Vostock Ice Cores and Climate, Why 100,000 year cycles in past?

Those not familiar with the topic might want to refer to this good short summary press release from the American, Russian and French scientists.
http://www.cnrs.fr/cw/en/pres/compress/mist030699.html

Many more references, along with a useful graphic can be found at
http://www.daviesand.com/Choices/Precautio...nning/New_Data/

The original publications along with much more detailed graphics are at the Nature website at http://www.nature.com/services/link.taf?id...927DE5E41B7E0A6
, though I cannot seem to get it to respond. Anyone else have a working link?

My question is in reference to the 100,000 year cycles referred to a "orbital forcing", presumeably stable repeating variations in solar insolation to earths atmosphere easily observed on the graphic referred to above, in the original article in Nature, and confirmed by the group drilling ice cores in Greenland, also published in Nature. To quote the press release,

"The climate and environment parameters show the existence of four major cycles, with a periodicity of 100,000, 40,000 and 20,000 years. During the four cycles, the atmospheric characteristics varied within rather stable limits, with a temperature amplitude variation in Antarctica of about 12°C at land level and 8°C in the troposphere."

The nearest reasonable attempt at an explanation I've come across is the "Croll-Milankovich Cycles" at http://www.bbm.me.uk/portsdown/PH_731_Milank.htm . Does this mechanism appear strong enough to cause the variations obxerved? Are other explanations possible? What is the maximum period with which a satellite could continuously orbit the sun excentrically and still remain captive?

lengould
Excellent thread. This 100 000 year cycle may or may not be directly due to the planet's orbit around the sun. If it were, what would this planet, or the sun, be doing to create these alterations in the climate of Earth? I suspect that if the sun causes the Earth to do this, then there must be something that effects the sun, however galactic orbital shifts might occur. Lest the sun lets out some massive belch of radiation every 100 000 years, on its own, remains long to be seen. I would wager much on it entering some multi-facetted galaxial alignment that causes a great reduction in the power of the sun. Furthermore, it is yet to be determined which extra-solar entities may have such effect. I think analysis of what foreign stars, or possibly galaxial clusters, or maybe even entire galaxies, could have precisely such effect on the sun, would be to blame. I would analyze what extra-solar entities can be attributed to having an effect on the power of the sun, then, attempt to quantify those factors. Once that is done, you may be able to find the orbits of one of those factors is possibly blocked from the transmission of usual energies to the sun, at some point. Possibly it may be a star that is eclipsed by another star, or a massive planet, or any unknown amount of matter that orbits every 100 000 years between the sun and some star. That would be my estimation.

Possibly it is only the Earth itself that has growing pains every so often, but I would not think so, for 100 000 years seems well out of normal range of Earths time-walls, but who knows? So many unknowns...

Paul: Thanks for the input. One matter to clarify, the variations appear to be 90,000 year cold periods with short 10,000 year warm periods. (We're just exiting the end of a 10,000 year intergalacial warm period now.)

I got some input from a respected professional astronomer on the issue. His statement was to the effect that any "captive satellite of the sun" large enough to affect it's radiation output at perigee would also be large enough to destroy the planet system, so that one's out the window.

Interesting hypothesis regarding "galactic alignments".

What is the period of the solar system's orbit around the Milky Way galaxy? (I seem to recall knowing that once, it's about exactly double the 100,000 year period if i remember). Sun traverses dust clouds 10,000 yrs each 100,000? Infalling matter increases solar output?

Hi PaulVWWhalen and lengould,

Very interesting cycles. I have mentioned in other posts on this site that there is a possible positive feedback mechanism involved with sequestered methane both in the tundras and in deep oceans as methane "ices". A couple of degrees would be enough would tip the scales in releasing this stored gas. I am not certain about what actual amounts of Methane Hydrates are sequestered in the bottom of all the oceans but I will guess that they are highly significant if released over a short period of time. Carbon Dioxide is also a factor since a lot is also found absorbed in the Tundra. While the oceans will probably absorb the excess CO2 it will do nothing for the methane in the short term. Over thousands of years the methane will break up due to methane eating bacteria and other chemical processed which will disintegrate the molecules. This leads to the next cycle where these processes start over again.

