Why Seaweed Is Not A Sustainable Food Option.
Farmed seaweed, particularly kelp, is often promoted as the future of food. The odds are that it will not be unless the industry makes dramatic changes that will require large investments and changes in the supply chain.
Farming kelp removes carbon from the ocean, requires no arable land, and requires no fresh water. All good news. Farming seaweed has been promoted as being a climate and ocean friendly food that helps support local coastal communities.
The bad news is that seaweed is highly perishable and must be stabilized in a shelf stable form within a day or so of harvest. This stabilization is often either drying, blanching and drying or freezing, or just freezing. All these methods are extremely energy intensive. In fact, these methods actually return more CO2 to the ocean than the weight of the seaweed harvested, and twice that amount to the atmosphere. Keep in mind this just to stabilize the seaweed which still needs to be processed into a food for consumers—another significant contributor to greenhouse gas emissions.
Eating seaweed today simply not sustainable.
Is there a way to reduce the carbon footprint of seaweed? There is. Solar drying which has been used for centuries has very low carbon footprint. This is why companies like Springtide Seaweed, LLC in Gouldsboro Maine only solar dries its seaweed for a near carbon neutral product.
Unfortunately, solar drying is not an option for most seaweed farmers. First, there is limited access to drying facilities which are generally greenhouses. Second, seaweed farming leases are commonly seasonal. This means that these farms must be fully harvested in a short period of time, often days, which means large amounts of seaweed must be quickly stabilized or destroyed. Thus, why so much seaweed is frozen.
So, what can be done if seaweed is to be a viable food? One is investment in solar drying facilities or facilities that utilize geothermal or other sustainable energy sources. The other is modifying seaweed farm leasing terms so that farmers can harvest over months versus days so that as not to overwhelm existing drying capacity.
What to do now if you care about climate change? The only sustainable option is to only consume solar dried seaweeds or seaweeds that can document little or no greenhouse gas emissions in stabilization.