Updated: December 20, 2021
About Grain Growing & Carbon Storage
Agriculture products leaving the agriculture sector are net-negative, there are over 100,000,000 tonnes of CO2e stored in our products.
Canadian 2017 Emissions by IPCC Sector with Cropland and Grain
60 Mt (ag) + 14 Mt (fuel) – 7 Mt (soil) – 100 Mt (ag products) = -33 Mt net storage/year
How Do We Get 100 Mt CO2e Stored in Ag Products?
- In 2017, Statistics Canada estimated all grain production (1) in Canada at:
- 74 Mt grains and
- 21 Mt canola
- Grains are 61% carbohydrates (2)
- Carbohydrates (C6H10O5) are 44% carbon
- To be conservative, the carbon in fiber protein and lipids has not been included
- Therefore grains are 27% carbon
- CO2 is also 27% carbon
- 1 tonne of grain contains 1 tonne of CO2e
- 74 Mt of grains = 74 Mt CO2e
- Canola is 44% oil (3)
- Canola oil is made of oleic and linoleic acids which are >75% carbon
- To be conservative, the carbon in fiber and protein has not been included
- Therefore canola is 33% carbon 0.8 tonne of canola contains 1 tonne of CO2e
- 21 Mt of canola = 26 Mt CO2e
74 Mt CO2e + 26 Mt CO2e = 100 Mt CO2e in ag products
This number does not include meat, vegetables or dairy. Including these carbon rich products would increase this number.
Is there a precedent in the NIR that gives credit to another sector for short term carbon capture?
Yes. Fertilizer manufactures are able to reduce their emission totals by the amount of short term CO2e stored in their products. Why not Agriculture?
“The amount of C02 recovered for urea production is then subtracted from the process-related emissions.”(4)
Short-term carbon storage is credited to fertilizer companies in the industry sector, why not the ag sector?
Statistics Canada reported that in 2017, 3.85 Mt of urea and 1.26 MT of UAN were produced in Canada (5). This totals 4.62 Mt of urea equivalent produced.
The NIR uses the equation 4-2 on p.101 that shows ammonia manufacturing emissions are reduced by the following amount due to short term carbon capture:
- =kg Urea produced x 0.728 kg C02/kg urea
- =4.62 x .728
- = 3.7 Mt C02e reduction
The NIR also states that ammonia manufacturing (nitrogen generation) was 2.6 Mt C02e (6). However this is after the short term carbon reduction has been applied. Actual ammonia emissions are 2.6 + 3.7 = 6.3 Mt CO2e. In the NIR, fertilizer manufactures have been given a credit for short term carbon and are able to reduce their ammonia production emissions by 59%:
- 3.7 / 6.3 = 59% reduction in ammonia production emissions based on short term carbon stored in “carbon-containing” fertilizers.
Farmers, in the ag sector release urea, we are the end user. In 2017 there was 2.5 Mt of short term CO2 passed from the fertilizer industry to farmers (7):
The ag sector and industry sector shouldn’t be treated differently. Agriculture should be given credit for short term carbon capture, just like the fertilizer industry. The ag sector net-negative, with an excess capture of -33 Mt CO2e in 2017.
(2): Chemistry of Cereal Grains – Peter Koehler and Herbert Wieser, Table 2.2
(4): 2019 NIR page 101, Section 4.5.2
(6): 2019 NIR, Table 2-8
(7): 2019 NIR, Table ES-2
Thank you to F. McPhee for his calculations and descriptions on this issue.