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From NPR News, this is ALL THINGS CONSIDERED. I'm Robert Siegel.
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And I'm Michele Norris.
Last week, diplomats from more than a hundred nations declared their opposition to one unusual and highly controversial method for slowing climate change. The technique is called geoengineering, and it would deploy technology on a massive scale to cool the planet.
As KQED's Amy Standen reports, there are worries that such huge science experiments could lead to disasters somewhere in the world. There's also little agreement on one fundamental question: Who gets to run those experiments?
AMY STANDEN: If you want to see what geoengineering might look like, go back to 1991.
Unidentified Man: The angry giant awoke on June the 9th after a 611-year slumber.
STANDEN: The giant was Mount Pinatubo in the Philippines.
Unidentified Man: A mushroom cloud of steam, ash and smoke rose 30 kilometers into the sky.
STANDEN: That smoke contained almost 20 million tons of sulfur dioxide. Those particles can reflect sunlight back into space, and for a while, that's exactly what happened - temperatures around the world dropped by an average of half a degree.
Now, it turns out you don't need a volcano to get the same effect. Scientists could use airplanes to inject sulfur dioxide directly into the stratosphere and bring down global temperatures.
What's more, says David Keith, who directs the University of Calgary's Energy and Environmental Systems Group, it would be pretty easy to do.
Mr. DAVID KEITH (Director, Energy and Environmental Systems Group, University of Calgary): It takes so little material to alter the whole planet's climate. So the costs of doing it are just absurdly cheap.
STANDEN: The Mount Pinatubo effect, as it's called, is just one of the ways that scientists believe they might use technology to counteract climate change or at least its effects. Another way might be growing algae in the ocean to suck up carbon dioxide.
But in order to have a real impact on climate change, the project would have to take place on a massive scale, and that could have all sorts of unintended consequences, which makes a lot of people really nervous.
For instance, Diana Bronson of the ETC Group, which has been skeptical of geoengineering.
Ms. DIANA BRONSON (Program Manager and Researcher, ETC Group): Who is liable when millions of people go hungry because the monsoon rains get canceled in East Africa?
STANDEN: In other words, who gets to set the temperature or at least try to?
Professor JAMES FLEMING (Director of Science, Technology and Society, Colby College): Where would a planetary thermostat be located?
STANDEN: James Fleming is a historian of science and technology at Colby College and the author of a new book called "Fixing the Sky."
Prof. FLEMING: Would it be at Lawrence Livermore Labs? Would it be in Indonesia somewhere? Would it be in China? What if a rogue nation wanted to have their own thermostat?
STANDEN: On Saturday, diplomats at a meeting in Japan on the U.N. Convention on Biological Diversity tried to set some rules for future geoengineers. They issued what some are calling a moratorium on all geoengineering activities, at least until the science is clear and there are global regulations in place.
Now, the convention does not include the United States. In fact, just hours earlier, Congressman Bart Gordon of Tennessee issued a statement encouraging research into geoengineering. But the ETC Group's Bronson says the international moratorium sends a powerful message.
Ms. BRONSON: It would be very foolish for the Obama administration to say we don't care what 193 countries said about this. We're going to go ahead anyways.
STANDEN: David Keith of the University of Calgary says he sees no real incentive at this point for any individual country to go out and geoengineer the climate, but that could change.
Mr. KEITH: I do think there's a potential risk of larger countries wanting to act unilaterally when they see their interest really at stake, and we simply don't have international mechanisms to really manage that.
STANDEN: And manage it, we must, he says, because geoengineering may turn out to be a critical tool in dealing with climate change, but there's no reason to rush into it.
Mr. KEITH: I hope the debate goes a little slow, because there are risks on both sides. There are real risks to aggressive quick action, and there are real risks to inaction.
STANDEN: Like climate change itself, the impacts of geoengineering may be global, which means it will take global cooperation to get it right.
For NPR News, I'm Amy Standen.
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