Farmers in focus: Effects of elevated CO2 concentration on crops

Modelling has usually been carried out for scenarios that both include and exclude the effects of elevated atmospheric CO₂ concentrations on crops, as the uncertainties were considered too high to exclude one of the two. An international team of agro-climatic experts, led by Andrea Toreti (European Commission, Joint Research Centre JRC, Ispra) and Delphine Deryng (NewClimate Institute/IRI THESys, Humboldt-Universität zu Berlin), collected and evaluated experimental and modelling research on the effects of elevated CO₂ concentrations on crops. The team concluded that recent efforts and the accumulated evidence are such that scenarios that exclude the effects of elevated CO₂ can finally be eliminated from climate change impact assessments.

Putting an end to misinterpreted models

"Presenting scenarios that do not consider CO₂ effects on plant growth as plausible future projections have been causing confusion in the public debate. Our study shows that crop models need to be improved, especially at high levels of CO₂, to better understand the threat of climate change to agricultural production and how much land can be made available for other purposes, such as nature conservation or land-based climate mitigation measures", explains Christoph Müller, researcher from the Potsdam Institute for Climate Impact Research (PIK).

This represents a fundamental step towards improving the communication of climate change impact assessments for agriculture, while laying out strategies for further narrowing the uncertainties. These assessments are used to inform policymakers, as well as to design future adaptation and mitigation pathways.  The team also identified key uncertainties and knowledge gaps that still remain, especially on nutritional aspects and on the complex effects of climate extremes. Therefore, the paper proposes a roadmap for the coming years to support targeted experimental and modelling research.