Hold back the geo-engineering tide
Kristina Gjerde, BBC News 11 Dec 07;
Projects that add nutrients to the world's oceans in order to create algal blooms that will absorb more carbon from the atmosphere are scientifically unsound, argues Kristina Gjerde, high seas policy advisor to the World Conservation Union.
In this week's Green Room, she calls on delegates at the UN climate conference to halt schemes that could do more harm than good.
Current proposals to combat climate change by stimulating phytoplankton or algal blooms in the ocean may violate fundamental principles of international law, as well as common sense.
Adding nutrients, such as iron or nitrogen, or pumping nutrient-rich deep waters up into surface waters in the hope that the resulting bloom will provide long-term storage of carbon dioxide, should not be considered as a potential solution to climate change.
We first need regulations based on credible science to ensure that the method is safe and effective, and that we can verify the results.
Two decades of scientific study have shown that ocean fertilisation offers a low probability of lasting benefits and a high probability of harm.
The Intergovernmental Panel on Climate Change (IPCC) considers ocean fertilisation as "speculative and unproven, and with the risk of unknown side effects".
Nevertheless, it continues to be touted as a simple solution to climate change.
Uncertain science
For such a practice to be effective in mitigating climate change, substantial amounts of additional carbon dioxide must reach the deep ocean and, ideally, be incorporated into the sediments.
Experiments to date have shown that the amount of carbon actually exported to the deep ocean is small and highly uncertain. At present, it is unlikely that significant and verifiable sequestration will occur.
For ocean fertilisation to be safe, and in compliance with international law, it must not harm the marine environment.
However, possible ecological effects include shifts in plankton community structure that could dramatically alter food webs, creation of dead zones deprived of oxygen as the excess plant life decays, and harmful algal blooms.
In addition, the bloom may affect areas far from the original site. One fertilised patch travelled 1,500 km in 19 days, while modelling studies show that adding nutrients to one area can lead to reductions in productivity in other areas.
Though it is difficult to predict with certainty, activities conducted in one nation's waters may affect the waters of another state, or the high seas. Similarly, activities on the high seas could impact not only the direct area, but also waters under national jurisdiction and control.
Furthermore, atmospheric scientists are concerned that artificially-stimulated blooms could exacerbate climate change by increasing the production of nitrous oxide, a greenhouse gas far more potent than carbon dioxide.
This may well offset any benefits from carbon dioxide reduction, while the marine ecosystem side-effects remain.
Moreover, additional atmospheric side-effects such as the production of methane, another important greenhouse gas, as well as other gases that are known to influence clouds and ozone, may also result.
Need for common sense
No evidence has been produced to allay these concerns. Difficulties in actually proving or verifying carbon dioxide sequestration, should it occur, make the current informal and unregulated market for carbon offsets vulnerable to unsubstantiated and unverifiable claims.
All this makes ocean fertilisation a highly unfit candidate for carbon credits.
Recently, a meeting on the international agreements that regulate dumping of wastes and other matter at sea (the London Convention and London Protocol) urged states to use the utmost caution when considering proposals for large-scale fertilisation operations.
It also stressed that "such large-scale operations are currently not justified".
The decision of governments at the London meeting could not be more timely, as some commercial operations are carrying out pilot projects of ever-increasing scale.
One company is already offering carbon offsets to the public on its website to support its work.
The recently published IPCC Fourth Assessment Synthesis Report again confirmed that the effects of climate change are real and that they are already upon us.
But in our efforts to find a quick fix, international law and common sense should not be the first victims.
The oceans are complex, dynamic, unpredictable and already vulnerable to the effects of climate change and acidification. We need mechanisms that will build their resilience, not undermine it.
Independent look
The concept of ocean fertilisation needs to be stringently scrutinised through independent peer-reviewed science, not left in the hands of entrepreneurs.
It should not be allowed to proceed until these two preconditions have been met:
* the benefits, if any, need to outweigh the risks to the marine environment
* we need to be able to independently verify and regulate any real, measurable, long-term carbon dioxide sequestration benefits, if they are found to occur
During the second week of the UN climate change conference in Bali, governments should apply similarly rigorous standards to all proposed "geo-engineering" solutions.
We don't need quick fixes to this global problem that may, in the long-term, cause far more harm than good.
Kristina M Gjerde is a high seas policy adviser to the World Conservation Union (IUCN)
The author would like to acknowledge the assistance of Rosemary Rayfuse from School of Law, University of New South Wales, and Mark Lawrence of the Max Planck Institute for Chemistry, Germany.
This article is based on a forthcoming publication in the International Journal of Marine and Coastal Law.
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
