You may have heard of windfall tax. But how about taxing the wind that rises?

The United Nations is proposing a levies on livestock to reflect, potentially, their gaseous emissions, which taken on a broad measure contribute some 7,000bn tonnes or so of greenhouse gases a year, in carbon dioxide equivalents.

This calculation, which includes estimates for gases released through feed manufacture, forest destruction for pasture and abattoir energy bills, is only one of the environmental costs of the livestock industry.

The sector also threatens "enormous pressure on ecosystems, biodiversity, land and forest resources and water quality".

'Financial incentives'

But the emissions issue appears especially big. The greenhouse gas figure equates to 18% of man-made greenhouse gas emissions, largely thanks to the methane and nitrous oxide animals' "enteric fermentation".

And it may be best tackled by a levy to apply on farmers the appropriate incentives, the UN's Food and Agriculture Organisation said.

"There is a trend towards taxation of environmental damage and provision of financial incentives for environmental benefits," the organisation said.

"Market-based policies, such as taxes and fees for natural resource use, should cause producers to internalise the costs of environmental damages."

Alternative strategies

Farmers, after all, have alternatives, even those who cannot turn to arable.

One is to reduce livestock numbers, to focus on fewer, more efficient animals.

A second is to fine tune feed, with diets high in concentrates, or with the appropriate additives or antibiotics, producing more enviromentally-acceptable animals.

A third is to turn to chickens, livestock farming's equivalent of the hybrid car, with cattle or sheep the four-by-fours.

After all, the first half of this century is currently on course to see a 70% jump, to 2.6bn head, in cattle numbers, the FAO believes. That rise represents a lot of emissions – or taxes.