Ironing the Oceans
A New Hope for Climate Change or Reckless Tampering with the Sea?
Amidst gusting winds and across vast expanses of the stormy Southern Ocean, ships carrying teams of scientists and engineers are preparing to release hundreds of tons of iron dust into the sea in an effort to save the planet.
Could this be the start of the next Armageddon sci-fi flick, or a clever, realistic and economically lucrative solution to managing climate change? Due to the scarcity of scientific data about the long-term effects and effectiveness of the method, a debate rages among environmentalists, scientists, and private companies about whether dumping iron into international waters would mitigate climate change or cause irreparable damage to the earth’s ecosystem.
This activity, called Ocean Iron Fertilization (OIF), has become increasingly associated with geo-engineering. This emerging and controversial field aims to manipulate our planet’s natural processes in an effort to reduce the concentration of carbon dioxide in the atmosphere, known to be a cause of climate change. To succeed, schemes such as OIF must change the earth’s chemistry and ecology, and so may have unforeseen, or even disastrous, consequences.
OIF would make use of phytoplankton, the microorganisms which form the foundation of the marine food web. These organisms carry out photosynthesis, drawing CO2 out of the atmosphere. When they die and sink to deeper water, the carbon they have absorbed enters long-term storage, potentially lasting for decades to centuries. Because a lack of iron may limit phytoplankton growth in certain otherwise nutrient-rich regions, the idea behind iron fertilization is that increasing the iron concentration in these places would boost phytoplankton growth and thus remove carbon dioxide from the atmosphere.
The Iron Hypothesis
Oceanographer John Martin first described this idea, dubbed the ’iron hypothesis‘, in a 1990 article in the journal Paleoceanography. Since then, research groups around the world have completed 13 fertilization experiments, monitoring the effects of adding hundreds to thousands of kilograms of iron sulphate, an industrial by-product that is soluble in seawater. The fertilized patches ranged in size from 40 to 300 square kilometres.
The results validated the first part of Martin’s hypothesis. Increasing the iron concentration in the targeted areas created phytoplankton blooms that were visible by satellite, confirming that a lack of iron had previously limited plankton growth. Evaluating the second part of the hypothesis – that an increase in phytoplankton population would help transfer CO2 from the atmosphere to long-term storage – is more difficult. Results varied considerably, depending on geographic and biological factors. For instance, other organisms eat many of the phytoplankton in a bloom before they sink, which means that much of the carbon absorbed by the phytoplankton is quickly recycled back into the atmosphere. As past experiments did not focus on the fate of the phytoplankton bloom, it has been difficult to estimate how much of the carbon reaches the depths necessary for more secure storage.
To better estimate how much carbon the OIF process actually removes from the atmosphere, researchers from India and Germany recently designed an experiment to observe what happens when the bloom sinks. It was named LOHAFEX (LOHA is Hindi for iron, FEX stands for Fertilization EXperiment). The group spread 6 tons of iron dust across 300 square kilometres in the Southern Ocean and then monitored the area for 45 days. The results were disappointing. The iron-induced bloom, made up of a variety of phytoplankton species, was low in diatoms, the phytoplankton that are best for storing carbon as these organisms sink quickly when they die. As a result, relatively little carbon reached the depths necessary for long-term storage.
OIF Makes Waves
LOHAFEX made headlines for another reason. Just before the expedition set out in January 2009, protests erupted on the grounds that the experiment violated a United Nations convention prohibiting dumping in international waters. This caused the German government to detain the research team. Only after a two week delay were the scientists allowed to proceed, based on a clause permitting OIF for scientific research purposes. The incident left in its wake frustrated scientists, politicians, and environmentalists.
The controversy surrounding LOHAFEX stemmed from two general concerns about OIF. The first concern is that at present, there are insufficient data demonstrating that it is an effective, practical way to prevent climate change. In a 2008 article in Science, co-authored by 16 iron fertilization researchers, American oceanographer Ken Buesseler explains, “Although [our] experiments greatly improved our understanding of the role of iron in regulating ocean ecosystems and carbon dynamics, they were not designed to characterize OIF as a carbon mitigation strategy.”
