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Clearing the air on livestock emissions - gross exaggerations rubbished!

- Wednesday, November 04, 2009

Over recent weeks there have been some extraordinary claims made about the significance of livestock emissions (see earlier post on Oct 28) including claims that livestock may be responsible for more than half global greenhouse emissions. These claims have now been rubbished in a detailed review by scientists at the University of California, who conclude that direct livestock emissions only account for 3% of global emissions, and that indirect livestock emissions are also substantially less than previously claimed.

In a peer-reviewed paper published in September, the scientists identified numerous errors in previous analyses of livestock emissions, including the much-quoted "Livestock's long shadow" report, released by the FAO. Common errors include using elevated Global Warming Potential (GWP) conversion factors for methane, including livestock CO2 respiration in the account but not including CO2 fixation by pastures, using exaggerated assumptions about the extent of landuse change associated with livestock production, and using exaggerated and incomplete assumptions about post-farm emissions associated with processing and transport.

The exaggeration of livestock emissions is not confined to international sources, with one Australian commentator recently claiming "The methane from (Australia's) livestock creates more more warming than all our coal fired power stations" . This is despite the most recent official Australian Government national greenhouse inventory report  stating that emissions associated with electricity generation were 200 Mt CO2-e in 2007 and had increased by 54% since 1990, while enteric methane emissions from livestock were 61 Mt CO2-e in 2007, and had declined by 7.5% since 1990. In addition, these livestock emissions estimates are based on Kyoto Protocol accounting rules, which ignore emissions that are sequestered as part of the annual production cycle by plants and in the soil.

This raises some real questions about the motives of some who appear to be using exaggerated claims about livestock emissions to advance other agendas. It also highlights the need for the livestock industry to develop some good, robust data about the real emission profile of the sector.  
Christophe Pelletier commented on 04-Nov-2009 05:02 PM
Good that this group of scientists looked at the numbers in a more systematic way.
Clearly, the stories about livestock causing 51% of total emissions did not make any sense, otherwise global warming would have happened a long time before there were cars. Those stories were spread by groups whose agenda is vegetarism. As such, there is nothing wrong being a vegetarian, but there is something definitely unacceptable about spreading non-sense. That said, it is also true that 100 kg of meat per capita per year, like Westerners consume, is substantially above what daily individual nutritional requirements for protein are.
The FAO tends to be a bit on the romantic side and focuses a bit too much on the small farmer in developing countries, while they should look at the food supply as a whole and think on how this will work to feed 9 billion people. They tend to look at modern agriculture a little too negatively.
Yes, modern agriculture has some negative sides, and it has been develped thanks to cheap oil, and this is why it needs to find innovative ways to still be highly efficient and move away from fossil fuels.
There is always a trade-off between necessity and ideal.

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