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Much to learn about ocean fertilisation

06 Feb 2012


The oceans store a huge amount of carbon compared with the Earth’s atmosphere.  This fact has led some scientists and institutions to ask the question of whether human intervention might be used to cause an increase in oceanic uptake of atmospheric carbon whereby a small relative increase in carbon stored in the oceans would have a significant impact on CO2 concentrations in the atmosphere. Following the recent Ocean Fertilisation seminar, Nigel Moore from the Oxford Geoengineering Programme explains.

One ocean fertilisation method is known as the ‘biological pump’—essentially adding nutrients (such as iron) in areas of the ocean where they are limited, in order to cause more plankton blooms.  When plankton grow they require carbon, which they get from the atmosphere, and thus it is posited that increasing the amount of oceanic plankton blooms would cause more carbon to be pulled out of the atmosphere and—potentially—be sequestered for a long period of time in the ocean once the plankton die.

Thus far, investigation into the effectiveness of the technique has included computer modelling and theoretical calculations as well as some bench-top experimentation and even a number of small tests in various locations across the globe.  According to Professor Richard Lampitt of the National Oceanography Centre, who spoke at the seminar, research to date has led to a number of conclusions:

  • When limiting nutrients are added phytoplankton always bloom.
  • This probably enhances export of carbon from the atmosphere, which may enhance carbon sequestration and may generate N2O, a potent greenhouse gas.
  • The spatial and temporal extent of experiments has been insufficient thus far.
  • Physics of the process is not adequately understood.
  • Models are presently inadequate at predicting the outcomes of large-scale fertilization.

Specific concerns that need more investigation were outlined at the seminar by Dr. David Santillo of Greenpeace.  They included the question of whether the process might release non-carbon green house gases and the potential for making acidification in the deep ocean worse.  Such effects are subject to the complex ‘4-dimensional’ nature of ocean dynamics.  Determination of potential unintended consequences, and even of the effectiveness of the technique in sequestering carbon is thus incredibly difficult.  Any addition of nutrients is uncontained, with affected zones moving in all directions over time (the 4th dimension), thus making it difficult to measure.  

It seems that in order to learn a great deal more about ocean fertilisation’s potential, experiments will have to last longer and be far larger in physical scale.  Experiments are not without their own risks however, and the larger they are, the riskier they become.

Dr Chris Vivian, Centre for Environment, Fisheries and Aquacultural Science,  spoke about his engagement with the London Convention/London Protocol process which has led to the regulation of any ocean fertilisation experiments carried out today.  Signatories to the convention have implemented a case-by-case assessment framework for experiments and a group of nations will soon be delivering a proposal which would stand as a basis for future regulation of ocean fertilisation.  An integral part of the new mechanism would have to be flexibility, according to Dr. Vivian, as the science is in such a formative stage and may evolve to produce differing proposals for carrying out ocean fertilisation in the future.  It is hoped that any new regulatory framework would be highly (and quickly) adaptable for regulation of any marine geoengineering proposals, be they ocean fertilisation or otherwise. 

Dr. Vivian’s view is that the London Convention/London Protocol is likely to be the best venue for regulation of marine geoengineering from an environmental protection perspective.  However, a potential conflict with the Convention on Biological Diversity could arise due to its recent engagement in geoengineering regulation.  At present there is no mechanism for bodies like this to liaise and co-ordinate their efforts.  Because the notion of geoengineering is so nebulous and far-reaching it seems likely that conflicts might arise between these and/or other international regulatory frameworks.  Creation of a mechanism for co-ordination seems like a good idea for the future, though it has never existed before. 

Much like scientific research, governance is itself an iterative process.