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Type: Journal article
Title: Evaluating the utility of dynamical downscaling in agricultural impacts projections
Author: Glotter, M.
Elliott, J.
McInerney, D.
Best, N.
Foster, I.
Moyer, E.
Citation: Proceedings of the National Academy of Sciences of USA, 2014; 111(24):8776-8781
Publisher: National Academy of Sciences
Issue Date: 2014
ISSN: 0027-8424
Statement of
Michael Glotter, Joshua Elliott, David McInerney, Neil Best, Ian Foster, and Elisabeth J. Moyer
Abstract: Interest in estimating the potential socioeconomic costs of climate change has led to the increasing use of dynamical downscaling — nested modeling in which regional climate models (RCMs) are driven with general circulation model (GCM) output — to produce fine-spatial-scale climate projections for impacts assessments. We evaluate here whether this computationally intensive approach significantly alters projections of agricultural yield, one of the greatest concerns under climate change. Our results suggest that it does not. We simulate US maize yields under current and future CO 2 concentrations with the widely used Decision Support System for Agrotechnology Transfer crop model, driven by a variety of climate inputs including two GCMs, each in turn downscaled by two RCMs. We find that no climate model output can reproduce yields driven by observed climate unless a bias correction is first applied. Once a bias correction is applied, GCM- and RCM-driven US maize yields are essentially indistinguishable in all scenarios ( < 10% discrepancy, equivalent to error from observations). Although RCMs correct some GCM biases related to fine-scale geographic features, errors in yield are dominated by broad-scale (100s of kilometers) GCM systematic errors that RCMs cannot compensate for. These results support previous suggestions that the benefits for impacts assessments of dynamically downscaling raw GCM output may not be sufficient to justify its computational demands. Progress on fidelity of yield projections may benefit more from continuing efforts to understand and minimize systematic error in underlying climate projections.
Keywords: Agriculture; food security; NARCCAP; CORDEX
Rights: © 2016 National Academy of Sciences
DOI: 10.1073/pnas.1314787111
Appears in Collections:Aurora harvest 3
Civil and Environmental Engineering publications

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