There are 7.9 billion people on Earth today, and by 2050 there will be 9.7 billion . The challenge of feeding a growing world population while preserving our environment is a major one.
Many countries are already suffering from food and water shortages, and the amount of arable land is decreasing dramatically every year (urbanisation, erosion and soil depletion) . It is therefore urgent to find solutions to safeguard these natural resources, slow down environmental damage and thus ensure our food security.
Algae could be part of the solution: they are the least widely used in the world, although these marine plants have many advantages.
Algae exploitation: big gains in land and water
The 2021 FAO (Food and Agriculture Organisation) report on the state of the world’s land and water resources warns of the pressures they are under. Anthropogenic land degradation and water scarcity have reached such a level that they compromise the productivity of major agricultural systems. There is limited scope for expansion of cultivated land and irrigation already accounts for 70% of all freshwater withdrawals .
The development of algal farming and the exploitation of wild edible algae could help to stem these problems:
- Algae do not encroach on agricultural land. It takes up 20 to 30 times less land than terrestrial agriculture: one hectare of cultivated algae is capable of producing as much as about 20 hectares of soybeans or 50 hectares of corn .
- Algae do not need fresh water either to grow or to be processed. In most food processes, they are rinsed with sea water. For example, 1,000 litres of fresh water are needed to produce 1 kilo of rice, 400 litres for 1 kilo of chicken  and zero litre for 1 kilo of algae.
In these respects, algae production is much less exposed to the effects of climate change than other land-based crops.
Algae: a sustainable solution
The majority of pressures on land, soil and water resources come from agriculture. The use of chemical inputs, farm mechanisation and grazing pressure is increasing. Environmental damage is increasing, and the growth of agricultural production is slowing down.
The 2021 FAO report on the transformation of food systems calls for the large-scale development of more environmentally responsible and intelligent production to reverse these trends . Algae meet a wide range of criteria, including the following:
- Algae need only salt water and sunlight to grow: no chemical inputs or human intervention are required.
- While agriculture contributes to about 24% of global greenhouse gas emissions, this crop generates none. On the contrary, algae capture and store carbon dioxide in the long term. The carbon footprint of algae farming is also very low: 296 kilograms per ton of consumable protein (far behind all meat production) . They are therefore a natural solution to combat global warming.
- About 50% of photosynthesis on Earth is carried out by marine algae and microalgae, contributing to the release of oxygen. Without aquatic plants, life on Earth would not be possible .
Due to the low investment required for its implementation, algae cultivation is gaining popularity, especially among coastal populations. Although some constraints are identified, the mitigation and adaptation features of climate change promise a flourishing future for algae farming.
Algae: a nutritional concentrate for everyone
No natural element provides as many nutrients as algae. Low in fat and high in proteins, fibres, minerals (calcium, magnesium, sodium), vitamins (B12, A, K) and essential trace elements (iodine, zinc, iron), algae have the potential to contribute to the human food system, as well as to terrestrial and aquatic animals and crop nutrition .
The prebiotic compounds and essential minerals contained in algae can improve livestock production and health, as well as replace the use of antibiotics in intensive livestock production.
For crop production, the potential benefits of algae are soil improvement through biochar (natural soil improver), nutrient rich compost and the biostimulant effect of algae extracts. This would increase crop productivity while avoiding emissions from synthetic fertiliser production .
Food systems are affected by environmental degradation, but they also have an impact on the state of the environment and are an important factor of climate change. One of the ways proposed by the FAO to ensure global food security is therefore to encourage consumers to promote eating habits that have a positive impact on human health and on the environment . As algae contribute to providing nutritious food for all (humans, animals and plants) with a low carbon footprint, the popularisation of algae in Western diets and agricultural production patterns can contribute to addressing the food challenge.
Larger-scale exploitation of algae must include intelligent and careful management of the marine environment so as not to repeat the mistakes made with “terrestrial” agricultural productions.
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