Fertile ground for exploitation

Adding iron to the seabed to generate the growth of microscopic plants is the latest solution to dealing with CO2. But is it safe?
Chris Baker
The Guardian,
Wednesday July 9, 2008

"Give me half a tanker of iron, and I will give you an ice age." The late American oceanographer John Martin's inflammatory comment - alluding to geological records that suggest there were high levels of iron in the ocean during the glaciations - was never likely to win prizes for making friends and influencing people.
Martin's "iron hypotheses", put forward in early 1990s, suggested seeding plankton-low areas of ocean in order to hotwire the so-called biological pump - a naturally occurring phenomenon that sequesters CO2 on the seabed.
His ocean fertilisation theory has never had an easy ride. Some researchers argue that it is an inefficient way of capturing and storing CO2; others say the technology could have disastrous consequences, such as damaging ecosystems, inadvertently releasing more potent greenhouse gasses such as methane, or stimulating the growth of toxic algae.
Scientists around the world began to test the idea, adding nutrients, usually iron, to the sea and watching what happened next. But it was not until fairly recently, when commercial companies began taking an interest in exploiting Martin's idea in order to make money from the carbon market, that the antennae of scientists and environment groups really began to twitch.
Carbon credits
Jim Thomas, researcher and writer at the Ottawa-based technology watchdog ETC Group, says: "It is the cheapest way of making carbon credits. Whether you mess up the oceans in the process does not matter to them as long as they can make money out of it."
The concerns recently prompted the UN's convention on biological diversity (CBD) to agree a moratorium on commercial ocean fertilisation, and on all but small-scale, scientifically controlled tests in coastal waters, at least until the technology is properly understood - already dubbed the first global attempt to police geo-engineering.
"Basically, it means nations around the world have agreed they are not going to permit large-scale ocean fertilisation to go ahead," Thomas says. "The work-round is to do small-scale, strictly scientific - not commercial - tests that are not for using or generating carbon credits."
The biological pump itself is quite elegant. Phytoplankton (microscopic marine plants) at or near the ocean's surface convert CO2 into organic matter and oxygen, and when they die carry small amounts carbon to the seabed, where it is stored in sediments for millions of years.
There is a physical pump too, where CO2 dissolves in the ocean at high latitudes, is carried to depth by sinking currents, and stays there for hundreds of years before returning to the surface. Exploiting the latter by piping liquid CO2 direct to the deep ocean has also been proposed, a different technology to ocean fertilisation but which has provoked many similar concerns.
Victor Smetacek, professor of biological oceanography at the Alfred Wegener Institute in Germany, was chief scientist on the European iron fertilisation experiment - the most recent and most thorough of about a dozen major ocean fertilisation tests. Three tonnes of iron sulphate - made from powder you can buy at garden centres to treat lawns - was poured from the research vessel Polarstern into a 150 sq km eddy in the southern ocean.
A bloom of phytoplankton occurred almost immediately, as expected. What surprised the scientists was the discovery four weeks later of a vast amount of dead and dying matter from their manmade bloom, sinking extraordinarily quickly. It was something nobody had properly witnessed before, and, as Smetacek says, "one of nature's mechanisms to regulate CO2 in the atmosphere, and ultimately global climate". The results are so far unpublished but, according to Smetacek, a "significant amount" of carbon sank with the dying bloom.
He says: "There is no question our bloom behaved the way blooms are supposed to behave, they build up and then they sink. We found it sinking down the water column, and all the previous experiments did not find that. I am of the opinion that you cannot afford not to do it, iron fertilisation. On the other hand, the outstanding question is who is going to do it? Is somebody going to make a profit out of it? I think this is too important to be left to the mercy of the profit-makers."
In about a third of the oceans - the so-called paradoxical zones - the growth of phytoplankton is limited by lack of iron, a nutrient essential for life. Adding iron to a quarter of the world's seas, in areas where amounts of the mineral are low, would, according to ocean fertilisation's proponents, remove about 1bn tonnes of CO2 a year from the atmosphere - roughly 15% of what accumulates annually because of human activity.
"If you get it wrong on that scale, things could be a bit serious," says Chris Vivian, chair of the Scientific Group of the London Convention, which regulates dumping waste at sea and has issued its own "statement of concern" about ocean fertilisation. "If we wanted to have an impact, we would probably have to do something on that scale. And if it worked, we would have to do this continuously, year after year after year. It is a continuous activity, which is another concern."
Gung-ho fertilisation
The moratorium is not a legal instrument and cannot be enforced, although countries usually respect CBD decisions. Southern countries, whose seas have been the target for commercial trials, were the most vocal in favour of a moratorium, supported by European nations. Worryingly for some, the US, home to the most gung-ho commercial ocean fertilisation companies, is not a signatory to the convention.
According to Dr Margaret Leinen, the chief science of Climos - whose aim is to use sea power to fight climate change - the CBD requested that governments exercise the precautionary principle and ensure further tests are adequately controlled, rather than specify an outright suspension. "They did not impose a moratorium, they identified conditions that they thought should be met," she says. "We have no disagreements with this call for scientific justification, an analysis of risk, and regulatory control."
Small-scale is expected to be defined at about the size of those experiments already carried out: 100-200 sq km. San Francisco-based Climos, the leading commercial ocean fertilisation company, has proposed testing an area of 40,000 sq km. Already, some scientific organisations have criticised the prohibition of large-scale trials, arguing it puts too strict a restriction on research.
David Santillo, senior scientist at Greenpeace International's research laboratory in Exeter, says: "It would be like doing an experiment in a laboratory with no ceiling, no walls and no floor. If something goes wrong, there is very little they could do, even if they could discover something had gone wrong in the first place.
"What they have come up with in terms of the moratorium is quite reasonable.What they have said is that there should be no pursuit of this, except small-scale experiments . . . which stops some of the more aggressive commercial exploitation of this and lets some experiments proceed.
If Martin were still alive, he would probably retract his incendiary comment about an ice age. Many would not. For the latter, the moratorium on ocean fertilisation is an important first step towards trying to control geo-engineered, sometimes science fiction-like, attempts to solve the climate crisis.