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Environmental Impact of Edible Insects

When insects are produced, either as a source of food or animal feed, this has an impact on the environment just like any other food production. When comparing the environmental footprint of proteins from insect with proteins from other animals, the conclusion is unambiguous.

Insects emit fewer greenhouse gases than cattle and require significantly less land and water for rearing. They also convert feed to protein more efficiently than livestock animals. Some species can be successfully grown on organic side streams, reducing environmental contamination, while converting low-value organic by-products such as food waste into high-value proteins.

Land and water use

Agriculture consumes about 70 percent of freshwater worldwide. Producing 1 kg of animal protein requires 5–20 times more water than generating 1 kg of grain protein. This figure approaches 100 times if the water required for forage and grain production is included in the equation.

When compared to chicken, 1 g of edible protein requires two to three times as much land and 50% more water compared to mealworms. A gram of edible protein from beef requires 8–14 times as much land and approximately 5 times as much water compared to mealworms.

Greenhouse gas emissions

With respect to greenhouse gas emissions, mealworms have a lower environmental impact than convention livestock systems. Broiler chickens are associated with 32–167% higher emissions, and beef cattle emit 6–13 times more CO2 equivalents, when compared to mealworms on an edible protein basis.

Among insect species, only cockroaches, termites and scarab beetles produce CH4.

greenhouse gas emissions of various animalsThe cost in terms of CO2 emissions associated with producing one kilo of insects and other types of livestock. Beef and lamb are the least environmentally friendly options, while fish and insects are the best. Danish chicken farms also have a relatively low carbon footprint. (Illustration: Afton Halloran, University of Copenhagen)

Feed Conversion Efficiency of Insects

One of the main reasons why insects are considered as potentially sustainable sources of animal protein is because of their high feed conversion efficiency. Whereas poultry provided with optimized diets converts 33% of dietary protein to edible body mass, yellow mealworms utilize 22–45% of dietary protein, black soldier fly larvae about half (43–55%), and Argentinean cockroaches 51 to 88%.

Feed-to-meat conversion rates (how much feed is needed to produce a 1 kg increase in weight) vary widely depending on the class of the animal and the production practices used. Typically, 1 kg of live animal weight in a typical commercial production system requires the following amount of feed: 2.5 kg for chicken, 5 kg for pork and 10 kg for beef. Insects require far less feed. For example, the production of 1 kg of live animal weight of crickets requires as little as 1.7 kg of feed.

feed conversion chart
Efficiencies of production of conventional meat and crickets.

Reducing Organic Waste

A number of species can successfully be grown on organic side streams, converting low-value organic by-products into high-value proteins. This is particularly important considering that on a yearly basis, 27% of all agricultural produce is wasted and 22%i f only the edible part is taken into account, or globally 1.6 and 1.3 billion t, respectively.

The by-product that can be used depends on the insect species. Mealworms, for instance, can be raised on dried organic waste materials from fruit and vegetable origins.

The best-known species for utilizing waste streams, such as rice straw, coffee pulp, fish offal, catering waste and swine, chicken and cattle manure  is the black soldier fly. It utilizes this waste and can simultaneously kill pathogenic bacteria such as Escherichia coli or Salmonella enterica present in, for instance, chicken or cattle manure.

Circular protein economy with insects

Insects offer a unique opportunity to address two of the major global challenges: protein supply and organic waste disposal. By recycling nutrients from organic waste and bringing them back into the local food value chain, large portions of the otherwise lost proteins can be recovered and turned again into valuable feeds or foods.

circular protein economy with insects
(Source: Bühler Insect Technology Solutions)

Life cycle assessment of insect production

Life cycle assessment is a technique to assess the environmental impacts associated with all stages of a product’s life, but of the edible insects only mealworms have been assessed in this way.

This study found that energy usage for the production of 1 kg of mealworm protein was lower than for beef, comparable with pork, and slightly higher than for chicken and milk. GHG emissions due to mealworm production were much lower than for the more common production animals. For every 1 ha of land required to produce mealworm protein, 2.5 ha would be required to produce a similar quantity of milk protein, 2–3.5 ha would be required to produce a similar quantity of pork or chicken protein, and 10 ha would be required to produce a similar quantity of beef protein. On the basis of this study, therefore, mealworms are a more environmentally friendly source of animal protein than milk, chicken, pork and beef.

Greenhouse gas production (global warming potential), energy use and land use due to the production of 1 kg of protein from mealworms, milk, pork, chicken and beef. The grey bars are minimal values and the dark green bars are maximum values found in the literature. (Source: Oonincx and de Boer, 2012)