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Carbon Emissions and how to calculate them
Mandy Curnow, DPIRD and
Richard Brake, Richard Brake Consulting
Not all gases are the same:
1 tonne of carbon dioxide CO2 = 1 tonne of CO2 e-
1 tonne of methane CH4 = 28 tonnes of CO2 e-
1 tonne of nitrous oxide N20 = 265 tonnes of CO2 e-
How do we measure Carbon emissions?
State and national emission inventories - direct emissions by emission source and sector (eg energy -
stationary energy, transport fuel)
Business/Farm Carbon Accounts include all levels of emissions to the point of export from the farm
gate:
Scope 1 - emissions that occur on site e.g. enteric methane, CO2 from diesel
Scope 2 - electricity emissions
Scope 3 – emissions associated with purchased inputs
Life Cycle Analysis – usually from inception including all inputs through to sale of the product,
including processing and transport.
Methods
Global Warming Potential (GWP) Values
From https://www.ghgprotocol.org/sites/default/files/ghgp/Global-Warming-Potential-Values%20%28Feb%2016%202016%29_1.pdf
State level Emissions Snapshot
Sectors reported in National Inventory (2019) and WA proportions1 Energy (92%)
2 Industrial Processes (5%)
3 Agriculture (11%)
4 Land Use, Land-Use Change and Forestry (-9%)
5 Waste (2%)
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
2005 2010 2015
CO
2 e
-G
g (
x 1
000 t
onnes)
WA agriculture emissions
3.A Enteric Fermentation 3.B Manure Management
3.D Agricultural Soils 3.F Field Burning of Agricultural Residues
3.G Liming 3.H Urea Application
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
-
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
1992 1997 2002 2007 2012 2017
Valu
e (
$1M
) G
HG
em
issio
ns (
Gg)
livesto
ck n
um
ber
(x 1
000)
WA livestock numbers, value and GHG emissions
sheep population (x 1000) cattle population (x 1000) total emissions from livestock (Gg) total livestock value $ x 1M
Source: the National GHG Inventory for emissions
DPIRD, ABS for production. Analysis by DPIRD
• Excludes transport and energy emissions as these are captured in energy sector reporting
• Excludes land use change on farm as these are captured in Land use sector reporting
National Greenhouse Gas Inventory reporting
1990 1995 2000 2005 2010 2015
0
1,000
2,000
3,000
4,000
5,000
6,000
0.0
0.5
1.0
1.5
2.0
2.5
Sta
te y
ield
(t/H
a)
est. c
rop e
mis
sio
ns (
Gg)
Crop emissions and average state yield WA
yield total crop emissions Linear (yield) Linear ( total crop emissions)
Source: the National GHG Inventory for emissions
DPIRD, ABS for production. Analysis by DPIRD
• Excludes transport and energy emissions as these are captured in energy sector reporting
• Excludes land use change on farm as these are captured in Land use sector reporting
National Greenhouse Gas Inventory reporting
Carbon Accounting at a farm or business level
We need to measure so we can manage!
In 2020 DPIRD ran a carbon account on Katanning Research Facility to:
1. Understand our own emissions so we could reduce emissions from a
key government asset
2. Understand the process and the challenges of reaching Carbon
Neutral on a mixed farm
3. Provide a place where different techniques for reducing emissions
could be demonstrated and host important research and trials on novel
methods.
Emission intensity by land area ~1.5t CO2 e- per arable/grazed hectare per year
Proportion of emissions from Livestock activities76% plus a portion of ‘other services’
Carbon Account - Katanning Research Facility
Thank you
Contact: Mandy Curnow e: [email protected] 08 98928444
For copy of the report and other information: agric.wa.gov.au//climate-change/livestock-and-carbon
Important disclaimer
The Chief Executive Officer of the Department of Primary Industries and Regional
Development and the State of Western Australia accept no liability whatsoever by reason of
negligence or otherwise arising from the use or release of this information or any part of it.
© State of Western Australia 2021
Richard Brake
Richard Brake Consulting P/L
Reference is to be paid to: - Level of detailed inputs vs simplicity of use - Appropriate inputs and language for Western Australian producers - Value of outputs and useability of outputs
Also required is the Identification of - Strengths and weakness of each tool - Consistency to other tools and calculators - Gaps or shortcomings in calculations or capture of relevant data
The Western Australian Department of Primary Industries and Regional Developmentestablished a project to assess the available tools that include livestock and grainproduction in a mixed farm system for a Western Australian agricultural environment aswell as deal with mitigation and sequestration functionality.
