues until all geological carbon fuel is burned and the feedbacks run around, making the tropics uninhabitable and melting all the glacial ice, and finally heating up the oceans.
    IIRC, ice melt will raise sea level 60 or 70 meters.
    HOWEVER, the oceans will also rise from thermal expansion of the sea water. How much will this contribute?
    How long will the rise take?
    In that hypothetical event, the transfer of all carbon into the atmosphere and oceans, Jim Hansen calculated from his study of Venus at NASA that the runaway greenhouse effect would cause the sea to boil. As a result, all the water would convert to steam, and the sea level would fall by an average of four kilometres.

    The biggest immediate risk though may be a repeat of the Permian Great Dying caused by ocean stratification. https://www.earth-syst-dynam.net/8/1...d-8-1-2017.pdf states "the largest mass extinction of ocean biota within the Phanerozoic epoch, during the Permian–Triassic transition, was induced by high temperatures as a consequence of elevated CO2 levels, which induced the change from a well-mixed oxic to a stratified euxinic–anoxic ocean (Kaiho et al.,2016)."

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    Quote Originally Posted by Robert Tulip View Post
    In that hypothetical event, the transfer of all carbon into the atmosphere and oceans, Jim Hansen calculated from his study of Venus at NASA that the runaway greenhouse effect would cause the sea to boil. As a result, all the water would convert to steam, and the sea level would fall by an average of four kilometres.

    The biggest immediate risk though may be a repeat of the Permian Great Dying caused by ocean stratification. https://www.earth-syst-dynam.net/8/1...d-8-1-2017.pdf states "the largest mass extinction of ocean biota within the Phanerozoic epoch, during the Permian–Triassic transition, was induced by high temperatures as a consequence of elevated CO2 levels, which induced the change from a well-mixed oxic to a stratified euxinic–anoxic ocean (Kaiho et al.,2016)."
    I had a very intelligent and experienced friend named Ed Langley (died Sep 2001) and I posed the "Venusification" of Earth as a possible end result of Fossil Fuel Burning. He replied "If the impossible can happen, then the impossible can occur." ie he did not believe it.
    Maybe he was wrong.

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    Quote Originally Posted by Tom Mazanec View Post
    I had a very intelligent and experienced friend named Ed Langley (died Sep 2001) and I posed the "Venusification" of Earth as a possible end result of Fossil Fuel Burning. He replied "If the impossible can happen, then the impossible can occur." ie he did not believe it.
    Maybe he was wrong.
    Your opening post presented a hypothetical scenario of the shift of all carbon from the crust to the atmospheric system of our planet. That scenario would produce a runaway greenhouse effect.

    However, it is impossible because the world economy would collapse long before such a dire result. The economic collapse would remove the ability and incentive to shift ever more carbon into the air.

    Just the proven reserves of oil and gas companies were calculated as five times more than the emission limit needed for a two degree warmer world back in 2012, so the potential damage of continued emission is high, even if your scenario is impossible.

    If people work out how to mine carbon from the air then the carbon carrying capacity of the atmosphere will not be relevant to any realistic prognosis.
    Last edited by Robert Tulip; 2017-Nov-05 at 04:06 PM.

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    Quote Originally Posted by Tom Mazanec View Post
    I had a very intelligent and experienced friend named Ed Langley (died Sep 2001) and I posed the "Venusification" of Earth as a possible end result of Fossil Fuel Burning. He replied "If the impossible can happen, then the impossible can occur." ie he did not believe it.
    Maybe he was wrong.
    I see a return to the Carboniferous, yes--but not "Venusification"

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    Quote Originally Posted by Tom Mazanec View Post
    Say global warming continues until all geological carbon fuel is burned and the feedbacks run around, making the tropics uninhabitable and melting all the glacial ice, and finally heating up the oceans.
    IIRC, ice melt will raise sea level 60 or 70 meters.
    HOWEVER, the oceans will also rise from thermal expansion of the sea water. How much will this contribute?
    How long will the rise take?
    All you really need is here, a list of the density of water at various temperatures. Plug your estimate into a calculator, do the math for volume of the world's oceans and you'll have the change in volume.

    If you want estimates of timelines, this is a good chart on the Sea Level Rise wikipedia article.

    Keep in mind, however, that warming sea water might not circulate as well, slowing the global conveyor and increasing the time it takes to warm the deep water. This might cause the surface water to become warmer faster than one might expect. Also keep in mind that melting ice will absorb a lot of heat, reducing some of the warming in some areas.
    Et tu BAUT? Quantum mutatus ab illo.

