Comments on NASEM Ocean CDR Research Strategy

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Geoeng Info

Jan 4, 2022, 9:00:40 AMJan 4

Comments on NASEM Ocean CDR Research Strategy

Robert Tulip

27 December 2021


Comments on NASEM Ocean CDR Research Strategy

  • National Academies of Sciences, Engineering, and Medicine 2021. A Research Strategy for Ocean-based Carbon Dioxide Removal and Sequestration. Washington, DC: The National Academies Press.

This NASEM report is immensely important as a public statement of current scientific consensus on the potential of ocean-based carbon dioxide removal to help stabilise the climate. However, in my view it is deficient due to its unstated acceptance of political pressures that distort its findings away from the best scientific information and practical implementation strategies. I did not engage with the report production process but hope that discussing it now will be of some value. I would welcome any challenge to my opinions expressed here as these are highly complex scientific and political issues that are important for our planetary future.

I have taken a strong interest in this topic since 2007, when I worked for the Australian Government on forest climate policy. I then formed the view that ocean-based CDR must become central to climate policy as the only option able to deal with the magnitude of the climate threat. That led me to work addressing large scale ocean-based algae production, linked to deep ocean water upwelling and ocean iron fertilization, including with iron salt aerosol.


A main problem arises from the following statement repeated in the summary and synthesis sections of the NASEM report as a key guiding policy principle:

  • “While rapid and extensive decarbonization and emissions abatement of other greenhouse gases in the U.S. and global economies are the primary action required to meet international climate goals, ocean-based and other CDR approaches could help balance difficult-to-mitigate human CO2 emissions and contribute to mid-century to late-century net-zero CO2 emission targets” (p2, p213). 

This statement represents current political consensus but is not itself based on scientific evidence and supports an incorrect strategic direction for climate policy. Cutting emissions alone falls far short of the action needed to prevent warming of 2°C, let alone the more stringent targets needed to prevent dangerous climate change. The NASEM claim should therefore be challenged as a dangerous underestimate of the severity of climate risk and the scale and urgency of the required response. It wrongly implies that cutting emissions could prevent dangerous warming, even though temperature and sea levels were far higher than at present when our planet last had current GHG levels. The statement ignores the problem of committed warming from past emissions, which is the main reason why CDR is needed, not to ‘balance’ the much smaller problem of ongoing emissions. 

Cutting emissions can only slow the rate of GHG increase and cannot cut existing GHG levels. That means the IPCC goal of net zero emissions would produce an end result of radiative forcing much higher than at present. Even at current GHG levels, unforeseen tipping points could lead to a hothouse earth. Decarbonisation as “primary action” as proposed by NASEM therefore represents a complacent and inadequate climate strategy, despite its popular support.


In fact, far from being “the primary action required” to stop dangerous warming, cutting emissions is far too small, slow and contested to achieve this climate goal. In the long term, CDR is needed to remove the trillion tonnes of carbon equivalents that humans will have added to the atmosphere by mid-century. CDR at much larger scale than total emissions will be the primary climate action required. Against that scale, emission reduction can make only a marginal contribution. Cutting emissions could at best reduce C addition by about 2-5 Gt C per year, given the intransigence and power of fossil fuel users, although even that looks very difficult.  The bulk of the work to achieve net zero emissions has to come from ocean-based CDR. This work could provide the momentum to scale up CDR to double total emissions, 30 Gt C per year, or 100 Gt CO2 equivalents. Only the ocean has the available area, energy, and resources needed to deliver CDR at that scale. In the interim, while ocean solutions are developed, action to brighten the planet and reflect excess solar radiation is the most immediate and urgent global responsibility to prevent climate tipping points.  That whole strategic outlook is excluded by the premise of the NASEM report.

Rather than accepting this prevailing orthodoxy of a focus on cutting emissions, climate policy should discuss more ambitious goals. An ambitious target of ocean-based CDR could be annual net removal of 30 Gt C. Using the massive area, energy and resources of the world ocean to stabilise and restore the planetary climate by achieving this target is technically possible but would require a major paradigm shift from the view that decarbonisation is primary. 

