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Debate: Geoengineering, iron fertilization of algae blooms

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Should iron fertilization of algae blooms be part of plans to combat global warming?

Background and context

Iron fertilization is the intentional introduction of iron to the upper ocean to increase the marine food chain and to sequester carbon dioxide from the atmosphere. It involves encouraging the growth of marine phytoplankton blooms by physically distributing microscopic iron particles in otherwise nutrient-rich, but iron-deficient blue ocean waters. An increasing number of ocean labs, scientists and businesses are exploring it as a means to revive declining plankton populations, restore healthy levels of marine productivity and/or sequester millions of tons of CO2 to slow down global warming.
Since 1993, ten international research teams have completed relatively small-scale ocean trials demonstrating the effect. In the context of strategies to combat global warming, iron fertilization is considered a form of geoengineering and mitigation. That is, it attempts to sequester and reduce carbon dioxide directly from the atmosphere. Clean-energy approaches attempt to reduce new additions of carbon dioxide and other greenhouse gas emissions into the atmosphere, so are a form of prevention. There are many questions surrounding iron fertilization that help frame the debate: Does iron fertilization and growing phytoplankton blooms help sequester significant quantities of carbon dioxide? Is it significant enough to have an impact in reducing global greenhouse gases and slowing global warming? Is this approach necessary at this stage in global warming? Are alternative forms of prevention, such as clean-energy, insufficient? Are phytoplankton populations above or below their ordinary levels currently? Is global warming killing-off phytoplankton, and would this contribute in a "positive feedback loop" to an acceleration of global warming? If so, is this further justification for iron fertilization? Are there negative effects on ocean ecosystems? Does iron fertilization risk growing harmful "red tides", depleting deep water oxygen levels, and damaging fisheries? If so, are these potential costs worth trading for the benefits of combating global warming (an environmental threat in its own right)? How should the precautionary principle be applied to iron fertilization? What principles of environmental justice are involved in this debate? Finally, is iron fertilization economically feasible?

Contents

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Global warming: Can iron fertilization help significantly combat global warming?

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Yes

  • Iron fertilization can dramatically reduce C02, combat global warming John Martin, former director of the Moss Landing Marine Laboratory, said in 1988, "Give me half a tanker of iron, and I’ll give you an ice age". This famous statement has highlighted the power of iron fertilization in spawning massive algae blooms to draw large quantities of C02 from the atmosphere, in the process of photosynthesis, reducing the greenhouse gas effect and helping cool the planet.
  • Iron fertilization reverses global warming; other solutions only slow it. All the main solutions to global warming entail cutting greenhouse gas emissions from future energy production. Yet, this does not reduce the amount of C02 currently in the atmosphere, nor does it promise to end C02 emissions any time soon. And, yet, global warming is occurring now from the existing quantities of C02 in the atmosphere. In other words, all plans to cut future emissions will not help actually reverse the current trajectory of global warming. The only real solution is to attempt to directly remove greenhouse gases from the atmosphere. Iron fertilization and algae blooms offer this kind of real solution to global warming, actually helping reverse it.
  • Irreversible climate change makes geoengineering unavoidable. There is a good chance that global warming is irreversible. Global warming is already occurring and there are no plans to reduce greenhouse gases that are already in the atmosphere. Greenhouse gas levels will continue to rise, despite reductions in new emissions. Geoengineering, therefore, is the likely last resort.
  • Algae need only sequester C02 for roughly a century. While ocean science does traditionally define "sequestration" in terms of sea floor sediment that is isolated from the atmosphere for millions of years, modern climate scientists and Kyoto Protocol policy makers, however, define sequestration in much shorter time frames. They recognize trees and even grasslands, for instance, as important carbon sinks. Forest biomass only sequesters carbon for decades, but carbon that sinks below the marine thermocline (100~200 meters) is effectively removed from the atmosphere for hundreds or thousands of years, whether it is remineralized or not. Since deep ocean currents take so long to resurface, their carbon content is effectively "sequestered" by any terrestrial criterion in use today.
  • Trials finding low results from carbon sequestration were faulty The studies concluding that iron fertilization lead to low levels of carbon sequestration suffered from numerous flaws: Timing - none of the ocean trials had enough boat time to monitor their blooms for more than 27 days, while blooms generally last 60~90 days; Scale - most trials used less than 1000 kg of iron and thus created small blooms that were quickly devoured by opportunistic zooplankton, krill and fish; Academic conservatism - with limited data sets, scientists have not been willing to (understandably) extrapolate upon their findings.


