[ATM] Shutting Down the Night Sky

[Michael Wheatley <mwheatley@telus.net>]

Could pollution help cool the planet?

     By Charles J. Hanley
     The Associated Press
     17 November 2006

    NAIROBI, Kenya - If the sun warms the Earth too dangerously, the time
    may come to draw the shade.

    The "shade" would be a layer of pollution deliberately spewed into the
    atmosphere to help cool the planet. This over-the-top idea comes from
    prominent scientists, among them a Nobel laureate. The reaction here
    at the U.N. conference on climate change is a mix of caution,
    curiosity and some resignation.

    "It was meant to startle the policymakers," said Paul J. Crutzen, of
    Germany's Max Planck Institute for Chemistry. "If they don't take
    action much more strongly than they have in the past, then in the end
    we have to do experiments like this."

    Serious people are taking Crutzen's idea seriously. This weekend,
    NASA's Ames Research Center in Moffett Field, Calif., hosts a
    closed-door, high-level workshop on the global haze proposal and other
    "geoengineering" ideas for fending off climate change.

    In Nairobi, meanwhile, hundreds of delegates were wrapping up a
    two-week conference expected to only slowly advance efforts to rein in
    greenhouse gases blamed for much of the 1-degree rise in global
    temperatures the past century.

    The 1997 Kyoto Protocol requires modest emission cutbacks by
    industrial countries - but not the United States, the biggest emitter
    of carbon dioxide and other heat-trapping gases, because it rejected
    the deal. Talks on what to do after Kyoto expires in 2012 are all but
    bogged down.

    When he published his proposal in the journal Climatic Change in
    August, Crutzen cited a "grossly disappointing international political
    response" to warming.

    The Dutch climatologist, awarded a 1995 Nobel in chemistry for his
    work uncovering the threat to Earth's atmospheric ozone layer,
    suggested that balloons bearing heavy guns be used to carry sulfates
    high aloft and fire them into the stratosphere.

    While carbon dioxide keeps heat from escaping Earth, substances such
    as sulfur dioxide, a common air pollutant, reflect solar radiation,
    helping cool the planet.

    Tom Wigley, a senior U.S. government climatologist, followed Crutzen's
    article with a paper of his own Oct. 20 in the U.S. journal Science.
    Like Crutzen, Wigley cited the precedent of the huge volcanic eruption
    of Mount Pinatubo in the Philippines in 1991.

    Pinatubo shot so much sulfurous debris into the stratosphere that it
    is believed it cooled the Earth by 0.9 degrees for about a year.

    Wigley ran scenarios of stratospheric sulfate injection - on the scale
    of Pinatubo's estimated 10 million tons of sulfur - through
    supercomputer models of the climate, and he reported that Crutzen's
    idea would, indeed, seem to work. Even half that amount per year would
    help, he wrote.

    A massive dissemination of pollutants would be needed every year or
    two, as the sulfates precipitate from the atmosphere in acid rain.

    Wigley said a temporary shield would give political leaders more time
    to reduce human dependence on fossil fuels - the main source of
    greenhouse gases. He said experts must more closely study the
    feasibility of the idea and its possible effects on stratospheric
    chemistry.

    Philip Clapp, president of the U.S. group National Environmental
    Trust, sounded a nervous note, saying, "We are already engaged in an
    uncontrolled experiment by injecting greenhouse gases into the
    atmosphere." But he added, "I certainly don't disagree with the
    urgency."

    In past years scientists have scoffed at the idea of air pollution as
    a solution for global warming, saying the kind of sulfate haze that
    would be needed is deadly to people. Last month, the World Heath
    Organization said air pollution kills about 2 million people worldwide
    each year and that reducing large sootlike particles from sulfates in
    cities could save 300,000 lives annually.

    American geophysicist Jonathan Pershing, of Washington's World
    Resources Institute, is among the wary, but said the idea might be
    worth considering "if, down the road 25 years, it becomes more and
    more severe because we didn't deal with the problem."

    Crutzen said that's what he envisioned: global haze as a component for
    long-range planning.

    Pershing added, however, that reaction may hinge on who pushes the
    idea: "If it's the U.S., it might be perceived as an effort to avoid
    the problem."

http://seattletimes.nwsource.com/text/2003434828_haze17.html

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