Carbon calculators
Primary Industries Climate Challenges Centre / University of Melbourne
Cool Farm Tool
AFI
Agrecalc
FarmPrint
LOOC – C
Other proprietary calculators
Evaluated Farm Data
Cropped area: 2,328 ha
Grazed area: 2,484 ha
2020 rainfall: 455 mm
Five-year average rainfall: 551 mm
Annual average temperature: 16oC
Soil type: Predominantly Forest Gravels
Crops grown and included: Barley, Canola, Oats
Flock size: 14,770
Crop Sheep Whole Farm
PICCC GAF 1681.60 3044.17 4725.77
AFI FarmGas 557.80 1632.82 2190.62
The Cool Farm Tool 2093.96 2861.96 4955.92
Agrecalc 3021.01 5487.07 8505.08
Average 1838.59 3256.50 5095.10
Results, tonnes CO2e/year
Emissions, tonnes CO2e/year
Variation from average, tonnes CO2e/year
Summary
Accuracy of results generated is highly dependent on the quality and accuracy of data entered into the calculator
The amount of information and level of detail required varied across the calculators
Each calculator covered emissions none adequately covered sequestration especially soil carbon although some briefly touched on tree plantings
Interpretation of results and application, and refining of management strategies outside of ERF methodologies is not well understood
Richard Brake Consulting Pty Ltd
Richard Brake Consulting Pty Ltd
Take home messages Carbon emissions provokes emotive responses
Markets are likely to require some form of carbon mitigation
As a farmer, be proactive
Focus on controlling the issues inside the farmgate
We know the climate is changing, we see it everyday
Richard Brake Consulting Pty Ltd
Extra detail on programs and
outputs
State level Emissions Snapshot
Sectors reported in National Inventory (2019) and WA proportions1 Energy (92%)
2 Industrial Processes (5%)
3 Agriculture (11%)
4 Land Use, Land-Use Change and Forestry (-9%)
5 Waste (2%)
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
2005 2010 2015
CO
2 e
-G
g (
x 1
000 t
onnes)
WA agriculture emissions
3.A Enteric Fermentation 3.B Manure Management
3.D Agricultural Soils 3.F Field Burning of Agricultural Residues
3.G Liming 3.H Urea Application
* Agriculture emissions excludes transport and energy emissions as these are captured in energy sector reporting
Definitions
• Enteric fermentationEnteric fermentation is a natural part of the digestive process in ruminant animals such as cattle, sheep, goats, and buffalo. Microbes in the rumen decompose and ferment food, producing methane as a by-product. Calculated by # of animals x class x feed intake x factor for methane
• Manure managementManure acts as an emission source for both methane and nitrous oxide, and the quantity emitted is linked to environmental conditions, type of management and composition of the manure. Organic matter and nitrogen content are the main things influencing emission of methane and nitrous oxide, respectively.
Calculated by # of animals x feed intake x factor for methane. NO2 for pasture grazing is added in agricultural soils.
• Agricultural soilsDirect and indirect emissions of nitrous oxide from soils arise from microbial and chemical transformations that produce and consume nitrous oxide in the soil. The transformations involve inorganic nitrogen mainly ammonium, nitrite and nitrate. Nitrogen compounds can be added to the soil through:
a) the application of inorganic nitrogen fertilisers
b) the application of animal wastes to pastures
c) the application of crop residues
d) mineralisation due to loss of soil carbon and cultivation of organic soils
e) atmospheric nitrogen deposition
f) leaching of N from soils and surface runoff, and subsequent denitrification in rivers and estuaries (Areas with evapotranspiration ratios less than 0.8 or more than 1 are deemed areas where leaching and runoff occurs).
• Field burning of residuesThe burning of residual crop material releases CH4, N2O, CO, NOx and NMVOCs into the atmosphere. CO2 is not included in the calculations as is assumed that an equivalent amount of CO2 was removed by the growing crop.
• LimingAdding carbonates to soils in the form of lime (eg. calcic limestone (CaCO3 ) or dolomite (CaMg(CO3 )2 )) results in CO2 emissions, as the carbonate reacts with acids in the soil to produce bicarbonate and eventually leading to the production of CO2 and water.
