Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA.
Nature. 2011 Jul 13;475(7355):214-6. doi: 10.1038/nature10176.
Increasing concentrations of atmospheric carbon dioxide (CO(2)) can affect biotic and abiotic conditions in soil, such as microbial activity and water content. In turn, these changes might be expected to alter the production and consumption of the important greenhouse gases nitrous oxide (N(2)O) and methane (CH(4)) (refs 2, 3). However, studies on fluxes of N(2)O and CH(4) from soil under increased atmospheric CO(2) have not been quantitatively synthesized. Here we show, using meta-analysis, that increased CO(2) (ranging from 463 to 780 parts per million by volume) stimulates both N(2)O emissions from upland soils and CH(4) emissions from rice paddies and natural wetlands. Because enhanced greenhouse-gas emissions add to the radiative forcing of terrestrial ecosystems, these emissions are expected to negate at least 16.6 per cent of the climate change mitigation potential previously predicted from an increase in the terrestrial carbon sink under increased atmospheric CO(2) concentrations. Our results therefore suggest that the capacity of land ecosystems to slow climate warming has been overestimated.
大气中二氧化碳（CO2）浓度的增加会影响土壤中的生物和非生物条件，如微生物活性和含水量。反过来，这些变化可能会改变重要温室气体一氧化二氮（N2O）和甲烷（CH4）的产生和消耗（参考文献 2、3）。然而，关于大气 CO2 增加条件下土壤中 N2O 和 CH4 通量的研究尚未进行定量综合。在这里，我们通过荟萃分析表明，增加的 CO2（体积浓度范围为 463 至 780 ppm）刺激了旱地土壤中 N2O 的排放以及稻田和自然湿地中 CH4 的排放。由于增强的温室气体排放增加了陆地生态系统的辐射强迫，这些排放预计将抵消至少 16.6%的先前根据大气 CO2 浓度增加预测的陆地碳汇减缓气候变化的潜力。因此，我们的研究结果表明，陆地生态系统减缓气候变暖的能力被高估了。
