SFR: Al Gore's mistakes?

Discussion in 'Fly Fishing Forum' started by Philster, Oct 11, 2007.

  1. BFK

    BFK Member

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    Here's an interesting read from the UK: http://news.bbc.co.uk/2/hi/science/nature/7049377.stm

    The short version is that last week a judge ruled that if the "Inconvenient Truth" is shown in British schools, then it must be accompanied by a disclaimer about it being one-sided and containing errors. The response from two scientists disputes that premise, but the article goes on to talk about the lack of consensus among climatologists.

    It certainly puts the "preponderance of scientists" claims in perspective.
     
  2. chadk

    chadk Be the guide...

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    http://web.mit.edu/newsoffice/tt/1990/jun13/23271.html


    Climate Experts Clash on Global Warming
    TECHNOLOGY DAY

    Climate Experts Clash on Global Warming

    Sharp differences as well as common ground were apparent when two
    experts on atmospheric dynamics and modeling engaged in their climactic
    debate on world climate change last Friday, Technology Day 1990.

    Dr. Stephen Schneider of the National Center for Atmospheric Research in
    Boulder, Colorado, who believes that a significantly warmer world
    climate is likely because of increasing greenhouse gases, challenged
    Sloan Professor of Meteorology Richard S. Lindzen of MIT's Department of
    Earth, Atmospheric, and Planetary Sciences, a well-known skeptic about
    global warming.

    The debate drew a full house of alumni, press, and interested citizens
    to Kresge auditorium.

    Moderating the good-natured though serious sparring was Professor Ronald
    G. Prinn of EAPS. He began with a crisp summary of present knowledge
    about the basic ingredients of potential global warming: the rising
    concentrations of gases that can absorb and re-emit infrared radiation
    that comes from the solar-heated surface of the Earth.

    For some of these gases, said Professor Prinn, sources are reasonably
    well understood, but the sources and sinks of others, including methane
    and even carbon dioxide, are less clear. Professor Prinn reminded the
    audience of an often overlooked fact: omnipresent water vapor itself is
    one of the most important and potent of the greenhouse gases.

    Concentrations of chlorofluorocarbons (CFC's) greenhouse gases, he said,
    are rising rapidly from five-11 percent per year, and these molecules
    have typical lifetimes in the atmosphere ranging from 75-180 years. By
    contrast, the greenhouse gas nitrous oxide rises at only 0.2 to 0.3
    percent per year, but has a 150 to 180 year lifetime in the atmosphere.
    Its main source is in the tropics, not from fossil fuel combustion

    Fossil fuel, however, is responsible for most of the carbon dioxide
    increase we see today, said Prinn, though some of that increase may be
    due to deforestation whose effects are still a matter of controversy.

    Regarding the very long atmospheric lifetimes of many greenhouse gases,
    Professor Prinn spoke of a risk factor. "We cannot just simply stop what
    it is we're doing and have these gases decay out of the atmosphere on
    very short time scales," he said. The gases are long-lived. Just
    bringing the rate of increase of some of these gases to zero would
    require cutting their emission by factors of three to six, according to
    Professor Prinn.

    Prinn sharpened the debate: "Greenhouse gases are increasing today at
    very substantial rates. Projected into the future, these rates, when
    included in most current climate models, lead to predictions of a
    significant global warming over the next century, but are these
    predictions reliable ? "

    He showed the controversial variation of carbon dioxide concentration
    and air temperature plotted for the past 160,000 years, a graph that was
    determined from air bubbles in glacial ice. Superficially, the two
    curves look like they track one another remarkably well. But Prinn
    asked, "Is this a chicken and egg problem? Is carbon rising merely
    because temperature is rising and the biosphere responds, or, is the
    temperature rise itself due to changes in carbon dioxide? We don't have
    an answer to that yet."



    Warming: Better than Even Odds

    Arguing in the affirmative on warming, Dr. Stephen Schneider spoke on
    the reliability of climate models: "The real question isn't whether they
    are reliable, yes or no," he said. The main issue is what decision-
    making purposes the models will be used--"reliability for what," as he
    put it.

    "I'd love to tell you we've made great progress [over the last 15 to 20
    years], but we haven't. The estimate has been, if carbon dioxide were to
    be doubled and held fixed--what we call equilibrium--then we'd warm up
    the climate something between 1.5 and 4.5 degrees Celsius. . . The
    question is, is that range reliable and what are the elements of it that
    are subject to question."

    After explaining the basic principles of computer modeling of global
    climate, Schneider termed as much as a 10oC temperature rise by the end
    of the next century "a low probability but still possible case."

    The most uncertain components of the models, he said, are the complex
    effects of clouds, including both cooling and warming effects. He also
    showed how difficult it is to forecast the specific geographic patterns
    of climate change, including temperature and moisture distributions.

    Schneider worried about the rapidity of change, saying that nature took
    about 10,000 years to warm 5oC (from 15,000 to 5,000 years ago) as
    compared to a possible impending rate of change five to 100 times that
    natural rate.

    "What is the probability of the catastrophic curve or the mild curve?
    The answer here is that there is no objective way to assign it,"
    Schneider said.

    "Simply looking backwards in the last century is not very instructive to
    give us reliability in the future, because too many things that we
    weren't measuring were occurring. We've only been measuring what's
    important for about the last ten years.

    "The bottom line is what's the probability of these curves and the
    answer is it depends on the intuition of experts. . . It's probably a
    better than even bet, according to most people who I've asked, that the
    truth will be somewhere in this part of the range [2oC increase]. My own
    view is that it's not likely to be up at the catastrophic end or at the
    low end--when I say not likely I mean maybe a 10 percent chance."

    "Are the models reliable? . . . In detail, 'no.' I'll join [Dr. Lindzen]
    in that. On the other hand, are they reliable to say that we have a
    better than even chance that there could be unprecedentedly large
    climate change [larger than 2oC]--when I say unprecedented, I mean in
    the 10,000 years of human civilization, then I think the answer is
    'yes.'"

    "Facing 50 percent or so odds of that kind of change is a reliable
    enough prediction in my value system to take quite seriously that we
    need to examine what we're doing that's causing these global changes
    that Ron Prinn showed, rather than waiting the 10 or 20 years to resolve
    the details."



    Minimal or No Warming Likely

    Speaking of the great difficulties inherent in computer modeling of
    climate, Professor Lindzen said, "I think the situation as we look at it
    today is that the warming, indeed, is much smaller than suggested by
    current large models, if indeed there is warming at all."

    Professor Lindzen believes that there will be a warming "under half a
    degree," though he does not even rule out the possibility of a cooling.

    Since he believes that the models are making erroneous predictions, he
    argued, "I think it is a pressing obligation of meteorologists and
    oceanographers to find out why the models are wrong."

    Professor Lindzen complained that atmospheric modeling ". . .used to be
    considered a tool of theory." Now, he suggested, the community of
    modelers and theoreticians has grown apart. "What I find increasingly
    worrisome is the notion that models are assessed by comparison with
    other models," he said.

    Professor Lindzen took exception to Dr. Schneider's range of warming
    prospects, saying, "whereas the small end of the diagram he last showed
    was quite likely [below 1oC rise] the high end would violate many, many
    things."

    Lindzen believes, for example, that the temperature record of the past
    is not compatible with the models that predict significant warming in
    the next century. He believes that there are "documented errors in
    models that are crucial to warming predictions." He said, "Much less
    certain, though potentially extremely important, the models have a
    behavior in the tropics that is crucial to present predictions and seems
    inconsistent with present and past tropical behavior."

    Lindzen said that models that currently predict a 4oC temperature rise
    some time next century for a doubling of carbon dioxide, suggest that a
    2oC rise should already have occurred for the carbon dioxide already put
    into the atmosphere by human activity--something that has not happened.

    Perhaps Professor Lindzen's sharpest criticism dealt with what he called
    the "circumvention" of Earth's "greenhouse" by vertical currents that
    bring water vapor upward and cause heat to be radiated back into space.

    He said, "The surface of the Earth cools bodily by motion that carries
    the heat around the bulk of the greenhouse gas and the radiation is
    emitted from upper levels which have much less infrared opacity. Thereby
    they circumvent about three-quarters of the greenhouse substance. . .
    Speaking of trapping of heat by greenhouse gases in the bulk of the
    atmosphere is no more impressive than the trapping of Germans by the
    Maginot line--there are plenty of good ways of getting around it."

    I think that the current evidence suggests that the overall feedback
    ought to be negative [restraining warming]. And, indeed, if we were not
    caught up in the politics of this problem, the normal response to the
    data and the models would be to intensify our search."



    What to Do

    Two MIT professors followed with brief remarks on what should be done,
    given our present incomplete knowledge. Professor of Economics Henry D.
    Jacoby of the MIT Sloan School of Management said, "I don't think that
    we are near a circumstance with a strong enough consensus to justify
    imposition of panic. We are not anywhere near, I think, the political
    consensus that would allow us to pull real cost out of people to solve
    this problem. . . I think we have to prepare ourselves for decades of
    work, and I think we have to pour more resources into that. The third
    thing we have to do is to buy options--primarily in the area of
    technology and institutional development. We're not going to severely
    restrict by regulation or pricing the use of carbon dioxide."

    Dr. Nazli Choucri, Professor of Political Science and Associate Director
    of the Technology and Development Program at MIT, emphasized the
    importance of deciding first what criteria we should use to decide what
    to do. Her advice was to "increase options," particularly by stabilizing
    global population, promoting institutional resiliency and international
    cooperation, and establishing appropriate priorities for research.
     

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