Lamb ‘most sustainable food you can eat’, CSIRO research shows

James Nason, November 24, 2023

AUSTRALIA should be riding on the sheep’s back once again according to climate science research that shows lamb is “the most sustainable food in the Australian food system.”

Dr Brad Ridoutt

“The most sustainable food you can eat by my calculations is lamb,” CSIRO principal research scientist Dr Brad Ridoutt told a Cattle Australia industry forum in Albury last week.

That was one of the key conclusions from a CSIRO research project he recently led, funded by the CSIRO and Meat & Livestock Australia, which demonstrated Australia’s sheep meat sector is already climate neutral, is making no contribution to global temperature increases, and its impact is trending downward.

Dr Ridoutt said the results of the research contrast directly with the common narrative “that the worst thing you can possibly eat for your health or for the climate is red meat”.

“On the calculations I have done, the most sustainable food in the Australian food system is lamb,” he said.

“It uses virtually no cropland. Uses virtually no extracted water. Uses virtually no pesticides. And the industry is climate neutral.

“I mean you can’t get much better than that.”

If climate change getting worse, it is “not because of red meat”

Dr Ridoutt told the forum last Friday that the bottom line of the research was that if climate change has been progressing and getting worse, it is not because of the Australian red meat industry.

While the conclusion “may appear shocking” to some, he said “that is the reality, because your balance sheet has not been increasing.”

“With the radiative forcing footprint (a metric used to determine the warming impact of methane emissions), your industry has more or less plateaued since around 2015.

“So that is the bottom-line story here, and if interventions (such as feeding methane reducing feed supplements) are successful, they lead to a negative (warming) scenario”.

Throughout his presentation Dr Ridoutt regularly quoted research and reports from the United Nations Food and Agriculture Organisation (FAO) and Inter-governmental Panel on Climate Change (IPCC), explaining: “I want you to know it is not just me saying something, this is in the words of these authoritative organisations.”

Some scientists, basing their conclusions on the metric known as Global Warming Potential 100 (GWP100), describe every emission of methane as bad, regardless of whether it originated from a fossil fuel or from a biogenic source such as livestock.

They have warned against industry debating which metric is the most appropriate for measuring the warming influence of methane emissions from livestock, saying the Paris Agreement has “explicitly adopted” the GWP100 metric as a way of converting methane into carbon dioxide equivalence, and say IPCC reports show the livestock sector will have to reduce emissions by 60 percent to achieve the Paris Agreement Goal (of limiting global temperature increases to well below 2 deg C above pre-industrial levels).

Yet the same IPCC science has led other scientists, who are independent with no vested interests in the livestock sector, to arrive at very different conclusions.

Among them is Dr Ridoutt, who explained last Friday that the choice of climate metrics in fact “makes a world of difference for beef”, because the industry’s emissions are mainly methane.

The reality is that there is “no absolute equivalence” between CO2 and methane and other greenhouse gases, he said: “all have unique characteristics, all last for different lengths of time in the atmosphere and all have different greenhouse effects”

“The most appropriate metric depends on the policy objective”

A recently published UN FAO report on methane emissions in agriculture states that “the most appropriate metric depends on the policy objective”, Dr Ridoutt said.

He also pointed out that the central aim of the Paris Agreement is to keep global temperature rises this century to below 2 degrees Celsius above pre-industrial levels, with a further aim of limiting rises to no more  than 1.5 degrees Celsius above pre-industrial levels.

“So all of this talk about greenhouse gas emissions and mitigation, it is all aimed towards a goal of stabilising the climate.”

He said the IPCC makes clear distinctions between CO2, which has a very long term impact (potentially thousands of years in the atmosphere), and gases such as methane which have a very short term impact (10-12 years).

“Methane comes and goes from the atmosphere very quickly, and a more or less steady rate of emission of methane is consistent with climate stabilisation, because new emissions are simply replacing emissions that are disappearing from the atmosphere, so it is a natural cycle so to speak,” he said.

