Would Switching to Organic Farming Cut Greenhouse Gas Emissions?

Check out this answer from Consensus:

Switching to organic farming has the potential to reduce greenhouse gas emissions, particularly through lower nitrous oxide emissions and enhanced soil carbon sequestration. However, the overall impact is influenced by factors such as yield, land use, and specific farming practices. To fully realize the GHG mitigation potential of organic farming, continued research, innovation, and supportive policies are essential.

The agricultural sector is a significant contributor to global greenhouse gas (GHG) emissions, primarily through the release of nitrous oxide (N2O) and methane (CH4). As concerns about climate change intensify, there is growing interest in the potential of organic farming to mitigate these emissions. This article explores whether switching to organic farming can effectively reduce GHG emissions, drawing on findings from multiple research studies.

Impact of Organic Farming on GHG Emissions

Reduction in Nitrous Oxide Emissions

Several studies have shown that organic farming can lead to a reduction in nitrous oxide emissions. For instance, a long-term field trial in Switzerland found that organic farming systems reduced N2O emissions by 40.2% per hectare compared to non-organic systems1. Similarly, a global meta-analysis revealed that area-scaled nitrous oxide emissions from organically managed soils were significantly lower than those from non-organically managed soils5.

Methane Emissions

The impact of organic farming on methane emissions is more complex. While some studies have reported modest CH4 uptake in organic systems1, others have found that the effect varies depending on specific practices and conditions. For example, a study on integrated organic farming in the UK highlighted that methane emissions from livestock, particularly dairy and beef cattle, were substantial contributors to the farm’s overall GHG emissions6.

Carbon Sequestration

Organic farming has the potential to enhance soil carbon sequestration, which can offset some GHG emissions. Research indicates that organic practices, such as the use of compost and cover crops, can improve soil organic carbon levels9. However, the extent to which this can compensate for other emissions remains a subject of debate. A study assessing the impact of a 100% shift to organic farming in England and Wales found that while direct GHG emissions were reduced, the need for increased land use abroad to compensate for lower yields resulted in higher net emissions4.

Challenges and Considerations

Yield and Land Use

One of the main challenges associated with organic farming is its typically lower yield compared to conventional farming. This yield gap can lead to increased land use to meet food demand, potentially offsetting the GHG benefits of organic practices. For instance, a study on the carbon footprint of a small-scale organic vegetable farm identified that while certain crops had lower emissions, the overall impact was influenced by the need for additional land and resources8.

Policy and Innovation

To maximize the GHG mitigation potential of organic farming, there is a need for innovation and supportive policies. Researchers suggest that life cycle assessments (LCAs) can help identify areas for improvement and guide the development of more efficient organic practices7. Additionally, integrating emerging technologies and optimizing farm management can further enhance the environmental benefits of organic farming.

 

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Would switching to organic farming cut greenhouse gas emissions?

Guy Kirk has answered Unlikely

An expert from Cranfield University in Soil Science, Organic Food, Agricultural Science

No. There are undoubted local environmental benefits to organic farming practices, including soil C storage, reduced exposure to pesticides and improved biodiversity. However, these potential benefits need to be set against the requirement for greater production elsewhere. As well as increased GHG emissions from compensatory changes in land use to make up for production shortfalls, there are substantial opportunity costs from reduced availability of land for other purposes, such as greater C storage under natural vegetation.

 

Would switching to organic farming cut greenhouse gas emissions?

Adrian Muller has answered Uncertain

An expert from Research Institute of Organic Agriculture FiBL in Agricultural Science, Organic Food, Environmental Science

No; but it would neither lead to an increase. Increased land use on the one hand and reduced nitrogen use and the ban on mineral fertilizers on the other work in opposing directions of increasing vs. reducing GHG emissions. If combined with the two strategies mentioned above, total emissions would even be lower than in a conventional reference case without changed consumption patterns and without reduced food waste and loss. Thus, organic agriculture is compatible with food systems that have lower emissions.

A specific aspect of the climate change mitigation potential of organic agriculture is soil organic carbon sequestration, which tends to be higher in organic than in conventional systems (Gattinger et al. 2012). Soil organic carbon sequestration is however not identical to emission reductions, as it absorbs CO2 from the atmosphere instead of avoiding its emission at the sources. This mechanisms shows a saturation dynamics (i.e. it comes to a halt after few decades) and it is reversible, i.e. when switching back from organic practices with increased sequestration (e.g. using compost, complex crop rotations, etc.) to conventional ones with lower sequestration rates, the carbon stored in the soils can be lost again.