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No

  • Algae blooms do not sequester much carbon "A scientific critique of oceanic iron fertilization as a climate change mitigation strategy". Greenpeace Research Laboratories. September 2007 - "With the scientific discovery that phytoplankton growth can be stimulated by the addition of iron to HNLC waters, some have proposed that the ‘biological pump’ could be enhanced by fertilizing the oceans with iron, as a way of drawing down more carbon dioxide from the atmosphere into the oceans and, in so doing, helping mitigate climate change. However, such proposals are founded on an incomplete understanding and highly simplified interpretation of current scientific knowledge. They have not taken properly into account the results of the 12 mesoscale iron enrichment scientific studies carried out to date which suggest that the amount of carbon sequestered in this way would be very small, nor the fundamental influence of hydrodynamics and large uncertainties and indeterminacies in ecosystem response which those studies highlight."
“You might make some of the ocean greener by iron enrichment, but you’re going to make a lot of the ocean bluer,” said Robert Anderson, senior scholar at Lamont-Doherty Earth Observatory."


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Economics/feasibility: Is iron fertilization economical/feasible?

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Yes

  • A global iron fertilization plan would cost only around $20 billion. Some ocean trials did indeed report remarkable results. According to IronEx II reports, their thousand kilogram iron contribution to the equatorial Pacific generated a carbonaceous biomass equivalent to one hundred full-grown redwoods within the first two weeks. Researchers on Wegener Institute's 2004 Eifex experiment recorded carbon dioxide to iron fixation ratios of nearly 300,000 to 1. Current estimates of the amount of iron required to restore all the lost plankton and sequester 3 gigatons/year of CO2 range widely, from approximately two hundred thousand tons/year to over 4 million tons/year. Even in the latter worst case scenario, this only represents about 16 supertanker loads of iron and a projected cost of less than €20 billion ($27 Billion). Considering EU penalties for Kyoto non-compliance will reach €100/ton CO2e ($135/ton CO2e) in 2010 and the annual value of the global carbon credit market is projected to exceed €1 trillion by 2012, even the most conservative estimate still portrays a very feasible and inexpensive strategy to offset half of all industrial emissions.



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No


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Ocean ecosystems: Does iron fertilization preserve ocean ecosystems?

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Yes

  • Global warming benefits of algae blooms outweigh ecosystem costs. Iron fertilization main be a central solution to the greatest modern environmental crisis; global warming. While it may cause some other problems in ocean ecosystems, these problems are outweighed by the environmental priority of combating global warming.
  • Algae blooms last for a short time; no long-term damage. Algae blooms last between 90 and 120 days. They never take root in an ocean ecosystem, so cannot permanently and dramatically alter or harm an ecosystem.
  • Growing algae blooms can help feed and revive fisheries. Algae are food for fish such as krill, which are food for larger fish, which are food for even larger fish. In this way, algae blooms can help feed and grow fisheries and cetacean populations. This is a compelling human interests, given the extent to which fisheries have been depleted in the last century.


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No

  • Iron-fertilization favors some phytoplankton, destabilizing ecosystems Depending upon the composition and timing of delivery, iron infusions could preferentially favor certain species and alter surface ecosystems to unknown effect. Population explosions of jellyfish, disturbance of the food chain with a huge impact on whale populations or fisheries are cited as potential dangers.


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Restoring phytoplankton? Is phytoplankton needing restoration?

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Yes

  • Iron fertilization would revive depleted phytoplankton populations. Iron fertilization would help to reverse what some believe to be a decline in phytoplankton. One study (Gregg and Conkright, 2002) reported a decline in ocean phytoplankton productivity between the period 1979–1986 and 1997–2000. If phytoplankton populations are down by natural standards, there should be not environmental argument against helping these populations rebuild. And, it could be argued that the decline of these phytoplankton are partly responsible for global warming, since it would reduce the capture of C02 in the process of photosynthesis.
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No

  • Phytoplankton populations have increased; no need for iron fertilization. One study (Antoine et al., 2005) found a 22% increase of phytoplankton populations between 1979–1986 and 1998–2002. Gregg et al. 2005 also reported a recent increase in phytoplankton. If phytoplankton are actually up compared to natural averages, it cannot be argued that iron fertilization can help re-stabilize the natural size of phytoplankton populations. In fact, iron fertilization would only accentuate the problem of currently over-sized phytoplankton populations.


