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1. RECCAP2 Future Component: Consistency and Potential for Regional Assessment to Constrain Global Projections

Author

Chris D. Jones, Tilo Ziehn, Jatin Anand, Ana Bastos, Eleanor Burke, Josep G. Canadell, Manoel Cardoso, Yolandi Ernst, Atul K. Jain, Sujong Jeong, Elizabeth D. Keller, Masayuki Kondo, Ronny Lauerwald, Tzu‐Shun Lin, Guillermo Murray‐Tortarolo, Gert‐Jan Nabuurs, Mike O’Sullivan, Ben Poulter, Xiaoyu Qin, Celso vonRandow, Marcos Sanches, Dmitry Schepaschenko, Anatoly Shvidenko, T. Luke Smallman, Hanqin Tian, Yohanna Villalobos, Xuhui Wang, and Jeongmin Yun

Subjects
carbon cycle, Earth system, Geology, QE1-996.5, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract Projections of future carbon sinks and stocks are important because they show how the world's ecosystems will respond to elevated CO2 and changes in climate. Moreover, they are crucial to inform policy decisions around emissions reductions to stay within the global warming levels identified by the Paris Agreement. However, Earth System Models from the 6th Coupled Model Intercomparison Project (CMIP6) show substantial spread in future projections—especially of the terrestrial carbon cycle, leading to a large uncertainty in our knowledge of any remaining carbon budget (RCB). Here we evaluate the global terrestrial carbon cycle projections on a region‐by‐region basis and compare the global models with regional assessments made by the REgional Carbon Cycle Assessment and Processes, Phase 2 activity. Results show that for each region, the CMIP6 multi‐model mean is generally consistent with the regional assessment, but substantial cross‐model spread exists. Nonetheless, all models perform well in some regions and no region is without some well performing models. This gives confidence that the CMIP6 models can be used to look at future changes in carbon stocks on a regional basis with appropriate model assessment and benchmarking. We find that most regions of the world remain cumulative net sources of CO2 between now and 2100 when considering the balance of fossil‐fuels and natural sinks, even under aggressive mitigation scenarios. This paper identifies strengths and weaknesses for each model in terms of its performance over a particular region including how process representation might impact those results and sets the agenda for applying stricter constraints at regional scales to reduce the uncertainty in global projections.

Published
2023
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2. Land-use emissions play a critical role in land-based mitigation for Paris climate targets

Author

Anna B. Harper, Tom Powell, Peter M. Cox, Joanna House, Chris Huntingford, Timothy M. Lenton, Stephen Sitch, Eleanor Burke, Sarah E. Chadburn, William J. Collins, Edward Comyn-Platt, Vassilis Daioglou, Jonathan C. Doelman, Garry Hayman, Eddy Robertson, Detlef van Vuuren, Andy Wiltshire, Christopher P. Webber, Ana Bastos, Lena Boysen, Philippe Ciais, Narayanappa Devaraju, Atul K. Jain, Andreas Krause, Ben Poulter, and Shijie Shu

Subjects
Science
Abstract

Land-based mitigation for meeting the Paris climate target must consider the carbon cycle impacts of land-use change. Here the authors show that when bioenergy crops replace high carbon content ecosystems, forest-based mitigation could be more effective for CO2 removal than bioenergy crops with carbon capture and storage.

Published
2018
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3. Contribution of environmental forcings to US runoff changes for the period 1950–2010

Author

Whitney L Forbes, Jiafu Mao, Mingzhou Jin, Shih-Chieh Kao, Wenting Fu, Xiaoying Shi, Daniel M Riccuito, Peter E Thornton, Aurélien Ribes, Yutao Wang, Shilong Piao, Tianbao Zhao, Christopher R Schwalm, Forrest M Hoffman, Joshua B Fisher, Akihiko Ito, Ben Poulter, Yuanyuan Fang, Hanqin Tian, Atul K Jain, and Daniel J Hayes

Subjects
US runoff, detection and attribution, MsTMIP, Environmental technology. Sanitary engineering, TD1-1066, Environmental sciences, GE1-350, Science, Physics, QC1-999
Abstract

