Milankovitch Cycles

Discussion in 'Earth Science' started by space_geek, Feb 28, 2009.

?

Your take on Milankovich Cycles

Poll closed Mar 15, 2009.
  1. Warming Earth

    14.3%
  2. Cooling Earth

    42.9%
  3. Insignificant

    14.3%
  4. Don't know about it

    42.9%
Multiple votes are allowed.
  1. space_geek Registered Member

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    I used to be a huge green freak and that we have to save the earth and stop waisting, until this morning, when I read on Wiki about Milankovitch cycles. They are the cycles that earth naturally goes through every certain number of years. Google Milankovitch cycles and click the Wikipedia link (usually at the top)
     
    Last edited: Mar 1, 2009
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  3. Trippy ALEA IACTA EST Staff Member

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    You do understand that the Milankovitch cycles predict the earth should be cooling not warming right?

    The Milankovitch Cycles are not the cause of this round of "global warming" (irrespective of whether or not you accept anthropogenic climate change).
     
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  5. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    perhaps you should explain what it is about the milankovitch cycles that you think is significant - then we might have something to discuss
     
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  7. space_geek Registered Member

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    19
    explanation

    Milankovitch cycles are the variables of earth's position orbitally and axially and have prolonged cycles. There are 4 "categories' of sorts: Eccentricity (orbital shape) has a cycle of 413,000 years; Obliquity (axial tilt) has a cycle of 41,000 years in which the earth's axial tilt shifts between 22.1 degrees and 24.5 degrees; Precession (axial rotation) has a cycle of 26,000 yrs.; and Orbital Inclination which has a cycle of 70,000 years.
     
    Last edited: Mar 1, 2009
  8. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    2,262
    I know that SG - what is it about this data that you find of particular interest or significance?

    Does this tell us anything about the world right now?
     
  9. Enmos Staff Member

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    43,184


    :wallbang:
     
  10. Buffalo Roam Registered Senior Member

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    16,931
    But are we warming? That doesn't seem to be supported by the average over the last 10 years.

    http://rogerhelmermep.wordpress.com/2008/10/22/global-cooling-continues/

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    This graph shows average global temperature records for the last
    five years from two of the world’s most respected meteorological
    institutes, the UK’s Hadley Centre, and the University of Alabama
    in the US. Both show a clear downward trend, and the graph
    contrasts that trend explicitly with the rising trend of atmospheric CO2.

    So we have two conclusions: first of all, Al Gore’s alarmist
    predictions of rapidly accelerating temperatures, run-away
    warming and imminent Armageddon are just plain wrong,
    with each year that passes adding more nails to the coffin of
    his disaster movie.

    Second, the supposed correlation between atmospheric CO2 levels
    and temperature just does not exist. For years, temperatures
    have been falling while CO2 levels have risen.

    http://network.nationalpost.com/np/...rty-years-of-warmer-temperatures-go-poof.aspx

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    Also in September, American Craig Loehle, a scientist who conducts computer modelling on global climate change, confirmed his earlier findings that the so-called Medieval Warm Period (MWP) of about 1,000 years ago did in fact exist and was even warmer than 20th-century temperatures.

    For nearly 30 years, Professor Christy has been in charge of NASA's eight weather satellites that take more than 300,000 temperature readings daily around the globe. In a paper co-written with Dr. Douglass, he concludes that while manmade emissions may be having a slight impact, "variations in global temperatures since 1978 ... cannot be attributed to carbon dioxide."

    Moreover, while the chart below was not produced by Douglass and Christy, it was produced using their data and it clearly shows that in the past four years -- the period corresponding to reduced solar activity -- all of the rise in global temperatures since 1979 has disappeared.

    It may be that more global warming doubters are surfacing because there just isn't any global warming.

    lgunter@shaw.ca
     
  11. weed_eater_guy It ain't broke, don't fix it! Registered Senior Member

    Messages:
    1,516
    I'm no statistician, but I see those charts and don't believe the trendlines associated with them can be considered statistically reliable.

    However, I still think the green movement is a good idea, whether or not global warming is fact. It's a neat excuse to fund a number of fledging technologies that can grant some energy independence, decentralized and renewable energy systems, cleaner cities, etc.

    Also, some more plants in a city is never a bad thing, right?
     
  12. Trippy ALEA IACTA EST Staff Member

    Messages:
    10,890
    I stopped reading after this point, because apparently you didn't do me the courtosey of reading my post. If you had, you should have been able to realize that the rest of what you had to say was actually completely irrelevant.

    The thrust of the opening post was that the Milankovitch cycles are somehow responsible for global warming.

    My response was to explain that the Milankovitch cycles predict that the earth should be cooling, so the Milankovitch cycles can not be responsible for Global warming.

