Volcano Blast Creates a Natural Test of a Geoengineering Scheme–Which Fails

By Eliza Strickland | October 13, 2010 5:38 pm

Alaska-volcanoA recent volcanic eruption let scientists watch Mother Nature try out one of the geoengineering schemes that has been proposed to reduce the amount of carbon dioxide in the air, and therefore cool the planet. But the results of this natural experiment left a lot to be desired.

The geoengineering technique known as ocean fertilization calls for scientists to dump iron into the ocean to “fertilize” it and spur blooms of phytoplankton. These tiny photosynthetic organisms will suck up CO2 as they grow, the thinking goes, but will then die and tumble down to the sea floor, where the CO2 will be safely stored in the heaps organic matter.

The same thing can happen naturally, though, if a volcano happens to erupt and spews iron particles over the ocean. That’s exactly what happened in the summer of 2008.

In August 2008, scientists in the northeastern Pacific Ocean were shocked to witness a sudden, huge spike in the area’s plankton population. Their investigation traced the bloom to an ash cloud from a volcano that had erupted in the Aleutian Islands only a few days before. The ash, it turned out, had fertilized the ocean with thousands of tons of iron, on which the plankton gorged. [ScienceNOW]

Researchers determined that the plume of ash from the Kasatochi volcano had been caught up in a severe windstorm, which helped disperse the material over a wide swath of ocean. The result, one of the researchers told LiveScience, was an “ocean productivity event of unprecedented magnitude.” So they set about monitoring the massive plankton bloom to see if it really would suck up carbon and drag it down to the bottom of the sea. The results, which they published in the journal Geophysical Research Letters, suggest that a manmade campaign of ocean fertilization wouldn’t have as big an effect as people hope.

Lead author Roberta Hamme explains that the huge plankton bloom absorbed 4 million tons of carbon dioxide–which sounds great, until you hear that the ocean naturally absorbs 8.1 billion tons of CO2 a year, and that the burning of fossil fuels releases about 26.4 billion tons annually.

“Despite the huge area of iron addition and the optimal time of year when there was plenty of sunlight, the impact of this August 2008 event in terms of carbon dioxide absorption was quite small,” Hamme said. “This tells us that iron fertilization would have to be performed on a truly gigantic scale to have an impact on our climate.” [LiveScience]

So would-be geoengineers who had their eye on ocean schemes should probably head back to the drawing board, says Philip Boyd, an atmospheric scientist who had conducted iron fertilization experiments:

“If I were a geoengineer and had a couple of venture capital people on the line I’d direct them elsewhere,” Boyd said. [Discovery News]

Related Content:
80beats: Study: Climate Hacking Scheme Could Load the Ocean With Neurotoxins
80beats: Iron-Dumping Experiment Is a Bust: It Feeds Crustaceans, Doesn’t Trap Carbon
80beats: If We Can’t Stop Emitting CO2, What’s Our Plan B?
80beats: Obama’s Science Adviser Kicks Up a Fuss Over Geoengineering
DISCOVER: Disaster! The Most Destructive Volcanic Eruptions in History (photos)

Images: Alsaska Volcano Observatory; Geophysical Research Letters / Hamme et al.

CATEGORIZED UNDER: Environment
  • Stosh Y

    I don’t see what all the fuss is about. Man will have destroyed the atmospheres ability to sustain him in a few more years and we will simply die off, At least enough of us so things will level out again. Man had his chance and chose poorly. Fast and easy vs long haul responsibility. Nothing changes.

  • Brian Too

    Next!

  • Rabidmob

    Whatever happened to the plan of shooting huge geysers of water into the atmosphere? That one seemed promising with little chance for chemically contaminating the ocean or atmosphere.

  • http://amrithemerickwind glen hemerick

    global warming occurs every 1000 years, lasts 500 years. cooling will start soon,
    without your help. carbon dioxide is a result of your killing plants, especially
    phytoplankton, using chlorine and herbicides. we cannot control polluters;
    but you can reduce co2 by planting plankton…
    Glen Hemerick, 15871 Peacock Hill Road SE, Olalla, WA
    98359. phone 253-857-7225. 253 229 5861 email:
    ghemerick@yahoo.com ,ghemerick@harbornet.com ,ghemerick@juno.com

  • scribbler

    Too bad science can’t come up with something small that you can drop into the ground that will change CO2 and H2O into a solid form about the same consistency as wood…

  • Daniel J. Andrews

    Or change CO2 into CaCO2 (limestone) cheaply and quickly. Then market the limestone for buildings, pathways, etc. I haven’t even googled this, but I bet there is someone looking at doing just that.

  • T. Coulter

    The chemical reaction of lime with carbon dioxide is:
    CaO + CO2 = CaCO3
    and would work quite well if you could find any cheap CaO without emitting a whole pile of CO2 in the manufacture of it; and you can’t! Lime (CaO) is made out of limestone by reversing the above reaction by heating above about 700 degrees C. So it makes just as much CO2 as you could absorb. Even worse, the heating is usually done by burning oil or gas and that liberates much additional CO2. You can’t win!

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