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.

暴露于极端高温会严重损害作物的生长和发育，准确评估此类暴露以最大限度地降低作物生产风险至关重要。然而，作物的实际分布及其变化既没有得到足够详细的研究，也没有被纳入暴露评估以确保其准确性。通过物种分布模型以高分辨率检查玉米的分布，我们评估了玉米过去和未来在全球 37°C 以上温度下的暴露情况。这种暴露可能是广泛和严重的，主要是在亚热带，甚至可能扩展到中纬度地区，包括一些主要的玉米产区。许多高纬度和低纬度地区可能在未来 20 年内首次暴露。到 2050 年代，总暴露面积可能增加185%，达到3.0818亿公顷，其中暴露60天以上的面积可能增加近7倍。平均暴露时间可能会增加 69% 到 27 天，最适合玉米种植的区域可能会增加最快，最多可达 772%。极端高温会严重威胁全球玉米生产，迫切需要采取措施减轻这种威胁并适应它。