Runoff in the United States is changing, and this study finds that the measured change is dependent on the geographic region and varies seasonally. Specifically, observed annual total runoff had an insignificant increasing trend in the US between 1950 and 2010, but this insignificance was due to regional heterogeneity with both significant and insignificant increases in the eastern, northern, and southern US, and a greater significant decrease in the western US. Trends for seasonal mean runoff also differed across regions. By region, the season with the largest observed trend was autumn for the east (positive), spring for the north (positive), winter for the south (positive), winter for the west (negative), and autumn for the US as a whole (positive). Based on the detection and attribution analysis using gridded WaterWatch runoff observations along with semi-factorial land surface model simulations from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we found that while the roles of CO _2 concentration, nitrogen deposition, and land use and land cover were inconsistent regionally and seasonally, the effect of climatic variations was detected for all regions and seasons, and the change in runoff could be attributed to climate change in summer and autumn in the south and in autumn in the west. We also found that the climate-only and historical transient simulations consistently underestimated the runoff trends, possibly due to precipitation bias in the MsTMIP driver or within the models themselves.

Published
2018
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4. The terrestrial carbon budget of South and Southeast Asia

Author

Matthew Cervarich, Shijie Shu, Atul K Jain, Almut Arneth, Josep Canadell, Pierre Friedlingstein, Richard A Houghton, Etsushi Kato, Charles Koven, Prabir Patra, Ben Poulter, Stephen Sitch, Beni Stocker, Nicolas Viovy, Andy Wiltshire, and Ning Zeng

Subjects
terrestrial carbon, land surface model, carbon budget, Environmental technology. Sanitary engineering, TD1-1066, Environmental sciences, GE1-350, Science, Physics, QC1-999
Abstract

Accomplishing the objective of the current climate policies will require establishing carbon budget and flux estimates in each region and county of the globe by comparing and reconciling multiple estimates including the observations and the results of top-down atmospheric carbon dioxide (CO _2 ) inversions and bottom-up dynamic global vegetation models. With this in view, this study synthesizes the carbon source/sink due to net ecosystem productivity (NEP), land cover land use change ( E _LUC ), fires and fossil burning ( E _FIRE ) for the South Asia (SA), Southeast Asia (SEA) and South and Southeast Asia (SSEA = SA + SEA) and each country in these regions using the multiple top-down and bottom-up modeling results. The terrestrial net biome productivity (NBP = NEP – E _LUC – E _FIRE ) calculated based on bottom-up models in combination with E _FIRE based on GFED4s data show net carbon sinks of 217 ± 147, 10 ± 55, and 227 ± 279 TgC yr ^−1 for SA, SEA, and SSEA. The top-down models estimated NBP net carbon sinks were 20 ± 170, 4 ± 90 and 24 ± 180 TgC yr ^−1 . In comparison, regional emissions from the combustion of fossil fuels were 495, 275, and 770 TgC yr ^−1 , which are many times higher than the NBP sink estimates, suggesting that the contribution of the fossil fuel emissions to the carbon budget of SSEA results in a significant net carbon source during the 2000s. When considering both NBP and fossil fuel emissions for the individual countries within the regions, Bhutan and Laos were net carbon sinks and rest of the countries were net carbon source during the 2000s. The relative contributions of each of the fluxes (NBP, NEP, E _LUC , and E _FIRE , fossil fuel emissions) to a nation’s net carbon flux varied greatly from country to country, suggesting a heterogeneous dominant carbon fluxes on the country-level throughout SSEA.

Published
2016
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6. The Global Methane Budget 2000–2017

