Europe-wide reduction in primary productivity caused by the heat and drought in 2003
Europe-wide reduction in primary productivity caused by the heat and drought in 2003
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DOI：
10.1038/nature03972
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发表时间：
2005-09-22
期刊：
影响因子：
64.8
通讯作者：
Valentini, R
中科院分区：
文献类型：
--
作者：
Ciais, P;Reichstein, M;Valentini, R
未来的气候变暖预计将促进温带生态系统中的植物生长，并增加碳固存（1，2）。但是，尽管在气候变化中，严重的区域热浪可能会变得更加频繁（3，4），但它们对陆地碳循环的影响尚不清楚。在这里，我们报告的测量生态系统的二氧化碳通量，遥感辐射吸收的植物，和国家一级的作物产量在2003年欧洲热浪。我们使用一个陆地生物圈模拟模型（5）来评估2003年大陆尺度初级生产力的变化，以及它们对净碳平衡的影响。我们估计，欧洲的总初级生产力下降了30%，这导致了大气中二氧化碳的强烈异常净来源（0.5 Pg Cyr（-1）），并逆转了四年的净生态系统碳固存的影响。我们的研究结果表明，在东欧和西欧的生产力下降可以解释为降雨量不足和极端的夏季高温，分别。研究还发现，随着温度的升高，生态系统呼吸作用并没有随着温度的升高而加速，而是随着总初级生产力的降低而降低。模型的结果得到了作物产量历史记录的证实，表明欧洲初级生产力的这种下降在上个世纪是前所未有的。未来干旱事件的增加可能会将温带生态系统变成碳源，促进热带和高纬度地区已经预期的正碳气候反馈（1，2）。
Future climate warming is expected to enhance plant growth in temperate ecosystems and to increase carbon sequestration(1,2). But although severe regional heatwaves may become more frequent in a changing climate(3,4), their impact on terrestrial carbon cycling is unclear. Here we report measurements of ecosystem carbon dioxide fluxes, remotely sensed radiation absorbed by plants, and country- level crop yields taken during the European heatwave in 2003. We use a terrestrial biosphere simulation model(5) to assess continental- scale changes in primary productivity during 2003, and their consequences for the net carbon balance. We estimate a 30 per cent reduction in gross primary productivity over Europe, which resulted in a strong anomalous net source of carbon dioxide ( 0.5 Pg Cyr(-1)) to the atmosphere and reversed the effect of four years of net ecosystem carbon sequestration(6). Our results suggest that productivity reduction in eastern and western Europe can be explained by rainfall deficit and extreme summer heat, respectively. We also find that ecosystem respiration decreased together with gross primary productivity, rather than accelerating with the temperature rise. Model results, corroborated by historical records of crop yields, suggest that such a reduction in Europe's primary productivity is unprecedented during the last century. An increase in future drought events could turn temperate ecosystems into carbon sources, contributing to positive carbon- climate feedbacks already anticipated in the tropics and at high latitudes(1,2).