Feeding the Planet in 2050
At NCEAS, Dean Steve Gaines discusses the potential role of aquaculture in meeting a projected 80% increase in global demand for protein over the next 35 years.
In June, Bren School dean, Steve Gaines, spoke at the UCSB National Center for Ecological Analysis and Synthesis (NCEAS) on the subject of major research being conducted by the Sustainable Fisheries Group, a collaboration between the Bren School and the UCSB Marine Science Institute. Bren School media liaison James Badham sat down with Dean Gaines and asked him about his talk.
JB: What is the challenge we face in terms of addressing future global food needs?
SG: It is estimated that by 2050, the global demand for animal protein may be 80 percent greater than it is now, for two main reasons: population and wealth. World population is expected to grow by 2.5 billion over the next 35 years, and wealth is increasing in developing nations. Historically, as people move from extreme poverty and become middle class, they dramatically increase their animal protein consumption. So the questions are, how will that food be produced, and what will be the impacts of producing it.
JB: Can it not be done on land?
SG: There are basically three ways to increase food on land. You can move more land into food production. That means cutting down wild forests, which has big consequences in terms of greenhouse gas emissions (GHGs) and biodiversity. You can use existing land more efficiently on the basis of what we already know how to do. That usually means more intense use of things like fertilizers, which can have negative consequences, like nutrient loading in rivers and coastal waters. Third are new technological advances. Those have led to big increases in food production in the past, but if they continue at their recent pace, they won't make a very big dent in meeting this future demand. Essentially, there are no great options for adequately increasing land-based food production enough to meet this demand.
A salmon farming operation in Chile
JB: A lot of the world's fisheries are facing challenges from things like overfishing. If the world's fisheries could recover, could they help address the protein challenge?
SG: One of best things we can do to start meeting the growth demand is to fix wild-caught fisheries. You get more food, plus environmental benefits and virtually no added environmental costs. It's sort of like the energy component of the GHG problem. More efficient light bulbs and things like that have a very short payback period. They're easy and they basically pay for themselves. That’s like the wild-fish side of the food problem.
JB: Are there limitations to that approach?
SG: Unfortunately, even if you could fix every wild fishery on the planet, you could only get about 10 percent of the projected 80-percent growth in demand. We're not saying you don't want to do that. We should be doing it as fast and as best we can, but it's not going to fix the problem.
JB: Can aquaculture supply the rest?
SG: In trying to understand the geographical scope of the challenge, we did a thought experiment. We said, suppose you try to meet the entire projected growth in protein demand purely by producing something like beef on land versus something like mussels in the ocean. To produce enough beef to meet the entire demand, you would need an area of land the size of South America. But you could produce exactly the same amount of protein just by growing mussels in a space less than the size of the continental shelf of New Zealand. We're not suggesting we put mussel farms everywhere and live only on mussels. But it's a useful comparison. Also, whereas there are no more South America???sized chunks of arable land, only a tiny fraction of the ocean is currently used for aquaculture.
JB: What about the much-discussed environmental impacts of aquaculture?
SG: Aquaculture gets more focus on its negative environmental impacts than almost anything I can think of in terms of food production. But it's not a level playing field for analysis. Yes, there are nutrient impacts from growing fish in pens and feeding them and the excess food and feces and things like that, which have to be addressed. There are issues with disease and antibiotics ??? a whole variety of things related to aquaculture that are not that different from the food-related impacts that occur on land. But until recently, no one had done the synthetic analysis to find out how the environmental impacts for aquaculture compare to other forms of food production, such as raising cattle. It's one thing to say, "I'm not going to eat farmed fish because it creates this environmental problem," but if the response is to choose something else that actually causes more of that problem and maybe other problems as well, we're not making informed choices.
SG: Over the past year, the Sustainable Fisheries Group has been working with [Bren professor] David Tilman's lab to pull together all the information from the life-cycle assessments (LCAs) of all forms of protein production from both land and sea. The goal is to be able to look across a variety of environmental impacts, such as GHGs, nutrient loading of watersheds, water use, and the biodiversity implications related to the amount of land or water you have to set aside. The striking thing that's coming out of this is that even if we look at just average practices in aquaculture today, not best practices, they're substantially better than most forms of land-based agricultural production. If you look at best practices in aquaculture, there's nothing comparable in terms of land-based meat production that has such a low level of environmental impacts in all these different metrics.
The point is not that there are no environmental impacts of aquaculture; there are impacts for all forms of protein production. The idea here is to make a full, level-playing-field analysis to help us think though what the consequences are of a variety of different policy options related to creating enough food in the future with the least impacts. The environmental impacts resulting from using aquaculture can be hundreds of times less than those generated by producing the same amount of protein on land.
JB: Is aquaculture improving?
SG: Because it is a comparatively new kind of food production, the range between average and best aquaculture practices is big. But because it is in its infancy, there is probably huge potential for reducing some of those impacts. Despite the fact that the impacts of average practices are already significantly lower than those associated with land-based protein production, there's still a lot of opportunity for technology to reduce those impacts dramatically.
JB: What did you want the audience to take away from the talk?
SG: That the oceans have an enormous amount to contribute in meeting the growing demand for protein, and that compared with comparable land options, aquaculture has a much smaller environmental footprint in virtually every metric that we can measure.