Alternative protein sources for human food and livestock feed are receiving considerable attention. Laboratory or 'clean meat' is one potential contributor to the human demand for protein in the future . Such technology may be highly disruptive to existing value chains but could lead to significant reduction in land use for pastures and crop-based animal feeds . The impacts on GHG emissions depend on the meat being substituted and the trade-off between industrial energy consumption and agricultural land requirements . Livestock feeds can make use of other protein sources: insects are generally rich in protein and can be a significant source of vitamins and minerals. Black soldier fly, yellow mealworm and the common housefly have been identified for potential use in feed products in the EU, for example . Replacing land-based crops in livestock diets with some proportion of insect-derived protein may reduce the GHG emissions associated with livestock production, though these and other potential effects have not yet been quantified . Other sources are high-protein woody plants such as paper mulberry  and algae, including seaweed. While microalgae and cyanobacteria are mainly sold as a dietary supplement for human consumption, they are also used as a feed additive for livestock and aquaculture, being nutritionally comparable to vegetable proteins. The potential for cultivated seaweed as a feed supplement may be even greater: some red and green seaweeds are rich in highly digestible protein. Asparagopsis taxiformis, for example, also decreases methane production in both cattle and sheep when used as a feed supplement . Novel protein sources may have considerable potential for sustainably delivering protein for food and feed alike, though their nutritional, environmental, technological and socioeconomic impacts at scale need to be researched and evaluated further.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report