Dairy farmers already using DairyBase can generate their carbon footprint using pre-populated data from their DairyBase farm dataset.
Greenhouse gas emissions represent an inefficiency in dairy systems. The loss of methane and nitrous oxide gases into the atmosphere means that energy and nitrogen that could be directed towards production are being lost. Some level of emissions is expected, but there are many opportunities within a typical dairy system to reduce greenhouse gases and achieve efficiency and profitability gains.
Although the carbon footprint of Australian dairying is one of the lowest internationally, there is still scope to improve efficiency. The Australian dairy industry has made a commitment to minimising its environmental footprint, including reducing greenhouse gas emissions intensity by 30% by 2030.
There is opportunity for the dairy industry – and the wider livestock sector of which it is a part of – to demonstrate its track record in addressing climate change and promote its commitments to being part of the solution to reduce greenhouse gas emissions on-farm.
The livestock sector has a large potential to reduce greenhouse gas emissions.
Many technical options to reduce emissions exist, including feed supplements and feed management, grazing land and manure management, health management and improved animal husbandry practices. These are documented below.
The first step towards reducing emissions is understanding the source of emissions on-farm and then highlighting the most effective options for reducing them.
Opportunities for incentives should also be considered. The Australian Government plans to reduce greenhouse gas emissions in Australia via its Emissions Reduction Fund and renewable energy targets.
Key points in these resources include:
The dairy industry accounts for 12.5% of agricultural emissions, or about 2% of total national greenhouse gas emissions. This may not sound significant, but for a typical dairy farm milking 300 cows producing 6,000 litres per lactation, this amounts to more than 2,000 tonnes of carbon dioxide equivalent (CO2e).
Most dairy farm emissions are from methane (CH4) and nitrous oxide (N2O). Methane from enteric fermentation is the biggest source of emissions from dairy farms, producing 57% of emissions on an average Australian dairy farm, followed by methane and nitrous oxide from urine and dung (18%). Nitrogen fertilisers cause emissions (6%) through both their production and application in dairy systems.
Farms also emit significant amounts of carbon dioxide through the on-farm use of fossil fuels and electricity (8.9% combined), purchased feeds and concentrates (7.9%) and purchased fertilisers (3.1%). There is a range of pre and post-farm gate activities that generate their own greenhouse gas emissions, which contribute to the dairy industry’s total carbon footprint.
Pre-farm gate emissions: Many inputs brought onto the farm have an embedded carbon footprint and become part of the total dairy industry carbon footprint despite the fact that in the national emissions accounting scheme, they are not reported as dairy farm emissions. These include embedded emissions from bought-in feed and fertiliser, as well as other pre-farm emissions associated with transport, farm chemicals and equipment, but these are very minor.
Post-farm gate emissions: The total amount of greenhouse gas emissions from dairy manufacturing in Australia is around 5% of the total emissions from dairy farms. Most of the dairy manufacturing in Australia occurs in Victoria. The majority of emissions from dairy manufacturing are carbon dioxide due to energy consumption through electricity and on-site energy use.
The most important factor in determining a dairy farm’s emissions is simply the amount of milk produced. On this emissions intensity basis (emissions per tonne of product), dairy farms are relatively low emitters.
Although the carbon footprint of Australian dairying is one of the lowest internationally, there is still scope to improve efficiency. The Australian dairy industry has made a commitment to minimising its environmental footprint, including reducing greenhouse gas emissions intensity by 30%.
There are many ways greenhouse gas emissions from dairy farms can be reduced, which includes via management changes to the herd, the feedbase and the soil.
The Australian Dairy Carbon Calculator (previously DGAS) is freely available for dairy farmers to identify their sources of greenhouse gas emissions (GHG) on-farm and benchmark their carbon footprint.
The Australian Dairy Carbon Calculator allows farm managers and other users to calculate the impact of adopting different emissions reduction strategies on their total farm emissions and emissions intensity. It can help them work out the strategies best suited to their farming system.
Abatement strategies modelled by the calculator fall into four categories; herd management, feeding management, soil management and farm intensification. Modelling shows that any farm efficiency improvement will lower GHG emissions per tonne of milk solids produced.
