Large potential for crop production adaptation depends on available future varieties

Florian Zabel,James A Franke,Alex C Ruane,Stefan Olin,Christoph Müller,Wolfram Mauser,Julia M Schneider,Sara Minoli,Louis Francois,Wenfeng Liu,Christian Folberth,Elisabeth Moyer,Thomas A.M Pugh,Sam S Rabin,Senthold Asseng,Jonas Jägermeyr,Joshua Elliott,Tobias Hank,Marie Dury

doi:10.1111/gcb.15649

Abstract

Climate change affects global agricultural production and threatens food security. Faster phenological development of crops due to climate warming is one of the main drivers for potential future yield reductions. To counter the effect of faster maturity, adapted varieties would require more heat units to regain the previous growing period length. In this study, we investigate the effects of variety adaptation on global caloric production under four different future climate change scenarios for maize, rice, soybean, and wheat. Thereby, we empirically identify areas that could require new varieties and areas where variety adaptation could be achieved by shifting existing varieties into new regions. The study uses an ensemble of seven global gridded crop models and five CMIP6 climate models. We found that 39% (SSP5-8.5) of global cropland could require new crop varieties to avoid yield loss from climate change by the end of the century. At low levels of warming (SSP1-2.6), 85% of currently cultivated land can draw from existing varieties to shift within an agro-ecological zone for adaptation. The assumptions on available varieties for adaptation have major impacts on the effectiveness of variety adaptation, which could more than half in SSP5-8.5. The results highlight that region-specific breeding efforts are required to allow for a successful adaptation to climate change.

Highlights

Climate change is expected to reduce agricultural productivity and increase risks of crop failures without adaptation (Challinor et al, 2014; Liu et al, 2016; Rosenzweig et al, 2014; Zhao et al, 2017)
We found that global caloric production declines by 2% when continuously using current varieties under SSP5-8.5 for the average of 31 years (2070–2100) compared to the baseline (1980– 2010) (Figure 1)
Crop production under potential variety adaptation is relatively stable between the considered SSPs and increases baseline production between 12% and 18%

Summary

Introduction

Climate change is expected to reduce agricultural productivity and increase risks of crop failures without adaptation (Challinor et al, 2014; Liu et al, 2016; Rosenzweig et al, 2014; Zhao et al, 2017). A simulation study with wheat has shown that the shortening of the growing period (time from sowing to maturity) with increasing temperatures reduces light interception, biomass accumulation and grain set and grain yield (Asseng et al, 2015). To counter the effect of faster maturity, Asseng et al (2015) suggest that varieties adapted to increased temperatures require more heat units to delay maturity and extend grain filling. Breeding lines with delayed maturity and improved heat tolerance do exist in current breeding programs and some regional modern varieties and have been shown to yield higher under increased temperatures in field experiments (Asseng et al, 2019)

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Results

Conclusion