photo: Sam Ismail
Here's a geoengineering approach you may not have heard of: Stuart Strand of the University of Washington proposes making bales of crop residue (stalks and other agricultural waste) and sinking them into the deep ocean to sequester carbon. Strand says they could reduce the build up of atmospheric carbon dioxide by up to 15% per year. Here's how:
Worldwide, farming is mankind's largest-scale activity. Thirty percent of the world's crop residue represents 600 megatons of carbon that, if sequestered in the deep ocean with 92 percent efficiency, would mean the amount of carbon dioxide in the atmosphere would be reduced from 4,000 megatons of carbon to 3,400 megatons annually, Strand says. That's about a 15 percent decrease.
The proposed process would remove only above-ground residue. Strand bases his calculations on using 30 percent of crop residue because that's what agricultural scientists say could sustainably be removed, the rest being needed to maintain carbon in the soil. Crop residue would be baled with existing equipment and transported by trucks, barges or trains to ports, just as crops are. The bales would be barged to where the ocean is 1,500 meters, or nearly a mile, deep and then the bales would be weighted with rock and sunk.
"The ocean waters below 1,500 meters do not mix significantly with the upper waters," Strand says. "In the deep ocean it is cold, oxygen is limited and there are few marine organisms that can break down crop residue. That means what is put there will stay there for thousands of years." (Science Codex)
But, but, but.... In the original piece Strand addresses potential environmental consequences and how to mitigate them. So, check it out—Some of Earth's climate troubles should face burial at sea—and come on back and weigh in.
Geoengineering to Stop Climate Change: The Effective, the Risky and the Useless Outlined in New Research Paper
Geoengineering Risk Potential Not An Excuse for Inaction, Scientist Says
Quote of the Day: James Lovelock on Geoengineering & The "Practice of Planetary Medicine"