Friday, 20 November 2015

Cows aren't destroying the planet. Ignorant folk like George Monbiot are.


George Monbiot is having a go at cows. Well, not just cows but sheep, pigs, chickens and goats as well. And probably alpaca, yaks and dromedaries too.

Raising these animals already uses three-quarters of the world’s agricultural land. A third of our cereal crops are used to feed livestock: this may rise to roughly half by 2050. More people will starve as a result, because the poor rely mainly on grain for their subsistence, and diverting it to livestock raises the price.

As usual with Monbiot, the article is replete with links to assorted stuff mostly from the more scaremongering end of the climate change community. And the premise seems superficially appealing - it does require a whole load of grass to fatten a cow and, if we're growing grass we can't be growing grain crops suitable for humans to eat. The problem with this argument is that the facts about agriculture's land use don't fit Monbiot's scare story:

Ausubel, Wernick, & Waggoner (2013) argue that ‘peak farm’ is already a reality, saying ‘while the ratio of arable land per unit of crop production shows improved efficiency of land use, the number of hectares of cropland has scarcely changed since 1990. Absent the 3.4 percent of arable land devoted to energy crops (Trostle 2008), absolute declines would have begun during the last decade.’

In simpler terms, improved agricultural efficiency is allowing us to feed the world's population while using less land. The main reason for this, of course, is that there is a lot less inefficient subsistence farming (the sort of farming that organisations like Oxfam spend a lot of time trying to preserve) and a lot more commercial and industrial agriculture. Moreover, in terms of resource use, this sort of intensive farming is far more environmentally friendly:

Agricultural economists at UC Davis, for instance, analyzed farm-level surveys from 1996-2000 and concluded that there are “significant” scale economies in modern agriculture and that small farms are “high cost” operations. Absent the efficiencies of large farms, the use of polluting inputs would rise, as would food production costs, which would lead to more expensive food.

Farming - not everywhere but in too many places - is treated as if it were some sort of cultural activity rather than the means by which we feed the world's population. Monbiot talks about waste management issues associated with farming but doesn't recognise that these exist because, unlike other industries, farming has not had to capture the cost of this waste. It is not an inevitable consequence of of the business. Moreover, as those chaps at UC Davis showed, less intensive production is more polluting.

Finally can we put this greenhouse gas malarkey to bed. The cow's only source of carbon is the grass she chews. And the grass only has one source of carbon - the atmosphere. A good chunk of that carbon ends up in those fine marbled steaks we eat. So saying that a lot of the 'greenhouse gas' emissions come from cows farting might be true, but only if we believe that somehow those cows are magically creating more carbon than they consume.

As usual Monbiot is telling half-truths and peddling misinformation.



Anonymous said...

Much livestock is raised on land that is not suitable for tilling.

Iain Roberts said...

Some good points, but I'm afraid you fall down on chemistry.

Climate change is not caused by carbon, but by gases which contain carbon, such as carbon dioxide and methane. Exhaling produces carbon dioxide (CO2). Cow farting produces methane (CH4). Methane, weight for weight, is more than 25 times more potent than CO2 as a greenhouse gas. So feeding grass to a cow contributes much more to climate change than using the same land to grow grain for human consumption.

(Of course, humans produce a little methane too; but cows produce huge amounts, as a side effect of being able to digest grass in the first place.)