Yet Another Geoengineering Scheme, Ocean Iron Fertilization, Could Backfire

Can we save the planet by ruining it (even more)? Argonne National Laboratory reports that “A new study on the feeding habits of ocean microbes calls into question the potential use of algal blooms to trap carbon dioxide and offset rising global levels.”

Four years ago, the journal Nature published a piece arguing that “fertilizing the oceans with iron to stimulate phytoplankton blooms, absorb carbon dioxide from the atmosphere and export carbon to the deep sea — should be abandoned.”

Now Argonne Lab reports so-called iron fertilization “may have only a short-lived environmental benefit. And, the process may actually reduce over the long-term how much CO2 the ocean can trap.”

The more you know about geo-engineering, the less sense it makes (see Science: “Optimism about a geoengineered ‘easy way out’ should be tempered by examination of currently observed climate changes”). The most “plausible” approach, massive aerosol injection, has potentially catastrophic impacts of its own and can’t possibly substitute for the most aggressive mitigation — see here. And for the deniers, geo-engineering is mostly just a ploy — see British coal industry flack pushes geo-engineering “ploy” to give politicians “viable reason to do nothing” about global warming.

Geoengineering is a problem in search of a problem. As the NY Times reported in 2011:

At the influential blog Climate Progress, Joe Romm, a fellow at the Center for American Progress, has made a similar point, likening geo-engineering to a dangerous course of chemotherapy and radiation to treat a condition curable through diet and exercise — or, in this case, emissions reduction.

You can find my previous writings on geo-engineering here. See in particular Martin Bunzl on “the definitive killer objection to geoengineering as even a temporary fix.”

Geo-engineering is a “smoke and mirrors solution,” though most people understand that the “mirrors” strategy is prohibitively expensive and impractical. One of the few remaining non-aerosol strategies still taken seriously by some is ocean fertilization. But it is no better than the rest

As the 2009 Nature piece explained:

The intended effect of ocean iron fertilization for geoengineering is to significantly disrupt marine ecosystems. The explicit goal is to stimulate blooms of relatively large phytoplankton that are usually not abundant, because carbon produced by such species is more likely to sink eventually to the deep ocean. This shift at the base of the food web would propagate throughout the ocean ecosystem in unpredictable ways. Moreover, nutrients such as nitrogen and phosphorus would sink along with the carbon, altering biogeochemical and ecological relationships throughout the system. Some models predict that ocean fertilization on a global scale would result in large regions of the ocean being starved of oxygen, dramatically affecting marine organisms from microbes to fish. Ecological disruption is the very mechanism by which iron fertilization would sequester carbon.

Argonne’s study finds another problem — ocean iron fertilization may have no positive climate impact and might even make things worse:

These blooms contain iron-eating microscopic phytoplankton that absorb C02 from the air through the process of photosynthesis and provide nutrients for marine life. But one type of phytoplankton, a diatom, is using more iron that it needs for photosynthesis and storing the extra in its silica skeletons and shells, according to an X-ray analysis of phytoplankton conducted at the U.S. Department of Energy’s Argonne National Laboratory. This reduces the amount of iron left over to support the carbon-eating plankton….

Rather than feed the growth of extra plankton, triggering algal blooms, the iron fertilization may instead stimulate the gluttonous diatoms to take up even more iron to build larger shells. When the shells get large enough, they sink to the ocean floor, sequestering the iron and starving off the diatom’s plankton peers.

Over time, this reduction in the amount of iron in surface waters could trigger the growth of microbial populations that require less iron for nutrients, reducing the amount of phytoplankton blooms available to take in CO2 and to feed marine life.

If only there were a way to prevent catastrophic global warming that didn’t risk making things worse ….

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20 Responses to Yet Another Geoengineering Scheme, Ocean Iron Fertilization, Could Backfire

  1. Mike Roddy says:

    Joe, thanks for your continuing efforts to educate the public, and bring us up to date on critical issues such as this one.

