Greenland icesheet melting

Discussion in 'Earth Science' started by James R, Jun 30, 2011.

  1. John99 Banned Banned

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    There is no rule that says natural occurnces cannot accelerate or that they proceed in a uniform time frame...on the contrary.

    One thing i will say is that marine organisms are remarkably resilient and i mean in a way that is difficult to fully believe...just wanted to point that out but there are no guarntees.

    Marine Life Survived 8X Current CO2 Levels, but that is a dire situatione nonethe less. Some specimens of their respective species seem to withstand more. So just pointing out there is some buffer in respect to bounce back.
     
    Last edited: Jul 1, 2011
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  3. arfa brane call me arf Valued Senior Member

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    So, what you're saying here is that you, like many other people, have only a basic understanding of climate, or of the history and causes of past changes in climate?

    For instance, you have no real idea how the current changes are unprecedented in terms of the rate of change? And that the current climate has been stable for millions of years, up until now?

    There is no rule that says climate changes can't be accelerated by evolution of species. Perhaps one of the big 'accelerations' was the oxygenation of the atmosphere several billion years ago. Back to the present, and we appear to be a species who can rapidly carbonate the atmosphere. So no loss of generality, then.
     
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  5. adoucette Caca Occurs Valued Senior Member

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    TOTAL BS

    I implied no such thing.

    I pointed to a link that showed that large volcanic eruptions cause their climatic effects via a different route because humans generate far more CO2 then Volcanoes do every year, and so the relatively small CO2 contribution of Volcanoes (creating a tiny additional warming effect) is DWARFED by their potential for massive injections of sulfuric aerosols and large amounts of dust into the stratosphere which can have a very strong cooling effect on the globe that can persist for years.

    .

    True, but CO2 from Volcanoes is inconsequential compared to human emissions and the tiny warming effect from Volcanic CO2 is not nearly as big as their potential for creating a much larger cooling effect. Indeed, it's actually the extreme climate change skeptics who claim that Volcanoes are responsible for much of the current atmospheric CO2, since the actual amount they release on a global basis is hard to precisely quantify. But does it really matter if they produce 1/100th instead of 1/1,000th of the CO2 we do each year?

    Typically yes, but while CO2 builds up year after year, volcanoes still have the potential to create a more dramatic, if less long lived change than our persistant warming trend caused by CO2. The negative impacts, from the cooling and acidic rains of a large Volcanic eruption such as has occured several times in the 1800's would potentially dwarf the negative impacts we have seen so far from our ~ half degree of warming. Indeed, it's easy to see the impact of Mt Pinatubo (1991) in the climatic record and it wasn't that big.

    And you actually can't point to a SINGLE post of mine that attempts to discredit the AGW theory that increased GHGs and Land Use Changes from Human activities is not largely responsible for most of the warming since the middle of the last century can you?

    (If it's not a typo, WTF do you think "AGM Theory" stands for?)


    There is no practical limit in global terms as we would run out of fossil fuels before we could reach levels that plants wouldn't be happy with or hurt us physiologically.

    The enhanced growth curve and maximum level of CO2 that plants can use is reached at around 1,500 ppm, though for most plants, the optimum level is reached much sooner, between 500 and 1,000 ppm, depending on light levels (At optimal temps and sufficient water, then the more light the more CO2 they can use).

    Which is why greenhouses enrich their atmosphere with CO2, but typically somewhat less than 1,000 ppm.

    http://www.hortnet.co.nz/publications/science/n/neder/co2_nr1.htm

    http://www.hydrogrowled.com//Growing-Tips-W10.aspx

    Arthur
     
    Last edited: Jul 1, 2011
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  7. adoucette Caca Occurs Valued Senior Member

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    Stable for millions of years?

    Amazing, yet you have the audacity to lecture others about our climate?

    http://upload.wikimedia.org/wikipedia/commons/f/f5/All_palaeotemps.png

    FYI

    For 90% of the last several million years the Earth's climate has been an ice age.

    The really cold periods last about 100,000 years, and are punctuated by short periods of warm climate, or interglacials.

    That's what we are living in now, an Interglacial.

