Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA.
School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA.
Nat Commun. 2021 Jun 18;12(1):3777. doi: 10.1038/s41467-021-24016-9.
Despite the growing interest in predicting global and regional trends in vegetation productivity in response to a changing climate, changes in water constraint on vegetation productivity (i.e., water limitations on vegetation growth) remain poorly understood. Here we conduct a comprehensive evaluation of changes in water constraint on vegetation growth in the extratropical Northern Hemisphere between 1982 and 2015. We document a significant increase in vegetation water constraint over this period. Remarkably divergent trends were found with vegetation water deficit areas significantly expanding, and water surplus areas significantly shrinking. The increase in water constraints associated with water deficit was also consistent with a decreasing response time to water scarcity, suggesting a stronger susceptibility of vegetation to drought. We also observed shortened water surplus period for water surplus areas, suggesting a shortened exposure to water surplus associated with humid conditions. These observed changes were found to be attributable to trends in temperature, solar radiation, precipitation, and atmospheric CO. Our findings highlight the need for a more explicit consideration of the influence of water constraints on regional and global vegetation under a warming climate.
尽管人们越来越关注预测气候变化对植被生产力的全球和区域趋势变化，但对水对植被生产力的限制（即植被生长的水分限制）的变化仍了解甚少。在这里，我们综合评估了 1982 年至 2015 年期间，北温带以外地区植被生长水分限制的变化。我们记录到这一时期植被水分限制显著增加。显著的分歧趋势是，植被缺水地区显著扩大，而水资源过剩地区则显著缩小。与缺水相关的水分限制的增加也与对水资源短缺的响应时间减少相一致，这表明植被对干旱的敏感性更强。我们还观察到水资源过剩地区的水资源过剩期缩短，这表明与潮湿条件相关的水资源过剩的暴露期缩短。这些观测到的变化归因于温度、太阳辐射、降水和大气 CO 的趋势。我们的研究结果强调了在气候变暖的情况下，需要更明确地考虑水限制对区域和全球植被的影响。
