Agriculture has rated poorly in the latest United Nations report on global greenhouse gas emitters.
The UN-led Climate and Clean Air Coalition has found agriculture accounts for 40 per cent of "human-caused" global methane emissions.
Livestock have been held responsible for 32 per cent of all human caused methane emissions.
Rice production was said to have caused the remaining eight per cent of emissions.
"Emissions from livestock are the largest source of agricultural emissions with enteric fermentation the dominant process and cattle the dominant animal causing the emissions," a report released last week says.
The report recommends "dietary modification" may be needed so people eat less meat and also discusses a global tax on methane production.
Fossil fuels accounted for 35 per cent of "human caused" methane, the Global Methane Assessment said. Although fossil fuel use is still the major culprit in the contribution of CO2 to total greenhouse gas.
The UN report said methane should be targeted because it was chiefly caused by humans and could just as easily be stopped by humans.
The report says human-caused methane emissions could be reduced by almost half in a decade.
Such reductions would avoid nearly 0.3°C of global warming by 2045, the report said.
"Fast and ambitious methane mitigation is one of the best strategies available today to deliver immediate and long-lasting multiple benefits for climate, agriculture, human and ecosystem health," UN Environment Program executive director Inger Andersen said.
But only last week at Beef Australia in Rockhampton, world-renowned climate expert Frank Mitloehner questioned the science of methane calculation.
Dr Mitloehner said "a lot" of purportedly expert information being used by opponents of the livestock industries was inaccurate.
"Methane is not only being produced but is being destroyed at almost equal rates," he said.
Dr Mitloehner also pointed to the issue of food waste as being a key area to be tackled to help drive down methane production.
The UN report did acknowledge methane was short lived but said "it is a potent greenhouse gas tens of times more powerful than carbon dioxide at warming the atmosphere".
The UN-led report said said a 45pc reduction in global methane production would prevent 260,000 premature deaths globally, 775,000 asthma-related hospital visits, 73 billion hours of lost labour from extreme heat, and 25 million tonnes of crop losses annually.
The report said more work needs to be done on reducing methane production from livestock and recommends "dietary modification" as part of the solution.
"Behavioural change measures and innovative policies are particularly important to prevent emissions from agriculture, given the limited potential to address the sector's methane emissions through technological measures.
"Three behavioural changes, reducing food waste and loss, improving livestock management, and the adoption of healthy diets (vegetarian or with a lower meat and dairy content) could reduce methane emissions by 65-80 million tonnes per year over the next few decades," the report says.
To tackle methane production in agriculture the report recommends:
- Improve animal health and husbandry: reduce enteric fermentation in cattle, sheep and other ruminants through: feed changes and supplements; selective breeding to improve productivity and animal health/fertility
- Livestock manure management: treatment in biogas digesters; decreased manure storage time; improve manure storage covering; improve housing systems and bedding; manure acidification.
- Rice paddies: improved water management or alternate flooding/drainage wetland rice; direct wet seeding; phosphogypsum and sulphate addition to inhibit methanogenesis; composting rice straw; use of alternative hybrids species.
- Agricultural crop residues: prevent burning of agricultural crop residues.
- Reduced food waste and loss: strengthen and expand food cold chains; consumer education campaigns; facilitate donation of unsold or excess food.
- Adoption of healthier diets: decrease intake where consumption of ruminant products is above recommended guidelines.
Given the limited technical potential to address agricultural sector methane emissions, behavioural change and policy innovation are particularly important for this sector, the report says.
It says three behavioural changes, reduced food waste and loss, improved livestock management, and adoption of healthier diets have the potential to reduce methane emissions by 65-80Mt/yr over the next few decades.
"Additional possibilities for mitigation of the large methane emissions from agriculture, especially livestock, exist and some cannot be easily characterised as solely targeted or additional.
"For instance, substitution of cultured meat for traditional livestock products could substantially reduce associated greenhouse gas emissions, especially methane.
"Such technologies are not yet commercially viable, however, and may not gain widespread consumer acceptance."
The report concluded "including behavioural change" in a broad portfolio of policies could help address and mitigate emissions.
The report said tackling diet was difficult because while many developed countries had an obesity epidemic, some developing countries suffered hunger and malnutrition among their population from having too little or not enough of the right types of food.
"Implementing structural and long-lasting changes in individual dietary intake, however, will likely require strong intervention, mitigation and incentivisation by governments through innovative policies.
"Social influence approaches can be an effective way of encouraging resource conservation as part of either government or non-governmental programs.
"Similarly, interventions in livestock management practices or efforts to reduce food loss and waste face considerable barriers in terms of institutional capacity, education and societal reluctance to change traditional habits as well as economic barriers.
"Nevertheless, given that the impact of the three elements with the strongest evidence base - reduced food loss and waste, improved livestock management, and change to healthier diets - is estimated here to have the potential to reduce methane emissions by up to 65-80Mt/yr over the next few decades, the impact of behavioural change and innovative policies on agricultural methane emissions should not be ignored.
In relation to the development of feed additives such as seaweed, the UN report says feed supplements offer potential for reducing methane emissions from the livestock sector but are currently considered experimental and are therefore not included in most abatement potential analyses.
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