Muscle power: Impact on nature
No exhaust, but a hungry food system behind it
What this tab covers What taking energy from this source does to land, water, air and climate, wildlife and ecosystems, with life-cycle emissions and land use where measured.Muscle power has no exhaust of its own, but its fuel comes from the food system, which uses over a third of the world's land and produces about a third of greenhouse gas emissions.
Effects on nature
| Area | Effect | Size | How it is reduced |
|---|---|---|---|
| Climate | Producing, processing and distributing food emits greenhouse gases, mostly from farming and land-use change.7 | 18 Gt CO2e a year, 34% of global emissions (2015); 71% of it from agriculture and land use | Less deforestation, lower-emission farming, less food waste |
| Land | Crops and pasture for people and draught animals occupy large areas.8 | 4.8 billion ha of agricultural land (2023), more than a third of global land; 1.6 billion ha cropland, 3.2 billion ha pasture | Higher yields, less land-hungry diets |
| Land-use change | Clearing land for food releases carbon.7 | About 5.7 Gt CO2e a year (32% of food-system emissions) | Protect forests and peatlands |
| Water and feed | Draught animals need fodder and water beyond what grazing in their working time provides.2 | Not quantified; where oxen lift water from very deep wells, the water raised may barely grow the extra feed they need | Use crop residues as fodder; share animals |
At the point of use muscle work is clean and quiet: no fuel is burned and the only by-products are body heat, carbon dioxide from respiration (recently taken from the air by the crops eaten) and, for animals, dung that can fertilise fields. A per-kWh emission figure is not meaningful because food is produced to keep people alive, not to make work.
The environmental footprint lies upstream, in the food system, which accounts for about a third of greenhouse gas emissions and uses more than a third of the world's land. As a source of mechanical energy muscle is therefore land-hungry: the fodder for a team of oxen must be grown on land that could otherwise grow food for people.
Sources
- Research on diversified uses of work animals: needs, experiences and methods (Thomas, Oram and Tembo) FAO
- Food systems are responsible for a third of global anthropogenic GHG emissions (Crippa et al., Nature Food) Nature Research, 2021
- Land statistics 2001-2023: Global, regional and country trends FAO, 2025