POTENTIAL USE OF ENGINEERED NANOPARTICLES IN OCEAN FERTILIZATION FOR LARGE-SCALE ATMOSPHERIC CARBON DIOXIDE REMOVAL

Since 1850, the 10 warmest years have all occurred in the last decade, and Earth is already at 1.35° C warmer relative to pre-industrial levels. Globally, it is now realized that our dangerously warming planet is far from having these trends reversed without massive and affordable CO₂ removal from the atmosphere in the relatively near future. This is despite important and often successful attempts to begin to reign in CO₂ emissions, to expand solar and wind energy even ahead of expectations, and to greatly improve machine and grid efficiencies. On the other hand, the oceans already absorb likely between a quarter and a third of the CO₂ that humans put into the atmosphere each year. The CO₂ ends up dissolved in sea water, some taken up by phytoplankton, which is partly stored as biomass in the deep ocean for decades to millennia.

Ocean experiments in the past have already shown that small amounts of iron distributed in parts of the oceans that lack sufficient nutrients, and therefore have low phytoplankton populations, can be stimulated, resulting in more photosynthesis, and therefore more CO₂ uptake. However, these original in situ experiments were rudimentary and many more are needed to refine the process, with the intent to duplicate nature as closely as possible and to keep the oceans in a healthy, balanced state. We describe in this talk ways that, in principle, synthetic nanoparticles can be designed to stimulate efficient phytoplankton population growth, and to possibly enhance phytoplankton aggregation and sinking so that a significant amount of biomass can reach ocean depths that will result in durable carbon storage. Modern nanotechnology could show the way to making ocean fertilization a reasonable and affordable way to sequester a substantial amount of atmospheric CO₂ per year, significantly and affordably slowing global warming.