Concern over human-driven climate change and the lack of success in constraining greenhouse gas emissions have increased scientific and policy interest in geo-engineering − deliberate interventions in the Earth's climate system that might moderate global warming.
One of the earliest proposed carbon-removal techniques is large-scale ocean fertilization.
Concern over human-driven climate change and the lack of success in constraining greenhouse gas emissions have increased scientific and policy interest in geo-engineering − deliberate interventions in the Earth’s climate system that might moderate global warming. One of the earliest proposed carbon-removal techniques is large-scale ocean fertilization.
This is accomplished by adding iron or other nutrients to surface waters. The intention is to enhance microscopic marine plant growth on a scale large enough to not only significantly increase the uptake of atmospheric carbon by the ocean, but also remove it from the atmosphere for long enough to provide global climatic benefit. This suggestion grew out of scientific ideas developed in the late 1980s, based on analyses of natural, long-term climate changes (i.e., ice age cycles) and experiments that provided new insights into the natural factors that limit ocean productivity, and thereby control the cycling of carbon between sea and sky.
Major political and ethical challenges
Unfortunately, the practicalities, opportunities and threats associated with ocean fertilization are only partly understood, and will in all likelihood include unintended ecological consequences, which in turn can pose important political, social and ethical challenges. Small-scale field experiments and associated modelling have shown that the likely maximum benefits of ocean fertilization as a negative emissions technique are modest in relation to anthropogenic climate forcing. It would also be highly challenging to quantify with acceptable accuracy the amount of carbon removed from circulation on a long-term basis, and in particular to adequately monitor unintended impacts over large space and time-scales.
Meeting the political, ethical and regulatory challenges of geo-engineering, including ocean fertilization, requires building toward an international governance framework to ensure that research of this nature is conducted responsibly and transparently. A global and effective regulatory mechanism is needed to be put in place for ocean fertilization, other than for small-scale scientific research studies within coastal waters.
The United Nations General Assembly has encouraged States to support further study and to enhance understanding of ocean fertilization (Resolution 62/215; December 2007). Four UN entities have major interests in this topic: the Intergovernmental Oceanographic Commission of UNESCO (IOC), the Convention on Biological Diversity (CBD), the London Convention and Protocol (LC/LP) and the UN Convention on the Law of the Sea (UNCLOS). Together they cover the spectrum of marine science, marine conservation and pollution regulation.
Ocean fertilization activities on hold
In response to concerns that large-scale ocean fertilization might be attempted before its consequences were fully understood, and upholding the precautionary principle, the Parties to the CBD decided in 2008 that no further ocean fertilization activities for whatever purpose should be carried out in non-coastal waters until there is stronger scientific justification, assessed through a global regulatory mechanism. Such a regulatory framework is now being developed by the LC/LP.
The IOC has been closely involved in CBD and LC/LP discussions. Our 2009 publication, “Ocean Fertilization: A Scientific Summary for Policy Makers”, was commissioned in conjunction with the Surface Ocean – Lower Atmosphere Study (SOLAS), the International Commission on Atmospheric Chemistry and Global Pollution (ICACGP), the World Climate Research Programme (WCRP), the International Geosphere-Biosphere Programme (IGBP) and the Scientific Committee on Oceanic Research (SCOR) of the International Council for Science (ICSU). It includes in its key messages that ‘large-scale fertilization could have unintended (and difficult to predict) impacts, not only locally… but also far removed in space and time. Impact assessments need to include the possibility of such ‘far-field’ effects on biological productivity, sub-surface oxygen levels, biogas production and ocean acidification’.
Despite this, an uncontrolled geo-engineering project was carried out in July 2012, which caused considerable scientific and public criticism when communicated to the general public in October 2012. A private company dumped more than one hundred tons of iron, ten times the amount used in any previous experiments, to deliberately fertilize and trigger a plankton bloom in the Pacific Ocean 300 km off the west coast of Canada. The stated intention was to enhance fisheries in the area.
Given the present state of knowledge, we should all be deeply concerned about activities such as this that are carried out in the absence of transparency, in contradiction of the precautionary principle and in violation of international conventions. The ocean is a single, contiguous body of water that is crucial to human life: an unauthorized experiment carried out in one place can have consequences hundreds of kilometres away. Our well-being depends on a healthy ocean. We must all take responsibility for this global commons, and build on shared knowledge and international cooperation to manage it sustainably.