Abstract：
Manual outdoor work is essential in many agricultural systems. Climate change will make such work more stressful in many regions due to heat exposure. The physical work capacity metric (PWC) is a physiologically based approach that estimates an individual\'s work capacity relative to an environment without any heat stress. We computed PWC under recent past and potential future climate conditions. Daily values were computed from five earth system models for three emission scenarios (SSP1-2.6, SSP3-7.0, and SSP5-8.5) and three time periods: 1991-2010 (recent past), 2041-2060 (mid-century) and 2081-2100 (end-century). Average daily PWC values were aggregated for the entire year, the growing season, and the warmest 90-day period of the year. Under recent past climate conditions, the growing season PWC was below 0.86 (86% of full work capacity) on half the current global cropland. With end-century/SSP5-8.5 thermal conditions this value was reduced to 0.7, with most affected crop-growing regions in Southeast and South Asia, West and Central Africa, and northern South America. Average growing season PWC could falls below 0.4 in some important food production regions such as the Indo-Gangetic plains in Pakistan and India. End-century PWC reductions were substantially greater than mid-century reductions. This paper assesses two potential adaptions-reducing direct solar radiation impacts with shade or working at night and reducing the need for hard physical labor with increased mechanization. Removing the effect of direct solar radiation impacts improved PWC values by 0.05 to 0.10 in the hottest periods and regions. Adding mechanization to increase horsepower (HP) per hectare to levels similar to those in some higher income countries would require a 22% increase in global HP availability with Sub-Saharan Africa needing the most. There may be scope for shifting to less labor-intensive crops or those with labor peaks in cooler periods or shift work to early morning.
摘要：
在许多农业系统中，手动户外工作至关重要。由于热暴露，气候变化将使许多地区的此类工作压力更大。体力劳动能力度量（PWC）是一种基于生理的方法，可以估算个人相对于没有任何热应力的环境的工作能力。我们在最近的过去和潜在的未来气候条件下计算了PWC。根据三个排放情景（SSP1-2.6，SSP3-7.0和SSP5-8.5）和三个时间段：1991-2010（最近）的五个地球系统模型计算日值，2041-2060（世纪中叶）和2081-2100（世纪末）。全年平均每日PWC值汇总，生长季节,和一年中最温暖的90天。在最近的气候条件下，在目前全球一半的农田中，生长季节PWC低于0.86（占全部工作能力的86％）。在世纪末/SSP5-8.5热条件下，该值降至0.7，东南亚和南亚受影响最大的作物种植区，西非和中非，和南美洲北部。在一些重要的粮食生产地区，如巴基斯坦和印度的印度恒河平原，平均生长季节普华永道可能低于0.4。世纪末PWC的减少量大大超过了本世纪中叶的减少量。本文评估了两种潜在的适应性：减少阴凉处或夜间工作的直接太阳辐射影响，并通过增加机械化来减少对艰苦体力劳动的需求。在最热的时期和地区，消除直接太阳辐射的影响将PWC值提高了0.05至0.10。增加机械化以将每公顷马力（HP）增加到与一些高收入国家相似的水平，将需要全球HP可用性增加22％，其中撒哈拉以南非洲地区最需要。可能有转移到劳动强度较低的作物或在较凉爽的时期有劳动力高峰的作物或将工作转移到清晨的作物。