• Urea applicationAdding urea to soils for fertilisation leads to a loss of the CO2 that was fixed during the manufacturing process. Similar to the reaction following the addition of lime, the bicarbonate that is formed evolves into CO2 and water
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
1990 1995 2000 2005 2010 2015
ente
ric e
mis
sio
ns G
g (
1000to
nnes)
CO
2-e
Livestock emissions WA
Cattle Methane Sheep Methane Manure Cattle Manure Sheep
0
500
1000
1500
2000
2500
1990 1995 2000 2005 2010 2015
GH
G e
mis
sio
ns (
Gg C
O2 e
-)
Cropping Emissions WA
Direct Soil Emissions Indirect Soil Emissions Field Burning of Agricultural Residues Liming Urea Application
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
2005 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
CO
2 e
-(G
g)
WA Agriculture emissions(from National Inventory)
total Livestock total soils and crops
(Agricultural soils: portioned 25% livestock 75% crops)
Approx 13.6 million Ha of agricultural pastures and crops with 25% livestock and 75% crop land use.
Includes all cattle – pastoral and agricultural (~50:50)
Crops include horticulture and grain
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
1990 1995 2000 2005 2010 2015
WA cropping production and GHG emissions(Ag soils and fertiliser)
total crop emissions total area cropped total tonnage Linear (total tonnage)
* Excludes transport and energy emissions as these are captured in energy sector reporting
Current Emissions Reduction Fund methods 1. Animal effluent management method
2. Beef cattle herd management method• increasing the ratio of weight to age of the herd;• reducing the average age of the herd;• reducing the proportion of unproductive animals in the herd;• changing the ratio of livestock classes within the herd to increase total annual liveweight gain of the herd
3. Estimating sequestration of carbon in soil using default values method• Conversion to pasture • Sustainable intensification • Stubble retention
4. Measurement of soil carbon sequestration in agricultural systems method• applying nutrients to the land in the form of a synthetic or non-synthetic fertiliser to address a material deficiency;
• applying lime to remediate acid soils;
• applying gypsum to remediate sodic or magnesic soils;
• undertaking new irrigation;
• re-establishing or rejuvenating a pasture by seeding;
• establishing, and permanently maintaining, a pasture where there was previously no pasture, such as on cropland or bare fallow;
• altering the stocking rate, duration or intensity of grazing;
• retaining stubble after a crop is harvested;
• converting from intensive tillage practices to reduced or no tillage practices;
• modifying landscape or landform features to remediate land;
• using mechanical means to add or redistribute soil through the soil profile;
5. Reducing greenhouse gas emissions in beef cattle through feeding nitrate containing supplements method
6. Fertiliser use efficiency in irrigated cotton method
7. Reducing greenhouse gas emissions in milking cows through feeding dietary additives method
Katanning livestock enterprise emissions
Katanning cropping enterprise emissions
Mitigation or sequestration option% of the emission profile
Technical mitigation potential
% of flock where applicable
% potential adoption across the fraction of flock
Estimated mitigation
potential for KRF livestock
Reducing carrying capacity and total livestock numbers by buying in replacement maiden ewes
75% 35% 98% 100% 25.7%
Introducing anti-methanogenic feed additive 3NOP
75% 70% 80% 40% 16.8%
Introducing anti-methanogenic feed additive Asparagopsis
75% 85% 100% 100% 63.8%
Breeding more efficient sheep — for fast growth, weaning rates and feed efficiency/low methane
75% 2% 28% 100% 0.4%
Introducing anti-methanogenic legumes, e.g. biserrula
75% 16% 98% 60% 7.1%
Potential strategies to reduce livestock emissions
Potential reduction of KRF total emissions ~ 32-35% (excluding potential additives)
Potential strategies to reduce crop emissions
Strategy% of the
emission profile
Technical mitigation potential
% of operation where
applicable
% potential adoption across the fraction of
operation where applicable
Estimated mitigation
potential for KRF cropping
Reduce crop by 30% at full N fertiliser
20% 30% 100% 100% 6.0%
Change crop types E at 50% N fertiliser
20% 23% 100% 100% 4.6%
Greater range of tools to control weeds F
20% 12% 100% 100% 2.4%
More efficient machinery or contractors with modern machinery
2% 10% 100% 100% 0.2%
