Dairy methane reduction in the spotlight at Australian Dairy Conference

That opportunity comes from not just meeting the demands of multi-national companies and helping the Australian government meet the Global Methane Pledge.

Because methane is relatively short-lived in the environment, any reduction in it has a bigger impact than cutting other greenhouse gas emissions.

And because dairy is such a nutrient-dense product, reducing its environmental footprint means it can make a vital contribution to world nutrition efficiency.

The good news is that a plethora of research is underway to help the industry cut all its greenhouse gas emissions.

In fact, dairy could reduce its emissions by 50 per cent tomorrow with the known technology and the right incentives, University of Melbourne Professor of Sustainable Agriculture Richard Eckard said.

But he warned the industry it could not be complacent about the issue.

There was an alarming and growing disconnect between where agricultural industries were at and where global environment policy was going.

Industry discussions about whether the greenhouse gas metrics were right, about biogenic versus fossil methane, about carbon neutrality or climate neutrality and about emissions intensity were at odds with global policy that set clear absolute targets for methane emission reductions.

READ MORE: Dairy Carbon Calculator launched

Arguments that there were more ruminants in pre-industrial times than now, so methane levels had fallen, had been debunked.

An isotopic signature for animal methane in the atmosphere revealed its level was increasing, particularly in the southern hemisphere and in Australia.

"I think we've got to take notice of and face this head on and say what we're going to do about it," Professor Eckard said.

"We are in a tenuous position in the dairy industry.

"The dairy industry occupies all the good soil, high rainfall combinations of coastal Australia.

"The competition for that land is going to get hotter over time.

"So we have got to make sure that dairy is the most valuable land use of the land that it's got.

"This is not a death knell to the dairy industry, it's a challenge."

Rabobank global head of sustainable business development Lachlan Monsbourgh backed Professor Eckhard's assessment that farms would need to evolve to meet the requirements of global commodity and finance supply chains.

Agriculture would be increasingly under pressure from its supply chains - not governments - to cut greenhouse gas emissions.

The top 10 fast-moving consumer goods (FMCG) companies were worth more than $US1.185 trillion - and everything agriculture produced touched at least one of these companies.

These companies were not industrialists, they were sellers of finished goods and brands.

They operated in an increasingly urbanised world, where consumers were disassociated from the source of their food.

"Different brands have had their brand diminished by environmental performance or enhanced by their environmental performance," he said.

Mr Monsbourgh urged farmers to start measuring what they were doing in key sustainability areas.

FMCG brands operating in the food and fibre sectors were focused on carbon emissions, animal welfare, water, biodiversity and soil health.

"I think every farmer who's in the room today can probably say 'OK yeah on some of these things I can quantify where I am reducing it'," he said.

"But on other things, like biodiversity, you might be saying 'geez where do I even start'.

"That's OK, we don't have to be there yet."

But farmers need to start quantifying their position and showing change or they would struggle to supply some of these companies.

Mr Monsbourgh said banking was also changing.

Loans were increasingly linked to sustainability credentials, while companies were expected to put something about climate in their finance reports.

But there were also opportunities for farms in this with the emergence of green loans aimed at improvements that enhanced sustainability.

University of California Davis Department of Animal Science Professor Frank Mitloehner told the conference methane was different from the other main greenhouse gases.

Although it had 28 times the global warming potential of carbon dioxide, it had a half life of just 12 years, compared with 1000 years for carbon dioxide.

Nitrous oxide had significantly higher global warming potential - 265 times the potential of carbon dioxide - and a half life of 110 years.

"Methane is special gas, I call methane the fast and furious," he said.

"Methane is not just produced like other gases but methane is also naturally destroyed, there's strong atmospheric removal of methane."

Professor Mitloehner said this had an important impact.

The number one source of human-induced climate change was the use of fossil fuels - oil, gas and coal.

These pure carbon sources were stored in the ground for millions of years until humans started extracting them.

"Now we have taken about half of all the fossil carbon out of the ground ... and burned it and it is now added to the atmosphere," he said.

