Up for the challenge: paving the way to emission-free food systems
RESEARCHED AND WRITTEN BY IBRAHIM MOHAMMED, PHD CANDIDATE IN ENVIRONMENTAL SCIENCE, SCHOOL OF ENVIRONMENTAL SCIENCES , UNIVERSITY OF GUELPH
Research shows agriculture contributes significantly to greenhouse gas emissions. These emissions must be cut down to attain sustainable food production.
What can the agriculture industry do to reduce these emissions and support sustainable food systems for Canada?
The current state of agricultural production
It is not alarming that agricultural emissions contribute to global warming. It is alarming that agricultural emissions contribute to global warming more than cars and vans combined[1]. In addition to the emission of CO2 due to poor cultivation practice, agriculture is poised to overtake industry as the leader in generating emissions causing global warming. The contribution of agriculture to global warming is bigger than we think. Emissions from agriculture must be cut down to attain sustainable food production. There are opportunities for action, but action must be preceded by a clear map of the landscape. The preface to this map is clarity on what we mean when we talk about the problem of agricultural emissions.
Glossary
Strategies or effort to reduce greenhouse gas (GHG) emissions.
Gases in the earth’s atmosphere that traps heat and lead to gradual warming of the planet (e.g. carbon dioxide, methane, nitrous oxide).
Total GHG emissions caused by agricultural activities.
One metric ton of carbon emissions that is avoided by completing an activity in a less carbon intensive way.
Number of metric tons of CO2 emissions with the same global warming potential as one metric ton of another GHG. When emissions causing global warming are measured, they are done as carbon dioxide equivalent (abbreviated as CO2-eq).
GWP is the heat absorbed by any GHG in the atmosphere. However, all GHGs are not equal in terms of their capacity to absorb heat. Each one has a unique atmospheric lifetime and heat-trapping potential. The GWP was developed to allow comparisons of the global warming impacts of different gases. The larger the GWP, the more that a given gas warms the earth compared to CO2.
A colourless, odorless, and highly flammable gas composed of one carbon atom and four hydrogen atoms. Methane is the primary component of natural gas and is used to produce heat and electricity around the world (Leman, 2020).
Emitted during agricultural, land use, and industrial activities; combustion of fossil fuels and solid waste; as well as during treatment of wastewater (United States Environmental Protection Agency, 2022).
Clearing the air: what “decarbonization” really means
Literally, decarbonization means removing carbon. To keep the planet’s temperature from rising more than 1.5oC above pre-industrial levels, most countries agreed to cut down emission of carbon and reach a point of net-zero. This means that all emissions produced by a country are neutralized by equal amount of emissions eliminated. To achieve this goal requires decarbonization.
There are many programs and projects aimed at curbing carbon emissions. Terms such as “decarbonization”, “decarbonizing”, “decarbonized”… and more recently “recarbonization” have become popular in the climate change parlance. Although “carbon” is common to all these terms, almost all effort aimed at decarbonization also aims at reducing emission of other greenhouse gases (GHGs) such as nitrous oxide and methane.
Why nitrous oxide? why methane? Shouldn’t decarbonization be about carbon?
Before answering this question, let’s consider another popular climate change terminology: global warming potential (GWP). GWP is the heat absorbed by any GHG in the atmosphere. However, all GHGs are not equal in terms of their capacity to absorb heat. Each one has a unique atmospheric lifetime and heat-trapping potential.
The GWP was developed to allow comparisons of the global warming impacts of different gases. The larger the GWP, the more that a given gas warms the earth compared to carbon dioxide (CO2). Thus, GWPs provide a common unit of measure, which allows analysts to add up emissions estimates of different gases and allows policymakers to compare emissions reduction opportunities across sectors and gases.
When emissions causing global warming are measured, they are done as carbon dioxide equivalent or CO2 equivalent, abbreviated as CO2-eq. A Carbon dioxide equivalent (CO2-eq) is the number of metric tons of CO2 emissions with the same GWP as one metric ton of another GHG[4].
Based on the Carbon dioxide equivalent rationale, decarbonization is thus broadly defined to cover the reduction of methane (CH4) and nitrous oxide (N2O) emissions, which represent 22% of global GHGs and 82% of total agriculture GHG emissions[6].
Livestock farming, which produces methane, and the use of nitrogen fertilizer, which produces nitrous oxide, represent the majority of agricultural GHG emissions.
CO2, by definition, has a GWP of 1 because it is the gas used as the reference. Methane (CH4) has a GWP of 28, because methane absorbs much more heat than CO2. Nitrous Oxide (N2O) has a GWP of 265 times that of CO2.
This means that CH4 and N2O are more potent than CO2 even though they represent only a quarter of all gas emissions worldwide (CO2 represents the remaining percentage at 76%).
While much of the public focus has been on CO2 mitigation, addressing agriculture-driven CH4 and N2O emissions is critical to mitigating climate change.
Therefore, decarbonizing the food system extends beyond carbon reduction in crop farming and soil management or farm machinery, to include reduction of carbon emission from livestock farming, and reduction of nitrous oxide and methane emissions from livestock production and manure management.
Strategies to reduce agricultural emissions
The strategies for sequestering more carbon and reducing emission from agriculture can be organized into three themes:
- Improved practices to ensure soils as carbon sink
- Technologies and materials to reduce crop related emissions and to reduce and capture livestock emissions
- Shifts in consumption patterns towards less carbon-intensive foods
Strategy: Carbon storage
As part of the natural functions and ecosystem services provided by soils, a healthy soil stores more carbon than that stored in the atmosphere and vegetation[7].
