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Science backs theories about global warming

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  • Patrick Neuman
    Science backs theories about global warming MAUNA LOA OBSERVATORY, Hawaii -- Two miles up, above black lava fields and a white blanket of clouds, a tower
    Message 1 of 1 , May 31, 2004
      Science backs theories about global warming

      MAUNA LOA OBSERVATORY, Hawaii -- Two miles up, above black lava
      fields and a white blanket of clouds, a tower rising from this U.S.
      government observatory gulps in some of the clear, crisp air and gets
      a taste of man's future on Earth.

      "As big as the atmosphere is, we're influencing it," says the
      physicist in charge, John Barnes.

      The tale told by the tower, atop a dormant Hawaiian volcano, can be
      read in the upward curve of a graph:

      Carbon dioxide in the atmosphere, which stood at 280 parts per
      million two centuries ago, has climbed to 379 parts per million since
      industrializing man began burning vast amounts of coal, oil and other
      fossil fuels.

      There has not been, for 450,000 years, this much carbon dioxide
      enveloping the planet, ice-core samples show.

      The news from Mauna Loa and other monitoring stations has
      increasingly disturbed scientists, because carbon dioxide traps heat,
      as do other "greenhouse gases," and global temperatures have, indeed,
      been rising -- by almost 1 degree Fahrenheit over a recent 18-year
      period, a relatively rapid increase, NASA experts reported in April.

      Warming will disrupt our climate, possibly drying out farmlands,
      stirring up fiercer storms and raising ocean levels, among other
      impacts, says the Intergovernmental Panel on Climate Change (IPCC), a
      U.N.-organized network of hundreds of climatologists and other

      But the climate tale is far from simple. Earth's behavior -- physics,
      chemistry, biology -- is an infinitely complex web of feedback loops,
      reactions, recycling among the atmosphere, ocean, land and all their
      components. Knowns are countered by unknowns, certainty by

      It was uncertainties that American oil, utility and other industries
      pointed to in the 1990s in fighting international efforts to cap
      fossil-fuel emissions. And President Bush cited the "incomplete state
      of scientific knowledge" when he renounced the Kyoto Protocol, the
      first step toward imposing those caps, in March 2001.

      Then, just three months later, a National Academy of Sciences report
      commissioned by the Bush White House supported the IPCC's finding.
      Last year, two more prestigious organizations -- the American
      Meteorological Society and the American Geophysical Union -- came to
      similar conclusions.

      Climatologists will never dispel the uncertainties "100 percent," but
      they're working on it, and the Geophysical Union said computer
      modeling of carbon, water and other cycles governing climate has
      improved greatly in the past decade.

      At universities and major centers worldwide -- such as the U.S.
      government's National Center for Atmospheric Research in Boulder,
      Colo., and Britain's Hadley Centre -- specialists peer into the
      future via supercomputers, setting in motion vast global calculations
      via thousands of interlocked mathemathical formulas.

      Weather fronts flicker past on screens as temperatures and rainfall,
      melting ice and ocean evaporation, cloud cover and a myriad of other
      factors play out over days, months, years in "general circulation
      models," or GCMs.

      The leapfrogging of computer speed has boosted scientists'
      confidence. But if computer power is meeting the challenge,
      brainpower -- numbers of trained specialists, hands on keyboards to
      input, minds to analyze -- is coming up short, scientists say.

      "Climate change probably deserves a Manhattan Project-scale effort,"
      said Scripps meteorologist Richard C.J. Somerville, referring to the
      World War II atom-bomb project. "What there is, is a few dozen GCM
      projects, each with a handful of people."

      Whatever the resources, no one expects a "eureka moment" from the
      modeling -- ironclad proof that last month's automobile exhausts
      caused this month's warming. In fact, the added sophistication raises
      new questions even as it helps answer old ones.

      "All these little things now pop up. What about the size of
      raindrops, what about sea ice, what about forests?" said senior
      scientist Wallace Broecker of Columbia, who in the 1970s raised early
      alarms about global warming. "We're going to have to make a decision
      on what to do on the basis of insufficient evidence."

      The uncertainty compounds the concern. For example, some believe
      global warming will shrink "natural carbon sinks" -- that is, drought
      will kill off rainforests, which absorb carbon dioxide. That would
      raise levels of the gas in the atmosphere, worsening warming in a
      dangerous circular feedback.

      "If we get going now (on emission controls), we essentially buy time
      for further research" on such questions, said Princeton University
      climatologist Jorge L. Sarmiento.

      Newer concerns focus on the unknowns of aerosols, or particulates --
      tiny atmospheric particles of many kinds, from smokestack soot to
      dust blown off the desert. Some particulates cool by scattering
      sunlight, some warm. Some help clouds form, some break up clouds.

      Atop Mauna Loa, amid the silvery domes of the National Oceanic and
      Atmospheric Administration observatory, Barnes is researching
      aerosols in the stratosphere, firing a laser's green beam into the
      night sky to measure particles as far as 50 miles up.

      Leading NASA scientist James Hansen believes climate models may have
      missed a major particulate effect, from industrial soot accumulating
      on snow and ice. Instead of reflecting almost all sunlight, the
      darker landscape must be absorbing more heat, his team theorizes.

      An aura of quiet urgency is building around climate research.

      The tools deployed can dazzle, from distant space to ocean depths. A
      NASA satellite, from 1 million miles away, will view the entire
      sunlit Earth and measure its heat exchanges. To study ocean-climate
      interaction, meanwhile, 20 nations are sending 3,000 technology-
      packed floats as much as a mile deep in seas worldwide to drift with
      currents for years, taking temperature and other readings, and
      surfacing regularly to radio home the results via satellite.

      Many believe the most urgently needed data will come from ICESat, a
      newly launched satellite that for the first time will measure the
      Greenland and Antarctic ice sheets, to monitor melting as the world
      warms. Although full meltdowns would take centuries, runoffs could
      raise the seas by dangerous inches in the coming decades.

      Oceanographers report the North Atlantic is growing less salty
      because of melt runoff and increased precipitation. This may be
      ominous: It's the sinking of heavier, saltier water that draws warmer
      surface waters from the south and keeps the climate warmer than
      otherwise. A slowing of that ocean "conveyor" could drive down
      northern temperatures.

      This uncertain threat of a regional "ice age" was featured in an
      internal Pentagon report in October, subtitled "Imagining the
      Unthinkable." Describing a "plausible" though "not most likely"
      scenario, it said abrupt climate change could stir conflict by
      prompting mass migrations in search of shelter and food.

      The extreme vision disturbed climatologists. "Irresponsible," one
      said privately. But some hoped a Pentagon warning might arouse
      concern in Washington, D.C.

      "Maybe it's time for science fiction," said Harvard's Daniel Schrag,
      an expert on Earth's ice ages. "The science is not exciting people."

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