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Red tides: Does iron fertilization risk stimulating harmful red tides?

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Yes

  • Deep sea iron fertilization would not grow coastal red tides. Red tides and other harmful algal blooms are largely coastal phenomena and primarily affect creatures that eat contaminated coastal shellfish. Iron stimulated plankton blooms only work in the deep oceans where iron deficiency is the problem. Most coastal waters are replete with iron and adding more has no effect. Since all phytoplankton blooms last only 90~120 days at most, in the open ocean fertilized patches of any species will dissipate long before reaching any land.
  • Most algae is harmless and understood; red tides can be avoided. Most algae is harmless. All the major types of algae, harmful and innocuous, are well understood. This makes it fairly easy to avoid fertilizing harmful algae and growing red tides.


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No

  • Some plankton species cause red tides and other toxic phenomena. How do we know what kind of plankton will bloom in these events? What will prevent toxic species from poisoning lagoons, tide pools and other sensitive ecosystems along our coasts? Highly increased and intensified Red Tide Blooms have been wreaking havoc on the west coast of Florida for the last ten years. The argument that red tide blooms cause no harm is ridiculous. Once the chain of a HAB gets started, no one knows how to end it. The Red Tide Bloom in Maine over the last three years is testament to this. Even though the water is too cold to be very favorable to red tide (K. Brevis), these Red Tide Blooms have flourished. When even harmless species of plankton die they decompose and this brings about a very bad situation like the giant and growing dead zone in the Gulf of Mexico.[


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Deep water oxygen depletion: Is this a consequence of algae blooms?

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Yes

  • Deep water dieoffs have not been reported after natural algae blooms. The largest plankton replenishment projects now being proposed are less than 10% the size of most natural wind-fed blooms. In the wake of major dust storms, many extremely vast natural blooms have been studied since the beginning of the 20th century and no such deep water dieoffs have ever been reported.


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No

  • Sinking organic blooms can render the deep sea anoxic. When organic bloom detritus sinks into the abyss, a significant fraction will be devoured by bacteria, other microorganisms and deep sea animals which also consume oxygen. A large bloom could, therefore, render certain regions of the sea deep beneath it anoxic and threaten other benthic species.


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Environmental justice: Does iron fertilization uphold environmental justice?

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Yes

  • If natural iron fertilization occurs, it is OK for humans to do it Nature has caused massive-scale iron fertilizations in the past. One example is sand storms in northern Africa blowing iron into the Atlantic and spurring algae blooms. If this occurs naturally, is it really wrong for humans to intentionally stimulate the process? No.
  • Avoiding iron fertilization is greatest environmental injustice. It is important to recognize that global warming is the greatest environmental crisis in modern times. It is necessary, therefore, to prioritize solutions to this crisis, and to weigh the benefits of solving the crisis over any other incidental environmental costs.


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No

  • Tampering with the environment to solve global warming is wrong. Humans have for too long tampered with the environment. We have felt at liberty to burn fossil fuels and release millions of tonnes of carbon into the atmosphere. Now, we should not again tamper with the environment as a means of solving an environmental crisis that we created: global warming.


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Precautionary principle: Is iron fertilization consistent with this principle?

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Yes

  • Precautionary principle favors solving global warming. Global warming is the principle risk facing planet Earth, ecosystems around the world, as well as human civilization. The greatest risk in modern times, therefore, is not being able to find a solution to global warming. While there are some risks involved with iron fertilization, the greater risk is not pursuing it, when we know there is a very good chance that it will make a major contribution to combating global warming. The precautionary principle would have us error on the side of precaution toward global warming, and pursuing all logical strategies toward solving the crisis.


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No

  • Iron fertilization is unproven, violating precautionary principle. We do not know the possible side-effects of large-scale iron fertilization. Not enough research has been done. We should not risk iron fertilization on the scale needed to affect global CO2 levels or animal populations. Creating blooms in naturally iron-poor areas of the ocean is like watering the desert: you are completely changing one type of ecosystem into another.


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Pro/con sources

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Yes


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No


See also

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