As to the mechanisms that "naturally" periodically release this gas into the atmosphere... they could have a variety of mechanisms. One might be related to changing in the set point in the nuclear fires inside stars due to external phenomena. One such mechanism might be dark matter that is "sorta" known to be concentrated in the arms of the Milky Way where we are. This may provide some kind of moderator of accelerator to nuclear fires whose variation in density periodically spatially distributed by the clumping of other matter along the spiral arms may provide the trigger. This would work by the spiral galaxy's rotation of its visible mass causing periodic clumping of the dark matter much like the clumping of electrons in magnetrons.

This suggests that there may be unknown influences at work. One possible direction of investigation would be looking at possible contenders for this material. One obvious possibility would be neutrinos. Clumping of Neurinoes might cause some nuclear moderating or accelerating effect owing to the fact that Neurtinoes travel at the speed of light and they can easily penetrate to the core of a star and they would be affected by the "refractive index" of the stellar material but not be significantly absorbed by it. It is suggested that Neutrinoes are approximately 60% of the material in the Universe and is totally unseen. Almost all Neutrinoes ever produced are still with us today.

It is possible that Neutrino flux alone may be responsible for brightening and dimming of our star by a couple of percent, enough to affect solar insolation and affect all these other processes as a "knock on effect”. It may be possible to test this theory broadly by observation of other stars in our galaxy and in other galaxies and see if there is any periodicity in their output that may be spatially related to the geometry of the shape of its galaxy.

Cheers

GoodElf & LenGould,
I find myself leaning more towards Len's idea of galaxial orbit and how it effects our solar system and the Sun. So, I had the periods reversed and they are moreso cold than hot. I would venture that the Sun is fed energy along this galaxial orbit somehow, for small periods of 10 000 years. May it be also possible that the galaxy itself, on the whole, is fed energy from some other?

Neutrinos, are definitely in play right now. Isnt it true that neutrinos are being trapped within Earth, due to the greenhouse effect? If this is so, then that further dooms us, for it is probably the upmost level of effect upon us, due to the pollution levels causing the majority of this global warming now. For, how could we ever reverse these neutrinos from being trapped on Earth, and what effect will they be proven to have. Maybe they are the cause of the mutigenic effects we are seeing all over the planet now...

Regardless, space colonization is as crucial to our future, as fixing the man-induced environmental cataclysms upon Earth...

Happy 2005!

Paul: I don't think anything can "trap" neutrinos, though my memory is not absolute and that may only apply to one of the three flavours. Present detectors are designed to pick up the ones which have travelled through the entire earth first as that weeds out all other possible sources of particles.

It occurs to me that what is more crucial than absolute control of greenhouse gas emissions is to calculate and manage the release rates to offset our scheduled drop into the next 90,000 yr glacial period. Agreed, methane hydrate releases are far more worrisome GHG's than CO2, though my understanding is that unlike CO2 individual methane molecules don't last very long in the atmosphere.

Hi,

There is a sine wave aspect to the sun's orbit around galactic center. It goes up and down thru the galactic plane as it orbits.

When it is farthest above and below the galactic plane there is less "dust" in its path. As it approaches and recedes from the plane this galactic planar ;'dust' increases.

This is probably a large factor in any long term climate cycle. The perhelion and aphelion of the earth's orbit are also probably large factors as is any variation in the inlination of the earth's orbit. Another factor is the actual inclination of the spin axis.

z

Personally, I'm not even convinced there were climate changes. It seems to me that going from changes in the quatities of CO2 to changes in temperature is a bit of a jump. Furthermore, they give no explanation as to how they dated those cores. (I'm guessing they used the rings.) If the dates on those CO2 measurements are off, then whatever caused the statistical cycles may have a very different cause. the1

Hi PaulVWWhalen, z, lengould and the1physicist,

I do not think that matter actually falling into the sun or intra-galactic "dust" would affect the output of the sun. I am more inclined to the idea that something is interfering with the nuclear processes within our own star (locally). This is not the only cause of problems since at the same time we are interfering with the heat balance of our atmosphere. The combined effect may be fatal because of the cascade of other intra-atmospheric effects on earth such as the release of stored methane and CO2.

I am convinced by other data that the Suns output is at an all time high for quite some time and this may be due to the factors noted previously in the spiral arms of our galaxy and maybe neutrinos. We can do something about all this if we wanted to as a species. It depends on what we consider dear to our hearts. That new car in the driveway or the starving millions burning forest firewood to survive. choices choices.... Its a pretty red sports model. At the same time what about the other species on this planet? If not for us they would fare OK. Because of us they are probably mostly doomed.

