Policy brief - Is Ocean Fertilization a possible solution for mitigating Climate Change?

In the coming COP17/CMP7, one of the topics discussed will be on blue carbon credit and the importance of oceans' role in mitigation and adaptation of Climate Change. Some of my friends will be attending the talks in Durban and from the looks of it, it's going to be an experiential one for them all... :) For us, climate change is an important event as it affects all life forms at various degrees, and cannot be overlooked when we view the bigger picture.

For my last class, Marine Conservation taught by Professor Chou Loke Ming, we had a report assignment to write a policy brief on the topic of Ocean Fertilization (OF). Through this assignment, I have learnt a lot about OF and its application, and how it has a role in Climate Change mitigation. Yet, so little is known of its functional status. In this post and in view of the upcoming Climate Change talks in Durban, SA, I will share my own opinions and conclusions about the use of OF as an option in mitigating against climate change.

1. General Overview

The impending increase in anthropogenic carbon dioxide (CO₂) concentrations in the atmosphere, together with the lack of success in reducing greenhouse gases emissions have been recognized as accelerating global problems of climate change. The need for mitigation options has incited scientific and policy interests in geoengineering techniques that allow deliberate interventions to moderate Earth’s climate system. Ocean fertilization (OFN) had been one of earliest proposed mitigation to counter climate change problems. It is the intentional act of increasing phytoplankton production in the open ocean and this can be achieved by direct nutrient supply, or increasing nutrient supply from deep waters. Therefore, increasing oceanic CO₂ uptake by phytoplankton while reducing atmospheric CO₂, but OFN utilization and mitigation potentials had been highly controversial and not yet well explored.

As early as in the 1980s, the idea of fertilizing oceans came about when scientists made observations of glacial-interglacial CO₂ changes and insights on the natural components that limit oceanic biological production in both high macronutrients, low chlorophyll (HNLC) and low macronutrients, low chlorophyll (LNLC) regions. Although 13 small-scale fertilization studies have shown some encouraging results, proposals for large-scale application of OFN have attracted much criticism and skepticism from the scientific and public. On the precautionary principle, the Convention on Biological Diversity (CBD) declared in 2008 that no OFN should be carried out for any given purpose until scientific justification was stronger and assessed through a global regulatory mechanism. Regulatory frameworks are being developed currently, through the London Convention and London Protocol (LC/LP).

2. Scientific background

Oceans act as a biological pump whereby photosynthetic primary productivity takes place in the ocean surface followed by sinking of materials into the deep ocean; this increases CO₂ uptake into ocean interior and reduce anthropogenic CO₂ in ocean upper layer. Oceans are potentially huge carbon sinks that almost a third of the anthropogenic atmospheric CO₂ since 1750 has moved into the ocean. Natural fertilization such as iron defecation by sperm whales could stimulate carbon export in Southern Ocean (Table 1). However, natural fertilization itself is not enough as macronutrients such as nitrogen, phosphorus and (for diatoms) silicon, and the micronutrient iron continue to limit marine primary productivity. Therefore, through artificial fertilization (Table 1), we can potentially increase phytoplankton production that would result in the sequestration of inorganic carbon into the deep ocean (Figure 1).

Figure 1 shows the main processes and inefficiencies involved with ocean fertilization for carbon sequestration. Blue arrows represent the intended sequestration paths while red arrows represent the inefficiencies of sequestration paths. Adapted from: Wallace et al. (2010).

All of the OFN approaches to date have focused on increasing the external supply of nutrients, especially iron. Small-scale, experimental iron additions to HNLC regions have shown great increases of phytoplankton biomass, and CO₂ uptake in the surface waters (Table 2). However, these scientific studies were short-term and relatively small-scale, and information on how OFN affects marine biota, the magnitudes of carbon export and fertilization effectiveness are still uncertain. No experimental studies on large-scale fertilization have been carried out at larger spatial and temporal scales, thus even less information is available on the possible impacts.