Improve pasture legume content prior to crop to reduce N fertiliser
6%A 50%B 75%C 30%D 0.8%
Potential reduction of KRF total emissions ~ 6-9%
Soil and pasturesAverage soil organic carbon at Katanning
Research Facility2008 2014 2017 2020
Soil organic carbon (%) top 10cm 2.02 2.31 2.40 1.81
Mitigation/sequestration option Contingencies and method used to estimate mitigation potentialEstimated
reduction in KRF emissions
Conduct green and brown manuring with legumes on 50ha per annum1
Assumes green manure yield of 4t DM/ha/yr (based on KRF pasture data). If 40% of yield is carbon = 1.6t C/ha. With a 50% degradation rate, this is equal to 3.2t CO2-e /ha times 50ha = 160t CO2-e . Requires trialling and further investigation
6.5%
Apply biochar applied at 1t/ha to 50ha per annum2
Assumes 1t/ha application of biochar over 50ha per annum, of which 0.594t C. This amounts to 109t CO2-e /yr. If biochar could be made on KRF, this is an attractive option. Requires trialling and further investigation
4.4%
Implement limingSupports livestock options: 1. Increasing pasture production to allow better growth rates and lower (50%) supplementary feeding, and 2. Increasing perennials and/or legume content in pastures
4.1%
Plant longer season annualsSupports livestock option 1. Increasing pasture production to allow better growth rates and lower (50%) supplementary feeding
4.1%
Extend the length of pasture in cropping system impact on soil C sequestration
Assumes moving from ‘3 years in pasture and 1 year in crop’ to ‘4 years in pasture and 1 year in crop’, which results in an additional 80ha in pasture per annum3 (absolute rate of 0.33t C/ha/yr on average sequestered by improved pastures compared with cultivated controls)
3.9%
Better match pasture availability and livestock feed requirements leading to quicker turnoff
Based on turning off stock 2 weeks earlier 3.1%
Plant anti-methanogenic forages Assuming 10% reduction in CH4 emissions from sheep due to anti-methanogenic forages only sown on 10% of pasture area
0.6%
Use rotational grazing Increases in soil organic carbon as a result of rotational grazing are small or nil 0.0%
Potential reduction of KRF total emissions ~ 12-15% plus additional 11% if biochar and manuring successful
Next steps to achieve zero emissions at 2030
Description Strategies
Current
Scenario 1
Reduce sheep flock to 60% of current (assumes either buying in
replacement adults or maidens), reducing crop to 50% of current
and changing wheat to barley. Planting 70ha of permanent
pastures, forages and shrubs and saltbush, 10% new trees
Changing the crop type to barley and the
rotation to 3 years of pasture, 1 year of
crop. This gives lower N use due to more
and improved pastures, tree planting.
Scenario 2
Reduce sheep flock to 60% of current (assumes either buying in
replacement adults or maidens). Planting 70ha of permanent
pastures and 117ha saltbush and 20% new trees
Changing the crop type to barley with
rotation to 1:1, improving legume content
of pastures. This gives lower N use due
to pasture, improved pastures, tree
planting
Scenario 3Reduce sheep flock to 85% sheep, (assumes moving to Merino
replacement flock), crop rotation to 2:1
Changing the crop type to barley and the
rotation to 2:1. This gives lower N use
due to pasture, improved pastures, tree
planting
Scenario 4
Reduce sheep flock to 85% sheep of current (assumes moving
to Merino replacement flock), 100% current crop with rotation at
1:1. Planting 70ha of permanent pastures and 117ha saltbush
and 20% new trees
Changing the crop type to barley,
improving legume content of pastures,
tree planting
Scenario 5
Reduce sheep flock to 85% sheep of current (assumes moving
to Merino replacement flock), reducing crop to 50% of current
and changing wheat to barley. Planting 70ha of permanent
pastures and 117ha saltbush, 20% new trees
Changing the crop type to barley and the
rotation to 3:1. This gives lower N use
due to pasture, improved pastures, tree
planting
Best bet
scenario
Reduce sheep flock to 85% sheep, of current (assumes moving
to Merino replacement flock), reducing crop to 50% of current
and changing wheat to barley, using biochar, Asparagopsis and
manuring, Planting 70ha of permanent pastures and 117ha
saltbush, 20% new trees
Increasing ewe flock efficiency, feed
supplement and growth (lamb weight per
ewe hectare). Changing crop type to
barley and rotation of 3:1. This gives
lower N due to improved pasture, more
pastures, tree plantingAll scenarios require Asparagopsis supplements in diet of 90% of the flock by 2027
