Unless humanity achieves United Nations Sustainable Development Goals (SDGs) by 2030 and restores the relatively stable climate of pre-industrial CO₂ levels (as early as 2140), species extinctions, starvation, drought/floods, and violence will exacerbate mass migrations. This paper presents conceptual designs and techno-economic analyses to calculate sustainable limits for growing high-protein seafood and macroalgae-for-biofuel. We review the availability of wet solid waste and outline the mass balance of carbon and plant nutrients passing through a hydrothermal liquefaction process. The paper reviews the availability of dry solid waste and dry biomass for bioenergy with CO₂ capture and storage (BECCS) while generating Allam Cycle electricity. Sufficient wet-waste biomass supports quickly building hydrothermal liquefaction facilities. Macroalgae-for-biofuel technology can be developed and straightforwardly implemented on SDG-achieving high protein seafood infrastructure. The analyses indicate a potential for (1) 0.5 billion tonnes/yr of seafood; (2) 20 million barrels/day of biofuel from solid waste; (3) more biocrude oil from macroalgae than current fossil oil; and (4) sequestration of 28 to 38 billion tonnes/yr of bio-CO₂. Carbon dioxide removal (CDR) costs are between 25–33% of those for BECCS with pre-2019 technology or the projected cost of air-capture CDR.

A framework is presented with examples of technologies capable of achieving carbon neutrality while sequestering sufficient CO to ensure global temperature rise less than 1.5°C (after a small overshoot), then continuing to reduce CO levels to 300 ppm within a century. Two paths bracket the continuum of opportunities including dry, sustainable, terrestrial biomass (such as , paper, and plastic) and wet biomass (such as macroalgae, food, and green waste). Suggested paths are adaptable, consistent with concepts of integral ecology, and include holistic, environmentally friendly technologies. Each path addresses food security, marine plastic waste, social justice, and UN Sustainable Development Goals. Moreover, oceanic biomass-to-biofuel production with byproduct CO sequestration simultaneously increases ocean health and biodiversity. Both paths can accomplish net-zero fossil-CO emissions by 2050. Both paths include: (1) producing a billion tonnes/yr of seafood; (2) collecting six billion dry tonnes of solid waste (any mix of organic waste, paper, and plastic) to produce twenty million barrels/day of biocrude; and (3) installing a million megawatts of CO-sequestering (Allam Cycle) electric power plants initially running on fossil fuels. Resulting food production, solid waste-to-energy, and fossil-fueled Allam Cycle infrastructure will strengthen the economies in developing countries. Next steps are (4) sequestering four billion tonnes of byproduct CO/yr from solid waste-to-biofuel by hydrothermal liquefaction; (5) increasing macroalgae-for-biofuel production; (6) replacing fossil fuel with terrestrial biomass for Allam Cycle power plants; (7) recycling nutrients for sustainability; and (8) eventually sequestering a total of 28 to 38 billion tonnes/yr of bio-CO for about $26/tonne, avoided cost.

A framework is presented with examples of technologies capable of achieving carbon neutrality while sequestering sufficient CO to ensure global temperature rise less than 1.5°C (after a small overshoot), then continuing to reduce CO levels to 300 ppm within a century. Two paths bracket the continuum of opportunities including dry, sustainable, terrestrial biomass (such as , paper, and plastic) and wet biomass (such as macroalgae, food, and green waste). Suggested paths are adaptable, consistent with concepts of integral ecology, and include holistic, environmentally friendly technologies. Each path addresses food security, marine plastic waste, social justice, and UN Sustainable Development Goals. Moreover, oceanic biomass-to-biofuel production with byproduct CO sequestration simultaneously increases ocean health and biodiversity. Both paths can accomplish net-zero fossil-CO emissions by 2050. Both paths include: (1) producing a billion tonnes/yr of seafood; (2) collecting six billion dry tonnes of solid waste (any mix of organic waste, paper, and plastic) to produce twenty million barrels/day of biocrude; and (3) installing a million megawatts of CO-sequestering (Allam Cycle) electric power plants initially running on fossil fuels. Resulting food production, solid waste-to-energy, and fossil-fueled Allam Cycle infrastructure will strengthen the economies in developing countries. Next steps are (4) sequestering four billion tonnes of byproduct CO/yr from solid waste-to-biofuel by hydrothermal liquefaction; (5) increasing macroalgae-for-biofuel production; (6) replacing fossil fuel with terrestrial biomass for Allam Cycle power plants; (7) recycling nutrients for sustainability; and (8) eventually sequestering a total of 28 to 38 billion tonnes/yr of bio-CO for about $26/tonne, avoided cost.

Unless humanity achieves United Nations Sustainable Development Goals (SDGs) by 2030 and restores the relatively stable climate of pre-industrial CO2 levels (as early as 2110), species extinctions, starvation, drought/floods, and violence will exacerbate mass migrations. This paper presents conceptual designs and techno-economic analyses to calculate sustainable limits for growing high-protein seafood and macroalgae-for-biofuel. We review the availability of wet solid waste and outline the mass balance of carbon and plant nutrients passing through a hydrothermal liquefaction process. The paper reviews the availability of dry solid waste and dry biomass for bioenergy with CO2 capture and storage (BECCS) while generating Allam Cycle electricity. Sufficient wet-waste biomass supports quickly building hydrothermal liquefaction facilities. Macroalgae-for-biofuel technology can be developed and straightforwardly implemented on SDG-achieving high protein seafood infrastructure.). The analyses indicate a potential for (1) 0.5 billion tonnes/yr of seafood; (2) 20 million barrels/day of biofuel from solid waste; (3) more biocrude oil from macroalgae than current fossil oil; and (4) sequestration of 28 to 38 billion tonnes/yr of bio-CO2. Carbon dioxide removal (CDR) costs are between 25−33% of those for BECCS with pre-2019 technology or the projected cost of air-capture CDR.

A framework is presented with examples of technologies capable of achieving carbon neutrality while sequestering sufficient CO to ensure global temperature rise less than 1.5°C (after a small overshoot), then continuing to reduce CO levels to 300 ppm within a century. Two paths bracket the continuum of opportunities including dry, sustainable, terrestrial biomass (such as , paper, and plastic) and wet biomass (such as macroalgae, food, and green waste). Suggested paths are adaptable, consistent with concepts of integral ecology, and include holistic, environmentally friendly technologies. Each path addresses food security, marine plastic waste, social justice, and UN Sustainable Development Goals. Moreover, oceanic biomass-to-biofuel production with byproduct CO sequestration simultaneously increases ocean health and biodiversity. Both paths can accomplish net-zero fossil-CO emissions by 2050. Both paths include: (1) producing a billion tonnes/yr of seafood; (2) collecting six billion dry tonnes of solid waste (any mix of organic waste, paper, and plastic) to produce twenty million barrels/day of biocrude; and (3) installing a million megawatts of CO-sequestering (Allam Cycle) electric power plants initially running on fossil fuels. Resulting food production, solid waste-to-energy, and fossil-fueled Allam Cycle infrastructure will strengthen the economies in developing countries. Next steps are (4) sequestering four billion tonnes of byproduct CO/yr from solid waste-to-biofuel by hydrothermal liquefaction; (5) increasing macroalgae-for-biofuel production; (6) replacing fossil fuel with terrestrial biomass for Allam Cycle power plants; (7) recycling nutrients for sustainability; and (8) eventually sequestering a total of 28 to 38 billion tonnes/yr of bio-CO for about $26/tonne, avoided cost.