The second defect of the quoted NASEM statement is in its assertion that “ocean-based and other CDR approaches could help balance difficult-to-mitigate human CO2 emissions and contribute to mid-century to late-century net-zero CO2 emission targets.” Again, this assertion expresses current broad IPCC policy consensus, but its logic and vision are flawed. The conceptual connection it proposes between new emissions and CDR makes no sense. CDR removes well-mixed CO2 emitted a thousand years ago and is needed on a scale far exceeding total emissions. The “balancing” concept adopted by NASEM from IPCC literature is therefore fundamentally misleading, orders of magnitude smaller than the need. It appears to be political in intent, designed to retain the political primacy of the strategy of emission reduction through shutting down fossil fuel industries. Unfortunately, this way of thinking ignores how this current orthodoxy presents immense risks and challenges, including opposition from major world governments and industries despite their lip service. The fifty-year time frame for scaling up CDR suggested in the NASEM policy statement is grossly inadequate against the real climate security risks. This timeframe should instead be compressed to target large ocean CDR deployment within this decade.

This NASEM strategic policy statement represents a complacent political strategy that colours the analysis of the entire report. The unfortunate situation is that such complacency dominates climate policy advocacy. It produces a timid and hostile approach toward geoengineering with a lowest common denominator position in which the immediate need for climate repair is ignored.

Since studying ocean algae as a climate solution for more than a decade, I have recognised ocean iron fertilization as a primary strategy to increase ocean algae biomass, together with upwelling and seaweed production. I therefore read the NASEM Chapter Three on Nutrient Fertilization with great interest and look forward to reading the other chapters. My comments below are solely on the Nutrient Fertilization discussion, primarily addition of iron.

The discussion of nutrient fertilization contains much informative technical material and excellent references to scientific research. However, I was surprised by the assertion (Summary Table S1, p7) that enhanced fisheries is possible but has not been shown and is difficult to attribute. This criticism appears to conflict with available analysis.  There is a strong intuitive argument that adding iron, especially where targeted to optimise the fisheries life cycle by fertilizing waters where juvenile fish are most vulnerable to starvation, can be as effective as fertilizer on land. Of course, fish are underwater and moving around, unlike wheat. The measurement and verification challenges can only be met by field implementation, not by theoretical debate.

The report recognises that increase in photosynthesis from addition of iron is proven, while noting that debate continues about how much iron fertilization increases long term removal of CO2. The only way to resolve such debate is through more field trials. Regrettably, field tests have been under an effective political ban for the last decade, despite their high potential to help mitigate climate change, increase world food stocks and enhance biodiversity. The report does not really engage with this intimidating political context, reflecting the cautious attitudes that generally characterise scientific literature.

The origin of the political ban on iron fertilization arose from attacks on the fisheries enhancement work of one of its main proponents, Russ George, who has been the target of a vicious and sustained political campaign of disinformation and intimidation since leading the Haida Salmon experiment in 2012. This campaign has included bizarre and unconscionable strategies, such as mobilising the resources of the United Nations to declare that efforts to enhance salmon fisheries constitute dumping of waste, preventing collegial scientific discussion, and arranging for the Government of Canada to steal project data. A 2019 update at states “George points out that, according to the Alaska Department of Fish and Game, the year after his venture saw a record salmon harvest. He also insists that the data he was collecting would have demonstrated that he had succeeded in removing carbon, if the Canadian government hadn’t seized it for an investigation.”

A description of some of these problems is at It states “the entire scientific data collection of the office has been taken, notebooks and journals, electronic data, legal files, reference books, scientific paper collections, much of what we work with on an everyday basis. So far in spite of being told we would be given a list of what they took no such list has arrived.” I understand much of this material was never returned. Such serious allegations of political misconduct should be recognised as constraining the scientific context of this activity, and should be recognised in the NASEM report, not ignored and distorted.

The intimidatory political context is further described at, with distinguished scientists allegedly placed on a Canadian government blacklist for cooperating with the project. This illustrates how the policy context for this work has been badly corrupted by political influence.  The tragedy of this influence is that it sets the agenda of political polarisation as more important than cooperation to fix the climate or restore fisheries. This polarised approach was explained by anti-geoengineering campaigners at Greenpeace, when Dr. Paul Johnston, head of Greenpeace International’s science unit, said in an ETC Group press release “Climate change should be tackled by reducing emissions, not by altering ocean ecosystems”. This stance is unscientific and mercenary, reflecting the ignorant prejudices of the Greenpeace donor base rather than empirical evidence.