Learn how Shawn and Tanya Robbins (Boorcan, VIC) have used the Australian Dairy Carbon Calculator (formerly called DGAS) to identify opportunities for reducing emissions on-farm.
Cows produce and release methane courtesy of their rumen microbes. The methane produced by fermentation in the rumen is largely belched and breathed out by the animal. As a ruminant-based industry, this is something that is hard to avoid.
However, as methane is a high energy source (see Table 1), this represents a significant loss of energy from the production system, with 8% to 10% of gross energy intake lost as methane. Some of this energy can and should be redirected back into production (Eckard 2011).
Table 1: Typical ranges in methane emissions, energy lost as methane and effective annual grazing days lost from three classes of ruminants. Source: Eckard 2011.
Methane is 34 times more potent than carbon dioxide in its global warming potential. That potency –combined with the fact that a dairy cow belches about 600 litres of methane each day – make the annual emissions of a cow similar to a family car in terms of its effect on global warming. More information on this is available in an article published by The Age. It is estimated that a quarter of human-caused methane emissions are due to enteric (rumen) fermentation.
Methane production in the rumen of dairy cows is strongly associated with the digestion of forages, so high energy supplements such as grain or the use of total mixed rations reduces methane per litre of milk. As a result, there is roughly 30% difference in emissions intensity between the two extremes of dairy systems. Fully pasture-based systems produce roughly 17.5 tonnes of CO2-equivalent per tonne of milk solids. Fully lot-fed systems produce roughly 12.5 tonnes of CO2-equivalent per tonne of milk solids.
The proportion of an animal’s intake that is converted into methane is dependent on both the amount of feed eaten and the characteristics of the animal and the feed.
Currently, well-managed dairy farms have few options to reduce methane emissions without significant changes to their farming or feeding system. Making changes to reduce emissions would require analysis of the impacts on productivity and profit. For example, if grain supplementation is increased then three things tend to happen concurrently:
In this example, while methane per litre of milk almost certainly falls, methane per cow and per farm can rise. This means that reducing emissions intensity (emissions per litre of milk) is potentially a win:win for the dairy industry. Any improvement in productivity and/or production efficiency is likely to give an associated reduction in emissions per litre of milk.
Possible options for reducing methane on dairy farms include:
Nitrous oxide (NO2) emissions on dairy farms can be up to 25% of total farm emissions. However, three distinctly different processes contribute to this total:
Current farming systems that are operating at or near best practice management of cows and pastures already minimise nitrogen losses and maximise dairy production. If nitrous oxide is to be significantly reduced, new options and strategies will need to be developed and tested.
Possible options for reducing nitrous oxide emissions on dairy farms include:
Using effluent to offset fertiliser use can result in significant savings. Each tonne of nitrogen fertiliser applied to pastures emits 1.9 tonnes of CO2 equivalent directly and 2.3 tonnes of CO2 equivalent indirectly. In addition, the manufacture of fertiliser (urea) emits 1.9 tonnes of CO2 equivalent. Therefore a one-tonne reduction in the use of nitrogen fertiliser will reduce emissions by 6.1 tonnes of CO2 equivalent.
Similarly, reducing phosphorous and potassium fertiliser use by one tonne would save 4.6 tonnes of CO2 equivalent and 0.3 tonnes of CO2 equivalent, respectively, due to the reduction in emissions from manufacturing.
In an average farm system, reducing the time spent in the dairy and yard by 10%, with cows instead spending this time on pastures, would reduce emissions by around 10 tonnes of CO2 equivalent per annum.
The extent to which financial incentives via the Emissions Reductions Fund offered to farmers to reduce greenhouse gas emissions may change the economics of any of these options remains to be determined.
Nitrogen fertiliser use is essential in most dairy systems but the low efficiency of its use means that more than 60% of nitrogen added to pasture systems is lost to the environment.
With nitrogen efficiency often below optimum in dairy systems, there are a number of practical ways farmers can better match their nitrogen fertiliser applications with pasture demand, other inputs and prevailing conditions, thereby reducing input costs.
Practical advice on soil and fertiliser management is available via the Fert$mart website.
Key points to consider in nitrogen management:
Suggested practices for nutrient management:
Applying best practice management to improve herd longevity, fertility, transition cow management and health can have major effects on lifetime cow productivity, and therefore profitability and farm emissions intensity.
