Shifting diets could yield major improvements for climate and biodiversity. IIASA researchers found that replacing half of all main meat and milk products with plant-based alternatives by 2050 can reduce agriculture and land userelated greenhouse gas (GHG) emissions by 31% and halt the degradation of forests and natural land.

IIASA researchers and colleagues developed scenarios of dietary changes based on plant-based recipes for beef, pork, chicken, and milk. The recipes were designed to be nutritionally equivalent to the animal products and realistic for the existing food manufacturing capabilities and globally available ingredients.

The study shows that a partial dietary shift toward plant-based alternatives could help to reduce GHG emissions and agricultural input use, almost halt deforestation, and reduce the number of undernourished people  globally by millions. If spared agricultural land is restored through afforestation with biodiversity-friendly management, climate benefits could more than double. In the 50% substitution scenario, this could account for  reductions of 6.3 Gt CO2eq/year in 2050 – 92% of the previously estimated land sector mitigation potential. This measure would also more than half the future declines in ecosystem integrity.

While the replacement of beef is expected to provide the largest impacts, the researchers deduced that substituting multiple products could yield even better results. Impacts across regions would differ due to differences in population size and diets, unequal agricultural productivity, and participation in international trade. The main impacts on agricultural input use are in China and on environmental outcomes in sub‑Saharan Africa and South America.