Changing the use of agricultural land could massively reduce greenhouse gas emissions

A Bangor University academic has contributed to a new study which provides a radical and important new perspective on how to address the UK’s climate change commitments.

The research has found making farmland more productive could increase the amount of food it produces and bring about significant reductions in the UK’s greenhouse gas emissions.

Agriculture contributes towards greenhouse gas production, through the heavy machinery needed which runs on fossil fuels, nitrogen inputs to soil, and through livestock emissions. However, it can also substantially reduce the natural ability of some types of land – especially peat and wetlands - to reduce climate change by storing carbon.

Professor Dave Chadwick from Bangor University’s School of Environment, Natural Resources and Geography, was part of an international consortium of researchers including Cambridge University and the University of California. They found that increases in farmland yields could be a key factor in addressing the UK’s binding commitments to reduce greenhouse gases by 80 per cent - of 1990 levels - by 2050. He contributed to the study by providing expertise on the effects of farm management practices on nitrous oxide emissions from soil. He recently led the >£6.5M consortium project to improve the nitrous oxide component of the UK’s agricultural greenhouse gas emissions inventory.

Increasing output per hectare will allow reductions in the amount of land needed to maintain food output, even with a growing population. The ‘spared’ land can then be restored to its natural habitat which would store large amounts of carbon.

The research, published in Nature Climate Change, shows that there is the potential to achieve more than the required 80 per cent reduction in greenhouse gases if increases in yield are combined with land being taken out of farm use and used to store carbon. The reductions in greenhouse gas emissions become even greater if the spared land is used in ways which store more carbon, such as planting trees, or if consumers were to cut food waste or reduce consumption of high emission foods such as meat.

Professor Chadwick said: “This important study demonstrates the potential for land use optimisation to provide the increasing demand for food products, whilst delivering to national targets for greenhouse gas reduction. Moreover this form of sustainable intensification could also deliver wider benefits in terms of habitat generation.”

Professor Ian Bateman, from of the University of Exeter, said: “There is uncertainty about what will happen to both food prices and the climate in the future, but this study shows that investing in increased yields allows us to reduce the land used by farming and substantially cut UK greenhouse gases while still maintaining food production.”

“However, in doing this it is vital to ensure that we consider the wider environmental and social effects of such changes. Changing land use has multiple effects, not only on food and greenhouse gases but also on biodiversity, water quality, flooding risk, recreation and, if it is not compensated for, it can also impact agricultural incomes. Only by looking at the full range of effects can we really identify the right policies to pursue and this is a major focus of our ongoing research.”

The study, based on modelling and projections, was led by Andrew Balmford, Anthony Lamb and Rhys Green  from the University of Cambridge, and included work from researchers from the Universities of California, Bangor, Exeter, Aberdeen, the Royal Society for the Protection of Birds, Forestry Commission, Rothamsted Research, ADAS UK Ltd and Scotland’s Rural College (SRUC).

Senior author of the study, Professor Andrew Balmford, from Cambridge University, said: “Land is a source of greenhouse gases if it is used to farm fertiliser-hungry crops or methane-producing cattle, or it can be a sink for greenhouse gases – through sequestration.

“If we increase woodland and wetland, those lands will be storing carbon in trees, photosynthesising it in reeds, and shunting it down into soils.

“We estimate that by actively increasing farm yields, the UK can reduce the amount of land that is a source of greenhouse gases, increase the ‘sink’, and sequester enough carbon to hit national emission reduction targets for the agriculture industry by 2050.” 

Publication date: 4 January 2016