One study that has attracted attention in the high-tech algae industry recently concluded that if the world replaced a modest amount of its animal feed with algae-derived alternatives we could make a huge impact on atmospheric greenhouse gas concentrations.
Algae can be cultivated on non-marginal lands, using salt water or wastewater, and consume huge volumes of CO2 as they grow, so it makes sense that they could have a big impact in both agriculture and climate change efforts.
To make really big reductions the study recommended layering on a little carbon capture and sequestration (CCS) too. CCS is the process of capturing carbon emissions from a power plant before they enter the atmosphere and pumping them very deep underground where they will be permanently stored.
While CCS has been criticized for being expensive, the authors note that when combinedif the technology is combined with the use of algae-based feeds, we wouldn’t have to capture 100% of emissions from our power plants. In fact, my favorite part of the study might be this graphic that shows what atmospheric concentration we could achieve by using certain proportions of algae-feed and CCS.
A range of energy sector emissions mitigation from CCS (at top) are applied to a range of algae production scenarios (listed at left as percentages of total feed consumption). Yellow shaded cells indicate warming of 2.0 ± 0.2 ∘C. Red shaded cells indicate warming projections in excess of this threshold, while green shaded cells indicate sub-1.8 ∘C warming
Want to limit temperature changes to within 2 degrees C? The chart shows you need to replace only 10% of our livestock feed with algae, and capture only 25% of emissions from the energy sector.
Want net zero emissions? Go for a mix of 40% feed replacement and 25% CCS.
Want to go backwards and limit CO2 to 310 ppm, similar to levels we enjoyed in 1950s? You’ll need to replace 40% of feed with algae, along with at 75% capture rate.
It’s true that large-scale algae cultivation and CCS are technologies are just beginning to get traction, yet we found this story inspiring for illustrating just how big an impact they may have.