Effect of climate change, CO2 trends, nitrogen addition, and land-cover and management intensity changes on the carbon balance of European grasslands
Effect of climate change, CO2 trends, nitrogen addition, and land-cover and management intensity changes on the carbon balance of European grasslands
复制标题
DOI：
10.1111/gcb.13050
复制
发表时间：
2016-01-01
影响因子：
11.6
通讯作者：
Soussana, Jean-Francois
中科院分区：
文献类型：
--
作者：
Chang, Jinfeng;Ciais, Philippe;Soussana, Jean-Francois
有几条证据表明，欧洲受管理的草原生态系统是碳汇。在本研究中，我们应用基于过程的orchide - gm碳循环模型，该模型描述了牧场的具体管理实践和碳循环动态，以响应气候和生物地球化学驱动因素的变化。该模型用于在25km × 25km网格上模拟1991-2010年欧洲草原碳平衡[即净生物群系产量（NBP）]的变化。模拟的NBP在过去20年的平均趋势为1.8-2.0g Cm(-2)yr（-2）。这一趋势的归因表明，管理强度是解释模型中NBP趋势的主要驱动因素（所有驱动因素占趋势的36-43%）。由于牲畜数量减少，整个欧洲草原管理强度发生了重大变化。这一变化无意中增强了土壤碳固储，减少了1.2-1.5亿吨二氧化碳当量的N2O和CH4排放，抵消了1991-2010年期间整个欧洲农业部门7%以上的温室气体排放。土地覆盖变化、气候变化和二氧化碳上升对NBP趋势也有积极和适度的贡献（所有驱动因素对NBP趋势的贡献在24%至31%之间）。氮添加（包括施肥和大气沉降）的变化对NBP趋势只有边际净效应。然而，这可能不能反映现实，因为我们的模型只有一个非常简单的氮对光合作用的参数化。每个驱动因素的NBP趋势之和大于所有驱动因素一起变化时得到的趋势，留下一个残余-非归因-项（所有驱动因素导致的趋势的22-26%），表明驱动因素之间的负相互作用。
Several lines of evidence point to European managed grassland ecosystems being a sink of carbon. In this study, we apply ORCHIDEE-GM a process-based carbon cycle model that describes specific management practices of pastures and the dynamics of carbon cycling in response to changes in climatic and biogeochemical drivers. The model is used to simulate changes in the carbon balance [i.e., net biome production (NBP)] of European grasslands over 1991-2010 on a 25kmx25km grid. The modeled average trend in NBP is 1.8-2.0g Cm(-2)yr(-2) during the past two decades. Attribution of this trend suggests management intensity as the dominant driver explaining NBP trends in the model (36-43% of the trend due to all drivers). A major change in grassland management intensity has occurred across Europe resulting from reduced livestock numbers. This change has inadvertently' enhanced soil C sequestration and reduced N2O and CH4 emissions by 1.2-1.5 Gt CO2-equivalent, offsetting more than 7% of greenhouse gas emissions in the whole European agricultural sector during the period 1991-2010. Land-cover change, climate change and rising CO2 also make positive and moderate contributions to the NBP trend (between 24% and 31% of the trend due to all drivers). Changes in nitrogen addition (including fertilization and atmospheric deposition) are found to have only marginal net effect on NBP trends. However, this may not reflect reality because our model has only a very simple parameterization of nitrogen effects on photosynthesis. The sum of NBP trends from each driver is larger than the trend obtained when all drivers are varied together, leaving a residual - nonattributed - term (22-26% of the trend due to all drivers) indicating negative interactions between drivers.