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Land sparing policies can deliver biodiversity and climate targets at less cost to food production and at half the cost to taxpayers

Professor Andrew Balmford & Dr Lydia Collas

December 2022

Science for Sustainable Agriculture

A study recently published in the journal People and Nature by researchers at the Universities of Cambridge, Leeds and Glasgow is the first of its kind to compare the taxpayer costs of different farm policy approaches to meeting future biodiversity and climate objectives. It concludes that a land sparing approach of focusing some land entirely on food production to allow more space for nature on unfarmed land would be far more cost-effective than prolonging the current land sharing approach of paying farmers to adopt lower-yielding production systems. To achieve the same overall outcomes, sharing will cost twice as much and see loss of 27% more food production, while potentially also increasing environmental damage in food-exporting countries and reducing the space available for wild species that cannot live on farmed land. The study's findings should inform a rethink of the funding and direction of England’s Environmental Land Management Scheme (ELMs), argue two of the study’s authors, conservation scientists Andrew Balmford and Lydia Collas.  


  • First research of its kind to compare the cost-effectiveness of farm policy solutions to delivering environmental and food production targets; 

  • Land sparing would cost the taxpayer 52% less than land sharing to deliver the same environmental outcomes for biodiversity and climate mitigation;

  • At a time of heightened concern over food security, land sharing would lower food production by 27% more than a land sparing approach;

  • Analogues in the Countryside Stewardship Scheme to the land sharing approaches explored in the study currently receive 10 times more public funding than the studied sparing measures;

  • Prolonging the current policy approach risks delivering environmental outcomes at twice the cost to the taxpayer while potentially increasing environmental damage in food-exporting countries and reducing the space available for wild species that cannot live on farmed land.


There can be no doubt that figuring out how to feed, clothe and power 11 billion people without wrecking the climate and causing mass species extinction is this century’s greatest challenge.


In a UK context, the government has legally binding commitments to reverse nature declines by 2030 and to reach net zero in terms of carbon emissions by 2050. Defra’s recent Government Food Strategy policy paper (June 2022) also commits the government to ‘broadly maintain’ current levels of domestic food production.


Protecting biodiversity and averting a climate crisis while meeting humanity’s needs will force enormous trade-offs, but the evidence is starting to point in one direction. Across many different farming systems and many different environments, studies on five continents have consistently found that most species fare much better if habitats are left intact or restored, which means reducing the space used for farming. This ‘land sparing’ approach involves making room for more unfarmed habitat by making areas that are farmed as productive as sustainably possible.


However, the current direction of travel for farm policy in England – exemplified through the apparent budget split across the sharing and sparing policy strands of ELMs - appears to favour a ‘land sharing’ approach. Sharing seeks to combine (typically) lower-yielding farming practices with a range of small-scale conservation measures, such as the addition of feed or nest plots for birds to arable fields. Public money compensates farmers for these public goods and their reduced output.     


The findings of our study, The costs of delivering environmental outcomes with land sharing and land sparing, published in the British Ecological Society journal People and Nature, should give Defra Ministers and their advisers cause to rethink.


This research, the first of its kind to quantify the cost effectiveness of these two contrasting farm policy options, found that incentivising farmers to focus on producing food on some land while putting aside other land for nature would cost just 48% of the taxpayer funds required to achieve the same biodiversity and climate outcomes through land sharing.


The research centred on a choice experiment study involving 118 farmers responsible for managing 1.7% of all England’s arable land, asking them to estimate the payments they would require to implement land sharing practices or habitat-creating “sparing” approaches on their land.


Farmers chose from a variety of agricultural approaches, nature interventions and, crucially, payment rates. We also considered the government's costs of administering and monitoring these schemes.


We used three bird species – yellowhammers, bullfinches and lapwings – as a proxy for effects on farmland-tolerant biodiversity, as well a range of ways farmers could help slow climate change, such as woodland and hedgerow creation.


