Update: a interesting and tought provokin presentation on this paper by the author is filmed here
When Ray Hilborn publishes a new paper, you know that controversy will start soon after, environmentalist see him as an ultra-optimistic at best and a fishing industry apologist at worst. I been to a couple of his talks (in fact once he quoted something I sent him). His wife is (or was) an organic farmer, and while people may disagree, I allways found his arguments convincing and well-grounded in solid research.
Radar plots comparing environmental impacts (a) between different food production methods, (b) within aquaculture production methods, (c) within livestock production methods, and (d) within capture fisheries across all four impact categories examined (energy demand [MJ], GHG emissions [CO2-eq], eutrophication potential [PO4-eq], and acidification potential [SO2-eq]). Solid lines represent median impacts across broad food production system categories (ie aquaculture, livestock, capture fisheries); dashed lines represent median impacts of product subcategories (eg salmon aquaculture). From Hilborn et al. 2018
I always liked his efforts in measuring the environmental cost of food production, which is an area that many people that criticise fisheries, seems to conveniently forget. In a similar vein, recreational fishers are quick to point to the levels of biomass extracted and discards by the comercials, yet never mention the obnoxious amounts of fuel consumed and greenhouse emission produced per kg of fish by their wildly inefficient outboards. I really believe that in fisheries, pointing fingers to others only does not help... we all need to do better... end of story.
Anyway, in a paper published yesterday in the journal Frontiers in Ecology and the Environment, in what Hilborn and co-authors believe it is the most comprehensive look at the environmental impacts of different types of animal protein production, this is discussed with a lot of detail.
This is a compressive review that based on nearly a decade of analysis, in which he and his co-authors reviewed hundreds of published life-cycle assessments for various types of animal protein production. Also called a “cradle-to-grave” analysis, these assessments look at environmental impacts associated with all stages of a product’s life.
Of the more than 300 such assessments that exist for animal food production, the authors selected 148 that were comprehensive and not considered too “boutique,” or specialized, to inform their new study. The results are quite "illuminating".
The paper can be accessed accessed from the links in the sustainablefisheries-uw.org page, from where I sourced part of the text of this entry, or directly from here.
They start by recognising that something that many people seem to forget: Currently, agriculture uses 38% of the world’s land and accounts for over 90% of freshwater use. Farming and food production has been and continues to be, the largest driver of habitat and biodiversity loss on the planet.
Quantifying environmental costs of animal protein
The 148 different life-cycle assessment papers (also known as “cradle-to-grave” analysis) used as references, studied the environmental impacts associated with every aspect of animal protein as food. The researchers quantified 4 different kinds of major environmental impacts caused by food production:
- electricity/energy use;
- greenhouse gas emissions;
- potential for nutrient runoff—this causes most of the world’s water quality issues;
- potential to cause air pollution.
By standardizing environmental impacts per 40g/protein produced researchers were able to compare different kinds of animal proteins. Basically, the paper answers the question: what are the environmental costs of producing a hamburger patty’s worth of protein from different animal sources?
This is not small task, ince the found out that there are up to 100‐fold differences in impacts between specific products and, in some cases, for the same product, depending on the production method being used.
Energy & Greenhouse Gasses
- Overall, livestock production uses less energy than most forms of seafood aquaculture. Farmed catfish, shrimp and tilapia use the most energy, mainly because constant water circulation must be powered by electricity. Climate impacts depend on the source of electricity. A tilapia farm powered by solar energy will be much less impactful than one that gets its electricity from a fossil fuel power plant.
- Catfish aquaculture and beef produce the most amount of greenhouse gases.
- Best choices for low-carbon protein are: small capture fisheries (like anchovy, herring, or sardines); farmed mollusks— such as oysters, mussels and scallops; whitefish like pollock, cod and haddock; farmed salmon; and chicken.
- For capture fisheries, fuel to power fishing boats is the biggest factor, but fuel use varies dramatically depending on the kind of fish being caught and the gear being used. For example, using a purse seine net to catch small schooling fish like herring and anchovy uses the least fuel, while, perhaps surprisingly, pot fisheries for lobster use a great deal of fuel and have the highest impact per 40g of protein produced. Dragging nets through water, known as trawling, is quite variable and the impact appears related to the abundance of fish. Healthy stocks take less fuel to capture.
Nutrient runoff & Air Pollution
- In addition to using very little energy, mollusk aquaculture actually absorbs excess nutrients that are harmful to ecosystems. Farmed mollusks also produced the least amount of air pollution, with small capture fisheries and salmon aquaculture close behind.
- Livestock beef production has many environmental issues. Manure washed away by rain is a major concern for healthy waterways. Also, because cows produce methane, they contribute to pollution that causes acid rain.
- Capture fisheries scored best in nutrient runoff because no fertilizer is used.
An interesting takeaway:
- When compared to other studies of vegetarian and vegan diets, a selective diet of aquaculture and wild capture fisheries can have a lower environmental impact than either of the plant-based diets.
This later, of course, will cause a lot a noise, for sure…
My take is: I’m culturally primed to listen (and read) to my elders (those who know more than me) as much as I can. Then I keep what I think is the best they have to offer. I’m sure we all have an angle on everything, but I never understood why some angles would be better than others? Is up to you to decide where you fit in the opinion spectrum. Yet there is something I’m totally sure: truth is never at the extremes of it, and to live is to compromise. How far do these compromises go? Well, that is a matter of personal choice and/or public policy, but I believe this cannot be determined unequivocally by science.