By Emma Bryce

Anthropocene Magazine

October 2022

There’s an opportunity to feed the world by farming fast-growing algae on marginal coastal lands around the globe, researchers show in a recent study. 

The highlights:

• Nutrient-rich algae could be farmed along coastlines in ponds of seawater pumped up from the ocean.  

• The system could produce enough food to feed 10 billion people in the next 25 years.

• It would use one-tenth of the area now required by conventional food production.

• The farmed algae would require less resources—no soil, no freshwater, and less fertilizer —than conventional crops.

• Much of the production land would be in places like coastal desert environments and wouldn’t compete with other uses.

• The single-celled algae has highly efficient growth -- 10 times faster than regular crops. 

Algae farming could contribute “significantly to reducing the carbon footprint of our food production system and the detrimental environmental impacts of agriculture,” says Charles Greene, the lead author on the new Oceanography study and professor of earth and atmospheric sciences at Cornell University.

He and his research team relied on GIS models to identify locations across the planet that are close to the sea and have the right levels of sunlight to propel the growth of single-celled algae. 

They identified the most suitable locations in southern parts of the planet—which may help shift centers of global food production from the north to the south, the researchers believe.

If produced across the identified area, algae alone could generate more than the total planetary protein demand projected for 2050. That’s in addition to providing a rich source of minerals and omega-3 fatty acids, among other things. 

As for how to make algae palatable to consumers, Greene explains that when dried and powdered, the algae could be “added to the supply chain for meat substitutes, cheese substitutes, dairy substitutes, and baked-good substitutes. The marketed products will have the taste, look, smell, and texture of the foods that people have traditionally consumed.”

He added that plenty of countries, especially in Asia, already consume algae as part of a regular diet.

Algae additives are already part of several widely-eaten foods:  meat products, such as pasty, steaks, frankfurters and sausages, as well as to fish, fish products, and oils. Cereal-based products, such as pasta, flour and bread, are another group of products enriched with algae.

There are a few caveats the researchers recognize in their projections, such as algae’s huge nutrient demand, which would eat into global phosphorus reserves and may require alternatives. Rapidly-growing algae also absorb CO2 faster than it can diffuse from air into water, meaning additional CO2 would have to be pumped into algae ponds to aid growth — which could be costly in both energy and financial terms.

These may prove to be big hurdles to overcome. But we need to make some shifts away from our conventional food systems if we’re going to meet future challenges. 

Algae farming is one vision of how to do that—and it could contribute “significantly to reducing the carbon footprint of our food production system and the detrimental environmental impacts of agriculture,” Greene says.