Cooling Down Greenhouse Gas Debate

Global warming has become one of the foremost environmental challenges of modern times, with agricultural industries being particularly scrutinised. The Australian wool industry is working collaboratively with other livestock industries to accurately assess and mitigate their greenhouse gas emissions.

AWI-funded studies of Life Cycle Analysis (LCA) have shown that to fully understand the eco-credentials of a wool garment, it is crucial that its whole lifespan be considered – from the production of greasy wool on sheep farms through to the garment’s end-of-life.

While the length of time a garment stays in active use has been found to be the most influential factor determining the garment’s environmental impact, the results of the LCA studies are also helping AWI to identify and focus its efforts on environmental ‘hot spots’ that will most effectively reduce wool’s footprint.

The largest ‘hot spot’ in the wool supply chain is the on-farm production of greenhouse gases (GHGs) – primarily methane belched by sheep. The methane is produced by micro-organisms in the stomach of sheep to assist with digesting fibrous materials such as grass.

“With growing international alarm at global warming and climate change, many if not all industries are under increasing scrutiny to assess, report and mitigate their greenhouse gas emissions,” said AWI’s Program Manager for Fibre Advocacy and Eco Credentials, Angus Ireland.

“The risk is that the wool and other livestock-based industries could be harmed if consumers’ purchasing decisions or governments’ regulatory decisions are based on ill-informed information, which is why AWI is undertaking objective research that provides scientific evidence to back up wool’s eco-credentials.”


AWI collaborates with other rural Research & Development Corporations on several GHG-related projects, including a project that is investigating whether the impact of methane emissions from livestock on global warming is being accurately assessed.

The current global standard metric for reporting GHG emissions and impacts (known as GWP100) uses a unit of measurement of ‘carbon dioxide equivalents’ over a timeframe 100 years. However, while carbon dioxide is a ‘long-lived climate pollutant’ and stays in the atmosphere indefinitely, methane is a ‘short-lived climate pollutant’ that has a far shorter atmospheric lifetime of about 12 years.

“Therefore, GWP100 arguably does not accurately reflect the decomposition of methane and has limitations as a metric,” Angus said.

“This is particularly important for ruminant-based agricultural industries as their emissions of GHGs contain a considerably higher proportion of methane compared to other greenhouse gases, such as carbon dioxide and nitrous oxide.”

An experimental method of accounting for methane, known as the GWP* method, is currently being investigated. GWP* uses ‘carbon dioxide warming equivalents’ as a unit of measurement and specifically aims to rectify the problems identified in the GWP100 method.

AWI is funding a study to calculate the GHG emissions at the individual wool-growing property scale as well as the national scale; the study will provide a comparative assessment of the flock’s emissions calculated using the experimental GWP* method and the current GWP100 method. In addition, the study will model and assess two hypothetical scenarios for the flock: a 25% decrease and a 25% increase in flock numbers.

Analysis of the national flock emissions will identify the long-term, industry wide implications if the GWP* metric were applied.


Significant research is also under way to assess and identify the technical feasibility, the cost-benefits, and the key opportunities, risks and barriers to achieving lower emission wool.

It aims to identify plausible mitigation strategies for the wool industry, capitalising on previous industry research, and assess potential adoption rates, including an economic assessment of the cost to woolgrowers of implementing the mitigations options.

Potential GHG mitigation strategies to be examined could include options such as feed additives or low methane pasture species, improving soil management, tree planting and increasing flock productivity (producing more lambs and wool from each sheep).

This article appeared in the September 2020 edition of AWI’s Beyond the Bale magazine. Reproduction of the article is encouraged, however prior permission must be obtained from the Editor.

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