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Effect of climate change, CO 2 trends, nitrogen addition, and land‐cover and management intensity changes on the carbon balance of European grasslands
Author(s) -
Chang Jinfeng,
Ciais Philippe,
Viovy Nicolas,
Vuichard Nicolas,
Herrero Mario,
Havlík Petr,
Wang Xuhui,
Sultan Benjamin,
Soussana JeanFrançois
Publication year - 2016
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.13050
Subject(s) - environmental science , climate change , grassland , greenhouse gas , carbon sink , biome , biogeochemical cycle , carbon cycle , carbon sequestration , ecosystem , primary production , atmospheric sciences , cycling , land use, land use change and forestry , ecology , land use , carbon dioxide , geography , forestry , biology , geology
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 25 km × 25 km grid. The modeled average trend in NBP is 1.8–2.0 g C m −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 N 2 O and CH 4 emissions by 1.2–1.5 Gt CO 2 ‐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 CO 2 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.