Detection of a direct carbon dioxide effect in continental river runoff records
Detection of a direct carbon dioxide effect in continental river runoff records
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DOI：
10.1038/nature04504
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发表时间：
2006-02-16
期刊：
影响因子：
64.8
通讯作者：
Stott, PA
中科院分区：
文献类型：
--
作者：
Gedney, N;Cox, PM;Stott, PA
尽管人类的用水量越来越大（3），但大陆径流量在整个世纪（1，2）一直在增加。增加的可能原因包括：气候变化和可变性，森林砍伐，太阳变暗（4），以及大气二氧化碳（CO2）对植物蒸腾作用的直接影响（5）。所有这些机制都有可能影响降水和/或蒸发，从而改变径流。在这里，我们使用机械陆面模型（6）和最佳指纹统计技术（7）将观测径流变化（1）归因于这些因素的贡献。该模型成功地捕捉到气候驱动的年际径流变化，但二十世纪的气候本身是不足以解释径流的趋势。相反，我们发现的趋势是一致的抑制植物蒸腾由于CO2诱导气孔关闭。这一结果将影响对淡水供应量的预测，也代表着检测到二氧化碳对陆地生物圈功能的直接影响。
Continental runoff has increased through the twentieth century(1,2) despite more intensive human water consumption(3). Possible reasons for the increase include: climate change and variability, deforestation, solar dimming(4), and direct atmospheric carbon dioxide (CO2) effects on plant transpiration(5). All of these mechanisms have the potential to affect precipitation and/or evaporation and thereby modify runoff. Here we use a mechanistic land-surface model(6) and optimal fingerprinting statistical techniques(7) to attribute observational runoff changes(1) into contributions due to these factors. The model successfully captures the climate-driven inter-annual runoff variability, but twentieth-century climate alone is insufficient to explain the runoff trends. Instead we find that the trends are consistent with a suppression of plant transpiration due to CO2-induced stomatal closure. This result will affect projections of freshwater availability, and also represents the detection of a direct CO2 effect on the functioning of the terrestrial biosphere.