Dining on crickets, locusts, or even cockroaches, instead of cattle or pigs, could ease both food insecurity and climate change, according to researchers.
Insects caught in the wild are already eaten widely in the developing world. Now a study says that farming them on a large scale for food would damage the environment far less than equivalent livestock production.
Scientists compared emissions, by livestock and by insects, of the greenhouse gases methane and nitrous oxide, which have a greater warming effect than carbon dioxide. They also measured ammonia production, which harms the environment by acidifying soil and water.
They reared mealworms, locusts and crickets, all of which are consumed around the world, as well as sun beetles and cockroaches, which people do not eat, despite their potential as a protein source, while monitoring the amount of gas produced per kilogram of insect growth.
Compared to cattle, weight for weight, insects emitted 80 times less methane — a gas with 25 times more impact on global temperature levels than carbon dioxide.
And crickets produced 8–12 times less ammonia than pigs.
According to the study's lead author, Dennis Oonincx, an entomologist from Wageningen University in the Netherlands, 80 per cent of the world's population eats insects, particularly in the developing world.
"It's a normal part of the menu there," said Oonincx. "If you look at the mopane ['worm' or edible caterpillar] industry in Africa, it's a million dollar business."
Most of these insects are harvested live in the wild, so collection is subject to seasonal variation — they are only farmed in a few countries, he said.
Arnold van Huis, the paper's co-author and professor of tropical entomology at Wageningen University, helped formulate the Food and Agriculture Organization's (FAO) policy on edible insects.
He said they are an "excellent food source ... that should be nurtured" and taken up as an alternative to cattle.
"I don't think we can continue eating beef like we did in the past and the FAO has already predicted that in 2050 it will become so expensive no-one [will be able to] pay for it any more."
In Kenya, Monica Ayieko, a family and consumer economist at Maseno University, is studying insect production but said the 'Westernisation' of diets could pose an obstacle to encouraging consumption.
A spokesperson for the International Livestock Research Institute, in Kenya, which published a paper last year on improving the carbon efficiency of cattle farming, said that it recognises the value of widening the use of nutritious insects in poor communities. But "no one solution — livestock or otherwise — is going to provide sufficient food and do so sustainably".