183 gigatons of CO2 are fixed by marine algae every year (Field et al., 1998).
~20.6% of that carbon fixation is performed by coastal microalgal blooms. Yet, none of this enormous capacity is used for deliberate Direct Air Capture to mitigate climate change. What if we brought some of these algal blooms onto unused desert land? Would it be possible, and would it make any difference?
This presentation outlines how to bring the power of the ocean onto land, while de-acidifying very large volumes of seawater to pre-industrial levels. With a little local help, combining abundantly available, seawater and seawater-based nutrients, sun, land and low levels of renewable energy enables natural microalgae to sequester CO2 at gigaton scale in coastal deserts. Importantly, this can be done in a truly additive way, where no ecosystem services or other resources are depleted or displaced.
There is no competition for agricultural or forested land, no freshwater is used, no fisheries are affected. We outline that this can be done worldwide, at surprisingly low cost, with existing equipment and well-established tools, learning from established industries. Many aspects of the technology take advantage of recent advances in remote sensing, in-pond sensor technology and ecosystem physiology. All aspects of this approach can be accessed, measured, verified and reported well within the local boundaries of host countries to ensure adoption and supportive regulation of the process.