New research shows how land sparing can reduce greenhouse gas and benefit wildlife

Guest blog by Dr Rob Field, Senior Conservation Scientist, RSPB Centre for Conservation Science

A recent paper 'The potential for land sparing to offset greenhouse gas emissions from agriculture' in the journal Nature Climate Change has attempted to show that land sparing has the technical potential to significantly  reduce agricultural emissions, by balancing them with greenhouse gas uptake from ‘spared land’.  The land spared including new woodlands and wetlands would be more than just a carbon sink. They would help support declining UK wildlife – including many species of conservation concern – provide more areas for nature recreation, and help to reduce flooding.

What is land sparing?

The concept of sparing land for conservation purposes has been around for about a decade now, and was first proposed and investigated as a way of saving further loss of pristine natural habitats to agriculture – the idea being that the more food you can produce per area of land, the less extra land you require, thereby sparing that land for conservation goals.  This has been largely examined in tropical, high biodiversity countries, and shows large benefits for the majority of species endangered by agricultural expansion. 

The UK is slightly different, in that virtually all our land surface is at the very least ‘semi-natural’ and most is highly ‘anthropogenic’ (human altered).  This means that most of our wildlife in the wider countryside is well-adapted to living alongside people and living in our landscapes.  In spite of this, wildlife declines in the UK countryside are now well documented. 

A very small proportion of the UK land surface is already spared from agriculture (nature reserves etc), but this largely covers the rarer habitats remaining unconverted to intensive agricultural use. Most widespread wild nature in Britain survives in farmed landscapes. 

Meeting the requirements to reduce gas emissions by 80% by 2050

By virtue of the climate change act of 2008, UK agriculture is bound to cut its 1990 greenhouse gas emissions by 80% by 2050.  This is already acknowledged to be a tough ask, as most emissions are associated with fertiliser use, and most crops need fertilisers. 

Photo of wheat harvest by Andy Hay (rspb-images.com)

Land sparing for climate mitigation and for wildlife

Our study has looked at the role of land sparing (to create new unfarmed areas in the wider countryside, additional to current nature reserves) in not only providing habitat for declining species, but in mitigating the emissions of UK agriculture towards the 2050 target. 

We assumed that using the latest technological and agronomic advances, UK agriculture becomes more efficient – producing more crop per area, or more meat per weight of animal food (notwithstanding welfare and environmental restrictions). 

Using a range of these projections, we looked at how much food would be needed by 2050 (the projected population) and how much land would be needed to produce it – any extra would be spared and converted to natural habitats (woodland or marshland). 

Additionally, we combined these projections with other societal changes:  reducing food wastage (the percentage of food produced lost before consumption); and a reduction in meat in the UK diet (not total vegetarianism, just meat less often). 

Emissions from the UK farming industry could be largely offset by 2050 We found that increased agricultural efficiency was capable of balancing some of the UKs agricultural emissions (a combination of increased CO2 uptake by restored habitats and less emissions per unit food produced), but when combined with societal measures, these had the potential to essentially negate the entire 80% of 1990 emissions that is required of agriculture. 

Putting the science into practice requires changes in policy

That’s the easy bit – how to do this in practice is the hard bit!  Farmland is owned and managed by private businesses, all with their own pressures and incentives, and so sparing land would be the result of many individual decisions, based on individual business circumstances – therefore the most likely way to do this in the UK is through the Common Agricultural Policy and Agri-environment schemes.  It would require another big reform of these schemes to enable large scale land-sparing and habitat creation.

Reducing meat consumption and food waste

The task of changing diets seems herculean compared to even this however, although there does seem to be some popular momentum behind the reduction of food wastage.  In the event of a perfect storm of these three things becoming possible, there is also the small matter of the conservation policy behind such huge landscape changes – how would we view changes to our wildlife that such wholesale changes to the countryside would bring? 

Changes to the countryside – more wetland and woodland

By upping forest cover from 12% to 30% of UK land over the next 35 years – close to that of France and Germany and restoring 700,000 hectares of wet peatland, would act as a carbon ‘sink’: sucking in and storing carbon. Creation of large areas of wetland and woodland would likely favour such declining species as wood warblers, lesser spotted woodpeckers and cuckoos as well as some of the recent success stories – bitterns, little egrets etc, but would this be acceptable at the cost of fewer yellowhammers, corn buntings, and stone curlews? 

Photo of wood warbler by Andy Hay (rspb-images.com)

Agricultural intensification

If we spare land, we’ll have to intensify the production on the remaining farmland, and on current form, this will be bad for our farmland specialists, which currently do best on ‘shared land’ (where conservation and farming are not separated spatially, e.g. Environmental Stewardship) or on High Nature Value Farming land (where low intensity farming persists due to subsidy or cultural factors).  Which do we choose, and how will we know? 

More research

Current work 'Reconciling food production and biodiversity conservation in Poland' is looking at the comparative benefits of sparing or sharing in Eastern Europe after the collapse of the Soviet Union (which led to a reduction in farming efficiency) and will also do the same in the UK, so we may then have a better idea of what different land-use plans will suit which species.