    This is what North America looked like 18,000 years ago (much of that ice is over 1 mile thick)

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    The other significant part of the climatic record is that warm periods end about as abrubtly as they start.

    Arthur
     
    Last edited: Jul 1, 2011
  8. arfa brane call me arf Valued Senior Member

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    Yes you did.
    But human emissions have only been a part of global climate change for an inconsequential amount of time compared to the effects of volcanism and tectonic activity.
    I think it stands for the theory that humans are generating changes in global climate, by increasing the CO2 load in the atmosphere.

    Oh really? Can you back that up with something more convincing than a couple of articles about horticulture?
    Ok Mr Climate expert: what do you think "stable climate" means?

    The climate has been oscillating between long term glaciation punctuated by short interglacial periods, in a stable pattern, for several million years. This stable pattern is apparently coming to an end, apparently because humans have extended the current interglacial, perhaps indefinitely. The past is a lot easier to study than the future, however.
     
    Last edited: Jul 1, 2011
  9. adoucette Caca Occurs Valued Senior Member

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    No I didn't.
    Your lying about it doesn't make the case either, since you can't point to any part of my post that implies that at all.

    Doesn't matter, the biosphere acts to remove the small amount of CO2 they produce thus preventing a buildup. The problem with human emissions (coupled with land use changes) is that they are ocurring at a rate FASTER than the biosphere can deal with them, hence the buildup in the atmospheric CO2 concentration (about 100 ppm since the start of industialization).

    That would be AGW then, not AGM.
    What would be more convincing than people who make their living out of growing bigger healthier plants by enriching them with CO2 under controlled conditions? The fact is they enrich their greenhouses to ~500 to 1,000 ppm and the plants love it and the earth will never see 1,000 ppm due to Anthro sources.

    Well not having 10 friggin ice ages in the last million years would be a good start towards climatic stability, you know not having it get and stay so cold so long that NY is under a mile of ice and the oceans drop 60+ meters, that sort of thing.

    The period from about 10 million years ago, till 3 million years ago (before the start of the ice ages) would be considered a very stable time in our climatic history.

    http://upload.wikimedia.org/wikipedia/commons/f/f5/All_palaeotemps.png

    Arthur
     
  10. adoucette Caca Occurs Valued Senior Member

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    Well then you apparently have a bizarre definition of STABLE, because when the earth's temperature swings 5 C more or less over relatively short time frames that clearly is NOT stable by any rational definition of the word.

    Your contention that we have extended the current Interglacial is also unfounded as the one before this one lasted ~16,000 years.

    http://en.wikipedia.org/wiki/Eemian_Stage

    And the current Holocene interglacial has persisted since the end of the Pleistocene, about 11,400 years ago.

    http://en.wikipedia.org/wiki/Interglacial

    If it's still warm, say 5,000 years from now, you might be able to make your case.

    Arthur
     
  11. arfa brane call me arf Valued Senior Member

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    7,721
    If you think that's a convincing argument, you are a blinkered idiot.
    If you're implying that the ice age over the last ~3My isn't a stable climate, you're an even bigger idiot.

    If you think everything you post about "the problem" is infallible, you're a moron.
     
  12. adoucette Caca Occurs Valued Senior Member

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    What more proof do you need than people actually doing it every day to make a living? See I don't ever expect to convince YOU of anything. But others reading this will see that I provided the proof you asked for.

    Nope, stability would imply a more modest swing in temperature extemes, of one or two degrees, a decent climate and releatively constant sea levels.
    But for the last 3 million years it's been unstable and swinging much more, 5 or 6 C and trending downward with each swing with sea levels rising and falling as ice covers the earth and then recedes during the warm spells.

    I'll put my posts up against your totally unfounded assertions every day of the week.

    But the proof that you have no argument is you simply resort to ad hominums.

    Which is the entirety of your last post.

    Arthur
     
    Last edited: Jul 1, 2011
  13. arfa brane call me arf Valued Senior Member

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    7,721
    According to whom?

    Look, moron, the climate is stable when there's an ice age and glaciers everywhere.

