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Questions about Global Warming

  1. Feb 13, 2007 #1
    I'm a non-scientist trying to understand a bit about climate science and the state of it. It's mysterious to me why so many people (some on both sides of most debates I see!) seem to treat this as though it were a religious issue and not a scientific one.

    1. My understanding is that the strongest support for human beings causing observed global warming is that computer models that have been made don't agree with observations for recent years unless human induced factors like CO2 and sulphate aerosols are included. Is this correct? Is there other strong evidence? (Surely, such a rapid change, by geological standards, coinciding with humans producing massive amounts of greenhouse gases, is very suggestive, but circumstantial.)

    2. Are the models that are compelling for #1 old enough and established enough that they have been tested and confirmed with future data, and made interesting and accurate predictions, rather than just being correct by being fit to the data itself? Was the error margin of any such study small enough that current observations give a very high degree of confidence in them?

    3. Do current models make future predictions in a way that makes them falsifiable? E.g. what's the margin of error on the expected global temperature in 20 years? Is there a strong consensus? What of data would be needed for scientists to throw away a notion that the earth is definitely warming in a predictable way?

    4. Is there effort being spent on attempting to create a consistent model of the world's climate that does not include human induced greenhouse gases? (E.g. supposing a change in the sun's output or volcanic activity, or some other factors, have a larger than expected effect.) If this has been tried, does it turn out to be impossible to retrofit something to real observed climate data? If it does manage to fit, is it somehow less parsimonious? Were such models ever created in the past and allowed to "compete" with models that use anthropogenic greenhouse gases, using future unknown data rather than just being fit to something already known?

    5. How does one address claims that the climate is inherently chaotic, and can be expected to change in something like a fractal pattern, with unpredictable shifts at all scales. How can we rule out a hypothesis of a large scale shift taking place right now simply due to chaos and sensitivity to initial conditions, and not to anything understandable?
  2. jcsd
  3. Feb 14, 2007 #2
    Hi William, Sorry it took a while. That’s unusual for the resident globa warming sceptic but anyway,

    but what is a scientist then? I say the same, but I wonder how I would do in a general quiz about everything pertaining Earth's geology, geography, geophysics, oceanography, paleo-specialisms etc, What would be the criteria? Being able to make logical deductions and recognise and avoid fallacies? You'd be surprised how many "scientists" would not pass that filter. Perhaps it’s also an idea to tick off the fallacies in all the arguments for and against global warming.

    This little essay may help.

    Roughly, that’s what they say. However, it is also (erroneously) believed that northern hemisphere temperatures fluctuated “ten-degrees-within-a-decade” during the last glacial without the help of mankind. Perhaps the models have not captured all the elements yet that mold our climate.

    What is evidence. The overall temperatures have been risen for about two centuries but have also dropped in the late 18ths, in the 1960ies, there has been a rather strong warming in the 1990ies but temps have stabilized as of 1998, what would you make of that?

    Don’t know. Gavin Schmidt from the other camp has some ideas. I guess that my model predict that in a few decades from now, it will be prohibited by law to use climate models for predictions, other than verifying an hypothesis, their original function.

    Just as curiosity, any idea what the etymological meaning of the word “sophisticated” is, and why that would even be more appropriate?

    here is the longest running prediction.. I added land and sea data. Scenario C was with direct cutting CO2 action in 1988. The actual scenario with CO2 emissions is close to B, perhaps a tad higher

    Some climatologists expect a new solar minimum around 2030 like the Maunder minimum of ~1730. By then things should be straightened out.

    I believe that’s standard benchmarking. I believe that has been done. I have no details however.

    No doubt about the chaos but it would be nice to understand the interactions a bit more which would be a formidable job to accomplish.
  4. Feb 15, 2007 #3
    Anthropogenic global warming supposedly began with the industrial revolution. We see this attribution made in various places. The mean global temperature seems to have increased from 1900 to around 1945: http://www.aip.org/history/climate/20ctrend.htm#temp2002.

    Yet the carbon emissions over that period (1900 to 1945) were very small relative to today, roughly peaking at 1/8th of today, and almost entirely from burning coal: http://en.wikipedia.org/wiki/Image:Global_Carbon_Emission_by_Type.png

    If anthropogenic global warming started at the industrial revolution, that implies the natural carbon cycle can be imbalanced by a fraction of today's emissions. Since even today's emissions only account for about 3% of natural emissions (natural plant decay, etc), that means the 0.4% peak anthropogenic carbon emissions in 1945 were sufficient to cause the significant global warming shown in the above graph from 1900 to 1945. The amount under the curve would be much less than this.

    This seems like a very small amount. IOW to accept that the more recent global warming is of anthropogenic origin requires we likewise accept the 1900-1945 global warming was anthropogenic. Yet the carbon emissions in that period were very small relative to today.

    That in turn implies reducing anthropogenic emissions by 7/8ths is insufficient, and would simply slow (not stop) global warming. It also implies the earth's natural carbon source/sink cycle has almost zero tolerance for imbalance -- whether the imbalance is of human or natural causes. It further implies than any natural phenomena such as increased volcanic activity, change in vegetation, etc. which imbalanced the natural source or sink only 0.4% would cause a runaway warming or cooling.

    I'm struggling to understand this. Any advice or comments?
    Last edited: Feb 15, 2007
  5. Feb 15, 2007 #4
    Perhaps you're proving to yourself that's all a hoax.
  6. Mar 20, 2007 #5


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    Gold Member

    I just came across this article that states:


    I know its FOXNews but their just drawing on the research of

    Habibullo Abdussamatov, the head of space research at St. Petersburg's Pulkovo Astronomical Observatory in Russia.

