Dr Amanda Thomson of the Centre for Ecology & Hydrology discusses her research into reducing greenhouse gas emissions from land use, which informed a recent report by the UK’s Committee on Climate Change...
The Centre for Ecology & Hydrology and Rothamsted Research were commissioned by the Committee on Climate Change (CCC) to examine how greenhouse gases could be reduced while maintaining food production per capita in the UK despite a growing population, rather than increasing imports and displacing emissions abroad.
Our research, now available online, will inform the CCC’s 2019 report on the development of the UK government’s future land strategy.
The agriculture and land use sectors need to make considerable progress on reducing greenhouse gas (GHG) emissions for the UK to meet its statutory reduction targets in 2032 and 2050 and to fulfil the ambition of the Paris Agreement to keep global warming to 1.5°C.
Under current patterns of agricultural land use and management, we calculated GHG emissions in the UK could increase by the equivalent of 9 Megatonnes of CO2 a year by 2050 compared with 2016. There could be insufficient agricultural land to maintain per capita food production at 2016 levels given population growth plus associated housing and infrastructure expansion.
"The agriculture and land use sectors need to make considerable progress on reducing greenhouse gas (GHG) emissions for the UK to meet its statutory reduction targets in 2032 and 2050 and to fulfil the ambition of the Paris Agreement to keep global warming to 1.5°C."
Land-based mitigation measures include increased forest, tree and hedgerow planting, better forest management, peatland restoration and increased areas of biomass energy crops. Better livestock, manure and soil management plus technology innovation can reduce GHG emissions and increase productivity, so less land is needed to grow the same amount of food, freeing up land for further mitigation measures.
We modelled GHG emissions and the production of food, timber and fuel up to 2050 for three levels of ambition for each mitigation option:
- Low ambition (continuation of current trends)
- Medium ambition (implementation of currently available measures)
- High ambition (novel or radical measures).
These measures were combined into five scenarios, to explore a range of 'what if' land use change/agriculture options that are technically feasible between now and 2050, and are not constrained by economic, social or policy factors.
Our modelling took account of the area of available agricultural land (pasture, rough grazing and cropland) across the UK, and balanced the need for climate change mitigation with future demands for increased food production, housing and infrastructure.
Large reductions in GHG emissions are possible by implementing the high-ambition mitigation measures, by 35%-80% below 2016 levels by 2050.
Our modelling suggested that the biggest potential reduction in land-use emissions would come from forest planting and peatland restoration.
The biggest cuts in emissions in the agricultural sector are through changes in people’s dietary habits, as less red meat and dairy consumption would mean fewer livestock and fewer emissions of methane and nitrous oxide from livestock digestion, manure and fodder production. Advances in the health and breeding of both livestock and crops would also produce significant cuts in emissions.
Implementing the higher ambition mitigation measures could greatly change the UK agricultural landscape. Our research estimated:
- Forest cover in the UK would increase from 13% to 17-19% of the total land area.
- Permanent pasture and rough grazing land would reduce by 26-36% because these areas would be in most demand for land-based mitigation measures plus housing and infrastructure expansion
- There would be increased tree cover and hedgerows on agricultural land and more permanent biomass energy crops.
- Restoration of up to 1.1 million hectares of peatlands in the UK could reduce greenhouse emissions from these areas by 24-42% by 2050.
While rewetting peatlands would mean some loss of agricultural land, it would 'lock in' these areas’ vast stores of carbon, thereby reducing CO2 emissions, and would have benefits for biodiversity and ecosystem functioning.
Overall, the changes in the agricultural landscape could be beneficial for both climate change mitigation and adaptation if transformation is managed in an integrated, strategic way.
The full report, titled Quantifying the impact of future land use scenarios to 2050 and beyond, is now available online.
Committee on Climate Change report: Land Use: Reducing emissions and preparing for climate change