    Geoengineering has always consisted of harebrained ideas such as iron fertilization, and has mostly functioned as a way for the fossil fuel and banking crowd to be allowed to continue to pile up cash. Little do they realize that when the full horror of their actions become apparent, cash won’t help them.

  2. BillD says:

    Diatoms are an important part of oceanic phytoplankton and would be a key to getting organic matter into deeper waters before it is decomposed back to CO2. My understanding of the earlier papers on this topic is that too much of the organic matter would be decomposed before sinking to make much difference. Also, keeping iron in solution and the scale of continuous and widespread additions that would be needed was deemed unfeasible. The oceanographers that I know and have heard speak have long ago given up on this means of reducing atmospheric carbon.

  3. aweb says:

    I agree that in general trying to trick the biosphere into regulating our CO2 isn’t likely to end well.

    Is large-scale solar shading from space not a possibility? Sure, rockets aren’t great, but a huge solar shade in orbit, reflecting sunlight away…why not? Obviously synchronos orbits are out, but if it zipped around like the space station….

  4. Mark E says:

    As told to me in the 1980s in Glacier National Park, Montana…..

    In 1914 people wanted to catch “better” fish, so they introduced Kokanee Salmon to Flathead Lake (south of the park).

    When the spawning runs began, bald eagles for miles around changed their migratory patters to gather at the park and feast on fish.

    But people wanted to catch even bigger better fish, so they later introduced a freshwater shrimp to Flathead Lake. The idea was that the shrimp would eat up the tiny critters the salmon were eating, and then the salmon could eat the shrimp, thus getting a much larger meal for the same energy output. This had had great results elsewhere, so why not?


    It seems that shrimp and salmon feed at different times of day, and in this particular lake, the shrimp were able to sink into very deep water to hide, before the salmon would come out to eat.

    When the salmon did get hungry what did they find?

    No shrimp, and none of the original little critters either, since the shrimp had eaten them all.

    The salmon run collapsed, and until the eagles figured things out there was hunger and chaos in the eagle migration.


    Someday we’ll get very good at shaming profiteers who show cavalier attitudes towards unknown risks, and all will see projects of this sort as immoral hubris against creation.

  5. Joan Savage says:

    The iron-sprinkling notion reminds me of the 19th century belief that wearing garlic around one’s neck would ward off tuberculosis.
    Because TB takes time to become fully symptomatic, the garlic wearers refused to believe they were making a mistake until it was too late. That surely sounds like the current inadequate measures to reduce symptomatic climate change.

    The iron sprinkling and the garlic are also somewhat similar in terms of dose and effect.
    Garlic extract can kill Mycobacterium tuberculosum, at least in a Petri dish, but it’s not proven that eating a huge amount constantly is possible at therapeutic doses. Similarly, the iron sprinkling has the now-identified bad side effects and is not possible at a therapeutic dose.

    To wrap the analogy, TB levels go down when preconditions for communicability are reduced. Even today with cures available, prevention is a better epidemiological approach than trying to treat millions of cases.
    Same goes for climate impacts.

    Being hopelessly addicted to puns, I must say that it felt good to get that off my chest.

  6. rollin says:

    The best and most sensible geo-engineering solutions involves farms and ranches. Growing and building sustainable grasslands, making permanent pastures so hay growing can be reduced, they seem to be viable carbon sinks and can be done over vast areas while still producing food.

    The rest of the geo-engineering schemes should be dumped in the circular file.

  7. Doug Bostrom says:

    The assault on science and law going on in Canada is in the thrall of an updated, 21st-century version of the smelly corruption that is nearly always found in conjunction with petroleum. Too much money testing too many weak characters. In this case the weak characters have a thicker-than-usual veneer of social comportment so we see better cosmetics on the the corruption. Still, the skin lies only so deep over greed. How long will it be until rot really sets in, leaving Canada as the new Nigeria of North America?

