“Passing gas” could sink the planet!

The policy debates surrounding global warming tend to focus on fossil fuels and carbon emissions. Solutions to climate change, correspondingly, centre on developing renewable energies and increasing efficiency in the transport and building sectors. Far less attention is garnered by the warming consequences of rearing and consuming livestock. In fact, the methane released when ruminants like cows and sheep belch or pass gas, which they do copiously, combined with the indirect emissions associated with their life cycles, contributes 18 percent of greenhouse gas emissions worldwide, even more than the transport sector.

This figure was arrived at by a United Nation’s Food and Agriculture Organization study, conducted in 2006. Yet, meat and dairy consumption continue to suffer from scant mention in most popular expositions of climate change science. Al Gore’s movie, An Inconvenient Truth, avoids what may be the most inconvenient truth of all – that what’s on the dinner plate can link to climate change as much as driving an SUV.

The FAO study took into account both the direct and indirect emissions related to livestock. Thus, emissions arising from feed production, including chemical fertiliser production, deforestation for pasture and feed crops, cultivation of feed crops and feed transport were added to the direct emissions of the animals in question, in particular their enteric fermentation (which results in their passing gas) and the nitrous oxide emissions released from animal urine and manure. Animal waste management and livestock transportation were other aspects accounted for.

The FAO study has met with considerable criticism. Mick Keogh, Executive Director of the Australian Farm Institute, lists some of these in a recent article, in which he claims the FAO methodology was faulty, leading to substantial double-counting of emissions. He also objected to the fact that the FAO included emissions from deforestation and desertification as part of the impact of livestock, when much of this activity occurs for non-livestock related reasons. And, while admitting that methane has a far greater warming potential than carbon, he noted that carbon stays in the atmosphere for up to 100 years, whereas methane only lingers for eight to 12 years.