Author

Marielle Saunois, Ann R. Stavert, Ben Poulter, Philippe Bousquet, Josep G. Canadell, Robert B. Jackson, Peter A. Raymond, Edward J. Dlugokencky, Sander Houweling, Prabir K. Patra, Philippe Ciais, Vivek K. Arora, David Bastviken, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Lori Bruhwiler, Kimberly M. Carlson, Mark Carroll, Simona Castaldi, Naveen Chandra, Cyril Crevoisier, Patrick M. Crill, Kristofer Covey, Charles L. Curry, Giuseppe Etiope, Christian Frankenberg, Nicola Gedney, Michaela I. Hegglin, Lena Höglund-Isaksson, Gustaf Hugelius, Misa Ishizawa, Akihiko Ito, Greet Janssens-Maenhout, Katherine M. Jensen, Fortunat Joos, Thomas Kleinen, Paul B. Krummel, Ray L. Langenfelds, Goulven G. Laruelle, Licheng Liu, Toshinobu Machida, Shamil Maksyutov, Kyle C. McDonald, Joe McNorton, Paul A. Miller, Joe R. Melton, Isamu Morino, Jurek Müller, Fabiola Murguia-Flores, Vaishali Naik, Yosuke Niwa, Sergio Noce, Simon O’Doherty, Robert J. Parker, Changhui Peng, Shushi Peng, Glen P. Peters, Catherine Prigent, Ronald Prinn, Michel Ramonet, Pierre Regnier, William J. Riley, Judith A. Rosentreter, Arjo Segers, Isobel J. Simpson, Hao Shi, Steven J. Smith, L. Paul Steele, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Francesco N. Tubiello, Aki Tsuruta, Nicolas Viovy, Apostolos Voulgarakis, Thomas S. Weber, Michiel van Weele, Guido R. van der Werf, Ray F. Weiss, Doug Worthy, Debra Wunch, Yi Yin, Yukio Yoshida, Wenxin Zhang, Zhen Zhang, Yuanhong Zhao, Bo Zheng, Qing Zhu, Qiuan Zhu, and Qianlai Zhuang

Subjects
Earth Resources And Remote Sensing
Abstract

Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions and concentrations of CH4 continue to increase, making CH4 the second most important human-influenced greenhouse gas in terms of climate forcing, after carbon dioxide (CO2). The relative importance of CH4 compared to CO2 depends on its shorter atmospheric lifetime, stronger warming potential, and variations in atmospheric growth rate over the past decade, the causes of which are still debated. Two major challenges in reducing uncertainties in the atmospheric growth rate arise from the variety of geographically overlapping CH4 sources and from the destruction of CH4 by short-lived hydroxyl radicals (OH). To address these challenges, we have established a consortium of multidisciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate new research aimed at improving and regularly updating the global methane budget. Following Saunois et al. (2016), we present here the second version of the living review paper dedicated to the decadal methane budget, integrating results of top-down studies (atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up estimates (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven extrapolations). For the 2008–2017 decade, global methane emissions are estimated by atmospheric inversions (a top-down approach) to be 576 Tg CH4/yr (range 550–594, corresponding to the minimum and maximum estimates of the model ensemble). Of this total, 359 Tg CH4/yr or ∼ 60 % is attributed to anthropogenic sources, that is emissions caused by direct human activity (i.e. anthropogenic emissions; range 336–376 Tg CH4/yr or 50 %–65 %). The mean annual total emission for the new decade (2008–2017) is 29 Tg CH4/yr larger than our estimate for the previous decade (2000–2009), and 24 Tg CH4/yr larger than the one reported in the previous budget for 2003–2012 (Saunois et al., 2016). Since 2012, global CH4 emissions have been tracking the warmest scenarios assessed by the Intergovernmental Panel on Climate Change. Bottom-up methods suggest almost 30 % larger global emissions (737 Tg CH4/yr, range 594–881) than top-down inversion methods. Indeed, bottom-up estimates for natural sources such as natural wetlands, other inland water systems, and geological sources are higher than top-down estimates. The atmospheric constraints on the top-down budget suggest that at least some of these bottom-up emissions are overestimated. The latitudinal distribution of atmospheric observation-based emissions indicates a predominance of tropical emissions (∼ 65 % of the global budget, < 30° N) compared to mid-latitudes (∼ 30 %, 30–60° N) and high northern latitudes (∼ 4 %, 60–90° N). The most important source of uncertainty in the methane budget is attributable to natural emissions, especially those from wetlands and other inland waters. Some of our global source estimates are smaller than those in previously published budgets (Saunois et al., 2016; Kirschke et al., 2013). In particular wetland emissions are about 35 Tg CH4/yr lower due to improved partition wetlands and other inland waters. Emissions from geological sources and wild animals are also found to be smaller by 7 Tg CH4/yr by 8 Tg CH4/yr, respectively. However, the overall discrepancy between bottom-up and top-down estimates has been reduced by only 5 % compared to Saunois et al. (2016), due to a higher estimate of emissions from inland waters, highlighting the need for more detailed research on emissions factors. Priorities for improving the methane budget include (i) a global, high-resolution map of water-saturated soils and inundated areas emitting methane based on a robust classification of different types of emitting habitats; (ii) further development of process-based models for inland-water emissions; (iii) intensification of methane observations at local scales (e.g., FLUXNET-CH4 measurements) and urban-scale monitoring to constrain bottom-up land surface models, and at regional scales (surface networks and satellites) to constrain atmospheric inversions; (iv) improvements of transport models and the representation of photochemical sinks in top-down inversions; and (v) development of a 3D variational inversion system using isotopic and/or co-emitted species such as ethane to improve source partitioning.

