Associate Professor Matthew Harrison is the Systems Modelling Team Leader at TIA.
He is also the Director of the Carbon Storage Partnership, a multi-million-dollar transdisciplinary initiative that is developing profitable, environmentally sustainable, and socially acceptable pathways to a carbon neutral livestock sector by 2030.
Australian agricultural greenhouse gas (GHG) emissions primarily come from farmed livestock. Grazing beef, pasture-based dairy systems, and grazing sheep combined make up 92 per cent of GHG emissions attributed to Australian agriculture.
“All farms have sources and sinks of GHG emissions. A source produces, a sink removes,” Assoc Prof Harrison explained.
“Methane from livestock and manure, for example, are sources, while carbon sequestration in trees and soils are sinks.”
Assoc Prof Harrison has been recognised for his work on climate change adaptation of agricultural systems and on mitigation of GHG emissions.
Part of this work has included the development of participatory win-win approaches for environmental stewardship, greenhouse gas emissions mitigation and improved profitability of livestock systems in Australia, New Zealand, China, Japan, Indonesia, Argentina, the US, and Europe, such as environmental plantings for improved carbon sequestration in soils and in vegetation.
Assoc Prof Harrison has more than 15 years’ experience in co-designing holistic integrated solutions with and for the agricultural community, particularly farmers. Below he has listed eight steps farmers can take toward carbon neutrality.
- Identify your main sources of GHG emissions
If your farm has a large number of cattle or sheep, it is likely that methane is your largest source of GHG emissions. If you are a horticultural producer, your main emissions are likely to be mainly nitrous oxides. Farms that regularly cultivate soils may also lose significant amounts of carbon from soils, while farms that have high energy usage (e.g., due to irrigation pumps or dairy infrastructure) may have substantial amounts of carbon dioxide generated from use of fossil fuels. It is important to identify what your major sources of emissions are before making any decisions regarding carbon farming interventions.
- Plan mitigation interventions for your main sources of GHG emissions
For livestock, consider adopting a feed supplement to mitigate enteric methane (e.g., seaweed, Bovaer or dietary oils). For cropping enterprises, consider the 4Rs of nitrogen fertiliser application: right place, right rate, right time, right type. For farms that use a lot of power or fuel, consider upgrading infrastructure or using power off-peak (e.g., after 5pm), using machinery less often and minimising use of diesel. For dairies and piggeries, consider manure management to capture and avoid production of methane.
Many greenhouse gas emissions mitigation interventions are outlined in this short YouTube video: https://www.youtube.com/watch?v=jnNNfFbY7Nw
- Consider whether you want to be paid for your direct GHG emission mitigation
Some payment schemes exist for some carbon farming interventions (e.g., Herd Management), but not all. Payment schemes usually require official certification via an accredited agent and involve transaction cost. Trading of some types of carbon (e.g., soil carbon) can carry inherent risk, because soil carbon is quickly lost during drought. This may expose you to increased financial risk.
- Consider carbon removal versus greenhouse gas emissions mitigation
Soils and trees actively remove CO2 from the atmosphere, whereas mitigation measures reduce the rate of GHG emissions (e.g., livestock feed supplement reduces the rate of enteric methane production). For degraded soils, improving soil carbon may be the most appropriate avenue to reduce farm emissions. Whether removal or mitigation is likely to be more effective for your farm depends on point 1 above.
- Carbon offsetting should be considered a last resort
You can make your business carbon neutral by purchasing carbon credits or “ACCUs.” The total credits purchased should match your net GHG emissions. It is preferable to prioritise reducing GHG emissions or increasing carbon sequestration on farm (if possible), rather than purchasing offsets from external providers. Reducing emissions or increasing sequestration on farm is likely to be less expensive and reduce exposure to concerns about offset integrity. The investment also remains within the boundaries of the farm business, providing more direct benefits. People looking to purchase offset credits to reduce emissions should seek those with assured integrity in their emissions reduction and ideally also provide co-benefits’.
- Consider positives (co-benefits) and negatives (trade-offs) associated with your nominated interventions
Improving soil carbon is conducive to improving soil health, improved water holding capacity, improved fertility, and improved crop/pasture production. Planting trees can improve livestock production through shading or shelter e.g., by reducing lamb mortality due to wind chill. Improving soil organic matter and trees on farm may also improve biodiversity and natural capital of your farm. Small areas of trees planted on farm often lead to capital appreciation, so your business may be worth more with a small area of trees (up to 4 per cent of farm area) compared with a farm with no trees.
- Calculate your farm carbon footprint
Calculating your own carbon emissions helps provide insight as to your whole farm GHG emissions as well as the major sources of emissions. The Tasmanian Institute of Agriculture will run free carbon accounting workshops in Tasmania in early 2022 to showcase options for calculating farm carbon footprints. Stay tuned.
- Talk to people who are already involved in carbon farming
This is one of the best ways to avoid past mistakes, ascertain practical details and determine which is the best carbon farming option for you.
More information: matthew.harrison@utas.edu.au
Watch Assoc. Prof Harrison’s Pathways to carbon neutral (or net zero) agricultural systems webinar here: https://www.youtube.com/watch?v=jnNNfFbY7Nw
This article was published in Tasmanian Country Newspaper on 18 March 2022.