    Its an interesting take on the warming of more than just our planet in the solar system. It also mentions how Mar's polar caps advance and recede with fluctuations in the temperature of the sun.
  7. Mar 21, 2007 #6
  8. Mar 21, 2007 #7
    Solar Variation & Global Warming

    Hi BillJx,

    There is most definitely correlation between 20th century solar changes and 20th century warming. The correlation is however not simply, more sunspots higher temperatures. The correlation is also not due to a significant increase in the solar output, but rather due to the sun's affect on planetary cloud cover. Those climatologists who say there is no correlation, refer to number sunspot numbers or changes in solar output. It is only in the last 5 years that a mechanism has been developed to explain how solar changes could cause a change in planetary temperature.

    Scientists specialize and in many cases do not explore competing hypothesis. There is often a delay from when a new hypothesis is developed, to when it is accepted.

    Attached is a paper that discusses the solar parameter that correlates with the 20th century observed planetary temperature changes. (i.e. Global warming.) From that paper:

    "It has been noted that in the last century the correlation between sunspot number and geomagnetic activity has been steadily decreasing from - 0.76 in the period 1868-1890 to 0.35 in the period 1960-1982, ... According to Echer et al (2004), the probable cause seems to be related to the double peak structure of geomagnetic activity. The second peak, related to high speed solar wind from coronal holes (my comment: For example coronal hole 254 that produced the Dec 16, 2006 peak in solar wind, during a sun spot minimum, see attached link to Solar Observation Data), seems to have increased relative to the first one, related to sunspots (CMEs) but, as already mentioned, this type of solar activity is not accounted for by sunspot number. In figure 6 long term varations in global temperature are compared to the long-term variations in geomagnetic activity as expressed by the ak-index (Nevanlinna and Kataga 2003). The correlation between the two quantities is 0.85 with p< 0.01."

    The thread Earth and Reflectivity provides a discussion of the hypothesized mechanism and links to papers that provide data and analysis to support the assertion that a signficant portion of 20th century global warming is due to changes in planetary cloud cover. (i.e. Solar variations affects the amount of planetary cloud cover, particularly over the oceans).

    As to evidence from the past, there is proxy data that indicates that there was been abrupt drops in temperature that coincide with solar changes. It is interesting to note that the sun is at its highest activity in 8000 years.

    2005 paper by Georgieva, Bianchi, & Kirov “Once again about global warming and solar activity”


    Attached is a link that to a NASA report that suggests that current solar activity that is the highest in 8000 years might be slowing down.


    Attached is a link to the a daily solar observatory.

  9. Mar 22, 2007 #8
    You can't be serious! We're talking about an extremely fast-moving field of study. Do you really think that 5 years is a short time? And that the climatologists are just too narrow minded to see the truth as clearly as you can?
  10. Mar 23, 2007 #9
    Sun is now Spotless!!!

    Hi BillJx,

    Did you check out the link in my comment to the Solar Observatory? Did you notice that the sun is currently spotless? Did you know that solar scientists do not understand why the solar cycle occassionally stops for 100 years. Did you know that there are 32 different solar models all of which give in correct answers?

    For some odd reason other stars that appear to be the same as the sun, also stop their equivalent to the solar cycle. Based on the Wilson observatory 50 year H-K study, where the objective was to study a group of sun like stars to try to better understand the sun. But before discussing the sun here is Bond's data about what has happened in the past.

    The following is a link to Bond’s paper “Persistent Solar influence on the North Atlantic Climate during the Holocene”

    http://www.essc.psu.edu/essc_web/seminars/spring2006/Mar1/Bond et al 2001.pdf

    Excerpt from the above linked paper:

    “A solar influence on climate of the magnitude and consistency implied by our evidence could not have been confined to the North Atlantic. Indeed, pervious studies have tied increases in the C14 in tree rings, and hence reduced solar irradiance, to Holocene glacial advances in Scandinavia, expansions of the Holocene Polar Atmosphere circulation in Greenland; and abrupt cooling in the Netherlands about 2700 years ago…Well dated, high resolution measurements of O18 in stalagmite from Oman document five periods of reduced rainfall centered at times of strong solar minima at 6300, 7400, 8300, 9000, and 9500 years ago.”
  11. Mar 23, 2007 #10
    Last Interglacial ended Abruptly!!!

    Hi BillJx,

    Did you know that the last interglacial ended abruptly?


  12. Mar 23, 2007 #11
    Abrupt Cooling Vs Gradual Warming?

    Interesting and controversially it appears there have been periods in the past history of the earth, when the planet was warm when CO2 levels where low and cold when CO2 levels were high.

    If the fact that the sun is now spotless, indicates that a period of strange very, very, low solar activity is now starting, then based on what has happened before, the 20th century warming will be followed by an abrupt cooling event.

    See the attached link to show what happened 8200 years ago.

    The papers I quoted in the thread "Earth's reflectivity" assert that solar activity forced the planet's temperature 7.5 W/m2 (1994 to 2001, or three times the estimated CO2 forcing of 2.5 W/m2). If the solar cycle stops, that forcing will of course also abruptly stop.

    In the Earth Reflectivity thread I referenced papers that provide data and analysis to support the hypothesis that past major climate changes (abrupt coolings warmings, glacial/interglacial cycle, and so forth) are caused by changes in the geomagnetic field, or the solar wind, or Galactic Cosmic Rays (GCR) all of which modulation the level of cloud cover, have a reduced estimate for the magnitude of warming or cooling due to change in CO2.
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