Pearls and Irritations

Much of the council’s reporting on the greenhouse gas emissions of agriculture is invalid or misleading and underplays the damaging effects of methane.

In June 2021, the Climate Council published an article in which it promoted a position that was arguably favourable to the meat sector. The article mentioned that Australia’s national greenhouse gas inventory indicated that agriculture was responsible for around 13 per cent of emissions.

That figure is conservative for reasons that were not mentioned in the Climate Council article. The reasons are that emissions from agriculture are either omitted entirely (for example, foregone sequestration), accounted for under categories other than those responsible for the emissions (for example, land use, land use change and forestry) or reported using conservative metrics (for example, using a 100-year time horizon for determining methane’s global warming potential).

To some extent these problems are systemic, as global and national reporting mechanisms fail to adequately account for agriculture’s greenhouse gas emissions. The systemic nature of the problem does not excuse it, however, and individuals or organisations seeking to learn the true extent of agriculture’s impact can readily do so with further investigation.

This article focuses on the reporting of methane emissions and changes in land use from animal agriculture.

Methane emissions

National greenhouse gas inventories generally use a 100-year time horizon for reporting non-carbon-dioxide emissions. However, the UN’s Intergovernmental Panel on Climate Change (IPCC) has made it clear there is no scientific argument for selecting that period and that other time horizons are valid depending on “the relative weight assigned to effects at different times”.

The 100-year time horizon vastly under-reports the shorter-term impact of methane emissions. That impact is critically important as we seek to avoid feedback mechanisms and tipping points potentially leading to runaway climate change.

Methane’s atmospheric lifetime

The Climate Council’s argument is primarily based on the relatively short atmospheric lifetime of methane, a greenhouse gas produced in large quantities in digestive systems of ruminant animals such as cattle and sheep. It breaks down in the atmosphere to a large extent within around 12 years. However, that point is well known and already allowed for in estimates of methane’s global warming potential (GWP) from the IPCC and elsewhere.

To explain its point, the Climate Council used the analogy of a tank being filled with water, with some being regularly removed by a pump in one scenario and the tank continuing to fill in another. The analogy is invalid for two reasons.

First, showing two volumes of water in separate tanks addresses only one of methane’s qualities: its relatively short atmospheric lifetime. It ignores the fact that methane’s radiative forcing (a precursor to temperature change) is far more significant than that of carbon dioxide while airborne. Over a 20-year time horizon, methane is more than 80 times as potent as carbon dioxide as a greenhouse gas.

Second, it fails to recognise the fact that methane’s atmospheric concentration has increased by about 170 per cent since pre-industrial times compared to around 50 per cent for carbon dioxide.

Biogenic vs fossil methane

The Climate Council argues that biogenic (non-fossil) methane such as that emitted by cattle is less harmful than fossil methane. However, according to the IPCC’s draft 6th Assessment Report, the GWP multiplier of non-biogenic methane is close to that of the fossil variety. The figures are 80.8 and 82.5 respectively over a 20-year time horizon, or 27.2 and 29.8 over 100 years.

Just as no coal is good coal, no methane is good methane in the context of climate change.

Illustrations of methane’s impacts

The council’s article contained cartoon-type illustrations depicting the life cycle of methane. Meat & Livestock Australia has used similar images in its promotional pages.

The illustrations missed key points made in this article, along with the fact that all warming, particularly the intense nearer-term warming of methane, may have catastrophic flow-on effects contributing to runaway climate change.

An example of flow-on effects involves the thawing of permafrost, which is frozen soil or sediment covering more than 20 per cent of exposed land in the northern hemisphere and extending to offshore Arctic continental shelves. As the planet warms, the permafrost thaws, releasing methane and carbon dioxide from decaying organic matter. Those emissions cause more warming, which causes more thawing, then more warming in a vicious cycle.

That is one of many climate feedback mechanisms that are not allowed for in the Climate Council’s simplistic depiction of methane’s impacts.

Changes in land use

Land clearing figures in national greenhouse gas inventories are reported under the category “Land Use, Land Use Change and Forestry” without seeking to attribute them to specific sectors that may be responsible. That approach was mentioned in the article without expressing concern about the lack of accountability.

Animals graze across 54 per cent of the Australian continent (on cleared and uncleared land), while 40 per cent of the nation’s grain harvest is used as animal feed.

In Queensland, the state with 46 per cent of Australia’s beef cattle, 91 per cent of clearing from 1988 to 2018 was for pasture. From 1995 to 2018, the state has identified the clearing of remnant (previously uncleared) and non-remnant vegetation, with 51 per cent of the overall clearing being remnant. If we were to assume pasture’s percentage of overall clearing applied equally to clearing of remnant vegetation, it would equate to 21 rugby fields per hour over the 13-year period.

Despite those alarming figures, in a 2018 report dealing solely with land clearing in Queensland, the Climate Council said nothing about clearing for the grazing of farmed animals.

Under-reporting of land clearing

A recent report from the University of Queensland indicated that land clearing figures based on the national carbon accounting system (NCAS), which are used for the national greenhouse accounts, severely understate the true extent of clearing. In some years, the NCAS figures for Queensland were less than half of those reported under the state government’s statewide landcover and trees study.

The issue was raised by the Australia Institute in 2007 and by the Wilderness Society in 2017.

Carbon opportunity cost

No official greenhouse gas reporting systems account for the loss of carbon sequestration that arises from changes in land use. That failure has massive implications when one considers the land area used for animal agriculture. The impacts have been highlighted by several papers in recent years.

A 2018 paper in the journal Nature reported on the carbon opportunity cost of alternative forms of land use. The researchers took into account various factors, including the quantity of carbon that could have been sequestered on the land if it had been used for regenerating forest instead of its current use.

The authors reported that the greenhouse gas emissions intensity of beef is 73 times that of soybeans and 26 times that of pulses (including chickpeas and lentils). The figures for pork and poultry were also multiples of the figures for pulses and soybeans.

A 2019 paper in the journal Science reported that non-animal agriculture occupies a mere 17 per cent of farmland globally while providing 63 per cent of protein and 82 per cent of calories. The authors estimated that a general transition away from animals as a food source would reduce the area used as farmland globally by 76 per cent (including 19 per cent of arable land), releasing an area equal to Africa or four times the contiguous US or four times Australia.

In a 2021 paper published in Nature Sustainability, the authors quantified the extent of carbon that could be sequestered between the present day (using 2015 as the base year) and 2050 by changing dietary patterns while feeding the world’s population.

The land use benefits of an animal-free diet would remove 547 gigatonnes of atmospheric carbon dioxide, which is roughly equal to the previous 16 years of fossil fuel emissions. It would reduce non-carbon-dioxide dietary emissions by around 70 per cent. In contrast, a business-as-usual approach would add 86 gigatonnes.

Conclusion

In the context of a climate crisis requiring emergency action, why is the Climate Council so far off the mark in terms of dietary impacts?

It appears to have fallen well short of its claim to have been “changing the narrative and ensuring Australians are equipped with the best information on climate change and solutions”.