Re: [asa] climate change severity

This is totally irrefutable and very balanced. We ignoring the problem at our peril.

Wont please Interfaith Stewardship Alliance though.

I get rather sick of these anti-environmentalists who simply wont accept the balance of scientific evidence.

Michael
  ----- Original Message -----
  From: Charles Carrigan
  To: asa@calvin.edu ; mrb22667@kansas.net ; dfwinterstein@msn.com
  Sent: Thursday, January 04, 2007 5:42 PM
  Subject: Re: [asa] climate change severity

  Don,

  Human beings began pumping CO2 into the atmosphere well before 1930. I understand wanting to be skeptical of bandwagons, but the data that indicate human impact are pretty strong. Natural warming may also be occurring, but the data clearly show a massive anthropogenic involvement.

  Ice core measurements indicate that in the year ~1800, the concentration of CO2 in the atmosphere was down near 275 ppm, but steadily rising over the next 100 years to reach ~300 ppm by 1900. Direct measurement of atomospheric CO2 goes back to the late 1950s, when the value was up to ~315 ppm; today it is near ~375 ppm. Although we've certainly done much more in the past 50 years, humans did plenty between 1800 and 1930.

  To put it in natural context - in the deep geologic record, CO2 has fluctuated in the atmosphere between ~180-280 ppm over the last at least 400,000 years, and I believe the record now goes back even further to the past 650 ka; at no point in that history has CO2 reached the levels it is at today, or even the levels it was at in 1950. The concentration of CO2 in past atmospheres is measured by trapped gas bubbles in deep ice cores from Antarctica. There is a tremendous inverse correlation between times of low CO2 (~180 ppm) and large amounts of continental ice as interpreted by delta18O data (stable isotopes of H2O), and also the reverse - times of high CO2 (~280 ppm) correlate with times of low continental ice. This obviously fits with the notion that CO2 is a greenhouse gas.

  A couple of references:
  Petit, J.R., et al., 1999, Climate and Atmospheric History of the Past 420,000 Years from the Vostok Ice Core, Antarctica. Nature, 399, 429-436.
  Friedli et al., 1986, Ice Core Record of the 13C/12C Ratio of Atmospheric CO2 in the Past Two Centuries. Nature, 324, 237-238

  There is no question that human beings over the past 200 years have dramatically altered the concentration of CO2 in Earth's atmosphere. There is also a clear connection between CO2 concentration and global T.

  Best,
  Charles

  _______________________________
  Charles W. Carrigan, Ph.D.
  Assistant Professor of Geology
  Olivet Nazarene Univ., Dept. of Physical Sciences
  One University Ave.
  Bourbonnais, IL 60914
  PH: (815) 939-5346
  FX: (815) 939-5071
  ccarriga@olivet.edu
  http://geology.olivet.edu/

  "To a naturalist nothing is indifferent;
  the humble moss that creeps upon the stone
  is equally interesting as the lofty pine which so beautifully adorns the valley or the mountain:
  but to a naturalist who is reading in the face of the rocks the annals of a former world,
  the mossy covering which obstructs his view,
  and renders indistinguishable the different species of stone,
  is no less than a serious subject of regret."
            - James Hutton
  _______________________________

>>> "Don Winterstein" <dfwinterstein@msn.com> 1/4/2007 10:27 AM >>>

  Merv wrote: "...If this has been a somewhat
  linear loss since 1906, then could human-caused global warming still be
  the primary agent? If it hasn't been a linear loss, then how much of
  that 90% loss occurred in recent decades? I'll need to research some of
  this on the web myself, but meanwhile, if there is a pool of experts
  right here...."

  I'm not one of your local experts on this, but I've read often enough that glaciers have been receding in many places starting well before, say, 1930, to have doubts about the degree of human causation. As anecdotal evidence, as a kid I used to visit Mt. Rainier in Washington regularly (late 1940s), and every time we went my Dad would remark how much smaller some of the glaciers had become since he'd visited as a young man--probably 15-20 years earlier. Park info also attested to rapid receding.

  I mistrust human causation of global warming to the degree that it's become a bandwagon. Bandwagons in general are suspect.

  Don

    ----- Original Message -----
    From: Merv
    To: asa@calvin.edu
    Sent: Tuesday, January 02, 2007 3:43 PM
    Subject: [asa] climate change severity

    This caught my eye this morning on the CNN site about the Ayles ice
    shelf collapse. ...quoting Vincent Warwick of Laval university:

    "It is consistent with climate change," Vincent said, adding that the
    remaining ice shelves are 90 percent smaller than when they were first
    discovered in 1906.

    I assume he was just referring to the six major Canadian ice sheets.
    Can this be right? Am I interpreting this correctly, then, that we
    have only 10% of the ice sheet area (or mass?) in the Canadian arctic
    than was known to exist in 1906? And, if this has been a somewhat
    linear loss since 1906, then could human-caused global warming still be
    the primary agent? If it hasn't been a linear loss, then how much of
    that 90% loss occurred in recent decades? I'll need to research some of
    this on the web myself, but meanwhile, if there is a pool of experts
    right here...

    Please note: I do NOT consider myself one of those who mistrusts all
    science in its advocacy for care of environment. Stewardship is a
    Christian calling (which predated the scientific enlightenment and is
    not founded on it.) Wendell Berry is a great author, IMO. I
    seriously endorse the bicycle as the superior transportation technology
    over the automobile (even if I hypocritically fall short of living that
    ideal -- I still aspire to it). My convictions here obviously are not
    based on science. But I am interested in any clarity science can bring
    to our knowledge of our footprint.

    --merv

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Received on Thu Jan 4 15:19:07 2007