Climate impact and adaptation to heat and drought stress of regional and global wheat production

Diego N L Pequeno,Matthew Reynolds,Wei Xiong,Richard D Robertson,Ixchel M Hernández-Ochoa,Anabel Moleromilan,Kai Sonder,Martin Kropff,Senthold Asseng,Marta S Lopes

doi:10.1088/1748-9326/abd970

Abstract

Wheat (Triticum aestivum) is the most widely grown food crop in the world threatened by future climate change. In this study, we simulated climate change impacts and adaptation strategies for wheat globally using new crop genetic traits (CGT), including increased heat tolerance, early vigor to increase early crop water use, late flowering to reverse an earlier anthesis in warmer conditions, and the combined traits with additional nitrogen (N) fertilizer applications, as an option to maximize genetic gains. These simulations were completed using three wheat crop models and five Global Climate Models (GCM) for RCP 8.5 at mid-century. Crop simulations were compared with country, US state, and US county grain yield and production. Wheat yield and production from high-yielding and low-yielding countries were mostly captured by the model ensemble mean. However, US state and county yields and production were often poorly reproduced, with large variability in the models, which is likely due to poor soil and crop management input data at this scale. Climate change is projected to decrease global wheat production by −1.9% by mid-century. However, the most negative impacts are projected to affect developing countries in tropical regions. The model ensemble mean suggests large negative yield impacts for African and Southern Asian countries where food security is already a problem. Yields are predicted to decline by −15% in African countries and −16% in Southern Asian countries by 2050. Introducing CGT as an adaptation to climate change improved wheat yield in many regions, but due to poor nutrient management, many developing countries only benefited from adaptation from CGT when combined with additional N fertilizer. As growing conditions and the impact from climate change on wheat vary across the globe, region-specific adaptation strategies need to be explored to increase the possible benefits of adaptations to climate change in the future.

Highlights

Wheat is the most traded and planted crop in the world, covering 216 million hectares with an average yield of 3.5 t ha−1 and a total production of 765 million tons worldwide (FAOSTAT 2019)
A multi-climate/multi-crop model ensemble suggested that climate change may have variable spatial impacts on wheat yields with global production being projected to decline by mid-century
Xiong et al (2019) used the three DSSAT wheat models to study the contributions of climate model, crop model, parameterization and management to the overall uncertainty of yield simulation responses under future warming climate and found that total uncertainty for mid- and high latitudes is larger than for low latitudes

Summary

Introduction

Wheat is the most traded and planted crop in the world, covering 216 million hectares with an average yield of 3.5 t ha−1 (at 11% moisture content) and a total production of 765 million tons worldwide (FAOSTAT 2019). Rainfall changes, and extremes in the future are projected to further affect wheat production by mid and end of century (Challinor et al 2014, IPCC 2014, Rosenzweig et al 2014, Asseng et al 2015). Asseng et al (2015) and Zhao et al (2017) estimated that wheat production is projected to decline by −6% per ◦C of further global warming. Developing countries may be more impacted by climate change because many of them have production systems with limited access to technology. These areas have a large improvement potential due to a large yield gap between current and attainable yields (Neumann et al 2010, Mueller et al 2012)

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