Researchers from Austria’s International Institute for Applied Systems Analysis (IIASA) and the University of Hamburg have suggested that there is only limited scope for European cropland to be used to sequester carbon, as part of efforts to mitigate climate changing greenhouse gas emissions.

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Yet the researchers said that carbon sequestration strategies might not be able to make enough of an impact. Computer modelling suggests action will need to be taken in different areas, as policies dealing with EU cropland might lead to repercussions outside of the EU, making them unviable on the whole.

Conducting research into greenhouse gas mitigation ahead of December’s climate summit in Paris, at which world leaders are expected to commit to measures to tackle climate changing emissions, the researchers said that emissions targets will be needed across most sectors in the EU. Looking specifically at agriculture, they said soils are the world’s third largest store of carbon, after oceans and the ‘geological pool’ (rocks and fossil fuels).  

Stefan Frank, who worked on the research at IIASA, said he and his fellow researchers reached their conclusions by using computer modelling programmes which take into account land use, trade and emissions from other areas. They looked at different scenarios in which carbon prices varied within the EU, mimicking emissions reduction targets for the agricultural sector.

Frank and his colleagues studied the potential of using reduced and no-tillage management to store more soil carbon, and also looked at different cover crops, rotation patterns, and shifts in production to more fertile soils. He explained, “In the analysis, we [looked at paying] farmers in Europe for carbon sequestration but at the same time also taxed emissions from soil carbon. The mitigation potential (inside EU) resulted mainly from improved management but also from set aside.”

Soil carbon is released into the atmosphere through land use changes and unsustainable land management, whilst good management practices and efforts to improve the health of soils and peatland can draw in more carbon, reducing atmospheric pollution.

Though it could mitigate polluting practices within Europe, the researchers investigating potential solutions said that a carbon tax could cause more polluting agricultural production systems to relocate outside of the EU, with rising emissions outside Europe offsetting any reductions achieved within EU states, a problem known as emissions leakage.  

Though they acknowledged that drastic action is needed to stave off the worst impacts of climate change and prevent further average temperature rises, the researchers concluded that “Given the… uncertainties, the small mitigation potential at carbon prices below 100 $/tCO2 and the potential leakage effects… carbon sequestration on European cropland will probably not contribute significantly to climate change mitigation and should therefore be accompanied by additional mitigation efforts.”

Although they think there is a great deal of potential for soil carbon storage to work in Europe, Frank and his team believe that more effective efforts may have to focus on areas other than cropland. This may present some challenges though as arable farmland makes up about a quarter of all EU landcover, according to the EU Commission’s CORINE land use programme.

Though Frank said that the range of mitigation options on offer for cropland might not yield significant benefits for the climate, he acknowledged that many of the actions they examined carry benefits of their own. He said, “For example, conservation tillage won't ‘save the climate’, [but] it still may offer benefits to farmers in certain regions which favour the adoption nonetheless [in terms of] cost savings and soil fertility.”

Discussing more effective areas to look at, Frank said the Intergovernmental Panel on Climate Change (IPCC) has made a number of recommendations for mitigation strategies in agriculture and forestry, including reducing deforestation, increasing tree planting and re-foresting work, restoring organic soils, and improving grassland, cropland and manure management. He also said other areas of agriculture and sectors other than farming have significant parts to play in avoiding climate change by curbing emissions.

Frank said that the leakage effect observed by researchers, involving damaging practices springing up outside of areas where climate saving policies have been introduced, could be mitigated through stronger international agreements, or certification schemes. He pointed out, “As indirect land use change emissions usually make up a significant share of the emissions ‘leaked’, tackling directly all drivers [in this case initiatives like the REDD+ programme to curb deforestation] can be an efficient approach if implemented at larger scale.”

More information on the research is available here.