    End of story.

    Debating whether or not it exists is actually irrelevant and off topic.

    I'll bet you'd be right in behind some of the posters on another forum I follow who seem to be under the delusion that because the winds on Titan blow in the opposite direction to what we expected, our models of climate change are wrong.

    I can't help but notice that in your zeal to dogpile someone who made a comment about climate change that disagreed with yours, you completely ignored the caveat that I included at the end of my post with regards to whether or not you acceptAnthropogenic Climate change.

    The same dam logic applies whether or not you think think Global Warming is imagined. Not accepting it doesn't make a single bit of difference as to whether or not something that should lead to cooling can give rise to warming. Even if you think Global Warming is the by product of a couple of scientests sitting around ingesting magic mushrooms, it still doesn't change the fact that with where the earth is currently placed in the Milankovitch Cycles, the Milankovitch cycles can not possibly cause Global warming we may or may not be experiencing, real or imagined, man made or natural.

    Do you understand yet?

    The first graph you posted. That's nice, it doesn't actually prove anything about long term climate change. All it shows is that, on average, the temperature for the last 30 months is cooler than the temperature for the 30 months preceeding it. The fact that this doesn't correllate with the ever increasing CO2 levels is completely MEANINGLESS, all that you could truthfully say from that, in that graph, is that the response of temperature to [CO2] is non-linear, and is currently being driven in a chaotic manner.

    You seem to be under the delusion that Al Gore invented global warming. This delusion is precisely that, a delusion. As for his movie? I personally found it to be factually inaccurate in several regards, and a lovely piece of alarmist media.

    Sorry to sound racist, but fancy that, an American publishing alarmist media. That's never happened before, ever.

    Personally, I think that Al Gore has done more damage to climate change science and its credibility than any single person in its history (irrespective of whether or not you accept global warming, irrespective of whether or not you accept that it is man made, we're still talking about the science behind the way the Earths climate changes in response to various parameters such as solar flux and composition).

    Second graph. Big deal. It's a little less selective than the first, and puts the first in context, but so what. If you were to place a linear least squares line on it, you would find that it still, over all displays a positive trend, even with the last set of data points. And again, nobody (at elast in modern climate change studies) is saying that the reposnes of the earths temperature to increasing CO2 is going to be a straight forward linear one.

    As for your last three paragraphs, they strike me as being copied and pasted without being cited, and i'm not going to adress them beyond that.

    In short? You jumped in with both feet on what you thought was being discussed, and went into an over the top spiel about how studies of global warming were wrong, without actually stopping to look at what was actually being said.
     
  13. iceaura Valued Senior Member

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    24,101
    For example? Aside from his taking sides in some unsettled debates, I didn't notice any factual inaccuracies.

    Or maybe instead:

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    btw: This
    does not argue against CO2 influence. If even the lowest solar minimum possible - no sunspots at all - only takes the temps back to average, clearly there has been a great deal of warming overall.
     
    Last edited: Mar 1, 2009
  14. iceaura Valued Senior Member

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    24,101
  15. Trippy ALEA IACTA EST Staff Member

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    Here's one example: New Zealand isn't taking on thousands of refugees from pacific island nations that are being flooded as a result of rising sea levels.
     
  16. iceaura Valued Senior Member

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    24,101
    So?
     
  17. cosmictraveler Be kind to yourself always. Valued Senior Member

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    Sometimes the Earth just does what it wants to whenever it wants to do it. Then again humans do have an impact on the Earth today more than ever with all of the pollution and crap they are doing to the environment.

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  18. space_geek Registered Member

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    19
    it means that the positions of the Earth, and not Co2, are causing the warming or cooling

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  19. space_geek Registered Member

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    maybe because they don't want to end up like lebanon which is holding thousands of palestinian refugees. They have to supply food and housing and in this economy, they can't
     
  20. space_geek Registered Member

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    19
    Iceaura, you realize in the second one, thermometers were only used for the last part
    and before they were only educated guesses that could be dead wrong. and in the third, it shows cycles of the spike in temp. so whose side are you on, iceaura!?:shrug:
     
  21. space_geek Registered Member

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    i couldnt agree more

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    :
     
  22. Trippy ALEA IACTA EST Staff Member

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    So, that was one of the claims made by Al Gore that is wrong.

    I stated that I found his movie to be factually inaccurate.
    You asked why.
    I gave you an example.
     
  23. Trippy ALEA IACTA EST Staff Member

    Messages:
    10,890
    Ah, NO.

    NZ has a very open immigration policy with the Pacific Islands. They're not taking on board thousands of refugees from flooded islands in the pacific ocean because of rising sea levels because there aren't any refugees.
     

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