  8. Merrelyn Emery says:

    That could be an episode out of the history of Australia since the British invasion, just one stupid example after another. Probably why all my instincts are against geoengineering, ME

  9. Mulga Mumblebrain says:

    Why not raise the albedo back on earth, by painting every sky-facing surface white, and reflecting solar radiation back into space? An army of Tom Sawyers, young and old, could do a good job of it, I’m sure, but we’d better not have the children on rooftops, I suppose.

  10. Mulga Mumblebrain says:

    The introduction of Nile Perch to Lake Victoria by some far-sighted hominid ‘entrepreneur’ was another such triumph.

  11. Brian Smith says:

    White roofs are not a global warming silver bullet, study finds.

    Can White Roofs Fight Global Warming?

    White Roofs May Not Be Good for Climate, May Increase Global Warming (Shocker!)

    “ research has flipped this white roofs solution into a potential global warming problem (showing that even the simplest geoengineering solutions may have side-effects we didn’t think up from the start). The study, led by Mark Z. Jacobson, a professor of civil and environmental engineering at Stanford University, found:

    Jacobson’s computer modeling concluded that white roofs did indeed cool urban surfaces. However, they caused a net global warming, largely because they reduced cloudiness slightly by increasing the stability of the air, thereby reducing the vertical transport of moisture and energy to clouds. In Jacobson’s modeling, the reduction in cloudiness allowed more sunlight to reach the surface.

    The increased sunlight reflected back into the atmosphere by white roofs in turn increased absorption of light by dark pollutants such as black carbon, which further increased heating of the atmosphere.”

    Stephen Chu touted white roofs in 2009. My mother’s house got a white, rubber roof (Saint Paul, MN) in 2010 and it was shortly half as white with mold, soot etc. We don’t know how well reduced summer cooling factored (reduced nat. gas emissions). Lots of companies are specializing in the fad. I am looking into costs, materials footprints & effectiveness of painting parking lots & streets in my town. But it looks like the advantages are slim.

  12. AlexR says:

    And it may be that even less will be sequestered long term as the oceans warm. I don’t know how much follow-up study was done on this from 2002:

  13. Rabid Doomsayer says:

    But we love our black roofs. In a stinking hot climate.

  14. Mulga Mumblebrain says:

    Well that is disappointing. We are well and truly snookered. If albedo restoration is out, then it has to be sequestration of carbon, I suspect, which means lots of trees, biochar and soil sequestration, I suppose. The acidification of cold waters will shortly cut off the sequestration of carbon by marine plankton, too, I assume, as well as starving the whales.

  15. Adam Sacks says:

    As Rollin says, Joe. How about some discussion of the massive carbon sequestration possible in soils through grassland eco-restoration using non-tech methods developed by nature over millions of years? Isn’t it time to acknowledge that emissions reductions have been a failure to date and it’s urgent that we do something else?

    Perhaps it’s not to be summarily dismissed, as you have in the past. I’ll write a well-documented post for CP, let’s at least have an open debate about Holistic Management and the work of Allan Savory.

  16. Joe Romm says:

    We haven’t tried “emissions reduction” yet. And given how controversial Savory’s work is — see here — I seriously doubt we are going to be making that our top strategy anytime soon. If it can be proven to work as well as mitigation, then it probably will have a modest role at some point.

  17. max says:

    Emission reduction is certainly the best strategy but wonder if you could comment on this:

  18. Mark E says:

    In the post apocalyptic novel I’m never going to write, some sea side survivors on some isthmus will start spiking drift logs with iron, in a generations long bid to do what they can. As the story progresses, the original science will be lost, but the iron fertilization will endure, as a ritual enshrined in their descendants’ religion.

    If that’s absurd, it’s no more so than the real story.

  19. bcherry says:

    While testing the feasibility for geoengineering technologies likely will and should continue. If in the case where a viable technology is found, there is the much bigger problem of understanding its wider implications for policy as it is experimentingv on a planetary scale: