Why do crop models diverge substantially in climate impact projections? A comprehensive analysis based on eight barley crop models

A - Papers appearing in refereed journals

Tao, F., Palosuo, T., Rotter, R. P., Hernandez Diaz-Ambrona, C. G., Minguez, M. I., Semenov, M. A., Kersebaum, K. C., Cammarano, D., Specka, X., Nendel, C., Srivastava, A. K., Ewert, F., Padovan, G., Ferrise, R., Martre, P., Rodriguez, L., Ruiz-Ramos, M., Gaiser, T., Hohn, J. G., Salo, T., Dibari, C. and Schulman, A. H. 2020. Why do crop models diverge substantially in climate impact projections? A comprehensive analysis based on eight barley crop models. Agricultural and Forest Meteorology. 281, p. 107851. https://doi.org/10.1016/j.agrformet.2019.107851

AuthorsTao, F., Palosuo, T., Rotter, R. P., Hernandez Diaz-Ambrona, C. G., Minguez, M. I., Semenov, M. A., Kersebaum, K. C., Cammarano, D., Specka, X., Nendel, C., Srivastava, A. K., Ewert, F., Padovan, G., Ferrise, R., Martre, P., Rodriguez, L., Ruiz-Ramos, M., Gaiser, T., Hohn, J. G., Salo, T., Dibari, C. and Schulman, A. H.
Abstract

Robust projections of climate impact on crop growth and productivity by crop models are key to designing effective adaptations to cope with future climate risk. However, current crop models diverge strongly in their climate impact projections. Previous studies tried to compare or improve crop models regarding the impact of one single climate variable. However, this approach is insufficient, considering that crop growth and yield are affected by the interactive impacts of multiple climate change factors and multiple interrelated biophysical processes. Here, a new comprehensive analysis was conducted to look holistically at the reasons why crop models diverge substantially in climate impact projections and to investigate which biophysical processes and knowledge gaps are key factors affecting this uncertainty and should be given the highest priorities for improvement. First, eight barley models and eight climate projections for the 2050s were applied to investigate the uncertainty from crop model structure in climate impact projections for barley growth and yield at two sites: Jokioinen, Finland (Boreal) and Lleida, Spain (Mediterranean). Sensitivity analyses were then conducted on the responses of major crop processes to major climatic variables including temperature, precipitation, irradiation, and CO2, as well as their interactions, for each of the eight crop models. The results showed that the temperature and CO2 relationships in the models were the major sources of the large discrepancies among the models in climate impact projections. In particular, the impacts of increases in temperature and CO2 on leaf area development were identified as the major causes for the large uncertainty in simulating changes in evapotranspiration, above-ground biomass, and grain yield. Our findings highlight that advancements in understanding the basic processes and thresholds by which climate warming and CO2 increases will affect leaf area development, crop evapotranspiration, photosynthesis, and grain formation in contrasting environments are needed for modeling their impacts.

KeywordsAgriculture; Climate change; Crop growth stimulation; Impact; Model improvement; Uncertainty
Year of Publication2020
JournalAgricultural and Forest Meteorology
Journal citation281, p. 107851
Digital Object Identifier (DOI)https://doi.org/10.1016/j.agrformet.2019.107851
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDFW - Designing Future Wheat - Work package 1 (WP1) - Increased efficiency and sustainability
Output statusPublished
Publication dates
Online26 Nov 2019
Publication process dates
Accepted18 Nov 2019
PublisherElsevier Science Bv
ISSN0168-1923

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