"Marine microalgae-based aquaculture can offer mutually beneficial investment opportunities for both wealthy and developing countries by providing climate mitigation while simultaneously enhancing global food and water security."

By mid-century, society will need to significantly intensify the out-put of its food production system while simultaneously reducing that system's detri-mental impacts on climate, land use, freshwater resources, and biodiversity. This will require finding alternatives to carbon emissions-intensive agriculture, which provides the backbone of today's global food production system. Here, we explore the hypoth-esis that marine algae-based aquaculture can help close the projected gap in society's future nutritional demands while simultaneously improving environmental sustain -ability. Food production from marine algae-based aquaculture has the potential to con-tribute more than the total global protein demand projected for 2050, which ranges from 263.8 Mt/yr to 286.5 Mt/yr. It also offers important nutritional and environmen-tal sustainability advantages relative to terrestrial agriculture. Marine algae can pro-vide a better source of high-quality nutritional protein, essential amino acids, and other micronutrients relative to terrestrial plants. In addition, because marine algae do not require soil, irrigation, and the open application of fertilizer, their cultivation does not need to compete with agriculture for arable land and freshwater nor does it lead to fer-tilizer runoff and downstream eutrophication. Furthermore, by reducing agriculture's demand for arable land and freshwater, marine algae-based aquaculture can reduce the pressure for deforestation, potentially leading to globally significant reductions in car-bon emissions and biodiversity loss.