Aarghh!! The full learned study (so to speak):
Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments Stuart E. Strand, Gregory Benford, Environmental Science and Technology, January 12, 2009 <http://pubs.acs.org/doi/full/10.1021/es8015556> pdf: <http://pubs.acs.org/doi/pdfplus/10.1021/es8015556> ---- <http://www.newscientist.com/article/mg20126945.600-sinking-crop-waste-could-cut-global-warming.html> Sinking crop waste could cut global warming 04 February 2009 Magazine issue 2694. BURYING crop waste deep in the ocean could be an effective way to rein in global warming. The stalks and leaves left in fields across the world each year after harvesting contain a whopping 2 billion tonnes of carbon. Untouched, they decay and release carbon dioxide. One solution could be to drop the waste into the deep ocean. Up to 30 per cent of the leaves and stalks left in fields after harvesting can be removed without damaging soil fertility, say Stuart Strand of the University of Washington in Seattle and Gregory Benford of the University of California, Irvine. Sinking it could cut the annual rate of CO2 build-up in the atmosphere by 14 per cent, they say (Environmental Science and Technology, DOI: 10.1021/es8015556). When it comes to places to bury CO2, oceans are high on the list. While forests can also mop up CO2, trees release the gas when they burn or die. Carbon sunk in the deep ocean, however, will stay there for thousands of years. The method would cost about $95 per tonne of CO2, which is likely to be competitive with other methods, such as siphoning off CO2 from power stations and storing it in empty aquifers, says climatologist Stephen Schneider of Stanford University in California. <http://www.newscientist.com/article/dn16514-ocean-rubbish-dump-could-lock-away-carbon.html> Ocean rubbish dump could lock away carbon 30 January 2009 by Jim Giles Dumping crop waste in the deep ocean could be one of the best ways to rein in global warming, say researchers who have weighed the pros and cons of a range of carbon-capture schemes. Up to 30% of the leaves and stalks that remain in fields after harvesting can be removed without causing erosion or damaging soil fertility, estimate Stuart Strand of the University of Washington and Gregory Benford of the University of California, Irvine. This residue normally decays and releases carbon dioxide, but it could be collected, packed into bales and dropped into the deep ocean. Worldwide crop residues contain around 600 million tonnes of carbon. If all of it was sunk in this way, the rate of annual rate of build up of carbon in the atmosphere could be cut by 14%, say the researchers. Competitive cost Unlike some other carbon-capture schemes, ocean sequestration offers a higher degree of security about long-term storage. Forests mop up carbon dioxide, for example, but the trees release the gas again if they burn or rot. At depths of more than 1500 metres there is little mixing with surface waters, and this, argue proponents, combined with the high-pressure, low-oxygen conditions, would preserve carbon sunk in the deep ocean on the seafloor for thousands of years. The costs of capturing carbon using the technique would be around $95 per tonne of carbon dioxide. That could be competitive with proposals to siphon off the carbon dioxide generated by power stations and store it in empty aquifers, says Stephen Schneider of Stanford University. However, many questions about the crops plan remain, he adds. Little is known about the impact that the crop residues would have on ocean floor ecosystems, for example. _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/sustainablelorgbiofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (70,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
