Base of the food chain: Antarctic phytoplankton. Credit: RICHARD CRAWFORD, ALFRED-WEGENER-INSTITUT

When a marine research project is put on hold by the lead country's science ministry, after the research vessel has already set sail, it is clear that communication between scientists, the public and politicians has gone seriously wrong. The suspension of the Indo–German iron fertilization experiment LOHAFEX in January this year is a case in point.

LOHAFEX (taken from loha, the Hindi word for iron, and FEX, which stands for fertilization experiment) aims to study the biogeochemical effects of iron fertilization in the South Atlantic Ocean. Just when the research vessel was about to leave the port, environmental groups protested against the experiment, arguing that the experiment breached a May 2008 decision agreed on by the parties of the United Nations convention on biodiversity. The decision restricts iron fertilization to small-scale, scientific research studies within coastal waters. The protests resulted in a two-week suspension of the experiment, and left 48 scientists onboard the research vessel Polarstern wondering if they were sailing across the South Atlantic in vain.

By early February, the research was back on track. The scientists had made good use of the delay — identifying a suitable target eddy in the region. The team required a stable eddy that contained plenty of nutrients, but was low in productivity. This would allow the iron addition to have a significant effect and provide a fairly closed experimental system. So, when approval of the experiment came through the iron was injected promptly, and has since stimulated the expected plankton bloom. The fate of carbon in this system is now being monitored as planned.

However, the controversy leaves the scientists bruised, the environmental groups wondering whether the UN's moratorium on iron fertilization will prevent premature geoengineering, and the German Federal Environment Ministry — whose support of the environmental protesters was instrumental in achieving the experiment's suspension — unsatisfied.

The rationale of the UN moratorium on ocean iron fertilization was to stop the commercial companies who were getting ready to make money by adding large amounts of iron to suitable regions of the ocean and selling carbon credits in return (Science 318, 1368–1370; 2007). The UN convention on biodiversity decided that the world is not yet ready for widespread fertilization efforts, certainly not on an industrial-type scale: neither the capacity for carbon capture nor the potential adverse effects are sufficiently understood (see Nature Geosci. 1, 722–724; 2008) — an assessment most scientists would agree with.

The January controversy has raged over the definitions of the terms of exemption for scientific studies — 'small-scale' and 'coastal waters' — which were not clarified in the text of the decision. Whether fertilization of an ocean eddy with a surface area of around 300 km2, as planned in the LOHAFEX experiment, can be classified as small-scale is not straightforward, and a location hundreds of kilometres from the nearest land mass is not obviously within coastal waters.

These definitions must be seen in context. If the Southern Ocean were a garden, the fertilized eddy would be the size of a daisy, as pointed out by Karin Lochte — director of the Alfred-Wegener Institute for Polar Research under whose flag the Polarstern is sailing — in an online newspaper report (,1518,602984,00.html). The project scientists argue that the water in their study region is considerably influenced from land, by atmospheric deposits as well as some constituents from the water, and can therefore be considered coastal.

Whatever the answer, the row over definitions is missing the point. At least the restriction to coastal waters in the UN moratorium seems arbitrary. The London Convention and Protocol, a legal body within the framework of the international Law of the Sea, which regulates dumping and marine pollution, does not refer to the terms 'small-scale' and 'coastal waters' in its October 2008 resolution on ocean fertilization. Instead, it distinguishes between “legitimate scientific research”, which is permitted, and “other activities”. As a result of both the chronology and the fact that the international Law of the Sea takes legal priority over the UN convention on biodiversity, this emphasis on legitimate science seems more relevant.

The term 'legitimate', too, will need further definition. Indeed, a working group of the London Convention met in February with the aim of drafting more detailed regulations that will make it easier to assess whether expeditions are scientifically legitimate. However, there is little doubt that LOHAFEX passes this criterion.

Given this situation, the question arises as to why the research was held up in the first place. A press release issued by the German Federal Environmental Ministry to express its regret when the experiment was approved gives a clue. It states that in its own view “attempting to halt climate change by interfering with our marine ecosystems is a disastrous approach. This scientifically unsound thinking has been a direct cause of the climate crisis and is in no way suited to solving the problem.” If this is the reason for condemning LOHAFEX, then the statement seems to imply that ocean fertilization (and, by extrapolation, other options of geoengineering) must not be investigated at all.

But closing our eyes will not make global warming go away. In case climate change continues we should at least rule out scientifically, as early as we can, geoengineering proposals that do not work — so that future generations do not go down disastrous routes because there is no more time for detailed studies.