Resource ratios show gross inefficiency

The key to animal agriculture’s contribution to climate change lies in its relative inefficiency as a supplier of nutrition for humans. Raising livestock consumes 77% of agricultural land but supplies only 18% of global calories.^​1​

Obtaining protein from animals that eat plants, rather than directly from plants themselves, uses 11 times more fossil fuels,^​2​ 13 times more water and about 15 times more land.^​3​

The following table shows relative environmentally relevant differences between meat protein and a processed protein food based on soybeans (industrial countries)^​4​

Another study indicated that growing food exclusively for direct consumption by humans, not animals, could increase available food calories by as much as 70%, which could feed an additional 4 billion people (more than the projected 2–3 billion people arriving through population growth).^​5​

According to a March 2021 analysis from Oxford University’s Our World in Data project, if the world adopted a plant-based diet we would reduce global agricultural land use from 4 to 1 billion hectares – a 75% reduction. An area greater than the entire length and breadth of the Americas is currently used for meat and dairy production.

While all types of meat are more resource-intensive than all types of plant food, beef and lamb and particularly inefficient. It takes about 100 times as much land to produce a kilocalorie of beef or lamb than plant-based food, and almost 100 times as much land to produce a gram of protein from beef or lamb compared with peas or tofu.