Published
2020
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8. Carbon uptake in Eurasian boreal forests dominates the high‐latitude net ecosystem carbon budget

Author

Jennifer D. Watts, Mary Farina, John S. Kimball, Luke D. Schiferl, Zhihua Liu, Kyle A. Arndt, Donatella Zona, Ashley Ballantyne, Eugénie S. Euskirchen, Frans‐Jan W. Parmentier, Manuel Helbig, Oliver Sonnentag, Torbern Tagesson, Janne Rinne, Hiroki Ikawa, Masahito Ueyama, Hideki Kobayashi, Torsten Sachs, Daniel F. Nadeau, John Kochendorfer, Marcin Jackowicz‐Korczynski, Anna Virkkala, Mika Aurela, Roisin Commane, Brendan Byrne, Leah Birch, Matthew S. Johnson, Nima Madani, Brendan Rogers, Jinyang Du, Arthur Endsley, Kathleen Savage, Ben Poulter, Zhen Zhang, Lori M. Bruhwiler, Charles E. Miller, Scott Goetz, and Walter C. Oechel

Subjects
CO, Global and Planetary Change, carbon budget, remote sensing, Arctic-boreal, tundra, Ecology, Environmental Chemistry, CH, wetland, General Environmental Science
Abstract

Arctic-boreal landscapes are experiencing profound warming, along with changes in ecosystem moisture status and disturbance from fire. This region is of global importance in terms of carbon feedbacks to climate, yet the sign (sink or source) and magnitude of the Arctic-boreal carbon budget within recent years remains highly uncertain. Here, we provide new estimates of recent (2003–2015) vegetation gross primary productivity (GPP), ecosystem respiration (Reco), net ecosystem CO2 exchange (NEE; Reco − GPP), and terrestrial methane (CH4) emissions for the Arctic-boreal zone using a satellite data-driven process-model for northern ecosystems (TCFM-Arctic), calibrated and evaluated using measurements from >60 tower eddy covariance (EC) sites. We used TCFM-Arctic to obtain daily 1-km2 flux estimates and annual carbon budgets for the pan-Arctic-boreal region. Across the domain, the model indicated an overall average NEE sink of −850 Tg CO2-C year−1. Eurasian boreal zones, especially those in Siberia, contributed to a majority of the net sink. In contrast, the tundra biome was relatively carbon neutral (ranging from small sink to source). Regional CH4 emissions from tundra and boreal wetlands (not accounting for aquatic CH4) were estimated at 35 Tg CH4-C year−1. Accounting for additional emissions from open water aquatic bodies and from fire, using available estimates from the literature, reduced the total regional NEE sink by 21% and shifted many far northern tundra landscapes, and some boreal forests, to a net carbon source. This assessment, based on in situ observations and models, improves our understanding of the high-latitude carbon status and also indicates a continued need for integrated site-to-regional assessments to monitor the vulnerability of these ecosystems to climate change.

Published
2023

9. Effect of tree demography and flexible root water uptake for modeling the carbon and water cycles of Amazonia

Author

Emilie Joetzjer, Fabienne Maignan, Jérôme Chave, Daniel Goll, Ben Poulter, Jonathan Barichivich, Isabelle Maréchaux, Sebastiaan Luyssaert, Matthieu Guimberteau, Kim Naudts, Damien Bonal, Philippe Ciais, Systems Ecology, Earth and Climate, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Evolution et Diversité Biologique (EDB), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), SILVA (SILVA), AgroParisTech-Université de Lorraine (UL)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), Universidad Austral de Chile, Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), Vrije Universiteit Amsterdam [Amsterdam] (VU), Milieux Environnementaux, Transferts et Interactions dans les hydrosystèmes et les Sols (METIS), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, ANR-10-LABX-0025,CEBA,CEnter of the study of Biodiversity in Amazonia(2010), and European Project: 610028,EC:FP7:ERC,ERC-2013-SyG,IMBALANCE-P(2014)