    When the ice starts to retreat and temperatures increase, you get an interglacial which is "less" stable.
    In general, over the last 3My, the climate has followed a stable pattern of glaciation punctuated by interglacial periods. You may have heard of a physical process called stable hysteresis.

    No, you haven't?
     
  14. adoucette Caca Occurs Valued Senior Member

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    Yup, and the stability is BROKEN when the Interglacial arrives.

    And that lack of stability has been repeated about 10 times in the last million years, which in climatic terms is fairly short, or unstable.

    So, a recurring PATTERN and the climate being STABLE over the last 3 million years, which was your contention, are NOT the same thing.

    We could be a solid ice ball and have a stable climate or we could have no ice anywhere and have a stable climate, if those condtions persisted for millions of years, but the last 3 million years, are not indicative of a stable climate in comparison to the stable period of 10-3 MYA that I pointed out, where the temperature swings were much more modest over a much longer period of time.

    Arthur
     
  15. arfa brane call me arf Valued Senior Member

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    7,721
    Ok, let's pursue the idea of stability being "broken".

    1) the climate is stable when atmospheric temperatures are stable, and when surface temperatures are stable, and when ocean temperatures and currents are stable.
    2) the climate is stable during a glacial period, if all the conditions in 1) exist, and if all the conditions correspond to a stable climate (maybe they dont?).
    3) the climate is stable during an interglacial for the same reasons as in 2).
    4) the "instability" is in general a short period of non-equilibrium at the end of a glacial or interglacial period, but stabilises when a new equilibrium is reached.

    This is because hysteresis is generally stable if the forcing conditions are, although during a "switchover" instability can occur. That is to say, hysteresis appears to be based on the chaotic behaviour of a system, from which a stable pattern emerges.
     
  16. adoucette Caca Occurs Valued Senior Member

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  17. arfa brane call me arf Valued Senior Member

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    In your tiny little mind.
    Really all you've managed to do is demonstrate you have a very basic grasp of the science, or what "stable" means in the context of global climate.

    Your understanding is somewhere near the level of a first year high school student, which is why you can't think up anything to refute my previous post.

    Maybe someone who does know a bit more about it can point out the flaws in my argument about hysteresis, but I seriously doubt that you understand what I'm saying.
     
  18. Trippy ALEA IACTA EST Staff Member

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    10,890
    ***Moderator Note***
    Corners, please.

    Arfa, try and tone down the language please, calling people a moron is unacceptable. If you think your point isn't being understood correctly, it's generally more productive to provide a link that explains what your suggesting, than it is to start calling people names. Wikipedia is often a good source in this regard.

    Arthur - what Arfa appears to be addressing is that the climate of the Earth for the last 3million years has been switching between two stable states, and that this oscillation is itself representative of a stable state. The system as a whole, across both states, is considered stable because any deviations will either be damped, or force a switch to the other stable, where it will stay there - kind of like a Bifurcation in Chaos Theory - where a stable state can mean an osscillation between two modes. Specifically, what he seems to be referring to is Lewontin's Alternative Stable State Theory.

    Right, I want to see a good clean fight, hands above the belt line.

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  19. adoucette Caca Occurs Valued Senior Member

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    I know, but so what?

    Alternating between two stable states is still not the same as saying the climate has been stable for 3 million years which without further explanation is clearly misleading.

    Had he said that it was alternating between 2 stable states I wouldn't have argued the point.

    Arthur
     
  20. Trippy ALEA IACTA EST Staff Member

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    10,890
    So your beef is that he said that it was stable, rather than in a (dynamic, bimodal) stable state?
     
  21. arfa brane call me arf Valued Senior Member

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    I think the idea of hysteresis loops in climate patterns is well established.

    For instance:
     
  22. Trippy ALEA IACTA EST Staff Member

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    I don't think that's what Arthur was saying that he objected to.
     
  23. arfa brane call me arf Valued Senior Member

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    I don't think Arthur understands enough about what I was saying to object to it.
    As I think I've pointed out, the meaning of "climate stability" depends on the context you're using.

    And a system that switches "rapidly" between two stable states is itself considered to be a stable system, I think you will find this is quite general.
     

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