See also the papers by Searchinger et al. 2018 and Smith et al. 2019 criticising organic agriculture for the globally higher GHG emissions when switching to organic agriculture without complementing changes in consumption patterns (e.g. due to a relocation of production and increasing imports because of lower yields in organic agriculture, etc.). For a critical comment on Searchinger et al. 2018, see Muller 2018.

Gattinger, A., Muller, A., Häni, M., Skinner, C., Fliessbach, A., Buchmann, N., Mäder, P., Stolze, M., Smith, P., El-Hage Scialabba, N., Niggli, U., 2012, Enhanced top soil carbon stocks under organic farming, Proceedings of the National Academy of Sciences of the United States of America PNAS, 109 (44) 18226-18231

Muller, A., 2018, Comment on Searchinger et al. 2018, Short Report, Research Institution of Organic Agriculture FiBL, 18.12.2018 (https://orgprints.org/34496/).

Searchinger et al. (2018) “Assessing the efficiency of changes in land use for mitigating climate change”, Nature 564: 249, https://doi.org/10.1038/s41586-018-0757-z

Seufert, V., Ramankutty, N., 2017, Many shades of gray—The context-dependent performance of organic agriculture, Science advances 3(3): e1602638

Smith et al. (2019) “The greenhouse gas impacts of converting food production in England and Wales to organic methods”, Nature Communications, 10:4641; https://doi.org/10.1038/s41467-019-12622-7

 

Would switching to organic farming cut greenhouse gas emissions?

Dennis Hartmann has answered Likely

An expert from University of Washington in Climatology

Zero tillage, storing carbon in the soil, less use of fertilizer derived from fossil fuel can help. Health benefits may also result.

 

Would switching to organic farming cut greenhouse gas emissions?

Adriana Gomez-Sanabria has answered Likely

An expert from International Institute for Applied Systems Analysis in Energy Systems, Environmental Science, Climate science

I can in general say that organic farming reduces the consumption of artificial fertilizers and pesticides. It also sequesters more carbon in the soil than conventional farming.

 

Would switching to organic farming cut greenhouse gas emissions?

Grant Wilson has answered Uncertain

An expert from Birmingham University in Chemical Engineering

Not my area of expertise, but I think it greatly depends on the number and type of animals being farmed. If just arable, then yes – as they would not use fossil fuel based fertiliser.

 

Would switching to organic farming cut greenhouse gas emissions?

Aysha Fleming has answered Unlikely

An expert from Commonwealth Scientific and Industrial Research Organisation in Climatology, Agricultural Science, Sociology

Reducing nitrogen fertilizer is helpful to reduce emissions but it wouldn’t be enough alone.

 

Would switching to organic farming cut greenhouse gas emissions?

Roger Jones has answered Uncertain

An expert from Victoria University in Climatology, Environmental Science, Economics

I would expand this notion to any form of agriculture capable of soil improvement in its day-to-day practice; i.e., switching agriculture from being net extractive to net productive. The capacity of soils under good practice to take up carbon has barely been scratched. This needs to be scale independent. Existing assessments, including those summarised by metafact, have people looking at scale. Large-scale production is usually transported elsewhere. Small-scale production is usually consumed closer to home and sustains more people, so it often seen as economically inefficient if looked at in terms of ‘food energy’ per dollar, but may be more sustainable in terms of people and environment. This looks at different models and different scales throughout a system. Some areas may need to be offset by others, depending on operations, local advantage etc. Non-landed agriculture (e.g., urban high density, hydroponics) is totally artificial, so the whole production cycle can be measured and audited.

 

Would switching to organic farming cut greenhouse gas emissions?

Steven Sherwood has answered Likely

An expert from UNSW Sydney in Climatology, Atmospheric Science

I am no farmer, but I expect this would help. Agriculture is a significant source of emissions so we have to find ways to eliminate them, whether by organic farming, technological innovations, diet changes, or some combination.

 

Would switching to organic farming cut greenhouse gas emissions?

Gab Abramowitz has answered Unlikely

An expert from UNSW Sydney in Climatology, Hydrology

There are of course many things to dislike about factory farming and large scale agriculture, but I do not think organic vs non-organic farming will have a huge impact on GHG emissions, no.

 

Would switching to organic farming cut greenhouse gas emissions?

Richard B. Rood has answered Uncertain

An expert from University of Michigan in Environmental Science, Climate science

Depends on how you do your organic farming. Organic farming is not a magic solution to climate change.