July 08, 2004
Ocean Iron Fertilization Viable To Remove Atmospheric Carbon Dioxide?
Some scientists are questioning the viability of ocean iron seeding as a means to sequester carbon from atmospheric carbon dioxide. (The Scientist requires free registration - an excellent publication that is worth the trouble to sign up)
The idea can be traced back to a Woods Hole Oceanographic Institution meeting in 1985, when John Martin, then director of the Moss Landing Marine Laboratory, boasted: "Give me half a tanker of iron and I'll give you an ice age." Martin's general hypothesis that iron seeding would create a photosynthetic bloom proved correct, although the idea has turned out to be far less economical than he expected. The breakeven point for sequestration programs is $10 per ton of carbon dioxide; models based on the iron-seeding experiments still put the cost at $100 or more.
Many scientists involved in iron-seeding projects as well as those observing them from afar say that iron seeding for purposeful carbon sequestration just doesn't work. "In the beginning, the assumptions were that for every atom of iron, we could sink 500,000 atoms of carbon," says Ken Caldeira, an ocean carbon-cycle scientist at Lawrence Livermore National Laboratory in California, who helped to create computer simulations. Those estimates have since been revised downwards by hundreds of orders of magnitude, he says.
The article quotes a variety of scientists on whether the latest Southern Ocean Iron Fertilization Experiment (SOFeX) provides good or bad news for the prospect of iron fertilization as a way to increase photosynthesis by marine plant organisms as a way to cheaply remove carbon dioxide from the atmosphere. Some scientists still hold that it is the cheapest method to remove atmospheric carbon dioxide found to date. Read the full article if the debate interests you. I lack sufficient knowledge to render any sort of opinion on the subject.
Also see my previous post on the SoFEX results that links to more optimistic assessements of the experiment's results: Iron Enriching Southern Ocean Pulls Carbon Dioxide From Atmosphere.
This may be of interest to you:
Media Relations Office
Woods Hole Oceanographic Institution
Effects of Ocean Fertilization with Iron to Remove Carbon Dioxide from the Atmosphere Reported
The results, while positive, were less than spectacular. More difficult to determine are the secondary effects and possible unintended consequences. The oceans are highly complex environments, as I recently discovered through my reading.
Imagine the difficulty in modeling the effects of changing the abundance of tiny floating plant life (phytoplanktons) across large swaths of the oceans. How does that change the penetration of light? How does that change temperatures? How does that effect currents? How does that impact the migration of fish schools? It's a big, interesting question and probably deserves a lot more research.
I'm not a scientist but these articles are really interesting. Thanks for putting them up. I'm going to read more.
I am not a scientist but the above topic is really very interesting...i want to say that"when carbon dioxide be removed from atmosphere as a result the trees will not get sufficientCO2 for photosynthesis and will use CO2 producted from own....finally the the amount of O2 from trees into the atmosphere will reduce....atlast it wiil happen that"" the crisis of O2.....after that what will be the situation is well known to all""..."
DILIP KUMAR MAHATA
DEPART OF APPLIED GEOPHYSICS
The poster's comment "Those estimates have since been revised downwards by hundreds of orders of magnitude, he says," which the poster didn't feel comfortable quoting, is either sloppy writing or thinking. An "order of magnitude" is a factor of 10. Hundreds of them are surely not what they were talking about. Even 100 orders of magnitude would mean that the estimate was reduced from 500,000 to 5X10^-95 atoms, a nonsensical fraction of an atom.
"A factor of 100 or more" might have been accurate, and, hopefully something like what the scientist actually said. If the scientist actually said "hundreds of orders of magnitude" then they were engaging in hyperbole that could not be reflected in the physical universe.
Efficient carbon sequestration of some kind could be a big way to get over the hump until green technology is more readily available. A temporary market in carbon that would give rise to an industry doing carbon sequestration of some kind, is hardly one of the worst meta-phenomenon that could arise in the solving of a global problem.
Iron seeding of souther oceans to promote photosyntheses to remove CO2 from atmosphere sounds good to me but why not introduce a substance with strong affinity to CO2 directly into atmosphere and induce precipitation of the CO2 compound. For generating rain, for example,silver iodide has been used as nuclei to seed the clouds and has worked successfully. I think with a well funded research, Chemist and atmospheric scientists can find the proper seeds to turn CO2 to a liquid product which then precipitate out of atmosphere. The product should be harmless to human and animals.