Model-based predictions have helped in understanding the overall efficiency of atmospheric CO₂ uptake; where iron-based OFN simulations suggest removal of about 40% anthropogenic CO₂ into the ocean on timescales of hundreds to thousands. While improved models have been available to better predict both benefits and impacts, the totality effects still cannot be fully understood as the ocean is dynamic and connected. Model simulations of large-scale OFN predicted that overall costs are high (especially nutrients and transportation), with low fertilization frequency of 10-25% carbon sequestration. These cost estimates only covers the direct fertilization activity, but undervalue the costs for potential negative downstream effects (Table 2).

3. Regulatory, Governance and Policy

The regulation issue with OFN is that it predominately takes place on the high seas where no national jurisdiction or propriety rights apply and therefore anyone in principal could carry out OFN. In December 2007, the United Nations General Assembly encouraged states to support research and enhance understanding of OFN (Resolution 62/215). Four UN parties have taken an interest in this topic: the Intergovernmental Oceanographic Commission of UNESCO (IOC), the Convention on Biological Diversity (CBD), the International Maritime Organization (IMO) and the UN Convention on Law of the Sea (UNCLOS). All of which have put forth frameworks and agreements on OFN issues.

In response to the concerns with OFN, the recent CBD/COP10 (2010) re-emphasized that no OFN activities should take place unless justified scientific research with a regulatory mechanism are in place (CBD 2008; Decision IX/16C) while taking account of OFN progress (UNEP/CBD/SBSTTA/14/INF/7; paragraphs 57-62). In 2008, Parties to the London Convention (LC/1972) and London Protocol (LP/1996) decided that OFN activities other than legitimate science should not be allowed, while developing frameworks to re-assess compatibility of OFN experiments and formulate a potential legal binding to LC/LP.

The Kyoto Protocol (Article 12) defined the clean development mechanism (CDM) that looks into providing certified emission reduction credits as a standard offset instrument. With the potential to reduce carbon emissions, carbon markets and offset incentives are looking into the economic viability of selling carbon credits through OFN within the CDM framework. The main problems with creating carbon credits through OFN are the difficulty to verify, monitor and account for the permanence and leakage. Considering the minimal success from the 13 OFN experiments, the evidence of the benefits from OFN is still lacking and would be wise to remove carbon-offset incentives on OFN.

4. Conclusions

It is clear that anthropogenic carbon emissions contributing to climatic changes have severe effects on humans; we are in urgent need for mitigation options and OFN has been one of them. Small-scale fertilizing of the oceans has been demonstrated to increase productivity, likely resulting in drawdown of atmospheric CO₂. However, there are still significant unknowns in terms of its mitigation potential, sciences, and feasibility of implementation. Yet the presence of these unknowns hinders proper assessment of OFN potential contribution to climate change mitigation. Gap analyses for OFN need to be filled in order to reduce uncertainties and refine our understanding, so as to incorporate into future policies. In the context of a carbon-emission offset scheme, if OFN is implemented to generate carbon emission credits which leads to corresponding increase in fossil fuel emissions, then OFN is unlikely to be effective in the long run as it would result in further pollution to the deep ocean without conferring any environmental benefit or climate mitigation. Finally, one has to keep in mind that it is essential to engage the public concerning strategies for climate mitigation, as the negative effects of climate change can affect ecosystem services, land usage and health. Whilst discussions on OFN have not fully engaged the public, the decisions for full implementation of OFN should consider the public attitude to the solution.

5. References

· Gussow K, Proelss A, Oschlies A, Rehdanz K & Rickels W (2010) Ocean iron fertilization: Why further research is needed. Marine Policy 34: 911-918.

· Secretariat of the Convention of Biological Diversity (2009) Scientific Synthesis of the Impacts of Ocean Fertilization on Marine Biodiversity. Montreal, Tech Ser No. 45, 53pp.

· Wallace DWR, Law CS, Boyd PW, Collos Y, Croot P, Denman K, Lam PJ, Riebesell U, Takeda S & Williamson P (2010) Ocean Fertilization. A Scientific Summary for Policy Makers. IOC/UNESCO, Paris (IOC/BRO/2010/2).

· Woodward FI, Bardgett RD, Raven JA & Hetherington (2010) Biological approaches to global environment change mitigation and remediation. Current Biology 19(14): R615-R623.

· Zeebe RE & Archer D (2005) Feasibility of ocean fertilization and its impact on future atmospheric CO₂ levels. Geophysical Research Letters 32: L09703, 1-5.