The private sector was
quick to recognize that it could
potentially earn profits by
selling carbon credits in
exchange for carrying out OIF
In fact, modelling evidence suggests OIF is not an effective strategy. Computer models can pick up where the small-scale experiments leave off; the models use data collected to estimate what would happen if OIF were implemented on a much larger scale. Several such studies have been published in the last decade, all reaching similar conclusions. For instance, a 2008 model predicts that at most, OIF could reduce atmospheric carbon by about 1 Gt (109 tonnes) per year, about 11% of global anthropogenic emissions in 2004. However, this estimation rested on an unrealistic assumption of continuous fertilization over all iron-limited regions worldwide to find the upper limit of OIF’s potential.
The second concern is even more troubling: supposing OIF were found to be effective for carbon capture, what other effects would it have? The marine ecosystem is a complex network of chemical, physical, and biological processes. Disturbing this fragile equilibrium would undoubtedly have unpredictable consequences beyond the intended outcome of transferring carbon dioxide from the atmosphere to the ocean. Potential side effects include disrupting the ecosystem from minute bacteria to whales, reducing the water’s pH and dissolved oxygen levels and increasing levels of other greenhouse gases.
Spend a Buck, Save a Planet?
To further complicate the issue, the private sector was quick to recognize that it could potentially earn profits by selling carbon credits in exchange for carrying out OIF. Even though the Kyoto protocol does not currently recognize these types of credits, iron fertilization companies have formed. The only surviving company today is the four-year-old, San Francisco-based Climos run by a Silicon Valley entrepreneur. Although it has not yet begun any fertilization, the company has big plans. The largest experiment done to date covered 300 square kilometres, but Climos’ proposed experiment would cover a 40,000 square kilometre patch in the Southern Ocean. These persistent commercial interests have been driving the need to regulate iron fertilization.
So Is It Legal?
Although existing regulations could apply to OIF, the LOHAFEX confusion highlighted their ambiguity. OIF falls within the purview of a few different UN conventions. As of a few years ago, none of those addressed OIF directly, but additional legislation is in the works.
The Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter traditionally applies to waste dumping, but its groups have raised concerns about large-scale OIF. They banned any OIF activities other than “legitimate scientific research” and have begun work assessing OIF risks and outlining future regulation. The UN Convention on the Law of the Seas governs general conduct on the high seas. Its general assembly has not passed any specific resolutions on OIF, but did support calls for further OIF research and bans on large-scale OIF.
Our desire to save the
planet is proving
weaker than our
reluctance to make
the changes necessary
The UN Convention on Biological Diversity, cited by LOHAFEX protestors, has become known as the “UN moratorium” on commercial OIF. It bans large-scale fertilization and applies to OIF insofar as large-scale fertilization could impact the marine food web. Regulation remains incomplete, but the wheels of policy-making have been set in motion. Through OIF’s rapid evolution from a purely scientific pursuit to an attractive, prospective quick fix for climate change, it has become clear that specific legislation is required.
The Bottom Line
As the reality of climate change sets in, we face the dilemma that our desire to save the planet is proving weaker than our reluctance to make the changes necessary for reducing our energy consumption and greenhouse gas emissions. In light of this, geo-engineering proposals offering a way to combat climate change without changing our behaviour have an irresistible appeal.
Scientists on the whole agree that meddling with the planet’s complex ecosystems should be avoided when we cannot predict the outcomes of our actions, but are divided on whether or not to pursue further research into OIF as a geo-engineering option. Many worry that as carbon levels continue to rise, so will our willingness to try risky mitigation strategies. Those in favour of continuing research feel that the better we understand the effects of OIF, the better prepared we will be for pressure to implement it on a large scale. Those against argue that enough research has been done to demonstrate that OIF is risky for marine ecosystems and ineffective for climate change mitigation, and thus it should be abandoned as a geo-engineering solution. Still others, such as experts in international economics and law, feel that OIF does have significant potential and abandoning it now would be premature.
We cannot definitively resolve the controversy and quantify the impact of large-scale OIF without actually carrying out large-scale OIF experiments; instead we must use the evidence available to us to predict whether the benefits of trying such a manipulation of the environment outweigh the risks. Legislation must reflect the available evidence so that the lure of profit and the urge to find a quick fix for climate change cannot overshadow the facts about its side effects and potential for success.
A version of this article originally appeared in EUSci, the Edinburgh University Science Magazine, Issue 5, January 2010.
Catherine Lichten is a doctoral student in systems biology currently based in Edinburgh. She has been following news about ocean iron fertilization since 2004, when she first heard about it as an intern at Woods Hole Oceanographic Institution in the United States.