Food, climate change and land use
Tara Garnett of the Food Climate Research Network (FCRN) looks at a major new UK study on food, climate change and land use, commissioned by the Committee on Climate Change as supporting research for the publication of its latest Annual Report:
Audsley, E., Chatterton, J., Graves, A., Morris, J., Murphy-Bokern, D., Pearn, K., Sandars, D. and Williams, A. (2009). Food, land and greenhouse gases. The effect of changes in UK food consumption on land requirements and greenhouse gas emissions. The Committee on Climate Change.
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This study examines the land use and greenhouse gas implications of UK food consumption change away from away from meat and dairy consumption and associated production, showing that the UK agricultural land base can support increased consumption of plant-based products arising from the reduced consumption of livestock products.
This would not only reduce greenhouse gas emissions but would also reduce land requirements, bringing potential environmental benefits and significant opportunities to deliver other products ranging from biofuels production to rewilding, carbon sequestration and other ecosystem services.
The research addresses the following core questions:
- Land needs: Given land quality considerations, to what extent is it possible to support a change in the UK consumption of meat and dairy products with a corresponding increase in substitute goods from UK agricultural land? Can a reduction in meat and dairy product consumption release land for other purposes? To what use would this freed-up land be suitable?
- Greenhouse gas emissions: What are the implications of the transition in production for GHGs in the UK and abroad?
- Other effects: What are the other implications, including for water, other pollutants, farm incomes, availability of manure as a fertiliser input, public health, ecosystem services, biodiversity, and animal welfare?
- International implications: If UK agricultural land cannot support consumption changes, what are the international implications in terms of agricultural production and land-use displacement (eg deforestation, land for biofuels, land for food) and GHGs?
Consumption and production scenarios
To answer these questions, three consumption and three production scenarios were designed to examine options on both the demand and supply sides. The report emphasises that the scenarios contain a variety of assumptions about possible future demands and supplies of agricultural commodities. The scenarios are not forecasts. The focus is on the technical capacity of land and agricultural production, not on the market changes needed to enable change. The balance of supply from the UK and overseas is assumed to remain as it is now.
- 50% reduction in livestock product consumption is balanced by increases in plant commodities: consumption of milk and eggs is 60% of current consumption, and meat consumption 36%. Sugar consumption is reduced to align with healthy eating guidelines. Reduction in consumption of livestock products is balanced by increasing plant consumption on the basis of constant food energy supplied. Fruit and vegetable consumption is increased by 50% and basic carbohydrate and oil rich commodities (except palm oil) by 33%. This scenario aligns with healthy eating guidelines in other countries.
- Shift from red meat to white meat: red meat consumption is reduced by 75%.
- 50% reduction in white meat consumption balanced by increases in plant commodities
- Land is released from livestock production uniformly: ‘pro-rata’ changes in land requirements across land types.
- Emphasis on maximising the release of tillable land: so ruminant meat production is concentrated on lower quality land.
- Emphasis on maximising the release of low quality land: ruminant meat production is concentrated on high quality land.
The combination of consumption scenarios 1 and 2 and three production scenarios gives a total of 6 system scenarios. These are complemented by Consumption Scenario 3 giving a total of 7.
The study finds that all consumption change scenarios reduce the total amount of land estimated as required to support the UK food system.
In all cases the amount of extra land required for the direct consumption of plant products is less than the amount of arable land released from livestock feed production. This said, a switch from red to white meat increases the need for overseas arable land, although a larger area of UK land that can be tilled is released.
Releasing tillable land
Focusing a reduced cattle and sheep industry on non-arable land would result in the release of substantially more tillable land (currently grassland). In a 50% livestock production consumption reduction scenario, maximising the use of lower grade land (semi-natural grassland, hill land etc) releases 3.7 million of tillable grassland (including 1.3 million ha of good arable land). The opposite approach of withdrawing production from less capable land releases just 1.7 million ha of potentially arable land, with almost no release of the grassland well suited for to arable production. The land-use trade-off is clear.
Under a 50% livestock consumption reduction scenario, 2 million ha of tillable grassland is required to compensate for the withdrawal of cattle and sheep production from 6.9 million ha of non-tillable grassland.
A 50% reduction in livestock product consumption opens up the opportunity to release about half of UK land currently used for UK food supplies if remaining production is concentrated on the more capable land. If land is released uniformly, almost two-thirds of this release takes place on grassland not suited to arable production and the remaining third is grassland with some arable potential.
A large proportion of land released may be very unproductive, but about 5 million ha with potential for other agricultural uses would be available, for example for the production of livestock for export (if they did not reduce their livestock consumption), for producing arable biofuel crops, planted woodland and re-wilding (to natural woodland in many cases).
The study finds that all consumption scenarios reduce greenhouse gas emissions from primary production. The largest reduction is from a livestock reduction scenario (Consumption Scenario 1): from 81 to 66 Mt CO2e (19% reduction). The switch from red to white meat reduces emissions by 9% and a 50% reduction in white meat consumption by only 3%.
The effect of alternative land uses
The net effect on emissions depends greatly on the alternative use of the grassland released from food production.