The NASEM chapter on Nutrient Fertilization does not adequately explain this political context, which I would have thought should be essential to explaining why there have been no field tests for a decade. The chapter is quite badly organised, opening with highly uncertain, jargonistic and hypothetical analysis of the potential for permanent sequestration. As I read this chapter, I found myself wondering why the practical justification provided by the potential of ocean pasture replenishment as a way to improve fisheries productivity was not mentioned. It would provide the obvious, safe, simple and cheap way to test all the hypothetical problems and questions about longer term effects, and could be paid for by levies on the expected enhanced fish catch.

The report section 3.5 Viability and Barriers has a sub-section titled Fisheries that covers some of these questions, noting the obvious argument that fertilizing fishery locations could alleviate world hunger. The discussion of the 2012 Haida Salmon Restoration Corporation project led by Russ George does not read as balanced or astute. 

It makes the extraordinary comment that the Haida project “was lacking in the public release of data or peer-reviewed studies documenting the impacts. While after-the-fact study of remote sensing images and plankton sampling did document a bloom within the study area (Batten and Gower, 2014; Xiu et al., 2014), no links could be made to enhanced fisheries. We are thus left with no evidence on the potential positive or negative impacts on fisheries of the 2012 event.” 

Contrary to this NASEM assertion, Batten and Gower state “The evidence suggests that the iron-induced phytoplankton bloom in August [created by Russ George] fuelled the increase of crustacean zooplankton.” Together with claims from Russ George at, this cited scientific paper casts doubt on the NASEM assertion of no links between ocean pasture restoration work and enhanced fisheries.

As many of Russ George’s blog articles make clear, the assertion of a lack of data is disingenuous, and obviously has not been properly checked with sources. If scientists were blacklisted for speaking to the Haida project, and the Canadian government stole its data, it is unsurprising that there is a lack of peer reviewed analysis. The cited paper by Batten and Gower appears to contradict NASEM’s conclusion.

To illustrate how a narrow scientific approach can distort analysis of such a highly political topic, consider the NASEM statement “of significance to ocean CDR is (1) the need for through [sic] measurements and models, to quantify the permanence for a given site, and (2) deliberately selecting sites and enhancing export efficiencies to optimize for maximal sequestration time.” At face value this is reasonable, but in political context it is not reasonable, in view of the fervent popular view that such research must be prevented as the slippery slope to geoengineering deployment. It may be instead more sensible to explore if ocean fertilization could start with a focus on profitable fisheries enhancement, and then use practical lessons from scaling up this work to assess CDR potentials, rather than speculating about long term CDR in the absence of hard data from commercial sites.

A key observation in the NASEM chapter, which it does not seem to adequately address, is that “any attempt to deliberately alter the oceans’ Biological Carbon Pump will have consequences that should be considered relative to the status quo of doing nothing.” This is a highly charged political assertion, because this way of thinking appears to be basically ignored by the IPCC. Doing nothing presents existential risks which some see as potentially creating climate collapse, even as extreme as the Great Dying at the end of the Permian Age. Against that, the risks of testing ocean iron fertilization are minimal, easily addressed by stopping implementation. The main risk is political, that it will demonstrate that the approach to climate change proposed under the Paris Accord is unworkable. 

Robert Tulip

Jan 12, 2022, 1:09:02 AMJan 12
to Geoeng Info,, Planetary Restoration

Summary of post below.


The NASEM report well summarises current academic consensus on ocean CDR.  However, this accepts that emission reduction is the primary action required, a wrong assumption which badly distorts the NASEM approach, preventing recognition of the large scale of CDR that will be needed.  This distortion is highlighted in the NASEM discussion of ocean nutrient fertilization, which ignores the political malfeasance by the climate action movement in suppressing the Haida Salmon Restoration Project.  As a result, NASEM presents a complacent and unambitious policy outlook, ignoring the immediate need for climate repair, and failing to balance the significant tangible benefits of ocean CDR deployment against hypothetical risks.


The picture is of the plankton bloom caused by the Haida 2012 experiment which resulted in a massive salmon harvest increase by preventing starvation of young fish.


Robert Tulip

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