Key points to consider in reproduction efficiency:
Suggested herd management practices for maximising reproduction efficiency:
Greenhouse gas emissions are at their highest per kilogram of milk solids when cows are fed poor-quality diets. High-quality, high-digestibility feed will maximise milk production and minimise greenhouse gas emissions per kilogram of milk solids.
Suggested feeding management practices for feed efficiency:
Although effluent management comprises typically only 8% of total farm greenhouse gas emissions, managing effluent storage and re-use to minimise emissions can provide broader benefits for on-farm efficiency, profitability and the environment. By viewing effluent as a valuable source of nutrients rather than a waste product, there are opportunities to save money on fertiliser, improve soil fertility and condition and minimise the risk of water pollution, as well as reduce emissions.
Key points to consider in effluent management:
Key recommendations in effluent management:
Visit Dairying for Tomorrow for detailed information on effluent management, including short video clips and fact sheets on the following topics:
There is currently limited opportunity to establish forestry plantings with the intent of gaining a credit for the sequestered carbon. Dairy farms are usually small, intensively managed properties with little of the land class where government modelling indicates that forestry plantings for carbon sequestration may be economic, that being marginal and lowly productive farmland.
On the other hand, many dairy farms have small areas, including riparian zones, where revegetation for conservation purposes is already encouraged and common. An additional benefit from carbon sequestration may be available for existing or new plantings in these spots.
Shelter belts also provide a good opportunity to reduce the farm greenhouse gas footprint.
Soil carbon sequestration is the process of transferring carbon from atmospheric carbon dioxide into plant material, some of which is added to the soil carbon store as dead plant material or animal waste.
Soil is a complex mixture of organic compounds at different stages of decomposition. Soil organic carbon is divided into different ‘pools’ that are classified according to their rate of decomposition, as shown in Figure 1 below.
The amount of carbon in the soil depends on:
Dairy farmers have no control over their climate, little effective control over their soil fertility (most dairy soils are already highly fertile) and have a production system based on grazed pastures. Management is therefore the only significant option if dairy farmers wish to increase soil carbon.
The magnitude and rate of soil organic carbon decomposition and sequestration depends on a range of soil and environmental factors.
To boost organic carbon concentrations in soil, two main options are available:
In theory, any management practice that increases pasture production should lead to increased soil carbon because of the associated increase in plant material and animal dung. Practices such as fertiliser application, improved rotational grazing, irrigation and improved pasture species all have the potential to increase pasture production and thus soil carbon, though the impacts can be small and slow. Application of dairy effluent and sludge to pasture will also provide additional carbon inputs to the system.
These activities are already best practice on most Australian dairy farms because of the impact increasing soil fertility and pasture production has on farm profit. Therefore, while some farmers may have the option of implementing these management practices, for most the opportunities to significantly boost soil carbon will be limited. Additionally, if they are already considered good or best practice, such sequestration does not meet the requirement for 'additionality'.
For dairy farmers who grow crops and make silage, minimum tillage systems will reduce the rate of soil carbon decline in cropping paddocks. However, minimum tillage is already best practice for most soil types.
Biochar is a charcoal-like material produced by the pyrolysis (heating to between 350 degrees Celsius to 600°C under limited oxygen) of organic matter. This converts easily-decomposable organic matter into a highly biologically and chemically stable form of carbon that potentially has both soil improvement and carbon sequestration benefits.
Biochar is the solid by-product resulting from bioenergy production (Figure 2). The pyrolysis conditions can be optimised for bioenergy or biochar production.
Biomass for biochar production can comprise most urban, agricultural and forestry biomass such as wood chips, saw dust, tree bark, corn stover, rice or peanut hulls, paper mill sludge, animal manure and biosolids.
There are many issues and challenges to overcome before the production of biochar becomes a practical carbon sequestration option for dairy farmers. However, some large dairy farms and feedlots may produce sufficient manure from dairy effluent to make biogas generation from methane an option. For more information on biogas in dairy systems download the Feasibility of biogas technology in the Australian dairy industry fact sheet.
On-farm energy assessments have identified that to reduce energy use and consequently lower energy costs and greenhouse gas emissions, farmers need to both reduce demand and improve efficiency.