On average, farmers accepted lower payments per hectare to implement land-sharing practices. However, larger-scale habitat creation schemes typical of sparing deliver far greater environmental outcomes per hectare, so paying farmers to create woodlands, wetlands and scrublands would deliver the same overall biodiversity and climate mitigation benefits at half the cost to the taxpayer.


These findings indicate that farmers are generally willing to substantially change their business to generate public goods through larger-scale habitat creation, provided the government rewards them properly for doing so.


There are a number of key points to emphasise about this policy approach.


First, we are by no means advocating a wholesale relocation of productive farming from one side of the country to another, as some have mistakenly assumed. In fact, quite the opposite. Our detailed research to date has focused on the localised biodiversity associated with sub-regions, such as Salisbury Plain and The Fens. To be socially acceptable and biologically effective, land sparing in the UK should, we suggest, involve groups of neighbouring farmers co-operating to establish larger blocks of unfarmed land and inter-connecting corridors within each sub-region.


Second, delivering for nature will require a corresponding and renewed policy focus on high-yield production. Agricultural productivity growth in the UK lags behind most other developed nations. Some argue that this is because we (and the EU) have denied farmers access to the technologies enjoyed by producers elsewhere that enhance yields whilst typically reducing environmental costs per unit production, but it is also partly due to a confused approach to formulating policy, which does not necessarily follow the science.


As conservation scientists, it can be a difficult path to argue against the popular received wisdom that lower-yielding farming offers the best outcomes for nature and food production. But that is what the scientific evidence tells us. Trying to produce food, protect biodiversity and sequester carbon all in the same place is not efficient.


Supporting high-yield production does not mean returning to the days of rewarding individual farmers for producing greater and greater harvests. But it could mean more public sector investment in the infrastructure, scientific capacity, research, metrics and knowledge exchange needed to deliver sustainable, high-yield production on Britain’s farms. Both the domestic and overseas environmental costs of producing our food could be lowered by embracing technology and innovation to boost our food production capacity.


Third, we must be mindful of the impact of our policies on other food-exporting countries whose natural habitats may be more important for biodiversity and mitigating climate change than our own. Elsewhere, studies have found that food and other commodities imported to the UK already threaten five times more species overseas compared to the domestic threats that arise from UK exports. Furthermore, these imported goods come with a carbon footprint. International carbon accounting rules apply these emissions from land use to the exporting country's accounts. Domestic net zero targets, as the UK has, therefore provide no incentive to reduce emissions on imported goods.


Finally, we must recognise the biodiversity risks of a land-sharing approach in reducing the space available for wild species that do not tolerate conditions on farmed land. Our research indicates that land sharing would typically reduce yields, so to deliver the same outcomes for farm-tolerant biodiversity we would have to make up for lost food production in other ways, inevitably shrinking the area available for semi-natural habitats.


In conclusion, we found strong economic evidence in favour of a land sparing approach to reconciling environmental conservation and food production. Prolonging the current predominance of land sharing interventions risks delivering environmental outcomes at a greater cost to the taxpayer while potentially increasing environmental damage in food-exporting countries and reducing the space available for wild species that do not tolerate conditions on farmed land. We hope our study’s findings inform a rethink of the funding and direction of England’s Environmental Land Management Schemes (ELMs).


Andrew Balmford is a Professor of Conservation Science in the Department of Zoology at the University of Cambridge. His research focuses on the costs and benefits of conservation and how conservation can be reconciled with other activities. He was a research fellow at the Institute of Zoology in London, and then a lecturer at the University of Sheffield. Andrew was elected a Fellow of the Royal Society in 2011.


Lydia Collas joined Green Alliance as a Policy Analyst in April 2022. Prior to joining, she completed a PhD in Zoology at the University of Cambridge, analysing the cost-effectiveness of contrasting agricultural policy approaches to delivering ambitious biodiversity and climate mitigation outcomes. Lydia also has a Masters in Sustainability from Brock University, Canada, and a BA in Natural Sciences from the University of Cambridge.

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