GLOBAL WARMING: COWS OR CARS? - MEAT: A Benign Extravagance - page 213

fossil fuel demands are intrinsically low, or in the case of a grass fed, subsistence dairy cow
or goat, zero.
The more that agricultural climate change policy is focussed on biospheric emissions,
the more the Asian rice farmer, the UK arable farmer and livestock farmers everywhere
will be expected to reduce methane and nitrous oxide emissions, yet allowed to gloss over
the relatively low emissions emanating directly from intensive fossil-fuel based food pro-
duction (even though the inevitable corollary is an energy-intensive system of food distri-
bution which is central to a society whose carbon emissions are 62 per cent derived from
fossil fuels). Poultry factories producing packs of frozen turkey breasts will be viewed as
more sustainable than neighbourhood milk co-operatives, because all the energy-intensive
industrial infrastructure and consumer paraphernalia that is integral to the production and
distribution of turkey breasts is not factored within the farm budget, but clocked up un-
der other headings such as 'transport', 'industry' or 'built environment'. Such a policy is
suspect in itself; but it is especially prejudicial for those farming families who have few
fossil fuel expenses, and whose entire carbon budget on this planet is counted in the natural
currencies of nitrous oxide and methane - the 'poor livestock holders extracting marginal
livelihoods from dwindling resources'. These are the people targeted by Livestock's Long
Shadow - yet they expend far fewer carbon emissions than you or I.
A further matter of potential concern for livestock farmers is the growing interest in tar-
geting methane as a 'quick fix.' A salient feature of methane is that it doesn't stay in the
atmosphere very long: within 12 years it is nearly all converted into less harmful chemicals,
whereas carbon dioxide has an atmospheric lifetime of about 200 years. This means that a
given value of methane exerts most of its global warming impact at a high intensity with-
in 12 years, while the same value of CO 2 has its effect spread out over two centuries. The
CO 2 equivalent unit has been established by estimating the total Global Warming Poten-
tial (GWP) of each gas over a period of 100 years. The currently favoured exchange rate
of 25:1 between methane and carbon dioxide is therefore not a scientific fact; it is an as-
sessment, based in part on the rate at which we discount the future. 67 It has changed twice
in recent years, from 21:1 to 23:1 between 2001 and 2006, and in 2007 the IPCC recom-
mended a figure of 25:1. 68 If we were to estimate the GWP over a shorter timescale of
20 years, rather than 100 years, then the exchange rate would change drastically to around
72:1 rather than 25:1, and as a result methane would then be held to be as great a cause of
global warming as carbon dioxide.
In a context where addressing global warming appears to be a matter of urgency, and
might soon become a matter of emergency, methane's short lifetime makes it an attract-
ive target for policy makers and governments committed to reductions in greenhouse gas
emissions, because the savings will be realized sooner than with CO 2 . Oxford University's
Environmental Change Institute observes: