4.4 How far could changes in production practices reduce GHG emissions?
4.4.1 What production-side mitigation options exist?
Snapshot of production-side mitigation – the argument for this route
Focus of the argument: We need to produce more food for less environmental impact.
How: Change how food is produced and agriculture is practiced.
Example stakeholders: mainstream food industry.
- Store carbon in soils & plant matter – removing atmospheric CO2.
- Improve production efficiency and optimise input use (sustainable intensification).
- Breed for higher yields.
- Avoid land use change & biodiversity loss.
- Manage outputs: e.g. manure and biomass.
- Improve the efficiency and reduce the carbon intensity of transport and distribution.
- Adapt to climate change.
Some stakeholders believe that the fundamental problem is one of food supply – that we need to provide more food for a growing population, with less environmental impact.
Production-side GHG mitigation is based on the premise that our demand for food will inevitably increase (and little can be done to moderate it) and as such will require an increase in food supply.
To produce more food with minimum environmental cost we need to maximise the capacity of agricultural land to store carbon, improve production efficiencies, close yield gaps, and avoid additional land-use change and biodiversity loss (for example through deforestation).
There is further discussion on sustainable intensification later in this chapter.
Agriculture & land-use mitigation options summarised by IPCC 2007
+ denotes reduced GHG emissions
- denotes increased GHG emissions
CH₄ = methane N₂O = nitrous oxide
Climate change reports from the IPCC specify cropland management, grazing land management, management of soil organic content, restoration of degraded land, and management of livestock and manure as the most promising mitigation options.
This list does not include mitigation benefits from protecting forestry or through afforestation although that is a key mitigation option (see below).
4.4.2 How much production-side mitigation might be possible?
How much production-side mitigation potential might be possible?
The ‘answer’ depends on:
- The pace of technological change – i.e. the extent to which carbon intensity and yields can be decoupled
- How far land use change can be halted (or reversed)
- Political and economic will (policies to promote mitigation, the development of a functioning carbon market and the price of carbon) and practical implementation (farmer knowledge and translation of knowledge into action)
The ‘answer’ also depends on how far GHG mitigation is prioritised over other environmental and societal concerns
Smith et al. (2007)
This figure shows that the greater the price of carbon, the greater the mitigation potential as currently un-economic technologies start to become more attractive. A carbon price is a price that must be paid (e.g. through taxation) for the emission of one tonne of CO2 equivalent into the atmosphere (Source: http://www.ipcc.ch/publications_and_data/ar4/wg3/en/annex1-ensglossary-a-d.html)
However the magnitude of the error bars indicates major uncertainty with all these estimates. There are not just technical but also practical economic, political and logistical limitations to how far measures to reduce emissions can actually be implemented.
Additionally, while approaches aimed at reducing GHG emissions may yield other social or environmental benefits (e.g. reductions in nitrogen pollution) there may also be trade offs (e.g. increased irrigation water use to increase productivity thereby sparing land). The balance of positives and negatives is likely to be very locality and context specific.
IPCC estimates – mitigation potential by region
•Global economic mitigation potentials in agriculture in 2050 are estimated to be 0.5─10.6 GtCO2eq/yr.
•Reducing food losses & waste: GHG emission savings of 0.6─6.0 GtCO2eq/yr.
•Forestry mitigation options are estimated to contribute 0.2─13.8 GtCO2eq/yr.
•Acronyms used in graph: EIT – Economies in Transition; LAM – Latin America; MAF – Middle East and Africa
This graph shows the economically viable mitigation opportunities in AFOLU (Agriculture, Forestry and Other Land Use – see Chapter 3) in 2030 by region and by main mitigation option at carbon prices of up to 20, 50, and 100 USD / tCO2eq. This assumes the introduction of a carbon price, as an incentive for mitigation actions. A carbon price is a price that must be paid (e.g. through taxation) for the emission of one tonne of CO2 equivalent into the atmosphere (Source: http://www.ipcc.ch/publications_and_data/ar4/wg3/en/annex1-ensglossary-a-d.html).
The attractiveness of different mitigation options varies greatly with the carbon price, with low cost options such as cropland management being favoured at low carbon prices, but higher cost options such as restoration of cultivated organic soils being more cost-effective at higher prices.
At all carbon prices, key mitigation options are for better management of agricultural land (including cropland, grazing), restoration of degraded land and protection of forestry.
Across all options, Asia has the largest mitigation potential, with the largest mitigation in both forestry and agriculture.
Current rates of ‘decoupling’ of production from emissions can achieve substantial reductions without any additional mitigation effort
Bennetzen, Smith and Porter (2016).
But they will not get us to an 80% reduction in emissions
In the above figure, the red solid shading shows the ‘envelope of possibility’ – i.e. the range in quantity of reductions achievable if improvements in emission intensity continue in a linear fashion (upper limit) or an exponential fashion (not just improvements in emission intensity but improvements in the rate of improvements). However it also shows that technological innovation will not lead to cuts in emissions as low as 80% which is arguably what may be needed if agriculture is to make a proportional contribution to keeping the global temperature increase to below 1.5-2°C.
Some analyses suggest that production-side approaches may not be enough
- Ray et al. (2013): yield increases insufficient to meet food demand – alternatives are expanding cropland (deforestation) or addressing diets & waste.
- Smith et al. (2014): “while supply-side mitigation measures, such as changes in land management, might either enhance or negatively impact food security, demand-side …measures, such as reduced waste or demand for livestock products, should benefit both food security and greenhouse gas mitigation. Demand-side measures offer a greater potential …”
- Gerber et al. (2013) – on livestock: On a global scale, it is unlikely that the emission intensity gains, based on the deployment of current technology, will entirely offset the inflation of emissions related to the sector’s growth. However …it is possible that technological breakthroughs will allow mitigation above and beyond current estimates.
Possible reductions in emissions from production can lead to significant GHG mitigation. However the evidence suggests that rising food demand, especially for animal products, will offset production emission gains.
What this really means is that production efficiencies are necessary but, according to growing evidence, will not on their own be sufficient.
There will be a need for both production-side mitigation and changes in consumption (sometimes called demand-side mitigation).
Additionally, there is uncertainty about the impacts production-side mitigation will have on food security since increases in food supply do not necessarily lead to increases in consumption among those who are food insecure. Additionally the quality of food (rather than just quantity) needs to be considered.
Some have argued that measures to moderate demand for meat and to reduce waste could have positive effects on both GHG emissions and food security. However, the implications for the very food insecure need to be considered – there is no one size fits all solution.
The next section explores in more detail how changes in consumption might lead to reductions in food-related GHGs.
The range in estimates of the mitigation potential is enormous – and this uncertainty indicates that a production-only approach is risky
Bennetzen, Smith and Porter (2016).
Estimates as to future agricultural emissions (including those arising from agriculturally induced land use change) range from very pessimistic (yellow dashed line – assuming no improvements in technological efficiency and ongoing land use change) to very optimistic (the IPCC’s estimate of the technical potential achievable through measures to sequester carbon in soils). The purple dashed line shows how the reduction trajectory needed if agricultural emissions were to fall by 80%– this would be in keeping with the global requirement to keep the global rise in temperatures to below 1.5-2°C.
4.4.3 How does GHG mitigation fit into the wider discussion concerning agricultural progress?
Which farming systems are best suited to achieving mitigation in the context of other environmental and societal concerns?
A number of potential approaches for producing enough food with less environmental impact have been proposed.
One approach advocated by many agricultural and natural scientists and accepted by policy makers has been termed “sustainable intensification”. Sustainable intensification is defined as production wherein “yields are increased without adverse environmental impact and without the cultivation of more land”.
‘Agroecological’ approaches are often presented as an alternative, and in opposition to sustainable intensification. Agroecology has been defined as “the application of ecological concepts and principles to the design and management of sustainable agricultural ecosystems…This approach is based on enhancing the habitat both above ground and in the soil to produce strong and healthy plants by promoting beneficial organisms while adversely affecting crop pests". However it can also been seen as a “scientiﬁc discipline, as a movement, and as a practice” – sometimes all three – and the way it is used varies by context.
Other concepts and terms used include organic agriculture, permaculture, climate smart agriculture, eco-intensification and more.
What is the rationale for sustainable intensification?
Sustainable intensification is defined as production wherein “yields are increased without adverse environmental impact and without the cultivation of more land
There are a number of production-side approaches for reducing GHG emissions and/or adapting to the impacts of climate change, including climate-smart agriculture, agroecology, conservation farming, organic farming. One which is widely recognised, at least by the mainstream food industry, is “sustainable intensification”.
The premise for sustainable intensification is that we will need to produce more food in the future, at the same time as reducing environmental impacts. In order to do this, expansion of agricultural land (clearing more forests or other uncultivated land for agricultural purposes) is clearly a bad option (see Chapter 3 and Chapter 5 for more on deforestation, biodiversity and GHG emissions). Therefore we need an agricultural system that is capable of increased productivity, but where higher yields go hand in hand with a reduction in negative environmental impacts.
Sustainable intensification is a contested issue. It has been interpreted by some as a ‘green-washed’ version of industrial agriculture. Others however argue that this is a misinterpretation – that the ‘sustainable’ part of the phrase is just as important as the ‘intensive’. It denotes an approach to producing food founded on the principle that we must not cause more or future environmental damage. In this sense SI shares much in common with, for example agroecology, which is often seen as its direct opposite. Criticisms of sustainable intensification have much in common with criticisms of the term ‘efficiency’ as applied to the environment.
What is the rationale for agroecology? Is SI in conflict with agroecology?
“Food outputs by sustainable intensification have been multiplicative – by which yields per hectare have increased by combining the use of new and improved varieties and new agronomic–agroecological management …and additive – by which diversification has resulted in the emergence of a range of new crops, livestock or fish.”
But SI is nevertheless contested:
“an ideology that adheres to a productivist view of feeding the world…fails to take into account power, profit, politics and participation in the food system….business as usual intensive farming with slight modifications to try and tackle the growing environmental crises caused by industrial agriculture.”