Like I have said before it really does not matter whose fault it is or what is the "real" cause of all this.... Are we prepared to do anything about it? Is it simply the case that the rich people of the earth migrating to Mars or even further afield while the Earth dies... Or will they "exterminate" excess human vermin under the orders of a one-world government. Maybe the really rich will end up in special domes like in that old movie "Zardos" with Sean Connery? The wealthy segregated from the unwashed multitudes while the rest of the world goes to hell. I would remind you all what the ending of that was (not the one where Dorothy clicked her heels three times and said “no place like home”), but I think you know it can't be good. Get it out of your video store tonite.

Cheers

The video they need is "soylent green"

AR

All this discussion does is to worry people when there is little to be done when most of the trees are destroyed the CO2 goes above 4% and we gasp to death.

I'm glad I'm my age

AR

Hi ARtone,

Gee.... I thought I was the gloomy one. We all need to lighten up a little. We don't want to get a "PG" rating on this thread. Recent events have colored the global landscape a bit but they are beyond us as individuals.

I Good Elf solmnly swear not to eat anyone (except my best friends) and then only if they are dead first. To start the new "brighter" and "happier" Elf and ARtone outlook I suggest everyone watch "Shaun of the Dead" and not "Dawn of the Dead".

Cheers (I think)

PS: See you all "The Day after Tomorrow".

For all the doubters out there, try a close read of this USGS site. http://pubs.usgs.gov/fs/fs2-00/ . (btw, they seriously understate possible sea level rises, taking no account of antartic continental rebound or ocean thermal expansion).

The only real question is not "is earth warming, and why" but "how much do we want the earth to warm, and who gets to benefit from that?" It would be a lot more depressing if we weren't just now exiting an interglacial.

No offense GoodElf, but you have just proved what I have been saying for years: The real purpose of the environmental movement is the abolition of private property. Why is that? Well, if you do not own any property (not necessarily land), you are basically a slave to someone else: You still need whatever it is you do not own, so you will have to rent it or otherwise pay for it (with the money we don't have). So basically, as individuals gradually lose their property rights, the government quickly turns into a socialist, and then a communist dictatorship, all thanks to the 'environmentalist movement.' You can flame me if you want, but trust me, I am right on this one.

Hi the1physicist,

No offence meant here either. Why is it a question of politics when we are speaking about the survival of our species? What is your view about this problem? Left to natural processes you would have a pretty barren world devoid of any resources and unbreathable atmosphere.

I take it your solution is doing nothing and allow "natural" processes do something in lieu of you action. Your strategy appears to be all this will happen outside your lifespan so that’s OK then? I don’t think so! Nature abhors a vacuum. That goes for “mother nature” too. Something will fill the vacuum of your inaction. The question is which one do you want to be responsible for... Planetary ecosystem failure or a one world government?

Is that what you want? If so I think you better come up with a 'brighter" alternative that solves the problems and leaves you with your gas guzzler in the driveway (PS: I am not keen about the poor knocking down the forests either). I am all ears (no pun intended). I have plenty of private property and a car but no solution at present. I need practical alternatives… Not just "doing nothing".

And saying “trust me on this one”. I have no idea what environmental expertise you hail from but I am surrounded in my Department with chicken littles running in circles, much more radical than I, who have more PhD’s than we have had hot breakfasts. I am not hearing too many bright and shiny ideas from them either. Most seem to own RV's and they weep in their beards as they drive the kids three blocks to school each day. The RV's hardly ever leave that black strip of hydrocarbon that runs around all our houses. Just consider the heat balance problems from that alone.

You should also know that we ‘beat” communism and that’s in the past now (except for North Korea and they are no earth shattering superpower). If some one world government started to subdivide your property and dispense it to the underdeveloped nations of the world you would probably be “not too happy”, communist or not. The Nazi’s did similar things in Germany before WW2. It is very possible that either you have a family or intend to have a family… So what is in it for them? Future generations may spit when they mention our names with what we are intending for them as a legacy.

I understand your attitude but I can’t accept that ‘trust me” line is all we need to do. I can’t say which side of the queue either of us will be on when "they" begin to march us all into the “showers”.

Cheers