RealClimate, a blog run by leading climate scientists, thinks Planktos's scheme to dump iron particles in the ocean to make plankton bloom and sequester carbon is "thin soup."
I have some extended quotes from David Archer on the subject below the fold. But if you are interested, read the whole thing.
In spite of public relations claims by Planktos representatives in comments, it appears that most of the scientific community does not think highly of the Planktos claims.
Marinov et al (2006) showed that a stimulation of phytoplankton production in one part of the ocean usually acts to depress production elsewhere. So what's the point of paying for a carbon offset to fertilize a water parcel now, when nature would fertilize it soon anyway? That's against the rules of offsets; it has to be something that wouldn't happen anyway.
The one part of the ocean where fertilization of the ocean does not depress the fertility elsewhere is the deep Southern Ocean. Here the water sinks to the abyss, rather than taking a leisurely tour through the upper ocean. But now the practical picture looks different. Instead of the benign tropics, you have sea ice, waters mixed to hundreds of meters down (bad for phytoplankton) and total darkness for much of the year. Fertilize that!
Modelers have long ago concluded that iron fertilization of the ocean can play only a small role in managing the carbon cycle in the coming century. Part of the issue is that the Southern Ocean also covers only a very small area of the surface ocean, just a few percent. Model experiments where the Southern Ocean is completely fertilized show a drawdown of maybe 15 ppm by the year 2100 [Zeebe and Archer, 2005]. We could change a light bulb and do better than that.
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But the change in carbon chemistry of the ocean and ultimately the atmosphere need to be transparently documented, also, if we are to trade carbon offsets based on iron fertilization. Documenting a change in carbon content of surface waters might be possible in the tropics, but it would be a nightmare in the Southern Ocean, probably impossible to do reliably. Ocean chemistry data is generally cleaner than land data, less susceptible to local variability. In tranquil, well-behaved parts of the ocean like near the Galapagos, it would be probably easier to document changes in the carbon content of the upper ocean than it would be on land. On the other hand, the ocean moves around a lot more than the land does, in general. The Southern Ocean, in particular, is a maelstrom. Tracking a plume of fertilized water to measure the change in carbon content would be a mite trickier.
Southern Ocean surface water also has a harder time changing the CO2 concentration of the atmosphere, because it gets mixed into the interior so quickly. Ultimately it would take centuries to bring the atmospheric CO2 to a new equilibrium value. You would have to wait until your fertilized water filled up the entire deep ocean. I think the long time scale also means that a ton of carbon removed from Antarctic surface waters does not translate to a ton of carbon removed on some reasonable timescale from the atmosphere. The efficiency is much lower than that, and difficult to document.
I would put ocean fertilization on the avoid list, along with planting trees. It's too hard to pin down the actual amount of CO2 removed from the atmosphere by your actions. It's also not a long-term solution, since the ocean leaks. Humankind would have to keep fertilizing the ocean indefinitely in order to preserve the claimed CO2 drawdown. If you're concerned about climate change, build a windmill. Ocean fertilization does not seem to me suitable to be the basis for a reliable financial commodity, or a practical tool for geo-engineering climate.
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Comments
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SteveK Posted 3:32 am
04 May 2007
However, there are some scientists who are ideologically or politically opposed to iron fertilization science, and have been working over time in the past 15 years to try to block any and all study of the subject. This was a topic that we did a long expose about last year...the attempts by some scientists to retard the progress of this science.
And yes, the nice folks at RealClimate.org are very negative. I'm sorry to see that, because that kind of negativity is exactly what the climate change community doesn't need, if it wants to convince the public that it's serious about encouraging innovation.
In reality, most qualified scientists who I've talked to agree that this is potentially scientifically important work. Thus my position still is:
Let Planktos do their study, but watch them carefully and ensure that the work is done in a scientifically valid, ecologically cautious, transparent way.
These are the standards that we apply to most if not all other ecological work, commercial or not, and these standards work well. There is no reason to do otherwise.
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GreyFlcn Posted 4:05 am
04 May 2007
That taking some carbon down, isn't equivalent to blocking carbon from going up.
Because while over a geologic timescale it works great, from a year to year timescale you run up against the 100 year timeframe that the carbon says up in the troposphere.
Haven't quite confirmed this yet, but it scares me that we could be doing something on a large scale which is merely encouraging higher atmospheric levels of carbon in the troposphere.
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Gar Lipow Posted 4:37 am
04 May 2007
17. Geo-engineering options, such as ocean fertilization to remove CO2 directly from the atmosphere, or blocking sunlight by bringing material into the upper atmosphere, remain largely speculative and unproven, and with the risk of unknown side-effects. Reliable cost estimates for these options have not been published (m
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SteveK Posted 10:21 am
04 May 2007
They say it's unproven. I agree.
They say it's speculative. Right again.
They say there are risks of unknown side effects. Yes of course. Anything new has risks. The goal of research is to uncover and understand those risks.
Where do they say they "don't approve?" I don't see that. What they say is that it's unproven. Which would imply that someone should do the research to prove or disprove it.
Which is exactly what Planktos proposes to do. More research, in this case, funded by carbon credits. A rather clever way to fund scientific work.
And yes, the majority of ocean scientists do support more research, once it is presented to them without the emotional and political baggage that so many people want to throw on it.
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TinaM Posted 9:50 pm
05 May 2007
Restoration ecology (and its companion science conservation biology) has a decades-long history of contributing improved environmental quality on land -- reclaiming wetlands to support biodiversity and water quality goals, expanding populations of rare or endangered species, returning watersheds to near-pristine conditions. The methods are based on applying key concepts that mirror ecosystem structure & function. I don't see any reason in principle that these same methods can't be applied in the ocean where Planktos will be working.
Should the ocean be a target for restoration? If you look into the issues you'll discover that declines of pelagic ocean water quality and biodiversity are of a global scale too. With implications for ocean ecosystems and commercial fisheries. The two issues are clearly related.
Loss of open ocean plankton is an alarming idea to confront. Whole regions of the world's oceans seem to be facing `desertification' because of changing land use patterns, shifting currents & winds. Returning nutrients like iron to small patches of the ocean -- and carefully measuring the results -- seems to be one way we can address the problem. Otherwise, what is our alternative?
It seems to me that preventing pollution by reducing emissions is only part of the answer. The curative approach, via sequestration and ecosystem restoration, where we remediate damage already done to ocean and atmosphere, has an equally important role to play.
Tina M.
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spaceshaper Posted 12:18 am
06 May 2007
The true meaning of life is to plant trees, under whose shade you do not expect to sit.
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