Subjects
[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Root water uptake, Tropical forest, Ecological Modeling, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, Land surface model, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, Biogeochemical cycles, Demography
Abstract

International audience; Amazonian forest plays a crucial role in regulating the carbon and water cycles in the global climate system. However, the representation of biogeochemical fluxes and forest structure in dynamic global vegetation models (DGVMs) remains challenging. This situation has considerable implications to simulate the state and dynamics of Amazonian forest. This study aims at simulating the dynamic of the evapotranspiration (ET), productivity (GPP), biomass (AGB) and forest structure of wet tropical forests in the Amazon basin using the updated ORCHIDEE land surface model. The latter is improved for two processes: stand structure and demography, and plant water uptake by roots. Stand structure is simulated by adapting the CAN version of ORCHIDEE, originally developed for temperate forests. Here, we account for the permanent recruitment of young individual trees, the distribution of stand level growth into 20 different cohorts of variable diameter classes, and mortality due to asymmetric competition for light. Plant water uptake is simulated by including soil-to-root hydraulic resistance (RS). To evaluate the effect of the soil resistance alone, we performed factorial simulations with demography only (CAN) and both demography and resistance (CAN-RS). AGB, ET and GPP outputs of CAN-RS are also compared with the standard version of ORCHIDEE (TRUNK) for which eco-hydrological parameters were tuned globally to fit GPP and evapotranspiration at flux tower sites. All the model versions are benchmarked against in situ and regional datasets. We show that CAN-RS correctly reproduce stand level structural variables (as CAN) like diameter classes and tree densities when validated using in-situ data. Besides offering the key advantage to simulate forest's structure, it also correctly simulates ET and GPP and improves fluxes spatial patterns when compared to TRUNK. With the new formulation of soil water uptake, which is driven by soil water availability rather than root-biomass, the simulated trees preferentially use water in the deepest soil layers during the dry seasons. This improves the seasonality of ET and GPP compared to CAN, especially on clay soils for which the soil moisture potential drops rapidly in the dry season. Nevertheless, since demography parameters in CAN-RS are constant for all evergreen tropical forests, spatial variability of AGB and basal area across the Amazon remains too uniform compared to observations, and are very comparable to the TRUNK. Additional processes such as climate driven mortality and phosphorus limitation on growth leading to the prevalence of species with different functional traits across the Amazon need to be included in the future development of this model.

Published
2022

10. Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales

Author

Zutao Ouyang, Kyle B. Delwiche, Torsten Sachs, Matthias Peichl, Eric J. Ward, Ayaka Sakabe, Cove Sturtevant, Pia Gottschalk, Ivan Mammarella, Ben Poulter, Hiroki Iwata, Youngryel Ryu, Sheel Bansal, Higo J. Dalmagro, Etienne Fluet-Chouinard, Rodrigo Vargas, Sara H. Knox, Timo Vesala, Benjamin R. K. Runkle, Robert B. Jackson, Ankur R. Desai, Masahito Ueyama, Avni Malhotra, Karina V. R. Schäfer, Minseok Kang, Takashi Hirano, Lulie Melling, Jed P. Sparks, William J. Riley, Gavin McNicol, Housen Chu, George L. Vourlitis, Zhen Zhang, Qing Zhu, Jordan P. Goodrich, M. Goeckede, Gil Bohrer, David I. Campbell, Annalea Lohila, Keisuke Ono, Gerald Jurasinski, Jessica Turner, Alex C. Valach, Mika Aurela, Guan Xhuan Wong, Lisamarie Windham-Myers, Olli Peltola, Oliver Sonnentag, Pavel Alekseychik, Eeva-Stiina Tuittila, Dennis D. Baldocchi, Tuula Alto, Franziska Koebsch, Joe R. Melton, Jinxun Liu, Jiquan Chen, Eugénie S. Euskirchen, Mats Nilsson, Sarah Feron, Institute for Atmospheric and Earth System Research (INAR), Viikki Plant Science Centre (ViPS), Micrometeorology and biogeochemical cycles, and Ecosystem processes (INAR Forest Sciences)

