Carbon farming, crop yield and biodiversity in Mediterranean Europe: the dose makes the poison?

Abstract Background European agriculture causes 13% of the EU's GHG emissions, and attaining EU climate neutrality by 2050 requires both minimizing discharges and removing CO 2 from the atmosphere. Carbon farming, a promising removal strategy, is often accused of reducing crop yield and of conflicting with biodiversity. Concerns about potentially negative impacts are greatest in the Mediterranean region, where climate limits net primary production. Scope. A group of experts has been discussing for two years antagonisms and synergies between carbon farming, agricultural productivity and biodiversity to advise the European Commission on the best way to implement the “Union certification framework for permanent carbon removals, carbon farming and carbon storage in products”. We summarize here our conclusions about opportunities and barriers for carbon farming under Mediterranean conditions. Inspired by the points raised by the expert team, we discuss the scientific bases for trade-offs between carbon farming and crop yield, we review the main obstacles for carbon farming when water is scarce, and the availability of organic amendments is restricted. We also point to the effects of spatial scale on the relationship between biodiversity and food production. Conclusion Despite the scarcity of concluding data, everything indicates that the sign and size of the effects of carbon farming on crop yield are highly dependent on soil and crop type and on the correct and site-tailored application of agricultural techniques. Carbon farming is knowledge-demanding, and its successful application will require fluent knowledge exchange between farmers, scientists and technicians and the development of effective decision support systems.