After reading through Milankovitch Cycles (MC) and the genius behind their discovery, its pretty evident that ice-ages (glacials) in the last half million years are mostly influenced by this phenomenon [Fig. 1] ( Ref - http://goo.gl/piVTym ) albeit with some discrepancies [Fig. 2] (Ref - http://goo.gl/VE3htv ).
One of the observations from the past ice-ages is that, at the end of each ice-age, temperatures rise abruptly accompanied by rising CO2 levels and then both of them drop gradually. [Fig .3]
In an interglacial, if the greenhouse gas effect was significant, earth should stay warm and not heed to much weaker insolation variations due to Milankovitch cycles. [Fig. 4] From another perspective, we could attribute the gradual decline in temperatures after each interglacial to slow assimilation / absorption of CO2 by oceans. In which case, green house gases can have a long lasting impact on the climate.
All this calls for a closer examination of the significance of GH gas emissions, exclusion of other factors preventing faster glaciation after each interglacial and further investigation into the forcings behind rapid rise of temperatures at the end of each glacial.
Update: MC crests represent extreme seasonal variations and MC troughs represent moderate or low seasonal variations. Extreme summers melt glaciers away but extreme winters do not cause intense snowing. (Extremely cold air carries little moisture.) On the other hand, moderate summers melt less snow but moderate winters cause more snowing. Hence, glaciation progresses slowly with accumulating snow from successive winters during MC troughs but glaciers melt away fast in progressively extreme summers during MC crests.
Update: The CO2 system seems to act only as a buffer smoothing out short term variations in insolation but not influencing the trend as such at the observed levels of 180 - 280 ppm.
One of the observations from the past ice-ages is that, at the end of each ice-age, temperatures rise abruptly accompanied by rising CO2 levels and then both of them drop gradually. [Fig .3]
In an interglacial, if the greenhouse gas effect was significant, earth should stay warm and not heed to much weaker insolation variations due to Milankovitch cycles. [Fig. 4] From another perspective, we could attribute the gradual decline in temperatures after each interglacial to slow assimilation / absorption of CO2 by oceans. In which case, green house gases can have a long lasting impact on the climate.
All this calls for a closer examination of the significance of GH gas emissions, exclusion of other factors preventing faster glaciation after each interglacial and further investigation into the forcings behind rapid rise of temperatures at the end of each glacial.
Update: MC crests represent extreme seasonal variations and MC troughs represent moderate or low seasonal variations. Extreme summers melt glaciers away but extreme winters do not cause intense snowing. (Extremely cold air carries little moisture.) On the other hand, moderate summers melt less snow but moderate winters cause more snowing. Hence, glaciation progresses slowly with accumulating snow from successive winters during MC troughs but glaciers melt away fast in progressively extreme summers during MC crests.
Update: The CO2 system seems to act only as a buffer smoothing out short term variations in insolation but not influencing the trend as such at the observed levels of 180 - 280 ppm.
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It is commonly agreed that Milankovitch Cycle (MC) crests represent extreme seasonal variations and MC troughs represent moderate or low seasonal variations. Many climatologists also theorize that net glacial melting happens during MC crests and that glaciers form and advance during MC troughs. Extreme summers melt glaciers away but extreme winters do not cause intense snowing - Cold breeze carries less humidity and hence less precipitation / snow. Contd..
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In contrast to that, moderate summers melt less snow but moderate winters cause more snowing. To sum it up, glaciation progresses slowly with accumulating snow from successive winters during MC troughs but glaciers melt away fast in progressively extreme summers during MC crests. On the other hand, the CO2 system seems to act only as a buffer smoothing out short term variations in insolation but not influencing the trend as such at the observed levels of 180 - 280 ppm.
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water cycle earth average is 10 days. North America is a little faster. But last winter when we froze so much, there is more moisture trapped over our continent. This summer, the water cycle has been STRONG 7 day cycle. While rarely experiencing tornados ever in our region, we've had 3 or four "Tornado Tuesdays". And strong weather on other Tuesdays. Our water content is dissipating a little (down to 8 or so).
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Around 2/3 through last winter, we stopped getting any precipitation at all. Then in the late winter, we would get a thaw, then two days later, get all the moisture back again. The snow on the ground lasted till early May, from late october. That is the same ground with the same snow on it, for over 7 months. This winter looking equal or worse. Starting early, and wetter.
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@Alistair - Aren't we mixing Weather with Climate here. A couple of data points (weather) speak very little of the overall trend (Climate).
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when the fear is a positive feedback runaway warming spiral, then gaps prove that is not the case. If nature can dissipate heat, there is no topple point.
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but my comments about the snow, and water, was not to provide example of anything, but rather for the purpose of demonstrating the nature of the water cycle and it's ability to vary based on changing circumstances. (it's quite fickle, actually).
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Not very many people in the crowds I run in have any clue as to the atmospheric water cycle, would be shocked to learn the global average is it all falls down and all goes back up, an average of 35 times a year. Giver or take. Very fast. Very variable.
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@Alistair - True! That maybe the reason why water vapour, a potent greenhouse gas, is seldom counted towards global warming. It simply cannot cause long term effects because of its very short cycles.
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no. But it's existence totally overshadows the greenhouse effect of carbon. Most of the spectrum that carbon catches can also (and does almost exclusively) get caught by water vapor. gram for gram, water vapor is a more effective ( x a bunch) greenhouse gas, and it's existence in the atmosphere is something like 1.5% and the percentage of CO2 is 400/1000000 = .04%
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one thing I've noticed lately, is all the reasons why the globe might be warming, that the alarmists are proposing explains the pause. Simple question, if 30 or 40 things can stop warming, why are they not capable of starting it. Why one ( 1.0 ) "potential" reason for warming, and so many for not warming?? Pause can be natural variation, low solar, blah blah blah. Warming can be ONLY CO2, not strong solar, natural variation, blah blah blah???
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you recognize the warmists community has gone past being wrong and slipped into desperate, willfull, lying, obfuscating, twisting, sidetracking, and backpedalling, etc, to save face?? Statements like, "The Mitigation Express, has to leave the station soon, and by the entire global community, if we want to stop the world from warming by 2 degrees." That's the IPCC's current planned statement for later this month to the UN/World.
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Water vapour is ignored for a good reason. Because of its short half life in the atmosphere, it will only follow, reinforce and amplify trends but can never lead them. If you put a lot of water vapour in the air, it will simply rain! :-) On the other hand, CO2 has a half life of 30-95 years and ~20% of the emitted CO2 stays put for millennia in the atmosphere. ( Ref. - http://goo.gl/3xuK2t ) Lets leave the politics for now! We can get back to them once we figure out the whole thing. :-)
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@Alistair - What is your take on abrupt rise in temperatures and receding of glaciers at the end of each ice-age (glacial)? I am not sure if we can attribute such a drastic change to Milankovitch Cycles! There must be some positive feedback mechanisms at play here!
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@Nicholas - Fantastic observation! The subject matter deserves a separate post for clarity and continuity rather than spreading it over comments. Elaborate the same in a post for further discussion.
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@Praveen- Will do my friend.
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