The burning of fossil fuels (coal, oil and gas) is the major driving force for global warming¹. However, livestock rearing is responsible for around 18% of the anthropological greenhouse gas emissions (CO2 equivalent) and various edible insects are therefore excellent alternatives to meat in the fight against climate change. It is estimated that insects today is part of the diets of 25-30% of the global population and about 1,900 species are being used as human consumption. The following examine the climate- and environmental impact of different species of insects versus beef, pigs and chicken.
These are the most commonly consumed insects:
With regard to greenhouse gas emissions one study (Source 1, pdf page 79) suggests that 1 kg of edible insects such as beetles (mealworm), locusts and crickets emits about 1% of the emissions from 1 kg of pork or beef – which clearly illustrates the huge perspectives. Note that the global warming impact of beef or lamb is about 2-4 times the one of pork, and 4-10 times the one of chicken. Cattle (raised for both beef and milk) are responsible for almost two-third of the livestock sector’s emissions (Source 8, Key findings). However, due to different livestock rearing practices around the world the emission-variations per kg are large.
When consuming a range of different species the insects are highly nutritious with high content of protein, vitamin, fibers and minerals. Within the same group of species the nutritional value (and taste) may differ, depending on the stage of the insect and its diet.
The environmental benefits of rearing insects are mostly founded on the high feed conversion efficiency, in comparison with beef, pigs and chicken. Crickets, for example, require only 2 kg of feed for every 1 kg of bodyweight gain. In addition, insects can be reared on organic waste from humans and animals. Insects are also reported to emit less ammonia (urine and manure) than cattle or pigs. One study concluded that rearing of mealworm larvae, crickets and locusts emits about one tenth of the ammonia from pigs. Furthermore, production of insects requires significantly less land. Small-scale experiments (Source 1, pdf page 80) showed that mealworm protein produced on 1 ha of land would require 2.5 ha to produce a similar quantity of milk protein, 2–3.5 ha to produce pork or chicken protein, and 10 ha to produce beef protein. Note that habitat modification by livestock grazing can sometimes benefit the wildlife.
It is estimated that, by 2025, 1.8 billion people will be living in countries or regions with water scarcity and that two-thirds of the world population will likely be under stress. Agriculture consumes about 70% of the freshwater worldwide and the production of 1 kg beef requires 22,000 liters of water (or even more), 1 kg pork requires 3,500 liters and 1 kg chicken requires 2,300 liters (Source 1, pdf page 80). The volume of water required to raise 1 kg of edible insects is yet unknown, but is likely to be considerably lower.
The concept of farming insects for food is relatively new. In the tropics, cricket farming for human consumption are well established in Thailand, Laos and Vietnam. In temperate zones large scale insect rearing of mealworms, crickets and grasshoppers is mainly focused on pets and zoo-animals. However, in some firms a small fraction of insects is now intended for human consumption. In addition, a few industrial-scale enterprises in various stages of start-up for rearing insects for human consumption as whole insects or processed into meal for feed. Insects can also be processed into granular or paste forms, and extracting proteins, fats, chitin, minerals and vitamins is possible as well.
A major challenge of industrial-scale insect rearing is the development of automation processes to make rearing economically competitive with the production of meat. Critical elements for success include research on insect biology, diet formulas and rearing condition control. Nevertheless, insects are the food of the future.
¹As an ‘Example‘, around 82% of all anthropologic greenhouse gases in the United States are related to coal, oil or natural gas. This measure includes emissions of three different greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Globally, the animal sector’s contribution to greenhouse gas emissions is estimated to be: Carbon dioxide (CO2) 9%, Methane (CH4) 35-40%, and Nitrous oxide (N20) 65%.
Land area dedicated to livestock or feed-production covers about 29% of the Earth’s total land area. A hypothetical example: If half the global livestock meat production were to be replaced with production of edible insects with similar protein value, then 7-13% of the Earth’s land area would be released to other uses (with extreme caution due to lack of solid data). For comparison the precious Primary Forests cover 9.5% of the global land area, which is less than one-third of the total Forest Cover.
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