However, the world’s cultivated soils have lost between 25 to 75 percent of their original carbon stock[8], which has been released into the atmosphere in the form of CO2, mainly due to unsustainable management practices resulting in land degradation and amplifying climate change and its impacts.
On the other hand, excessive use of nitrogen fertilizer alone, coupled with conventional tillage practices is responsible for global emissions of CO2 and N2O from agricultural soils.
The adoption of best practices, such as no till and cover crops can turn agricultural soils into a carbon sink.
The strategies for increasing carbon storage in agricultural soils include:
- Adoption of cultivation techniques that convert atmospheric CO2 to carbon-based compounds in the soil, while also reducing soil emission and the need for fertilizers
- Examples of techniques:
- Increasing the mass and quality of plant and animal inputs to soils
- Improving soil microbial diversity and abundance
- Maintaining living plant cover on soils year round
- Examples of techniques:
- Breeding and choosing plants with deep roots and other characteristics favouring carbon sequestration
Strategy: Technologies and materials to reduce and capture emissions
Crop related emissions: Nitrous Oxide
- Crop related emissions of nitrous oxide can be reduced through improved management of nitrogen fertilizer. Emissions can be reduced significantly through adoption of the 4R’s of nutrient management (The 4R’s stand for right source, right rate, right time, and right place)
- Better tailoring the quantity and timing of fertilizer applications
- Improving fertilizer formulation
- Applying fertilizer directly to roots
- Adopting precision agriculture as a means of reducing fertilizer requirement
Livestock related emission: Methane and nitrous oxide
Livestock farming is the biggest source of agricultural emissions. Methane (CH4) represents 50% of these emissions, driven largely by enteric fermentation and manure management. Beef and dairy cattle account for 60% of all livestock emissions. Approaches to decarbonizing livestock farming include:
- Enteric fermentation emissions (a major source of methane emissions):
- This can be reduced through feed management and by breeding livestock that emit methane gas
- Manure management (a source of nitrous oxide emission):
- Anaerobic digesters (installed in livestock farms) can reduce emissions from manure management
Emissions from farm operations:
- Replacing traditional tractors with smart tractors that use renewable energy and produce less GHG
- Powering farm Plant and Equipment using renewable energy sources like windmill and solar power stations
Strategy: Shift in consumption pattern
Plant-based alternatives and lab-grown meat have the potential to significantly disrupt the meat industry. Consumer adoption of meat and dairy alternatives has the potential to reduce carbon emission from the food system more than improved practices in livestock production can.
Our food system contributes to GHG emissions through crop farming, livestock production, emissions from fertilizer production and fertilizer use, food waste, among others. Cutting down these emissions can facilitate building food systems that are resilient to climate change and sustainably meet the growing demand for food. Strategies for decarbonizing Canada’s food system at scale include adoption of improved practices to ensure soils as carbon sink; development of technologies and materials to reduce crop related emissions and to reduce and capture livestock emissions; shifts in consumption patterns towards less carbon-intensive foods. By implementing best practices related to these strategies and incentivizing activities that results in GHG-emission reductions, we can help Canada’s food system reach net-zero and make Canada’s agriculture a benchmark for sustainable production.
References
- EU’s farm animals ‘produce more emissions than cars and vans combined. https://www.theguardian.com/environment/2020/sep/22/eu-farm-animals-produce-more-emissions-than-cars-and-vans-combined-greenpeace
- Agriculture and climate change Reducing emissions through improved farming practices.
https://www.mckinsey.com/~/media/mckinsey/industries/agriculture/our%20insights/reducing%20agriculture%20emissions%20through%20improved%20farming%20practices/agriculture-and-climate-change.pdf - Low-carbon economy. https://www.wikiwand.com/en/Low-carbon_economy
What is low carbon economy? (LCE)? https://www.buschsystems.com/resource-center/knowledgeBase/glossary/what-is-a-low-carbon-economy-lce - Understanding Global Warming Potentials. https://www.epa.gov/ghgemissions/understanding-global-warming-p otentials#:~:text=The%20Global%20Warming%20Potential%20(GWP,carbon%20dioxide%20(CO2)
- Carbon dioxide equivalent (CO2e) https://www3.epa.gov/carbon-footprint-calculator/tool/definitions/co2e.html#:~:text=Carbon%20dioxide%20equivalent%20or%20CO,in%2040%20CFR%20Part%2098
- Duff and Lenox (2019). Path to 2060: Decarbonizing the Agriculture Industry. https://www.researchgate.net/publication/336035735_Path_to_2060_Decarbonizing_the_Agriculture_Industry
- Ciais, P., & Sabine, C. L. (2013, December). Carbon cycle and climate change, a tale of increasing emissions and uncertain future sinks. In AGU Fall Meeting Abstracts (Vol. 2013, pp. U22A-01).
- Lal, R. (2018). Digging deeper: A holistic perspective of factors affecting soil organic carbon sequestration in agroecosystems. Global change biology, 24(8), 3285-3301.
Others:
Sustainability Times (2020). Decarbonizing the global food system is a big step towards mitigating climate change. https://www.sustainability-times.com/green-consumerism/decarbonizing-the-global-food-system-is-a-big-step-towards-mitigating-climate-change/