Subjects
0106 biological sciences, synthesis, 010504 meteorology & atmospheric sciences, Vapour Pressure Deficit, Fresh Water, Wetland, Atmospheric sciences, 01 natural sciences, CARBON-DIOXIDE, mutual information, TEMPERATURE, EMISSIONS, General Environmental Science, Global and Planetary Change, geography.geographical_feature_category, Ecology, methane, time scales, GAS FLUXES, Vegetation, Biological Sciences, lags, 1181 Ecology, evolutionary biology, ECOSYSTEM METHANE, Seasons, Biogeochemical cycle, TABLE POSITION, Eddy covariance, 010603 evolutionary biology, wetlands, PERMAFROST, generalized additive modeling, Latent heat, eddy covariance, medicine, Environmental Chemistry, Ecosystem, 0105 earth and related environmental sciences, geography, CH4, Carbon Dioxide, 15. Life on land, Seasonality, medicine.disease, EDDY-COVARIANCE, predictors, 13. Climate action, MULTISCALE TEMPORAL VARIATION, Environmental science, Environmental Sciences, random forest
Abstract

While wetlands are the largest natural source of methane (CH4 ) to the atmosphere, they represent a large source of uncertainty in the global CH4 budget due to the complex biogeochemical controls on CH4 dynamics. Here we present, to our knowledge, the first multi-site synthesis of how predictors of CH4 fluxes (FCH4) in freshwater wetlands vary across wetland types at diel, multiday (synoptic), and seasonal time scales. We used several statistical approaches (correlation analysis, generalized additive modeling, mutual information, and random forests) in a wavelet-based multi-resolution framework to assess the importance of environmental predictors, nonlinearities and lags on FCH4 across 23 eddy covariance sites. Seasonally, soil and air temperature were dominant predictors of FCH4 at sites with smaller seasonal variation in water table depth (WTD). In contrast, WTD was the dominant predictor for wetlands with smaller variations in temperature (e.g., seasonal tropical/subtropical wetlands). Changes in seasonal FCH4 lagged fluctuations in WTD by ~17±11days, and lagged air and soil temperature by median values of 8±16 and 5±15days, respectively. Temperature and WTD were also dominant predictors at the multiday scale. Atmospheric pressure (PA) was another important multiday scale predictor for peat-dominated sites, with drops in PA coinciding with synchronous releases of CH4 . At the diel scale, synchronous relationships with latent heat flux and vapor pressure deficit suggest that physical processes controlling evaporation and boundary layer mixing exert similar controls on CH4 volatilization, and suggest the influence of pressurized ventilation in aerenchymatous vegetation. In addition, 1- to 4-h lagged relationships with ecosystem photosynthesis indicate recent carbon substrates, such as root exudates, may also control FCH4. By addressing issues of scale, asynchrony, and nonlinearity, this work improves understanding of the predictors and timing of wetland FCH4 that can inform future studies and models, and help constrain wetland CH4 emissions.

Published
2021

12. Author Correction: Large loss of CO2 in winter observed across the northern permafrost region

Author

Susan M. Natali, Jennifer D. Watts, Brendan M. Rogers, Stefano Potter, Sarah M. Ludwig, Anne-Katrin Selbmann, Patrick F. Sullivan, Benjamin W. Abbott, Kyle A. Arndt, Leah Birch, Mats P. Björkman, A. Anthony Bloom, Gerardo Celis, Torben R. Christensen, Casper T. Christiansen, Roisin Commane, Elisabeth J. Cooper, Patrick Crill, Claudia Czimczik, Sergey Davydov, Jinyang Du, Jocelyn E. Egan, Bo Elberling, Eugenie S. Euskirchen, Thomas Friborg, Hélène Genet, Mathias Göckede, Jordan P. Goodrich, Paul Grogan, Manuel Helbig, Elchin E. Jafarov, Julie D. Jastrow, Aram A. M. Kalhori, Yongwon Kim, John S. Kimball, Lars Kutzbach, Mark J. Lara, Klaus S. Larsen, Bang-Yong Lee, Zhihua Liu, Michael M. Loranty, Magnus Lund, Massimo Lupascu, Nima Madani, Avni Malhotra, Roser Matamala, Jack McFarland, A. David McGuire, Anders Michelsen, Christina Minions, Walter C. Oechel, David Olefeldt, Frans-Jan W. Parmentier, Norbert Pirk, Ben Poulter, William Quinton, Fereidoun Rezanezhad, David Risk, Torsten Sachs, Kevin Schaefer, Niels M. Schmidt, Edward A. G. Schuur, Philipp R. Semenchuk, Gaius Shaver, Oliver Sonnentag, Gregory Starr, Claire C. Treat, Mark P. Waldrop, Yihui Wang, Jeffrey Welker, Christian Wille, Xiaofeng Xu, Zhen Zhang, Qianlai Zhuang, and Donatella Zona

