The use of animals to convert plant proteins and nutrients into meat, milk, eggs and other animal products is hugely inefficient (see (1) Metabolism). High inputs are required (land, water, chemical fertilizers, pesticides) and high outputs are generated (greenhouse gases, acidifying gases, eutrophying substances) (see (1.1), (1.2)). On the one hand, animal agriculture contributes significantly to climate change through its direct greenhouse gas emissions and land lost to carbon sequestration. On the other hand, habitats are minimized, animals and plants are displaced and killed, complete ecosystems are destroyed, and species are extirpated through the clearing of forests, through high water consumption, through acidifying gases, and through eutrophying and toxic substances. This ultimately leads to a loss of biodiversity.
Climate change and biodiversity loss are closely related and mutually reinforcing (positive feedback loop).
The figures and calculations on the share of animal agriculture in climate change differ widely. The most common and at the same time smallest figure (14.5%) comes from the Food and Agriculture Organization of the United Nations (FAO). Here it must be taken into account that the FAO is steered and financed by all global animal industries.
The following slides provide an overview of various analyses, their calculations and main issues.
A tabular one-page overview (PDF) incl. list of references and links to all references can be downloaded here: