A Deep-Six Fix
Could burying fossil-fuel emissions save the climate?
`These guys are wacko!" was earth scientist Sally Benson's initial reaction several years back when two prominent scientists gave a talk about an answer to global warming that sounded too good to be true. Carbon dioxide from fossil fuels traps heat as it builds up in the atmosphere, and most scientists think the trend, if unchecked, bodes a scorching future. So why not catch the stuff before it goes up smokestacks, the speakers proposed? Why not simply bury it underground or in the ocean depths?
Today Benson heads a U.S. Department of Energy effort to explore just that idea, which is seeming less wacky every day. Last November, Energy Secretary Spencer Abraham announced that the Bush administration would invest as much as $90 million in research on burying carbon dioxide. BP and ChevronTexaco are studying the strategy, called carbon sequestration. Test projects in Canada and the North Sea are yielding encouraging results. Even many environmentalists support sequestration research. Says David Hawkins, director of the Natural Resources Defense Council's climate center: "The challenge of climate change is too large and looming too close in time for us to ignore the contribution that carbon storage could make."
Not in my ocean. Carbon sequestration schemes target emissions only from factory and power plant smokestacks, not from the tailpipes of cars and SUVs. And stripping carbon dioxide from the stew of chemicals emitted by these big polluters could be costly. Further, while carbon dioxide is hardly nuclear waste, there's a heated controversy about the safest place to put it. Just last August, Greenpeace helped scupper a test project that would have injected carbon dioxide into the North Sea, asserting that marine burial could damage ocean ecosystems. Underground repositories, for their part, might leak.
But if sequestration worked, the payoff could be huge. Most scientists concur that to prevent drastic global changes--which could include shifts in ocean currents, inundated coastlines, and expanded deserts--the atmosphere's carbon dioxide concentration will have to be capped at about twice its levels before the Industrial Revolution 200 years ago, when large-scale fossil fuel use began. That would mean limiting global emissions of the gas to current levels within two decades, even as the world's population increases and energy consumption jumps in the Third World as poor nations grow richer. We can't bury all the excess, says Benson, but carbon storage could "make a huge dent," buying precious time in which to shift from coal, oil, and gas to new, greener energy sources.
The world's first commercial-scale sequestration effort is already underway on a natural-gas rig off the coast of Norway. Each week, workers pipe 20,000 tons of carbon dioxide--an amount equivalent to the output of a 150-megawatt coal-fired power plant--into the porous rock of a saltwater aquifer more than half a mile below the seafloor. The source of the carbon dioxide isn't a power plant but the natural gas itself. It comes out of the well containing a high percentage of carbon dioxide, which must be stripped out before the fuel can be sold. After Norway levied a tax on offshore carbon dioxide emissions in 1996, the rig's owners decided to bury the waste gas instead of venting it.
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