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Global Warming And The Onward March Of The Pine

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  • Patrick Neuman
    Global Warming And The Onward March Of The Pine London - Apr 13, 2004 Climate change could dramatically increase the forest cover of the Earth s mountains,
    Message 1 of 2 , Apr 13 5:11 PM
      Global Warming And The Onward March Of The Pine
      London - Apr 13, 2004
      Climate change could dramatically increase the forest cover of the
      Earth's mountains, ecologists are predicting. Using data from the
      Austrian Alps, ecologists have developed a model that predicts the
      area covered by the local pine, Pinus mugo Turra, will increase from
      10% today to 60% by the turn of the next millennium.
      The findings are published in the April issue of the British
      Ecological Society's Journal of Ecology and the authors believe that
      this is the first paper to model tree line dynamics driven by climate
      change on a landscape scale in both time and space.

      The Earth's climate has warmed approximately 0.6°C over the past 100
      years and the rate of warming looks set to accelerate. Alpine tree
      lines are assumed to be particularly sensitive to climate change,
      with high mountain forests predicted to shift their ranges up-slope
      at the expense of alpine vegetation.

      According to one of the authors, Dr Stefan Dullinger of the
      University of Vienna, "Shrinkage and fragmentation of alpine
      habitats, as a consequence, may pose a serious threat to populations
      of many alpine plants, especially to regional endemics.

      On the other hand, expansion of mountain forests may also improve
      certain ecosystem services for human welfare, such as erosion control
      and increased water holding capacity in many high mountain water
      catchments."

      Dr Dullinger says that the findings will help the City of Vienna use
      pines to protect its drinking water catchment from erosion and
      pollution. However, he warns that the Viennese model is not easily
      transferable to other tree line systems.

      "Tree lines may respond quite idiosyncratically to global warming.
      Our model highlights the complex interactions of temperature rise,
      species specific traits and resident alpine vegetation cover in
      driving a possible future tree line expansion," said Dullinger.
      http://www.spacedaily.com/news/climate-04s.html
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    • P. Neuman self only
      http://www.spacedaily.com/news/climate-04s.html Global Warming And The Onward March Of The Pine London - Apr 13, 2004 Climate change could dramatically
      Message 2 of 2 , Apr 15 6:29 PM
        http://www.spacedaily.com/news/climate-04s.html
        Global Warming And The Onward March Of The Pine

        London - Apr 13, 2004
        Climate change could dramatically increase the forest cover of the
        Earth's mountains, ecologists are predicting. Using data from the
        Austrian Alps, ecologists have developed a model that predicts the area
        covered by the local pine, Pinus mugo Turra, will increase from 10% today
        to 60% by the turn of the next millennium.
        The findings are published in the April issue of the British Ecological
        Society's Journal of Ecology and the authors believe that this is the
        first paper to model tree line dynamics driven by climate change on a
        landscape scale in both time and space.

        The Earth's climate has warmed approximately 0.6�C over the past 100
        years and the rate of warming looks set to accelerate. Alpine tree lines
        are assumed to be particularly sensitive to climate change, with high
        mountain forests predicted to shift their ranges up-slope at the expense
        of alpine vegetation.

        According to one of the authors, Dr Stefan Dullinger of the University of
        Vienna, "Shrinkage and fragmentation of alpine habitats, as a
        consequence, may pose a serious threat to populations of many alpine
        plants, especially to regional endemics.

        On the other hand, expansion of mountain forests may also improve certain
        ecosystem services for human welfare, such as erosion control and
        increased water holding capacity in many high mountain water catchments."

        Dr Dullinger says that the findings will help the City of Vienna use
        pines to protect its drinking water catchment from erosion and pollution.
        However, he warns that the Viennese model is not easily transferable to
        other tree line systems.

        "Tree lines may respond quite idiosyncratically to global warming. Our
        model highlights the complex interactions of temperature rise, species
        specific traits and resident alpine vegetation cover in driving a
        possible future tree line expansion," said Dullinger.


        SPACE.WIRE
        http://www.spacedaily.com/upi/20040412-14293400.html
        Climate: Unraveling the borehole riddle

        By Dan Whipple
        Boulder (UPI) April 12, 2004
        Progress in the genuine understanding of climate change, as with all
        science, is achieved through the accumulation of detail and, in some
        cases, excruciating detail.
        Case in point: geologic boreholes.

        In order to understand whether the modern climate warming is exceptional,
        scientists must learn how the planet's atmosphere behaved in the past.
        This is a complex task. Few temperature records go back more than two
        centuries or so, and most of what does exist tends to be concentrated in
        particular regions. For instance, there are thermometer measurements for
        the 19th century for North America and Europe, but virtually none for
        anywhere in the Southern Hemisphere.

