GLOBAL WARMING: COWS OR CARS? - MEAT: A Benign Extravagance - page 206

Of course, it is unscientific to extrapolate from one example in this fashion, but Serengeti
does illustrate the rapidity with which abandoned rangeland can be repopulated with wild
ruminants. Before the arrival of 110 million cattle in the USA, there were 60 million
bison on the great plains and about 100 million small antelope, belching out proportionate
amounts of methane. 47 If the cows disappeared, it is possible that the bison would return,
not least because there is a significant movement in the US to establish a 'Buffalo Com-
mons'. 48 Bison emit the same amount of methane in relation to their weight and dry matter
intake as cows, suggesting that their total emissions might have been close to half those of
the present day US cows. 49 In an intriguing study called 'Methane from the House of Tudor
and the Ming Dynasty', Susan Subak concludes that in 1500 'emissions from bison alone
were as much as three million tonnes' and that with deer and other animals included this
might have risen to four million tonnes - compared with current livestock emissions from
North America of 5.05 million tonnes. 50
Who knows whether this is an accurate reflection of what might happen if the dry range-
lands of North, Central and South America and Sub Saharan Africa were relieved of their
cows? No one seems to have produced any models, though there is a lot of noise about it
on the internet from cowboy types. However it is safe to say that if cattle, sheep and other
domestic ruminants were eliminated, only a minority of their emissions would resurface in
a resurgent wild ruminant population. Less than a third of the world's cattle and sheep are
fed on rangeland; and if Australia removed its cows it would most likely see the resurgence
of the kangaroo, whose methane emissions are negligible.
However, there are many other natural sources of methane including wetlands, small
mammals, termites and other insects, trees and plants, most of which are very poorly un-
derstood, and some of which have only recently been discovered. The total dry weight of
humans, together with domestic animals, amounted to only 20 per cent of that of all ter-
restrial species of animals in 1980. 51 Wetlands are currently agreed to be the largest source
of methane - either natural or anthropogenic - and it seems likely that if cattle or sheep
farming in wet areas were abandoned, drainage systems might be neglected, or even delib-
erately abandoned for biodiversity reasons, leading to increased methane emissions. Ter-
mites are held responsible for about three per cent of global methane emissions; who knows
if they won't multiply if we remove all livestock from our farming systems? The contro-
versial wildlife biologist Allan Savory ob-serves that in the conditions which arise when
pastures are burnt, or irregularly grazed, 'termite numbers can increase to such an extent
that they consume all the soil-covering litter'. 52
Even more disconcerting for anyone seeking a reliable livestock methane emissions fig-
ure was the recent discovery in 2006, by the Max Planck Institute, that plant tissues can
generate methane under aerobic conditions, while they are alive, whereas previously it was
thought that they only produced methane in the absence of oxygen, for example when im-