Restoring pre-industrial CO2 levels while achieving Sustainable Development Goals

A framework is presented with examples of technologies capable of achieving carbon neutrality while sequestering sufficient CO2 to ensure global temperature rise less than 1.5°C (after a small overshoot), then continuing to reduce CO2 levels to 300 ppm within a century. Two paths bracket the continuum of opportunities including dry, sustainable, terrestrial biomass (such as Miscanthus, 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 CO2 sequestration simultaneously increases ocean health and biodiversity. Both paths can accomplish net-zero fossil-CO2 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 CO2-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 CO2/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-CO2 for about $26/tonne, avoided cost.