The study indicates the range of possible consequences on soil and biomass fluxes:
- If all tillable grassland released from food production was converted to arable use, about 160 Mt CO2e per year would be released over 20 years through the effects of land use change.
- Converting all released land with the potential to support good tree growth to woodland would cause a net carbon uptake equivalent to about 220 Mt CO2e per year in soil and wood per year over 20 years.
Land use preference (eg focusing remaining production on high quality land) has little effect on emissions. This is an important result indicating that supply chain emissions are unresponsive to changes in industry structure with respect to the land used.
About 36% of primary production emissions are overseas. All scenarios reduce UK emissions while Consumption Scenario 1 has little effect on overseas emissions and Consumption Scenario 2 reduces overseas emissions by 5%. None of the scenarios involve a net export of emissions and the GHG reduction benefits in the UK are proportionally greater than those overseas because of the tight link between UK livestock consumption and production.
There are substantial reductions in other negative environmental effects such as acidification and eutrophication.
The study’s analysis of land use statistics reveals the large proportion of UK land currently occupied by cattle and sheep. Without these livestock, this grassland (much of which is semi-natural grassland) would revert to the natural vegetation – deciduous woodland in many cases. The results show that the use of livestock to retain semi-natural grasslands is not dependent on the current high level of livestock product consumption.
A 50% reduction in demand still leaves a market which is large enough to support this activity.
However, since a declining market affects all suppliers, a livestock reduction scenario presents special challenges to the maintenance of semi-natural grasslands.
In a reduction scenario, rural areas lose skills and employment in the livestock sector and there would be ramifications for linked industries such as the meat processing or veterinary sectors. Culturally important features, for example, hedgerows and stone walls, and much of the fauna and flora associated with grassland would be no longer needed.
In the UK as a whole, land that is most likely to be taken out of production is associated with difficult production conditions. In England, upland moorland and common land now in a semi-natural state could change to fully natural vegetation cover. In upland areas, where the majority of re-wilding under Consumption Scenarios 1 and 2 would be located, various natural communities including scrub, bracken, bramble, and woodland with their own assemblage of flora and fauna are likely to develop, with potential increases in wild herbivores such as deer, hares, and rabbits.
The majority of SSSIs currently under-grazed occur in lowland areas, for example in southern and eastern parts of England, and a lack of livestock results in difficulty in applying the grazing pressure required to maintain the semi-natural faunal and floral diversity.
Whilst a reduction in the current ecosystem service provision associated with livestock production from cattle and sheep can be expected under Consumption Scenarios 1 and 2, the net change is also dependent on the alternative use to which land is put. In upland SSSIs, overgrazing is often problematic and reducing grazing pressure may allow semi-natural habitats to recover, in particular dwarf shrub heaths, bogs, acid grassland and upland habitats.
The release of large areas of land could also be used to diversify upland areas. For example, seminatural upland woodlands have declined by 30-40% since the 1950s and the UK Habitat Action Plan has therefore included a target to increase the area of upland oak woodland through planting or natural regeneration of current open ground.
In the lowlands, approximately 10% of the current arable land could be released for other activities, such as bioenergy crops, woodlands, recreational land, wetland creation, nature reserves, flood protection, carbon sequestration, and urban development. Each of these land uses will have its own specific range and flow of ecosystem services associated with it.
A 50% reduction in livestock product consumption (Consumption Scenario 1) reduces the UK farm-gate value of livestock products from £7.6 to 3.5 billion. The farm-level economic impact of a change along these lines will depend crucially on what replacement output is found for the land released and on market effects that are beyond the scope of this study. One economic response scenario is that the land resource released remains in agriculture, serving export markets.
Another strategy is to use the land for non-food purposes. Using biomass energy cropping as a benchmark andassuming a price of £40/tonne dry matter biomass wood, we estimate that replacing the value of the food output of higher quality land released will be challenging, although it is reported that biomass energy is an economically viable alternative to sheep production on uplands
This study has clearly shown that UK land can support consumption change that reduces greenhouse gas emissions from the food system.
The reduction in land needed to supply the UK that comes with a reduction in livestock product consumption brings potential environmental benefits and significant opportunities to deliver other products, including other ecosystem services, from UK agricultural land.
The study has shown that some risks currently argued as arising from consumption change are small. In particular arable land needs will not increase if the consumption of livestock products is decreased. The risk that emissions will be exported is also shown to be small.
The identification of the significant potential benefits of consumption change combined with the low risks of unintended consequences has far-reaching implications for guidance to consumers and the development of agricultural policy. The results are broadly applicable to other European countries which means they are relevant to international policy development, for example the reform of the Common Agricultural Policy.
- Food, land and greenhouse gases. The effect of changes in UK food consumption on land requirements and greenhouse gas emissions (The Committee on Climate Change): full report;
- How low can we go? An assessment of greenhouse gas emissions from the UK food system and the scope for reduction by 2050 (FCRN-WWF): report by the same authors;
- Cooking up a storm: Food, greenhouse gas emissions and our changing climate (FCRN): by Tara Garnett.
A longer version of this article appeared on the 12 December in the FCRN mailing.
The Food Climate Research Network is a UK research council-funded initiative. Its aim is to better understand how the food system contributes to greenhouse gas emissions, and to research and promote ways of reducing them.
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