Imma Perfetto
Cosmos science journalist
As all sectors of society transition to net-zero greenhouse gas (GHG) emissions, land managers are faced with the additional challenge of balancing farm production and profit with biodiversity, while ensuring continued social licence.
Experts believe that “climate mandated disclosures”, such as labels which reveal products’ emissions intensity, will be in place for agriculture, fisheries and forestry within a decade, and therefore climate interventions will be almost compulsory.
But new Australian research funded by industry bodies, shows there is a pathway to net-zero that won’t cost an arm and a leg and which can even increase production and profits.
The answer is not in sticking with the status quo, but in “stacking” multiple interventions.
According to study, continuing business-as-usual while purchasing carbon credits to offset emissions is the costliest pathway to transition to net-zero for livestock farmers, as well as being the intervention with the lowest community acceptance.
Professor Matthew Harrison of the Tasmanian Institute of Agriculture (TIA) and the University of Tasmania, says farmers could transition to net-zero in the easiest possible way, which is buying offsets, but that is likely to cost more than half the farm’s annual income every year.
“I can’t say that any farmer would ever do that,” Harrison told Cosmos.
Instead, they found that the key is to combine multiple mitigation strategies.
“You don’t get major reductions in on-farm emissions from a single practice change. But stacking interventions offers the most cost-effective route to net-zero emissions,” says Harrison, who leads the Carbon Storage Partnership, an initiative of Meat & Livestock Australia (MLA) that aims to build the capability and capacity of Australia’s livestock sector to become carbon neutral by 2030.
Funding for the study, which has been published in the journal Nature Communications, was provided by MLA, Australian Wool Innovation, and TIA.
According to the Intergovernmental Panel on Climate Change (IPCC), crop and livestock activities within farms contributes 9-14% of total global GHG emissions. Ever increasing GHGs in the atmosphere are trapping more energy in Earth’s system, driving an increase in global average temperatures and altering the climate.
“Future climates for most of mainland Australia will be hotter and drier, with more droughts, more bushfire events, more extreme [weather] events, and generally higher temperatures in winter and in summer,” says Harrison.
The researchers approached a group of livestock farmers and industry experts for insight into what they would do to reduce greenhouse gas emissions and to adapt to the predicted Tasmanian climate in 2030 and 2050.
“We got a whole bunch of different suggestions,” says Harrison.
“We bundled all those together and looked at the cost, we looked at the net effect on emissions, and we looked at how that might adapt to a future climate.
“We calibrated … economic, livestock production and greenhouse gas emissions models using real farm systems so our modelling frameworks produce realistic numbers.”
The team identified the mitigation strategies with the most impact when implemented together: carbon sequestration; reducing enteric methane; and improving livestock feed conversion efficiency.
“If you did those 3 things you could be net zero and … you would improve your profit,” says Harrison.
Carbon sequestration is process that sucks CO2 out of the atmosphere and stores it over long periods of time. In a farming context, this can be done in woody vegetation and soils. The study modelled planting 50-200 hectares of trees on unproductive land, or an extra block bought for that purpose.
Increasing livestock feed conversion efficiency allows animals to put on more live weight – growing faster or producing more milk or heavier eggs – for every 1kg of feed eaten. The study looked at improving livestock feed conversion efficiency by 20%, or 30% as a stretch target, through genetics.
Enteric methane, which livestock burp up, makes up 60-70% of a livestock farm’s GHG emissions and was responsible for 40% of global agricultural (farm level) emissions in 2019.
Supplementing livestock feed with an anti-methanogenic source such as the seaweed Asparagopsis taxiformis can reduce enteric methane emissions by up to 80%.
However, Harrison acknowledges that these interventions come with their challenges.
Carbon sequestration and improving livestock feed conversion efficiency are longer-term interventions, as trees planted today will take 10-20 years to mature and changing a livestock herd’s genetics does not happen overnight.
High potency anti-methanogenic feed additives can be costly, less readily available, and less practical in a grazing context.
“You have to feed [livestock] daily. That’s okay in dairies and feedlots, because you can manipulate what they eat every day,” explains Harrison.
“If you have animals in a 300ha paddock, you’re not certain that they will eat the feed supplement every day, or if it’s a lick block they might not come near it.”
Lower potency approaches, such as renovating pastures with anti-methanogenic plants like deep-rooted perennial legumes, can still make a demonstrable difference.
“Things like subterranean clover and lucerne can reduce enteric methane by up to 10% relative to grasses,” says Harrison.
“The animals are going to be eating pasture anyway, and so they don’t have to come over to a trough to eat an additional supplement to reduce enteric methane. They go out to the paddock and eat it.
“Farmers have to renovate their pastures every 5-7 years anyway … why wouldn’t you renovate with anti-methanogenic pasture species?”
The time to implement mitigation strategies is now, because Harrison says markets will increasingly look towards low emissions products with “kilograms of CO2 per kilogram of product” to appear on labels in our supermarkets.
He also predicts that Australian farms will have “climate mandated disclosures” from about 2035.
“It’ll be gentle at first and optional, but slowly and surely, it will become mandatory and tighten up so that farms will have to report their emissions,” he says.
“The way to think about it is not to compare your emissions against the next farmer, or the national average.
“If you have reduced your emissions relative to your GHG last year, that’s demonstrable improvement.”
The study was conducted as part of the Carbon Storage Partnership – an initiative of Meat and Livestock Australia (MLA) that aims to build the capability and capacity of Australia’s livestock sector to become carbon neutral by 2030. Funding was provided by Meat and Livestock Australia, Australian Wool Innovation, and TIA.