GWP100 initially adopted for ‘political convenience’

He said GWP100 was initially adopted in the 1990s for “political convenience” to help add up emissions for use in the Kyoto Protocol.

“In that protocol it was decided to have a multi-gas protocol. Policy makers needed a way of adding up the different emissions and the scientists at the time said, ‘well, there is no obvious way of adding up these emissions, you add them up in different ways you get all sorts of different answers’.

“And yet, to have a multi-gas protocol they needed something, and for political convenience this GWP 100 metric was adopted.

“It is probably the one you are most familiar with.

“But I want to point out the fact that it actually says there in the text there is no scientific argument for selecting this way of adding up the emissions, as opposed to other ways of adding up the emissions.”

IPCC language now differentiates between Carbon Neutral and Greenhouse Gas Neutral

He said the IPCC’s language has shifted over the years.

Its latest assessment report now uses the phrase “Carbon Neutral” specifically only in relation to CO2, while using the terminology “Greenhouse Gas Neutrality” when talking about other greenhouse gases.

The objective of a “Carbon Neutral” goal is a target to achieve no more emissions, he said.

The objective of a “Climate Neutral” goal was no more warming he said.

“Is the (red meat industry’s) objective no more warning? Or is it no more emissions?

“Because the current industry target is no more emissions. CN30 is about no more emissions.

“And that is where we come to this increasingly used terminology which relates to climate neutrality.

“It is not about no more emissions, it is about no more incremental contribution to climate change.”

He said there are three main metrics currently being talked about – GWP100, GWP* (GWP star) and radiative forcing footprint – and all are based on exactly the same IPCC science.

No single metric is “right or wrong”

He said there is no metric that is right or wrong. The question of which metric is the most appropriate relates to the policy or objective being pursued.

“The reality is that with GWP100, it does paint your industry as a very heavy polluting greenhouse gas polluting industry.

“On the other hand, other metrics show that the industry has not been making any contribution to climate change since around 2015 for almost a decade.

“So the first thing you can take away from that is the fact that it is the same emissions, you are just adding them up differently, the conclusion is entirely based on the choice of the model.

“And I would argue the GWP* or the radiative forcing footprint are much more relevant if the goal is to stabilise the climate.”

He said that while metrics matter little when the primary gas emitted is CO2, metrics made a huge difference when your primary emission is methane.

“Yours is a special case. It is mainly methane, and what’s more it is biogenic methane.

“It is not fossil methane that is adding new CO2 to the atmosphere.

“It is CO2 that was taken up in grass, that eventually goes back through methane to CO2 in the atmosphere.”

He said in his view the GWP star or the radiative forcing footprint were much more relevant metrics to use “if the goal is to stabilise the climate”.

“The industry is not making any contribution to climate change since about 2015, so if climate change has been progressing and getting worse, it is not because of your industry, that is the bottom line.”


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  1. Marilyn Mangione, November 30, 2023

    Also the fleece on the sheep stores up to 1-2kg of carbon every year that the sheep lives.

  2. Peter Small, November 29, 2023

    It is well known, I understand, that the oceans are the biggest storers of carbon, and the next biggest potential is the soil. If that is so, rangeland sheep and cattle framers who embrace practices that retain carbon in the soil are making a massive contribution to carbon storage without doing anything different, and at no cost to the community. Sheep and cattle farmers should be applauded.

  3. Francisco José BLAHA, November 28, 2023

    I agree fully with the conclusions of the report.

  4. David Hosking, November 25, 2023

    Despite all the reassurances of the desirability of lamb and its lack of antibiotics so prevalent in chicken meat, the supermarkets are not supporting it. Why are there virtually no prepared meals or easy cooking options for busy families on the shelves using lamb, whereas they do are inundated with preparations using chicken and pork. Is this MLA responsibility to address this opportunity?

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