Some global references which describe ideas to deal with the 3Rs.(REDUCE) (REMOVE) and (REPAIR)
- Jean-Pierre Gattuso et al. (2020) The potential for ocean-based climate action: negative emissions technologies and beyond. – https://hal.archives-ouvertes.fr/hal-03089974
- National Research Council 2013. Abrupt Impacts of Climate Change: Anticipating Surprises. Washington, DC: The National Academies Press. – https://nap.nationalacademies.org/catalog/18373/abrupt-impacts-of-climate-change-anticipating-surprises.
- National Research Council 2015. Climate Intervention: Reflecting Sunlight to Cool Earth. Washington, DC: The National Academies Press. –
- National Research Council 2020. Climate Change: Evidence and Causes: Update 2020. Washington, DC: The National Academies Press.
- National Research Council 2021. Reflecting Sunlight. Recommendations for Solar Geoengineering Research and Research Governance. https://nap.nationalacademies.org/catalog/25762/reflecting-sunlight-recommendations-for-solar-geoengineering-research-and-research-governance.
- 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. https://doi.org/10.17226/26278.
- Hall 2022. Ocean carbon sinks capture and sequester quite well. https://voteclimateone.org.au/ocean-carbon-sinks-capture-and-sequester-quite-well/
- Hall 2022. Direct Air Capture of CO₂ at PPM levels is a folly. https://voteclimateone.org.au/direct-air-capture-of-co%e2%82%82-at-ppm-levels-is-a-folly/
Ocean fertilization and farming to capture and sequester CO2 on the ocean floor
William P. Hall (PhD)
1. Significant evidence exists that we have already crossed the threshold where global warming will run away if we don’t actually stop and reverse the feedbacks very soon. We need zero carbon emissions ASAP – even if it involves rationing and hardship, but zero emissions on its own is unlikely to be enough to do this.
2. We need geoengineering (a) to capture and sequester atmospheric global warming potential and/or (b) to increase Earth’s albedo to reflect more solar energy away from the planet.
1. Ocean fertilization and farming to capture and sequester CO₂ on the ocean floor
ii. The biosynthesis of chlorophyll and the transfer of electrons in the photosynthetic pathway both require iron-based cofactors. A single atom of magnesium in the center of the chlorophyll molecule plays a crucial role in using energy from a photon to free an electron necessary to drive the process.
iii. ~ half the surface of the world’s oceans (shades of dark blue and lavender) is a desert because the availability of iron or magnesium is too low to support the formation of chlorophyll molecules that carbon-fixing phytoplankton require for photosynthesis.
i. Depending on local circumstances the addition of trace quantities of soluble iron or magnesium (i.e., as nitrates, sulfates, chlorates, etc. is sufficient to enable phytoplankton to bloom – capturing carbon from the atmosphere to produce biomass.
ii. Enabling the continued blooming of phytoplankton will support proliferation of zooplankton and develop a complete ecosystem of larger consumers able to package significant proportion of the carbonaceous biomass into feces and dead animal remains that will sink to ocean floor to form before decomposers can oxidize the carbon back to CO₂.
c. Farming (i.e., management)
i. Carbon fixation optimized by selective seeding with appropriate combinations of phytoplankton species. May benefit from fertilization with additional phosphates (possible limiting resource – but some could be diverted from animal husbandry on land – see pt. 3, and iv-3, below) and nitrates (explore adding/engineering nitrogen fixing species).
ii. Carbon sequestration optimized by selective seeding with appropriate combinations of zooplankton and larger consumers (possibly up to and including whales able to short-circuit food chains by vacuuming up krill and bait-fish) able to transport the maximum mass of carbon to the ocean floor.
iii. Consider managed harvesting of premium quality animal protein from larger consumers (e.g, tuna!) for human consumption with the aim of reducing/eliminating the need to farm large animals on land for protein consumption and optimizing the redundant agricultural land for carbon capture and sequestration in the soil. Note that all carbonaceous offal and organic waste from the harvested fish would also be allowed to carry its carbon to the ocean bottom; also there would be a direct economic return from the seafood harvest.
