COMMERCIAL OCEAN IRON FERTILIZATION: READY FOR THE OFFSET MARKETS? Justin Felt, Daniel Fishman, Daniel Horton, and Karla Knudson University of Michigan, Ann Arbor, MI, 48109, USA Abstract Ocean iron fertilization refers to the commercial scheme to sell carbon offsets generated by stimulating algal blooms in the open ocean. Ocean primary production accounts for half of the yearly global primary production. In large areas of the ocean, primary production is lower than would be otherwise expected due to acute iron limitations on phytoplankton growth. A fortuitous byproduct of the scientific exploration of the role of aeolian dust deposition on primary productivity, iron fertilization experiments have demonstrated that fertilizing small patches of the ocean with 1-3 tons of dissolved iron stimulates blooms of phytoplankton. The potential of these blooms to export carbon from the surface ocean and “sequester” it in the deep sea has drawn commercial interest due to the recent establishment of voluntary carbon offset markets. Increased phytoplankton populations potentially pose a number of ecological problems, and the overwhelming water quality management imperative of the last 50 years has been diminishing algal blooms by reducing anthropogenic fertilization of aquatic ecosystems. Current studies suggest that phytoplankton blooms in the open ocean do not export carbon in a predictable manner, and less than 1% is ever permanently sequestered. Significant advances in the scientific understanding, political and legal framework, and business model are necessary if ocean iron fertilization schemes are to be successful. This paper examines the scientific and economic rationale underlying ocean iron fertilization and the pratfalls therein. We conclude that the utilization of ocean iron fertilization technologies in carbon offset mitigation schemes is premature, though the nascent state of the science demands continued research and development. 1 INTRODUCTION The rise in atmospheric carbon dioxide (CO2) concentrations since the industrial revolution has been definitively linked to the anthropogenic release of combustion reaction gases driven by the burning of fossil fuels (IPCC Report, 2008). The role of atmospheric CO2 in driving global climate is complex, but the preponderance of scientific evidence tightly links CO2 concentrations to global temperature and climate (Royer, 2006). As a mitigation strategy to avoid harmful repercussions from altered global climate, strategies to increase global sinks of biological CO2 are being explored (Dilling -1 et al., 2003; Pacala et al., 2004). Approximately 105 Gt yr of CO2 are removed from the -1 atmosphere by photosynthesis (Field et al., 1998), while 23 Gt yr of CO2 are released by the burning of fossil fuels1. THE BIOLOGICAL PUMP Oceanic primary production represents 1% of global photosynthetic biomass but accounts for 50% of the carbon fixed by photosynthesis every year (Field et al., 1998). The cycling of primary production product (fixed carbon) in the ocean is referred to as the biological pump. Primary production by algae (phytoplankton) is consumed by higher trophic levels, which includes heterotrophs from zooplankton to whales. The gravitational transport of carbon-rich biomass detritus ‘pumps’ fixed atmospheric CO2 below the mixed layer (~100m depth; Figure 1). As in terrestrial ecosystems, the majority of the carbon fixed is assimilated in the higher trophic levels and respired back to the atmosphere as CO2 (Martin et al., 1987). Some primary production does sink to the ocean sediments. Areal primary production rates are lower in the ocean than on land and approximately 1/5 of the ocean surface is the aquatic analog to terrestrial deserts (Boyd et al. 2007) (Figure 2). While concentrations of macronutrients (nitrogen and phosphorous) are high, productivity in these oceanic deserts is limited by a lack of micronutrients (Martin, 1990). These ocean deserts are persistent and characterized by high nutrients and low chlorophyll (HNLC). The major HNLC zones are found in the Southern Ocean, the Equatorial Pacific, and the North Pacific sub-arctic (de la Rocha, 2004). By increasing the rate of primary production in HNLC areas some companies hope to profit via carbon offset sales. MARTIN’S HYPOTHESIS The idea of oceanic iron fertilization as a primary mechanism in the alteration of atmospheric CO2 concentrations is derived from studies of glacial-interglacial cycles. Evidence suggests that increased iron-rich dust deposition to oceanic waters may have spurred CO2 uptake in times of continental glaciation, further cooling the environment. Consequently, a reduction in dust deposition has been chronicled during the interglacial periods of the Pleistocene. Recently published data have