Published
2019
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13. Response of global land evapotranspiration to climate change, elevated CO2, and land use change

Author

Pierre Friedlingstein, Dongdong Kong, Danica Lombardozzi, Ben Poulter, Atul K. Jain, Jianfeng Li, Yuanyuan You, Hanqin Tian, Julia E. M. S. Nabel, Xingyu Feng, Xihui Gu, Jianyu Liu, Almut Arneth, Ming Luo, Stephen Sitch, University of South Alabama, University of Exeter, Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, National Center for Atmospheric Research [Boulder] (NCAR), Institut für Meteorologie und Klimaforschung - Atmosphärische Umweltforschung (IMK-IFU), Karlsruher Institut für Technologie (KIT), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-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), Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
Atmospheric Science, Global and Planetary Change, 010504 meteorology & atmospheric sciences, 0207 environmental engineering, Tropics, Climate change, Forestry, 02 engineering and technology, Global ecosystem, 15. Life on land, 01 natural sciences, 13. Climate action, Climatology, Evapotranspiration, General Circulation Model, [SDE]Environmental Sciences, Temperate climate, Environmental science, Land use, land-use change and forestry, Precipitation, 020701 environmental engineering, Agronomy and Crop Science, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Climate change (CLI), elevated CO2 concentration (CO2), and land use change (LUC) have strongly altered land evapotranspiration (ET) during the recent decades. The fingerprints of these drivers in ET change, however, have not previously been detected due to the lack of these three scenarios from global climate models (GCMs). Here we applied an optimal fingerprint method to detect and attribute ET change by integrated utilization of state-of-the-art global ecosystem models and GCMs. Results indicate that CLI provides the greatest contribution to increasing ET, and its fingerprint is detectable at different timescales. CO2 reduces ET in most areas covered by forests. LUC decreases ET over the tropics, while increases ET over temperate and high-latitude regions. To further subdivide the impacts of CLI, we extend the Budyko framework to quantify the contribution of precipitation (P) and potential evapotranspiration (PET) and find that the dominant role of CLI mainly depends on the contribution of P.

Published
2021

14. Reconciling carbon‐cycle processes from ecosystem to global scales

Author

Zhihua Liu, Kathy Kelsey, Joseph Vanderwall, Ben Poulter, Jennifer D. Watts, Jason C. Neff, William R. L. Anderegg, Ashley P. Ballantyne, Zicheng Yu, Paul C. Stoy, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, Ecology, business.industry, Environmental resource management, 010603 evolutionary biology, 01 natural sciences, Carbon cycle, Environmental science, Ecosystem, business, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Understanding carbon (C) dynamics from ecosystem to global scales remains a challenge. Although expansion of global carbon dioxide (CO

Published
2021

15. Uncertainty Quantification of Global Net Methane Emissions From Terrestrial Ecosystems Using a Mechanistically Based Biogeochemistry Model

Author

Narasinha J. Shurpali, Seung-Bum Kim, Licheng Liu, Qianlai Zhuang, Ben Poulter, and Youmi Oh

Subjects
Methane emissions, Atmospheric Science, Ecology, Paleontology, Soil Science, Biogeochemistry, Forestry, Aquatic Science, Atmospheric sciences, Environmental science, Terrestrial ecosystem, Uncertainty quantification, Global modeling, Uncertainty analysis, Water Science and Technology
Published
2020

16. Forest responses to last-millennium hydroclimate variability are governed by spatial variations in ecosystem sensitivity

Author

Ann Raiho, Christine R. Rollinson, Thomas Hickler, David J. P. Moore, Stephen T. Jackson, Mathias Trachsel, Andria Dawson, Jason S. McLachlan, John W. Williams, Michael Dietze, Ben Poulter, Jörg Steinkamp, and Tristan Quaife

Subjects
0106 biological sciences, Biomass (ecology), Ecology, 010604 marine biology & hydrobiology, Climate Change, Biodiversity, Climate change, Forest change, Forests, 010603 evolutionary biology, 01 natural sciences, Droughts, Trees, Ecosystem model, Climatology, Spatial ecology, Environmental science, Ecosystem, Sensitivity (control systems), Ecology, Evolution, Behavior and Systematics
Abstract

