NEWS OF THE WEEK GLOBAL
WARMING
DESPERATE COOLING MEASURE IS AIRED Injections of sulfur into the stratosphere would cool Earth, a chemist suggests
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H 2 S 0 4 , Crutzen suggests as a prod to his chemist colleagues. Crutzen describes his climate engineering proposal as a last-resort hedge on what he fears will become a too-little-too-late response to global warming. "I am only in favor of doing the manipulation if there are no severe side effects and the climate is running away," Crutzen tells C&EN. For now, he says, "I recommend research." In recognition of the controversial nature of Crutzen's ideas, Climatic Change commissioned a half-dozen articles to help readers develop a fuller perspective of the pros, cons, and uncertainties, Schneider says. Climate modeler Gavin Schmidt of NASA's Goddard Institute for Space Studies in New York City views Crutzen's essay as a strong but prudent call to other scientists to engage in "what if" scenarios, including the worst cases. "I am not as pessimistic as Crutzen," Gavin says. There's a chance the world will take steps that will make geoengineering experiments unnecessary, he says, a result that Crutzen rates as "a pious wish."—IVAN AMATO
fur (from the volcano's initial injecradically combat global tion of 10 billion kg) in the form of warming by deliberately inaerosol-forming sulfate remained jecting a small volcanic eruption's in the stratosphere. The result of worth ofplanet-cooling sulfur into this event was a 0.5 °C cooling at the stratosphere. That's the talkedEarth's surface in the year followabout proposal being set forth in a ing the eruption. controversial essay by Nobel PrizeIt would take about 5 3 billion winning chemist Paul J. Crutzen kg of sulfur introduced into the that appears in the August issue of stratosphere per year to compenthe journal Climatic Change (DOI: sate for a doubling of atmospheric 10.1007/sl0584-006-9101-y). carbon dioxide levels, Crutzen says. Increasing the amount of T h e journal's editor, climasulfate aerosols "can be achieved tologist Stephen H. Schneider of by burning S2 or [by] H 2 S carried Stanford University, says scientists into the stratosphere on balloons and politicians "must study the poand by artillery guns to produce tential" of geoengineering-based S0 2 ," he suggests in his essay. Perstrategies such as the global-scale haps a chemist could develop a cooling experiment that Crutsulfur-containing gas that is stable zen, of Max Planck Institute for lower in the atmosphere, where it Chemistry, in Mainz, Germany, would be easier to place, but which outlines in his essay. However, then would undergo a reaction in Schneider stresses that considering the stratosphere to produce S 0 2 such drastic measures to mitigate or another sulfur-containing gas global warming should in no way that can produce aerosol-forming reduce a sense of urgency for safer solutions, including more energyfrugal lifestyles and helping the CONGRESS developing world leapfrog over the carbon dioxide-emitting adventure of the Industrial Revolution. In his essay, Crutzen explains or the first time in more than a decade, a that global warming from the U.S. Senate committee last week checked buildup of carbon dioxide and up on the federal system for regulating inother greenhouse gases is partially dustrial chemicals. countered by a cooling effect due The Senate Environment & Public Works to backscattering of sunlight by Committee on Aug. 2 examined EPA's regulaaerosols that form from sulfate tion of commercial chemicals under the Toxic Subparticles. In this way, even the stances Control Act. Congress has not revised sulfurous pollution that has caused that statute since it was enacted in 1976 and has acid rain, now on a decline, has had paid little attention to TSCA in the past 30 years. a cooling effect. The panel heard from a representative of the Government Accountability Office, the investigaThe 1991 eruption of Mount tive arm of Congress, which in 2005 issued a rePinatubo in the Philippines proport critical of EPA's ability to manage chemicals vides a dramatic natural example of the power of aerosol cooling. Six and recommended changes to TSCA (C&EN, Aug. 8,2005, page 32). Also calling for amendments to months after the eruption, Crutthe statute were a Clinton Administration EPA aszen notes, about 6 billion kg of sulHE WORLD MIGHT NEED TO
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NATURAL COOLANT Sulfur from volcanic eruptions such as this one of Mount Pinatubo leads to atmospheric aerosols that cool the planet.
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Hearing Reviews Federal Chemical Rules
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sistant administrator and the lead author of a recent report recommending that California tighten its regulation of chemicals because TSCA authorities are deficient (C&EN, March 20, page 9). A representative of the American Chemistry Council spoke at the hearing, along with an attorney who counsels industry clients on TSCA. Both defended the law as written, saying it works well and affords flexibility to chemical manufacturers and EPA. James B. Gulliford, EPA assistant administrator for prevention, pesticides, and toxic substances, told the committee the statute provides sufficient authority for regulating commercial chemicals to protect health and the environment. "We think TSCA is a very effective statute," Gulliford stated.-CHERYL HOGUE
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