successfully tracked this 1 http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html 2 regulatory capacity of iron on atmospheric CO2 over the past 800 kyrs (Figure 3, Lambert et al., 2008). Dr. John Martin established that the reason for the persistent HNLC zones of the ocean was acute iron limitation. Iron is a necessary micronutrient for phytoplankton metabolism (Martin, 1990). In phytoplankton (the planktonic organisms responsible for oceanic primary production), iron limitation is particularly problematic. Aeolian iron-rich dust deposited in the ocean sparks massive phytoplankton blooms in HNLC zones (Figure 4). In essence, Dr. Martin’s hypothesis stated that on geologic time scales, increased iron deposition during glacial periods removed 30% of the 80 ppm CO2 decrease observed during glacial maxima (Sigman, 2000). The promise of increased productivity in HNLC ocean waters through iron fertilization is rooted in the evolutionary history of phytoplankton. The limitation of iron on biological ecosystems in today’s oceans stems from the earliest origins of life on planet Earth. The evolution of single celled organisms ~1.6 Ga occurred in an environment of low atmospheric and subsequently low oceanic oxygen concentrations. Low levels of oceanic oxygen allowed high levels of dissolved iron within ocean waters. It was under these high levels of dissolved iron that photosynthetic phytoplankton developed. As photosynthetic organisms became more prevalent, their primary waste product, oxygen, began to accumulate in the atmosphere. With the rise of atmospheric oxygen and the subsequent oxidation of dissolved iron within the water column, available dissolved iron levels dropped precipitously, and iron became the primary limiting micro- nutrient of phytoplankton (de la Rocha, 2004). The self-imposed evolutionary quirk that is iron limitation has persisted throughout much of geologic time. Starting in 1993, 12 oceanographic research expeditions tested Martin’s hypothesis with small scale iron fertilization experiments. For iron deposition to lead to a drawdown in global CO2 atmospheric concentrations, a net increase in the export of fixed carbon from the mixed layers of the ocean following fertilization is necessary. By adding small amounts (450-2800 kg) dissolved, biologically available iron to patches of HNLC ocean and observing the phytoplankton response (as chlorophyll concentration, a proxy for primary production), these experiments proved that iron fertilization can produce rapid, intense blooms of phytoplankton and exponentially increase carbon uptake (Boyd et al., 2007). The experimental success of ocean iron fertilization in increasing primary production in HNLC zones is drawing the attention of the private sector. There is already a growing commercial industry dedicated to generating “carbon offsets” in terrestrial forests. The timeframe of iron fertilization results (phytoplankton blooms occur over the course of days and weeks and can be captured with stunning space photography while forests grow slowly for decades) and the hypothetical maximum amount of carbon that HNLC zones could fix from the atmosphere (on the order of Gt of carbon) presents an attractive picture to investors. CLIMOS CASE STUDY Climos is a Silicon Valley startup attempting to commercialize large scale iron fertilization projects and convert the carbon sequestered into sellable carbon offsets. The company would release a form of iron into the open ocean from large ships and create large algae blooms that feed off the nutrients. Climos aims to quantify the carbon rich 3 detritus which descends below the mixed layer, and create carbon offsets for potential sale on the voluntary carbon offset market. The company was founded in November 2006 and is headed by CEO Dan Whaley, who previously created the pioneering internet travel company Get There. He is supported by Margaret Leinen, who serves as the Chief Science Officer. She previously served as Assistant Director for Geosciences at the National Science Foundation, were she managed a research budget of over $700M. The team in total has 8 employees. CARBON OFFSET MARKET Climos, as a private startup company, plans to build its business around the ability to “monetize” the carbon reductions and create carbon offsets. Carbon offsets represent the equivalent of one ton of carbon dioxide that would otherwise be in the atmosphere. In this case, the case for carbon dioxide reductions depends on the level of long term carbon sequestration into deep-ocean. Offsets can be also created through changes in behavior, through the implementation of a renewable energy generation, energy efficiency procedures, or incineration of greenhouse gases among others. In order to package them, offset projects need to