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Geoengineering Could Be Essential to Reducing the Risk of Climate Change
http://www.technologyreview.com/news/506256/geoengineering-could-be-essential-to-reducing-the-risk-of-climate-change/[font face=Serif][font size=5]Geoengineering Could Be Essential to Reducing the Risk of Climate Change[/font]
[font size=4]Using technology to cool the planet may be the only way to deal with the greenhouse gases already in the atmosphere, argues scientist David Keith.[/font]
[font size=3]By Kevin Bullis on October 25, 2012
Geoengineering—using technology to purposefully change the climate—is the only option for reducing the risk of climate change from greenhouse-gas emissions in the next few decades, says David Keith, a professor of public policy and applied physics at Harvard University. And he says that if it’s done in moderation, it could be much safer than some experts have argued. In fact, says Keith, effective methods of geoengineering are so cheap and easy that just about any country could do it—for better or worse.
Keith, speaking this week at MIT Technology Review’s annual EmTech conference, says it is already too late to avoid climate changes by reducing carbon emissions alone. The carbon dioxide that’s been released into the atmosphere by burning fossil fuels is already likely to cause significant harm, such as raising temperatures enough to hurt crop yields in many places. “If you want to, say, really stop the loss of Arctic sea ice or stop heat-stress crop losses over the next few decades, geoengineering is pretty much the only thing you can do,” he says (see “Why Climate Scientists Support Geoengineering Research”).
Keith’s preferred method of geoengineering is to shade the earth by injecting sulfate particles into the upper atmosphere, imitating a similar process that happens with large volcanic eruptions, which are known to temporarily cool the planet. The technique could be effective even if far less sulfate were injected than is currently emitted by fossil-fuel power plants. A million tons per year injected into the stratosphere would be enough—whereas 50 million tons are injected into the lower part of the atmosphere by coal plants, he says. (In the lower atmosphere, the sulfates are less effective at cooling because they stay airborne for shorter periods.)
One of the main objections to geoengineering is that the measures that might be taken to cool the planet won’t exactly offset the effects of carbon dioxide, so they could actually make things much worse—for example, by altering patterns of precipitation. Keith says recent climate models suggest that injecting sulfate particles into the upper reaches of the atmosphere might not affect precipitation nearly as much as others have warned.
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[font size=4]Using technology to cool the planet may be the only way to deal with the greenhouse gases already in the atmosphere, argues scientist David Keith.[/font]
[font size=3]By Kevin Bullis on October 25, 2012
Geoengineering—using technology to purposefully change the climate—is the only option for reducing the risk of climate change from greenhouse-gas emissions in the next few decades, says David Keith, a professor of public policy and applied physics at Harvard University. And he says that if it’s done in moderation, it could be much safer than some experts have argued. In fact, says Keith, effective methods of geoengineering are so cheap and easy that just about any country could do it—for better or worse.
Keith, speaking this week at MIT Technology Review’s annual EmTech conference, says it is already too late to avoid climate changes by reducing carbon emissions alone. The carbon dioxide that’s been released into the atmosphere by burning fossil fuels is already likely to cause significant harm, such as raising temperatures enough to hurt crop yields in many places. “If you want to, say, really stop the loss of Arctic sea ice or stop heat-stress crop losses over the next few decades, geoengineering is pretty much the only thing you can do,” he says (see “Why Climate Scientists Support Geoengineering Research”).
Keith’s preferred method of geoengineering is to shade the earth by injecting sulfate particles into the upper atmosphere, imitating a similar process that happens with large volcanic eruptions, which are known to temporarily cool the planet. The technique could be effective even if far less sulfate were injected than is currently emitted by fossil-fuel power plants. A million tons per year injected into the stratosphere would be enough—whereas 50 million tons are injected into the lower part of the atmosphere by coal plants, he says. (In the lower atmosphere, the sulfates are less effective at cooling because they stay airborne for shorter periods.)
One of the main objections to geoengineering is that the measures that might be taken to cool the planet won’t exactly offset the effects of carbon dioxide, so they could actually make things much worse—for example, by altering patterns of precipitation. Keith says recent climate models suggest that injecting sulfate particles into the upper reaches of the atmosphere might not affect precipitation nearly as much as others have warned.
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