Contributors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE); Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)); Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA); Commonwealth Scientific and Industrial Research Organisation Canberra (CSIRO); Northern Arizona University Flagstaff; Laboratoire de géologie de l'ENS (LGENS); Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris; École normale supérieure - Paris (ENS-PSL); Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL); Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL); Mathématiques et Informatique Appliquées (MIA Paris-Saclay); AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE); University of Freiburg Freiburg; Wageningen University and Research Wageningen (WUR); Agroscope; Mississippi State University Mississippi; University of Florida Gainesville (UF); Chinese Academy of Sciences Beijing (CAS); University of Chinese Academy of Sciences Beijing (UCAS); Y.H., P.C., D.Z., C.Q. and D.S.G. received support from the European Research Council Synergy project SyG-2013-610028 IMBALANCE-P and Y.H., P.C., D.Z., C.Q., D.S.G., B.G. and D.M. from the ANR CLAND Convergence Institute (ANR-16-CONV-0003).; ANR-16-CONV-0003,CLAND,CLAND : Changement climatique et usage des terres(2016); European Project: 610028,EC:FP7:ERC,ERC-2013-SyG,IMBALANCE-P(2014)
نبذة مختصرة : International audience ; The climate impact of water-table drawdown in peatlands is unclear as carbon dioxide emissions increase and methane emissions decrease due to drying. This study shows decreasing water-table depth results in net greenhouse gas emissions from global peatlands, despite reducing methane emissions.Water-table drawdown across peatlands increases carbon dioxide (CO2) and reduces methane (CH4) emissions. The net climatic effect remains unclear. Based on global observations from 130 sites, we found a positive (warming) net climate effect of water-table drawdown. Using a machine-learning-based upscaling approach, we predict that peatland water-table drawdown driven by climate drying and human activities will increase CO2 emissions by 1.13 (95% interval: 0.88-1.50) Gt yr(-1) and reduce CH4 by 0.26 (0.14-0.52) GtCO(2)-eq yr(-1), resulting in a net increase of greenhouse gas of 0.86 (0.36-1.36) GtCO(2)-eq yr(-1) by the end of the twenty-first century under the RCP8.5 climate scenario. This drops to 0.73 (0.2-1.2) GtCO(2)-eq yr(-1) under RCP2.6. Our results point to an urgent need to preserve pristine and rehabilitate drained peatlands to decelerate the positive feedback among water-table drawdown, increased greenhouse gas emissions and climate warming.
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