Vulnerability of European wheat to extreme heat and drought around flowering under future climate

Nimai Senapati,Nigel G Halford,Mikhail A Semenov

doi:10.1088/1748-9326/abdcf3

Abstract

Identifying the future threats to crop yields from climate change is vital to underpin the continuous production increases needed for global food security. In the present study, the vulnerability of European wheat yield to heat and drought stresses around flowering under climate change was assessed by estimating the 95-percentiles of two indices at flowering under rain-fed conditions: the heat stress index (HSI95) and the drought stress index (DSI95). These two indices represent the relative yield losses due heat stress or drought stress around flowering that could be expected to occur once every 20 years on average. The Sirius wheat model was run under the predicted 2050-climate at 13 selected sites, representing the major wheat-growing regions in Europe. A total of 19 global climate models (GCMs) from the CMIP5 ensemble were used to construct local-scale climate scenarios for 2050 (RCP8.5) by downscaling GCMs climate projections with the LARS-WG weather generator. The mean DSI95 due to extreme drought around flowering under the baseline climate (1981–2010) was large over Europe (DSI95 ∼ 0.28), with wide site variation (DSI95 ∼ 0.0–0.51). A reduction of 12% in the DSI95 was predicted under the 2050-climate; however, vulnerability due to extreme drought around flowering would remain a major constraint to wheat yield (DSI95 ∼ 0–0.57). In contrast, HSI95 under the baseline climate was very small over Europe (HSI95 ∼ 0.0–0.11), but was predicted to increase by 79% (HSI95 ∼ 0.0–0.23) under the 2050-climate, categorising extreme heat stress around flowering as an emergent threat to European wheat production. The development of wheat varieties that are tolerant to drought and heat stresses around flowering, is required, if climate change is not to result in a reduction of wheat yield potential under the future climate in Europe.

Highlights

The increasing probability of more intense and extreme climatic events occurring in the future, such as high temperature and drought episodes, is a major threat to sustaining food production at current levels, let alone achieving the increases in food production required for global food security in the coming decades
Some researchers have suggested that the impact of drought on crop yields will increase in the future under climate change, emphasising the importance of breeding for drought-tolerant crops globally, including in Europe [15, 75]
The present study demonstrates that drought stress around flowering will not increase the vulnerability of the current wheat cultivars under climate change in Europe, and relative yield losses are likely to decrease

Summary

Introduction

The increasing probability of more intense and extreme climatic events occurring in the future, such as high temperature and drought episodes, is a major threat to sustaining food production at current levels, let alone achieving the increases in food production required for global food security in the coming decades. An estimated 25%−70% increase in global food production is required by 2050 to feed the predicted population by that time of >9 billion people [1, 2], yet extreme climatic events will increase the risk of yield loss and crop vulnerability [3, 4]. Europe is a major wheat producer, contributing around 35% of global wheat production [8], but the frequency and intensity of heat and drought stresses are predicted to increase across Europe under the future climate [9, 10]. Evaluations of the absolute magnitudes of wheat vulnerability under the future climate due to extreme but short-term heat and drought stresses are sparse [14, 15]

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