Dynamic Assessment of Global Maize Exposure to Extremely High Temperatures

Abstract

Exposure to extreme heat can severely harm crop growth and development, and it is essential to assess such exposure accurately to minimize risks to crop production. However, the actual distribution of crops and its changes have neither been examined in sufficient detail nor integrated into the assessments of exposure to ensure their accuracy. By examining the distribution of maize at a high resolution through species distribution modeling, we assessed the past and future exposure of maize to temperatures above 37°C worldwide. Such exposure is likely to be widespread and severe, mainly in the subtropics, and may even expand to the mid-latitudes to encompass some major maize-producing areas. Many areas at both high and low latitudes may become exposed for the first time in the next 20 years. By the 2050s, the total area exposed could increase by up to 185% to 308.18 million ha, of which the area exposed for over 60 days may increase nearly sevenfold. The average length of exposure may increase by 69% to 27 days, and areas optimally suited to maize planting may see the fastest increase by up to 772%. Extreme heat can threaten global maize production severely, and measures to mitigate that threat and to adapt to it are urgently needed.

Historic evolution of population exposure to heatwaves in Xinjiang Uygur Autonomous Region, China

“…Most heatwave investigations includes limited metrics such as frequency, intensity, and duration 12 , 13 . Prolonged exposure to heatwaves can endanger human health 14 , thus more detailed studies of the adverse effects of heatwaves on population is required 15 . Previous studies have typically linked heatwaves to human health through heat-related morbidity and mortality data 16 , 17 .…”

Weather Extremes Shock Maize Production: Current Approaches and Future Research Directions in Africa

“…By the 2050s, the total area exposed could increase by up to 195% to 308.2 million ha, of which areas exposed for over 60 days may increase nearly seven-fold. The average length of exposure may increase by 69% to 27 days, and areas optimally suited to planting maize may see the fastest increase by up to 772% [ 86 ]. This extreme heat stress at anthesis by the 2080s under high emission scenarios (RCP8.5), taking into account CO 2 fertilization effects, could double global losses of maize yield [ 87 ].…”