According to a new report from the United Nations Environment Programme, the correlation between increasing meat production and rising greenhouse gas emissions is strong, estimating that animal agriculture's share of total global GHG emissions could be as much as 25%, encompassing the effects of deforestation and other land use changes to make way for livestock rearing.
The report, which was prepared for the UNEP Global Environmental Alert Service, cites also the role of changing population size and population demographics as key drivers behind meat production and consumption.
The alert compiles findings from previous studies prepared by the Food and Agriculture Organization, Environmental Protection Administration, and information from peer reviewed sources.
Population Growth, Meat Demand
Though the meat supply varies from country to country, the United States leads meat consumption with 322 grams of meat per person per day. Australia and New Zealand are next, followed by Europe and South Americans. Asia's meat consumption, however, is only 25% of the U.S. average, the report authors found.
Increasing income in Asia is leading to diets with more meat, particularly in China. This influx in meat eaters has grown the per capita meat consumption in China by 130% since 1990. Growing population overall has also contributed to higher demand for meat.
The report cites an FAO figure that estimates global meat consumption will rise from 278 million tonnes in 2009 to 460 million tonnes in 2050 – a 65% increase within the next 40 years.
The report authors found that Carbon dioxide (CO2) is only a small component of emissions in animal agriculture. The largest share of GHG emissions is from two other gases: methane (CH4) and nitrous oxide (N2O).
"The main sources of CH4 are the enteric fermentation of ruminants and releases from stored manure, which also emits N2O," the report says. "In Europe, for example, enteric fermentation was the main source (36%) of GHG emissions in the livestock sector."
Cattle are the largest contributors to global enteric CH4 emissions, the report says, pointing to Asia as the originator of much of the emissions (34%).
The report also places blame on large farms for use of high-energy feed and manure disposal methods, though points out that "both intensive (industrial) and non-intensive (traditional) forms of meat production result in the release of greenhouse gases."
The report, which supports climate change, says ecological foundations of agriculture are "being undermined" and industrial agriculture is "contributing to environmental problems."
Report authors point to fertilizers and crop production as contributors to GHG emissions, but say improving livestock feeding efficiency and reduction of food waste may be effective mitigation efforts. Changes in human diets may be a practical tool as well, report authors note, and "a switch to less 'climate-harmful' meat may also be possible."
The report says a target intake of meat shouldn't exceed 70-90 grams per day per person.
"The human health implications of a reduced meat diet need further exploration, but it seems probable that many benefits would accrue from lower consumption rates in many developed and some developing countries. At the same time, reduced meat production would ease both pressures on the remaining natural environment (i.e. less new land clearance for livestock) and on atmospheric emissions of CO2, CH4 and N2O," the report concludes.
View the full alert on the UNEP website.
Beef Producer blogger Jesse Bussard also has an interesting take on a previous UN study: Beef's 'Sustainability' Involves More Than Greenhouse Gasses