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21/10/2010
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Willem Brandenburg
To meet the increasing demand for agricultural products from a world population that will grow to 9.3 billion people in 2050, agricultural production must double. The essential problem is not whether this increased production is possible, but whether it can be achieved sustainably. This question is not easy to answer in view of all the competing claims on land and the need to maintain biodiversity. Consequently, considering sustainable marine agriculture is not a futuristic fantasy, but a necessity. It is comparable to the transition we made 10,000 years ago from hunting and gathering to agriculture and animal husbandry on land, but with the expertise and experience resulting from 10,000 years of agriculture.
Seaweed has been used as food for centuries, especially in Southeast Asia. For this purpose it is not only collected in coastal waters, but is also cultivated to a limited extent. Beginning in 1950, the production of seaweed start increasingly rapidly, especially in China, and has since matured into a full-fledged industry.
To double agricultural production, plant production must certainly be doubled; to achieve this target sustainably, we must turn to the ocean. And we must consider locations where we do not adversely affect the hotspots of marine biodiversity. We can utilise nutrients that have entered the ocean as a result of human activities.
Regarding food security, by 2050 the protein supply will play a central role. It now appears that seaweeds can provide an important part of this protein. Some seaweeds have a high protein content (above 25% in dry matter), and this protein is comparable in functionality to animal proteins. This means that the plant production systems of the future can safeguard the protein supply and simultaneously reduce the ecological footprint of food production. To supply all the protein required for human nutrition in 2050, only 180,000 km2 of seaweed production area would be required; this is equivalent to an area twice the size of Portugal.
In addition, in terrestrial agricultural production, phosphorus is becoming increasingly scarce. Now that we understand that every year approximately 30 million tonnes of phosphorus – more than the total amount of phosphate mined annually – enters the ocean [from runoff], it is a logical step to recycle this mineral. Why not do this in such a way that we first utilise this mineral for seaweed production, after which it can be extracted and used in terrestrial agriculture?
Willem Brandenburg, Wageningen UR Plant Research International / Agrosystems research