UN Report: Global Livestock Sector Generates More GHG Emissions than Transport
10 December 2006
|Greenhouse gas emissions from livestock in CO2-equivalent by species and main production system. Click to enlarge.|
According to a report published by the United Nations Food and Agriculture Organization, the livestock sector generates more greenhouse gas (GHG) emissions as measured in CO2 equivalent—18%—than transport. It is also a major source of land and water degradation.
When emissions from land use (such as production of feedcrops and grazing land) and land use change are included, the livestock sector accounts for 9% of CO2 deriving from human-related activities, but produces a much larger share of even more harmful greenhouse gases. It generates 65% of human-related nitrous oxide, which has 296 times the Global Warming Potential (GWP) of CO2. Most of this comes from manure.
And it accounts for respectively 37% of all anthropogenic methane (23 times as warming as CO2), which is largely produced by the digestive system of ruminants, and 64% of ammonia, which contributes significantly to acid rain.
Livestock now use 30% of the earth’s entire land surface, mostly permanent pasture but also including 33% of the global arable land used to producing feed for livestock, the report notes. As forests are cleared to create new pastures, it is a major driver of deforestation, especially in Latin America where, for example, some 70% of former forests in the Amazon have been turned over to grazing.
|The relationship between meat consumption and per capita income in 2002. Click to enlarge.|
With increased prosperity, people are consuming more meat and dairy products every year. Global meat production is projected to more than double from 229 million tonnes in 1999/2001 to 465 million tonnes in 2050, while milk output is set to climb from 580 to 1043 million tonnes.
The global livestock sector is growing faster than any other agricultural sub-sector. It provides livelihoods to about 1.3 billion people and contributes about 40% to global agricultural output. For many poor farmers in developing countries livestock are also a source of renewable energy for draft and an essential source of organic fertilizer for their crops.
The environmental costs per unit of livestock production must be cut by one half, just to avoid the level of damage worsening beyond its present level.—from the report, Livestock’s Long Shadow
Herds cause wide-scale land degradation, with about 20% of pastures considered as degraded through overgrazing, compaction and erosion. This figure is even higher in the drylands where inappropriate policies and inadequate livestock management contribute to advancing desertification.
The livestock business is also among the most damaging sectors to the earth’s increasingly scarce water resources, contributing among other things to water pollution, euthropication and the degeneration of coral reefs. The major polluting agents are animal wastes, antibiotics and hormones, chemicals from tanneries, fertilizers and the pesticides used to spray feed crops. Widespread overgrazing disturbs water cycles, reducing replenishment of above and below ground water resources. Significant amounts of water are withdrawn for the production of feed.
Livestock are estimated to be the main inland source of phosphorous and nitrogen contamination of the South China Sea, contributing to biodiversity loss in marine ecosystems.
Meat and dairy animals now account for about 20% of all terrestrial animal biomass. Livestock’s presence in vast tracts of land and its demand for feed crops also contribute to biodiversity loss; 15 out of 24 important ecosystem services are assessed as in decline, with livestock identified as a culprit.
The report, produced with the support of the multi-institutional Livestock, Environment and Development (LEAD) Initiative, proposes a number of remedies, including:
Atmosphere and climate. Increasing the efficiency of livestock production and feed crop agriculture. Improving animals’ diets to reduce enteric fermentation and consequent methane emissions, and setting up biogas plant initiatives to recycle manure.
Land degradation. Controlling access and removing obstacles to mobility on common pastures. Use of soil conservation methods and silvopastoralism, together with controlled livestock exclusion from sensitive areas; payment schemes for environmental services in livestock-based land use to help reduce and reverse land degradation.
Water. Improving the efficiency of irrigation systems. Introducing full-cost pricing for water together with taxes to discourage large-scale livestock concentration close to cities.
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