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    No, we can't go Venus. It's not in the planetary sciences options.

    The absolute worst case *real* scenario is a five to eight degree span around the equator becoming to hot for most multicellular live. With temps ranging from a low of 120F up to 140F during the day.
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    Quote Originally Posted by Robert Tulip View Post
    Your opening post presented a hypothetical scenario of the shift of all carbon from the crust to the atmospheric system of our planet.
    Not quite that much; just all available fossil fuel. The total amount of carbon in the crust is probably hundreds of times larger than the accessible fossil fuel reserves. But we would never be able to extract all that carbon, since it is too thinly distributed and would take more energy to extract than it would yield in energy. Thinly distributed kerogen isn't useful fuel, neither is calcium carbonate.
    Last edited by eburacum45; 2017-Dec-08 at 02:47 PM.

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    Quote Originally Posted by eburacum45 View Post
    Not quite that much; just all available fossil fuel. The total amount of carbon in the crust is probably hundreds of times larger than the accessible fossil fuel reserves. But we would never be able to extract all that carbon, since it is too thinly distributed and would take more energy to extract than it would yield in energy. Thinly distributed kerogen isn't useful fuel, neither is calcium carbonate.
    Then the carbon would not be a "fuel". To make this more plausible and explicit, assume just the economically and energetically available carbon is burned.

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    Quote Originally Posted by Tom Mazanec View Post
    Then the carbon would not be a "fuel". To make this more plausible and explicit, assume just the economically and energetically available carbon is burned.
    Bill McKibben, in his 2012 article Global Warming's Terrifying New Math, said total fossil fuel reserves accounted in stock values were five times the amount of carbon that could be added to the air to keep within two degrees of warming.

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    Quote Originally Posted by Robert Tulip View Post
    Bill McKibben, in his 2012 article Global Warming's Terrifying New Math, said total fossil fuel reserves accounted in stock values were five times the amount of carbon that could be added to the air to keep within two degrees of warming.
    So does this mean ten degrees of warming? Or is it logarithmic?

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    Quote Originally Posted by Tom Mazanec View Post
    So does this mean ten degrees of warming? Or is it logarithmic?
    Difficult to say when catastrophic things like the Clathrate gun hypothesis could easily be floating around in the system being modeled.

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    the role of water means at a "tipping point" to use an overused cliche, the greenhouse effect is logarithmic because a warmer atmosphere holds more water vapour. Finding that point is complicated by the role of clouds in the current situation. Recent research on dark coloured biofilms on ice has worried modellers. Greenland for example is not pure white with ice but has significant darkening from bacteria. So sea levels may rise faster than we thought. the volumetric expansion at 10C is 88 ppm, it's zero at 4 C and rises with temperature. It reaches 700 ppm at 90 C I hope we don't get there! 100ppm is 1% so the contribution to sea rise is under 1% for the time being. (per 1 degree C
    Last edited by profloater; 2017-Dec-16 at 11:17 AM. Reason: added per degree to clarify
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    https://www.researchgate.net/publica...m_2003_to_2012

    One point of agreement between global warming scientists and the few anti scientists is that clouds are important. The paper makes that point without coming to a conclusion. So these comments are mine.

    One strange question is why the increasing water content of the atmosphere since the end of the ice age, has not been a runaway effect during 10000 years and the answer might well be cloud cover. That suggests a negative feedback effect overall but that might not be sustained. This research is typical of recent surveys showing a wide variation but a trend toward less clouds over land and more over oceans.

    If the oceans are warming even a little, then the extra cloud cover is to be expected and you might think that is a positive feedback to ocean warming. The ocean area is of course larger than the land area.

    The clouds reverse their role from day to night, reflecting sunlight away by day but blanketing outward radiation at night. So the net effect is difficult to assess and still a major unknown in global warming models.

    Similarly the roles change from winter to summer and the cloud cover changes in the study are greatest at the poles.

    The clouds themselves are dynamic. In order to change from vapour to cloud, the latent heat must be absorbed by the air or radiated away. Warmer air will push clouds back into vapour, supplying the latent heat required. Thus they kind of switch on and off the net radiation balance between night and day.

    Then the air can be supersaturated with vapour and only flash into cloud by seeding. This may not be trivial in understanding whether local cloud cover is a positive or negative feedback for net warming.

    As for the role of CO2 , the present near 400 ppm are near the energy saturation levels for those wavelengths absorbed by CO2 , so does CO2 play a part in cloud cover? I do wonder. Does anyone know?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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