Investing in mini-livestock production for food security and carbon neutrality in China

Abstract

Future food farming technology faces challenges that must integrate the core goal of keeping the global temperature increase within 1.5 °C without reducing food security and nutrition. Here, we show that boosting the production of insects and earthworms based on food waste and livestock manure to provide food and feed in China will greatly contribute to meeting the country's food security and carbon neutrality pledges. By substituting domestic products with mini-livestock (defined as earthworms and insects produced for food or feed) protein and utilizing the recovered land for bioenergy production plus carbon capture and storage, China's agricultural sector could become carbon-neutral and reduce feed protein imports to near zero. This structural change may lead to reducing greenhouse gas emissions by 2,350 Tg CO₂eq per year globally when both domestic and imported products are substituted. Overall, the success of mini-livestock protein production in achieving carbon neutrality and food security for China and its major trading partners depends on how the substitution strategies will be implemented and how the recovered agricultural land will be managed, e.g., free use for afforestation and bioenergy or by restricting this land to food crop use. Using China as an example, this study also demonstrates the potential of mini-livestock for decreasing the environmental burden of food production in general.

Keywords: food security; greenhouse gas emission; insect; mitigation; protein.

Fig. 1.

The role of mini-livestock production in improving food security and mitigating GHG emissions from the agricultural sector in China and its major trading partners under a business-as-usual scenario (BAU) (A), a recovered land used for afforestation scenario (B), and a BECCS, (C) at the highest GHG mitigation rate with no land use restriction.

Fig. 2.

Food and feed protein production and imports (A), mini-livestock protein production capacity as food by black soldier fly larvae or mealworms or crickets (B), and mini-livestock protein production capacity as feed by house fly larvae, black soldier fly larvae or earthworms (C) in China in 2018. Number and the size of registered food waste collection and mini-livestock production plants (D), distribution of registered food waste collection plants and mini-livestock production plants in different agroecological area (E), and the contribution of different agroecological areas to total registered capital of different plants in China (F). Note: Error bars represent the SD for protein produced by the different insect species under various rearing conditions.

Fig. 3.

The estimated reduction in protein demand (A and B), land use change (C and D), reduction in GHG emissions (E and F), and nitrogen (N) fertilizer use reduction (G and H) when adopting the strategies of substitution of imported products only (SIP), substitution of domestic products only (SDP), and substitution of domestic and imported products hybrid form (SDIH) in the Afforestation (Left) and BECCS scenario (Right) at maximum (Max) mini-livestock protein substitution rate and land use restriction scenario (Land-R). All results show the contribution by China (blue) and its major trading partners (red) in 2018. Note: Land-R represents a scenario that restricts recovered agricultural land for afforestation and BECCS. For more details about the contribution sources see SI Appendix, Figs. S4–S7 and S9. All analyses are based on the best performance of one specific mini-livestock species, i.e., the species with the most significant reduction in GHG emissions (SI Appendix, Fig. S4). For information on the other insect or earthworm species, see SI Appendix, Figs. S4–S7.

Fig. 4.

The spillover effects of strategies of SIP only (Left), SDP only (Middle), and SDIH (Right) on reduction in GHG emissions in the main trading partner countries under the Afforestation (A–C) and BECCS (D–F) scenarios. The maps show the absolute reduction of GHG emissions from different countries; the green shaded boxes show the dominant contributors to reduction in GHG emissions. Note: Here, we only show the data from countries that contribute >95% of the total importation rate. The Tg values indicate reduction in GHG emissions. BRA, Brazil; CHN, China; URY, Uruguay; ARG, Argentina; NZL, New Zealand; CAN, Canada; AUS, Australia.