Reducing demand can be realised through implementation of some/all of the following actions:
Improving efficiency can be realised through implementation of new technologies, such as LED lighting and variable speed drive (VSD) pumps, better design, improved maintenance and/or use of high-efficiency motors.
The first step is to start measuring energy use and potential areas of inefficiency. Undertaking an energy audit would provide a good first assessment, as well as identifying goals, for potential energy savings. Alternatively, farmers should consider assessing the costs of the three main cost components – hot water, milk cooling and milk harvesting – against regional benchmarks
The most commonly identified savings were associated with:
In addition to energy savings, for some farms there were further dollar savings to be made with electricity billing arrangements and changeover to time of use contracts. Although these do not reduce energy use, they can substantially reduce total bills.
Regional analysis of the on-farm energy assessment data was also undertaken and made available in a series that can be found on the Resource Hub.
With costs falling and take-up rising of solar and other renewable energy systems, businesses are increasingly interested in storing the energy they produce to maximise its benefit and reduce their bills.
Renewable energy’s main challenge is that its use is restricted to when the renewable resource is available (when the sun shines or the wind blows). Storage allows more of that renewable energy to be retained so it can be used on-site at a later time and further reduce electricity consumption from the mains power grid.
Unfortunately, given the complexity of renewable energy and storage technology, there is no easy or quick way to answer the question of “how much storage do I need at my site and what will it cost?”
The only way to properly answer this question, which maximises the chance of implementing a cost-effective project at any given site, is to undertake a feasibility analysis. This analysis would take into account that site’s specific consumption patterns, electricity tariffs and solar resource.
It is important to note that renewable energy and storage technologies continue to evolve, with storage prices predicted to drop dramatically in the coming decade.
Individual businesses should seek expert advice to see whether renewables and storage is a viable option for that farm.
Some large dairy farms and feedlots may produce sufficient manure from dairy effluent to make biogas generation from methane an option.
Despite dairy farm waste being a good resource for biogas production, there are currently few working examples of biogas technology in Australia’s dairy sector. Biogas technology not only supplies renewable energy, but in addition the technology can simplify waste management, reduce odour and greenhouse gas emissions and improve fertiliser value of manure and other by-products.
Biogas technology does not have to be complex or difficult to operate, but it does need to be tailored to the specific needs of the farm in terms of farm management, waste characteristics and biogas use.
Before developing methane capture and use projects, the following questions need to be answered:
Climate change is a global problem that requires a global solution. Countries have agreed to a collective goal of limiting global average temperature rise to less than 1.5°C above pre-industrial levels.
In mid-2015, the Australian Government announced its emissions reductions target of 26% to 28% below 2005 levels by 2030. Australia will meet its 2030 target through the Climate Solutions Fund, which includes incentive payments for emissions reduction activities through the Emissions Reduction Fund.
The Emissions Reduction Fund is a voluntary scheme that aims to provide incentives for a range of organisations and individuals to adopt new practices and technologies to reduce their emissions.
The first Emissions Reduction Fund auction took place in April 2015. In that year, more than 47 million tonnes of carbon abatement was contracted at an average price per tonne of abatement of $13.95. Through that auction, the Government committed $660 million to 144 projects to reduce emissions in Australia. The emissions reductions from those projects will be delivered over 10 years, which means that reductions purchased in the first auction will contribute not just to Australia’s 2020 target, but to the 2030 target. Tracking of Australia's emissions is made publicly available on the Department of Industry, Science, Energy and Resources website.
The Government has published a range of methods that help businesses, communities and landholders to plan and undertake projects. The methods explain how to carry out a project, including how emissions reductions can be measured and the reporting requirements during the life of the project.
There are currently two Emissions Reduction Fund methods relevant to dairy:
Dairy Australia is working alongside other livestock industries to increase the opportunities for dairy farmer participation in market-based incentives for emissions reduction, such as the Emissions Reduction Fund.
Participation in the Emissions Reduction Fund is voluntary, so there is no pressure on dairy farmers to get involved. Current dairy industry modelling suggests that well-managed dairy farms have few options to profitably reduce emissions of methane and nitrous oxide.
As new methodologies are developed for the dairy industry beyond this project, these too will be incorporated into existing industry tools, such as the Australian Dairy Carbon Calculator, as appropriate.