And the rebound effect is a risk
“More efficient agriculture is likely to be more profitable and could lead to an expansion of the cultivated area". The magnitude of this direct rebound effect depends on the price elasticity—the ratio of the percentage change in resource demand to percentage change in resource price. If demand for a good is relatively elastic, the price decline expected from more efficient technologies will stimulate more demand. If demand is inelastic, a rebound effect can still take place through product
As shown above, there is an ongoing debate regarding the best farming approaches to deliver different GHG mitigation options.
Much of the debate stems from different ways in which people view sustainability itself. Is SI in conflict with other farming practices? In practice, there are a wide-range of approaches common to SI, agroecology and for example climate smart farming that have a role to play in different contexts.
What about land use? The land-sparing (SI) vs. land-sharing (“wildlife-friendly” W-F) debate
Since land use change is such a major cause of CO2 emissions and biodiversity loss further agricultural encroachment onto uncultivated land must be limited
One approach (land sparing) argues for intensifying production on existing land in order to ‘spare’ as much land as possible. Land sparing is central to the rationale for SI
In contrast, more wildlife-friendly farming practices (more in line with agroecological approaches) often enable higher on-farm biodiversity, but are lower yielding. This approach is known as land-sharing. For a given amount of production more land may be needed; alternatively consumption needs to be modified.
Some research supports land-sparing as a more promising strategy for minimizing farming’s negative impacts on biodiversity – although this conclusion is highly context dependent. Some farming systems have had an important role in shaping biodiversity and landscapes of particular regions
On-farm biodiversity is important too.
Governance of land-sparing
One important contribution that production-side practices can contribute to GHG emission reductions is by preventing further deforestation and land-use change (see the information on the IPCC mitigation options above). The SI rationale is that increasing crop yields on existing agricultural land will protect the world’s remaining natural habitats (land-sparing), thereby preserving biodiversity and carbon stocks in species-rich non-cultivated land (such as forests).
This is sometimes seen to be in conflict with “wildlife friendly” approaches, for example organic farming, which emphasise higher levels of on-farm biodiversity but potentially larger total agricultural land-use requirements. In this sense farmland is shared more with wildlife, hence the term land-sharing.
Some research finds in favour of land-sparing, protecting the natural habitats of outside farmland. This is disputed by some interest groups, for example advocates of organic farming, who point to the on-farm biodiversity benefits (land-sharing) of wildlife-friendly approaches. However research has also shown that on-farm biodiversity is influenced more by crop yield than farming practices (such as conventional vs. organic), further complicating matters.
This illustrates the disagreements that exist between different stakeholders and interest groups with regard to which farming approaches offer the greatest potential for GHG mitigation. The contention is not so much around what mitigation options are relevant, but what approaches are needed to do deliver the reductions.
Of critical importance is what actually happens to the ‘spared’ land. Is it really spared, or do higher profits arising from higher yielding farming simply enable further land clearance for more agriculture? Governance has an important part to play in ensuring that, where possible, land really is spared.
In addition it is essential to consider what is being produced. When thinking about productivity what type of foods are being grown, with what implications for human nutrition? What about jobs and livelihoods? Should a good environment (clean water, biodiversity etc. be seen as an ‘output’ of the system in its own right, of equal importance to wheat or maize?
Organic farming: implications for wildlife?
Gabriel et al. (2013)
TOP CHART showing that conventional farms (dark shading) tend to be higher yielding than organic farms (light shading:
Mean organic yield: 4.3 ± 0.24 t ha-1.
Mean conventional yield: 9.3 ± 0.25 t ha-1.
Middle Graph showing that as crop yield increases, the percentage of wild plant cover in organic farms decreases rapidly to similar levels as found on conventional farms.
Bottom Graph showing that as crop yield increases, the wild plant species density in organic farms decreases rapidly to similar levels as found on conventional farms.
Organic yields (at least of cereals from the Gabriel study) are usually about half those of non-organic (“conventional”) farms, and the lower yields in any farming system are usually positively associated with many measures of biodiversity (the Gabriel study focuses on weeds). However, when measures are taken to increase yields in organic fields, biodiversity decreases, so when yields of organic and conventional farming are similar, so is the biodiversity. High yielding organic agriculture can impact on ecology (wildlife and the wider environment) to a similar extent as conventional farming. In other words, a large part of the “wildlife-friendliness” associated with organic farming is simply because it is usually less intensive.
- Current high-input ‘industrial’ agriculture production has caused damage to:
- The environment – through overuse of chemical inputs and reliance on a few varieties of seeds
- People – through concentration of power in the agri-food system and displacement of farming communities
- Farm animals – as a result of confinement and breeding-feeding strategies that undermine their welfare
- ‘More food’ is not the answer to food security
- There is a need for more diverse systems delivering multiple outputs (including diverse foods and livelihoods).
- Such systems may not be as ‘productive’ as industrialised defined in terms of a single output but the focus on ‘more food’ is misguided
- Agricultural systems that mimic nature and draw upon traditional knowledge are more likely to be sustainable and resilient in the long term for people and the environment