Figure 2. Proportion of greenhouse-gas emissions from different parts of livestock production
Adapted from FAO.

Worldwide, greenhouse-gas emissions from agriculture (crop production and animal husbandry) and associated changes in land use, are estimated to exceed those from power generation and transport. Methane and nitrous oxide, combined, are more important emissions from this sector than is carbon dioxide. Methane is a potent greenhouse gas whose full contribution to climate change has recently been re-assessed as being more than half that of carbon dioxide.41

A recent FAO report42 focuses specifically on the current and future effects of livestock production on the world's environment and climate. The report states that the world's livestock sector, which provides the livelihoods of about 1·3 billion people, is growing faster than other agricultural subsectors. Yearly worldwide meat production is projected (in the absence of policy induced changes of trend) to double from 229 million tonnes in 1999–2001 to 465 million tonnes in 2050, and milk output to almost double from 580 million tonnes to 1043 million tonnes. Most of this increase is projected to occur in countries with low or middle incomes (figure 1). Livestock currently use almost a third of the world's entire land surface, mostly permanent pasture, but also including the third of the world's arable land that provides livestock feed.


Figure 1. Trends in consumption of livestock products per person (milk, eggs, and dairy products, excluding butter)
The projected trends assume no policy-induced change from present consumption. Note the rapid recent increase in east Asia, dominated by China, where per-head meat consumption would reach European levels by mid-century. Cultural, agricultural, and political factors will determine how the composition of animal products intake actually changes in the future. For example, in the near east and in north Africa, higher intake of milk, eggs, and poultry are likely, whereas greater consumption of beef and poultry is expected to dominate the increase in Latin America. Reproduced from FAO, with permission.