        The problem of determining a global average temperature, even today --
        never mind past millennia -- is further complicated by the fact that
        two-thirds of the Earth is covered by oceans, which until very recently
        had no current thermometry records and few ways of obtaining historical
        data.

        Scientists from various disciplines have devised clever ways to overcome
        this lack of data. They have relied on so-called proxy records, which can
        provide a great deal of information, albeit indirectly. As a result, each
        one, by definition, has limitations and each one has generated a
        controversy about its interpretation.

        To reconstruct Earth's climate, scientists have looked at a number of
        proxy records, such as tree rings. They contain potential temperature and
        precipitation data that can be preserved in fossilized remnants as well
        as living trees.

        Climate researchers also have examined coral reefs, whose growth varies
        with water temperature. They have studied ocean sediments, from which
        oxygen isotope contents can infer temperature. They have extracted ice
        cores, which trap oxygen and hydrogen and can provide a proxy for
        temperature records. They have calculated glacier movements, which
        advance and retreat depending on temperature.

        They also have drilled boreholes -- core samples extracted from soil and
        rock instead of ice -- to attempt to determine how climatic processes
        have transferred surface heat to the underground environment.

        Although all of these proxy records have drawn reactions ranging from
        differing interpretations to outright disagreement, a recent exchange
        over boreholes demonstrates how the details of climate science can affect
        very large conclusions about the warming Earth.

        Gavin Schmidt, of the NASA Goddard Institute for Space Studies and
        Climate Systems Research at Columbia University in New York, and Michael
        Mann, of the Department of Environmental Sciences at University of
        Virginia in Charlottesville, published a paper recently in the journal
        Geophysical Research Letters that argued snow cover affected and perhaps
        skewed the borehole record.

        "Our paper wasn't that fundamental," Schmidt told United Press
        International. "I'm not going to claim that it was groundbreaking work.
        Changes in snow cover can affect the temperatures that get transmitted to
        deep boreholes. You're not going to find anybody who is going to disagree
        with that."

        As it turns out, some geologists are taking exception, including David
        Chapman, Marshall Bartlett and Robert Harris, all of the Department of
        Geology and Geophysics at the University of Utah in Salt Lake City.

        In a comment published in GRL, Chapman and the others argued: "We have
        been working on the same question as Mann and Schmidt -- the fidelity of
        ground surface temperature and surface air tracking, in particular the
        effect of seasonal snow cover ... But our analysis, based not on model
        simulation but analysis of measurements of GST and SAT at observatories
        ... leads us to very different conclusions."

        The most important point, Bartlett told UPI, "is that there is a
        difference between the inferred amount of warming that has occurred. We
        have confidence that the physics is really well understood. Any change in
        the surface temperature gets conducted to the solid rock."

        The interpretation resulting from these differences could be substantial.
        Bartlett said the borehole records show warming to be about twice as
        large since the advent of the industrial age as other estimates. He also
        noted the trio's results "indicate that the warming induced by
        industrialization since 1750 is more than we see in the proxy records and
        agrees with the surface air temperature records."

        This seemingly technical matter attracted the attention of Harvard
        University astrophysicist Willie Soon, a controversial figure among
        climate scientists, who argues that modern warming is not exceptional in
        the historic period and the so-called medieval warm period -- from about
        800 to 1300 A.D. -- was warmer than today. Soon is also a senior
        scientist at the George Marshall Institute in Washington, D.C., one of
        the leading skeptical think tanks on climate.

        Soon e-mailed the analyses by Schmidt and Mann and by Chapman, Bartlett
        and Harris to journalists with a brief note: "Just in case it is of
        interest." What apparently attracted his attention was not the technical
        arguments so much as the fact Mann was one of the co-authors. Mann's work
        on modern temperature increases was cited by the Intergovernmental Panel
        on Climate Change's 2001 assessment on global warming.

        "Michael Mann has become a lightning rod for everybody and their dog,"
        Schmidt said. "It's a ridiculous tactic. Obviously, you know why they do
        it. Mike has been getting the same thing ever since that assessment
        report. He's a combative guy. He likes to carry ball to the opposition.

        "I work in a modeling group," Schmidt added. "I don't have any particular
        axes to grind. General climate model experiments give you a laboratory to
        test different things. You make things change with respect to solar
        forcing, to greenhouse gases. To what extent does this model reflect the
        real world?"

        Schmidt explained that because snow cover in Eurasia actually has
        increased over the last few decades.

        "It's a very complicated story and involves four dynamics of climate.
        There isn't going to be a 'gotcha' moment, when everything is going to be
        clear, where you get the temperature for the middle of the Little Ice
        Age," he said.

        --

        Dan Whipple covers the environment for UPI Science News. E-mail
        sciencemail@...



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