BBC
March 2010
Leading figures in the climate change establishment, such as Intergovernmental Panel on Climate Change (IPCC) chairman Rajendra Pachauri and Lord (Nicholas) Stern, have also quoted the 18% figure as a reason why people should consider eating less meat.
UN specialists are to look again at the contribution of meat production
to climate change, after claims that an earlier report exaggerated the link.
A 2006 report concluded meat production was responsible for 18% of
greenhouse gas emissions - more than transport.
The report has been cited by people campaigning for a more vegetable-based
diet, including Sir Paul McCartney.
But a new analysis, presented at a major US science meeting, says the
transport comparison was flawed.
Sir Paul was one of the figures launching a campaign late last year centered
on the slogan "Less meat = less heat".
“I must say honestly that he has a point,” Dr Pierre Gerber, FAO.
But curbing meat production and consumption would be less beneficial for the
climate than has been claimed, said Frank Mitloehner from the University of
California at Davis (UCD).
"Smarter animal farming, not less farming, will equal less heat," he told
delegates to the American Chemical Society (ACS) meeting in San Francisco.
"Producing less meat and milk will only mean more hunger in poor countries."
Leading figures in the climate change establishment, such as
Intergovernmental Panel on Climate Change (IPCC) chairman Rajendra Pachauri
and Lord (Nicholas) Stern, have also quoted the 18% figure as a reason why
people should consider eating less meat.
Apples and Pears
The 2006 report - Livestock's Long Shadow, published by the UN Food and
Agriculture Organization (FAO) - reached the figure by totting up all
greenhouse-gas emissions associated with meat production from farm to table,
including fertiliser production, land clearance, methane emissions from the
animals' digestion, and vehicle use on farms.
But Dr Mitloehner pointed out that the authors had not calculated transport
emissions in the same way, instead just using the IPCC's figure, which only
included fossil fuel burning.
"This lopsided 'analysis' is a classical apples-and-oranges analogy that
truly confused the issue," he said.
One of the authors of Livestock's Long Shadow, FAO livestock policy officer
Pierre Gerber, told BBC News he accepted Dr Mitloehner's criticism.
"I must say honestly that he has a point - we factored in everything for
meat emissions, and we didn't do the same thing with transport, we just used
the figure from the IPCC," he said.
"But on the rest of the report, I don't think it was really challenged."
FAO is now working on a much more comprehensive analysis of emissions from
food production, he said.
It should be complete by the end of the year, and should allow comparisons
between diets, including meat and those that are exclusively vegetarian.
Different Pies
Organisations use different methods for apportioning emissions between
sectors of the economy.
In an attempt to capture everything associated with meat production, the FAO
team included contributions, for example, from transport and deforestation.
By comparison, the IPCC's methodology collects all emissions from
deforestation into a separate pool, whether the trees are removed for
farming or for some other reason; and does the same thing for transport.
This is one of the reasons why the 18% figure appears remarkably high to
some observers.
The majority of the meat-related emissions come from land clearance and from
methane emissions associated with the animals' digestion.
Other academics have also argued that meat is a necessary source of protein
in some societies with small food resources, and that in the drylands of
East Africa or around the Arctic where crop plants cannot survive, a
meat-based diet is the only option.
Dr Mitloehner contends that in developed societies such as the US - where
transport emissions account for about 26% of the national total, compared
with 3% for pig- and cattle-rearing - meat is the wrong target in efforts to
reduce carbon emissions.
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