That carbon source was a one-way street from the ground to the atmosphere.

But animal contribution to greenhouse gases was different.

Carbon was taken from the atmosphere into plants, some of which was stored in the soil, and some of which was consumed by animals and converted in the rumen into methane.

A lot of that methane was belched out, while some came out as animal manure.

But that methane stayed in the atmosphere only for about decade before it was converted back into carbon dioxide.

Professor Mitloehner warned this cycle did not mean that methane could be ignored, because when it was in the atmosphere it was a potent greenhouse gas.

But it was significantly different to fossil fuels.

"Every time you ever burn fossil fuel, you add new and additional carbon to the atmosphere and that causes new and additional warming to our planet," he said.

So carbon dioxide was referred to as a stock gas because every time it added to the existing stock.

Methane was often treated as a stock gas too, but methane was destroyed in the atmosphere, as well as being produced.

This meant methane was a flow gas.

READ MORE: Dairy Industry sets new targets for sustainability

"As long as methane is produced at a constant rate, you're not adding new and additional warming to the planet," he said.

Some Oxford University researchers had suggested this meant methane should be measured differently.

The standard measure - Global Warming Potential 100 (GWP 100) - overestimated methane's impact by a factor of four in situations where methane production was constant, for example, where a cattle herd was the same size over a longer period.

The researchers developed a new matrix called GWP* to describe the impact methane production had on warming, not on carbon dioxide equivalents.

Professor Mitloehner said this meant reducing total methane emissions could reduce greenhouse gas emissions - particularly if methane was used in place of fossil fuels.

"If we manage to mitigate methane then we can reduce - not just hold - our contribution, so we can reduce the warming on our planet," he said.

"Animal agriculture has the potential of being part of a climate solution, if we manage this gas rather than just looking the other way.

"Methane is a super opportunity because when we mitigate it, we immediately have an impact on climate."

Professor Mitloehner said California had recognised this potential in introducing a carrot, not a stick, system for farmers on greenhouse gas emissions.

It used financial incentives to encourage farmers to invest in measures such as biogas production and feed additives to cut methane emissions.

Professor Mitloehner said dairy should be aiming for climate neutrality - not carbon neutrality.

It the industry can cut methane production by enough, it would offset the production of other greenhouse gases and mean the industry was no longer contributing to additional climate warming.

Fonterra chief science and technology officer Dr Jeremy Hill told the conference it was a nonsense to tell the dairy industry it could not exist if it did not reduce its emissions.

"The puzzle of feeding the global population becomes nearly impossible without nutrient-dense foods like milk," he said.

Milk was the largest contributor to the supply of calcium, vitamin B2, fat in the essential amino acid lysine and the second largest contributor to the nutrients phosphorus, potassium, and vitamins B5 and B12.

"So it is the most nutrient-dense food," he said.

A binary view of nutrition - plant foods were good and animal foods were bad - was a problem.

"The global food system is plant-based, with three-quarters of food consumption from the many and diverse plant foods," he said.

"But for nutritional adequacy, there is a need for our diet to be optimised with nutrient-dense animal-source foods like milk."

But that did not mean that dairy should not be reducing its greenhouse gas emissions, particularly enteric methane.

Enteric methane made up 50pc of Fonterra's environmental footprint and its global customers were seeking ongoing reduction.

Fonterra was investing heavily in finding viable solutions to reduce methane, particularly ones that worked in NZ's pasture-based farm system, where methane was distributed and diffused widely.

To be viable, a solution had to be good for the milk, good for the cow, good for the farmer and good for the planet.

It also had to be effective, affordable, easy to implement, safe, produce no residues and be scalable.

Dr Hill said Fonterra was looking carefully at a wide range of options including:

"There isn't going to be one silver bullet," he said.

"And even a solution that may be the best solution at this point in time may not be the best solution in five years' time.

"There may be another solution that gives you exactly the same reduction in methane, for example, but at half the price."

Want to read more stories like this?

Sign up below (select Dairy News) to receive our e-newsletter delivered fresh to your email in-box twice a week.