According to an American study, uncertainties in calculating methane emissions from livestock farming could jeopardise the achievement of sustainability targets.
With the publication, last May, of the report Global Methane Assessment, Unep (the United Nations Environment Programme) underlined the need for urgent measures to reduce methane emissions within the 2020–2030 decade. A 45 per cent reduction in emissions over ten years would, in fact, prevent around 0.3°C of global warming by 2040. According to a recent study, however, the available data on quantities of methane emissions, at least those deriving from intensive cattle farming, may be underestimated. And this "miscalculation" could undermine the achievement of the sustainable development goals and those of the Paris Agreement, which aim to limit the average global temperature rise to 1.5°C.
The analysis, conducted by researchers from New York University and Johns Hopkins University and published in the journal Environmental Research Letters, reviewed methane gas measurements from the Epa (the United States Environmental Protection Agency) in recent years relating to intensive cattle farming in the United States, concluding that emissions could be higher than estimated. In particular, the study's authors supplemented the Epa's calculations, which are based on mathematical models, with measurements of methane in the air, and found that emissions could be 39 to 90 per cent higher than the known figures. Furthermore, the research highlighted that, with demand for meat and dairy products from developing countries such as those in East and Southeast Asia, methane emissions could grow by a further 21 per cent by 2050. This could lead to a temperature rise of 1.5–2 degrees Celsius more rapidly than anticipated.
"Policymakers should consider methane emissions alongside a range of other significant environmental problems arising from the concentrated production of meat and dairy products, including water pollution and outbreaks of infectious diseases of animal origin, in order to steer food systems in a better direction" – said study author Matthew Hayek.
Methane gas is responsible for 10 per cent of greenhouse gas emissions, and that from agriculture and livestock farming accounts for 40 per cent of the total. The effect of methane, in terms of "warming potential", is greater over the long term than that of CO2, but the gas is present in the atmosphere in smaller quantities than carbon dioxide. Quantities that, according to this study, would need to be reassessed.