d. Logistics requirements can be met with zero carbon shipping
i. Stopping anthropogenic carbon emissions will release large numbers of bulk transports used for coal and oil. High port to port transport speeds will not be required, so green energy generation should suffice for transport power. These can be refitted with ‘fertilizer’ dispenser technology, and wind and photovoltaic generators to drive electric propulsion – probably for substantially less cost than for new-builds.
ii. Smaller vessels required for farm management functions could also be electrically fuelled – e.g., with topping up by large transports repurposed as mother ships connected to large floating solar arrays and. Consider a large container ship able to deploy and retrieve standard container-sized folding arrays as a strategy for minimizing damage from cyclones. It is likely that such mother ships would also optimally include fish processing, packing, freezing, and containerization for shipping to the land modules.
e. Resource requirements
i. Iron: powdered raw ore directly from the mine would suffice, however the ability to dispense the iron as an ionic liquid (e.g., as a solution of ferric nitrate where the ion can be immediately be absorbed by plants) to facilitate transport and dispensing. Existing mines would probably suffice to provide the iron in the trace amounts required. It may be possible to produce soluble iron directly from concentrated ores without the need for energy intensive smelting.
ii. Magnesium: common element, but costly in terms of energy to refine as a metal. One major source for refining is magnesium chloride salt harvested from concentrated brines. Probably the brine itself would be a suitable magnesium fertilizer – shortcutting all energy intensive processing steps
iii. Possible macronutrient requirements that may become limiting as photosynthesis ramps up: nitrogen – explore seeding photosynthetic layer with existing nitrogen fixing organisms or genetically engineering suitable phytoplanktonic species. Phosphorus – diversion from land-based animal husbandry for protein production replaced by marine protein; to explore lichen-based leaching from igneous rocks and separation from high phosphorus iron ore in beneficiation processing to increase the value of the ore..
f. Scalability and eco-safety considerations for global projects
i. Roughly half the surface of the world’s oceans qualify as ‘ocean deserts’ (i.e., roughly 25% of the Earth’s total surface). Potentially ALL of this area could be farmed to capture and sequester carbon. Without doing all the calculations this would seem to be more than enough to process the bulk of the planetary atmosphere within a few years. I know of no other technology that even approaches this apparent capacity.
ii. Aside from the fertilization that allows it to happen, solar energy drives the self-reproduction and multiplication of all biological components of the carbon capture and sequestration processes. The resources required for the fertilization and management are small to miniscule compared to other proposed mechanical and chemical technologies for carbon capture/ sequestration.
iii. The technology will undoubtedly require a lot of experimentation and in-practice learning to achieve maximum optimization, but some capture and sequestration will begin as soon as algae begin to bloom.
iv. The system is inherently ‘safe’ in that it comes with a built-in off switch. Stop the fertilization and the ocean will return to its ‘desert’ condition within a few months as the biomass starves, dies, and carries its iron/magnesium content out of the photic zone to the ocean bottom. Living systems simply cannot exist without the necessary trace elements they need for life.
g. The issue of abyssal anoxia.
i. Abyssal waters are already anoxic, or nearly so.
ii. The farming system needs to be optimized so carbon-rich detritus falls rapidly through the photic zone and mid-level depths.
iii. Recent studies of turbidity currents flowing out from marine canyons transports massive amounts of organic carbon to the abyssal plains where the ocean that produces completely anoxic bottom water. These areas are quickly colonized by the kinds of organisms adapted to live in the anoxic areas around sea-floor vents that support complex ecosystems.
iv. Given that the alternative to sequestering carbon is likely to be global mass extinction worse than the End Permian ‘Great Dying’, abyssal anoxia is a trivial issue.
2. Ultrawhite paint reflects radiates more heat away than it absorbs
a. good for passive local cooling thereby reducing the need for electrical energy.
b. based on barium sulfate.
c. Barium is a comparatively rare element
d. unlikely to work for global scale geoengineering.