Forecasts of forest responses to climate variability are governed by climate exposure and ecosystem sensitivity, but ecosystem model projections and process representations are under-constrained by data at multidecadal and longer timescales. Here, we assess ecosystem sensitivity to centennial-scale hydroclimate variability, by comparing dendroclimatic and pollen-inferred reconstructions of drought, forest composition and biomass for the last millennium with five ecosystem model simulations. In both observations and models, spatial patterns in ecosystem responses to hydroclimate variability are strongly governed by ecosystem sensitivity rather than climate exposure. Ecosystem sensitivity was highest in simpler models and higher than observations, suggesting that interactions among biodiversity, demography, and ecophysiology processes dampen the sensitivity of forest composition and biomass to climate variability and change. By integrating ecosystem models with observations from timescales extending beyond the instrumental record, we can better understand and forecast the mechanisms regulating forest sensitivity to climate variability in a complex and changing world.

Published
2020

17. Forest structure and vegetation dynamics as a driver of global carbon uptake

Author

Nuno Carvalhais, Philippe Ciais, Leo Calle, Paul Montensano, Ben Poulter, Christopher S.R. Neigh, Nate G. McDowell, Simon Besnard, and Thomas J. Pugh

Subjects
Carbon uptake, Environmental science, Forest structure, Atmospheric sciences, Vegetation dynamics
Abstract

The drivers for terrestrial carbon uptake remain unclear despite a clear signal that the land removes the equivalent of up to 25-30% of fossil fuel CO2 emissions each year. Recent work has confirmed sustained carbon uptake by the land that is proportional to anthropogenic emissions, meaning that the land 'sink' has strengthened over the past five decades, and with interannual variability driven by climate. Drivers responsible for sustained uptake include hypotheses related to lengthening growing season length, increasing nitrogen deposition, changes in the ratio of diffuse to direct radiation, and land-use and land cover change. More recently, land-use and land-cover change has been investigated as a driver of land carbon uptake owing to an emergence of global-scale datasets related to canopy disturbance, land use, and forest age. At the same time, land-surface models have increased their realism in terms of moving beyond 'big-leaf' model representation of ecosystems to including vertical structure and horizontal heteorogeneity via size-and-age structured approaches. This presentation will address recent work identified forest structure and vegetation dynamics as a driver for global carbon uptake and provide examples of how remote sensing observations have led to new datasets for initialization land-surface models. Compared to inventory-based approaches, land-surface models initialized with forest age show a lessor role in explaining net terrestrial carbon uptake at global scales, but at regional scales, vegetation structure is a key determinant of carbon exchange. New satellite missions improving forest structure observations are expected to reduce uncertainties and contribute substantially to ongoing land-surface model development.

Published
2020

18. Climate–fire interactions constrain potential woody plant cover and stature in North American Great Plains grasslands

Author

R. Scholtz, S. D. Fuhlendorf, S. R. Archer, and Ben Poulter

Subjects
0106 biological sciences, Global and Planetary Change, Geography, Disturbance (geology), 010504 meteorology & atmospheric sciences, Ecology, Cover (algebra), 010603 evolutionary biology, 01 natural sciences, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Woody plant
Published
2018

19. Fire in sub‐Saharan Africa: The fuel, cure and connectivity hypothesis

Author

M. Njoki Kahiu, N. P. Hanan, and Ben Poulter

Subjects
0106 biological sciences, Global and Planetary Change, Sub saharan, 010504 meteorology & atmospheric sciences, Ecology, Agroforestry, Environmental science, 010603 evolutionary biology, 01 natural sciences, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences
Published
2018

20. Spatially Resolved Isotopic Source Signatures of Wetland Methane Emissions

Author

Garry Hayman, Edward Comyn-Platt, Ben Poulter, Edward R. C. Hornibrook, Anita L. Ganesan, Angharad C Stell, Nicola Gedney, and Matthew Rigby

Subjects
GREENHOUSE GAS, 010504 meteorology & atmospheric sciences, Wetland, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Ecology and Environment, Methane, Atmospheric Sciences, chemistry.chemical_compound, METHANE, Isotopes, Ecosystem, 0105 earth and related environmental sciences, WETLANDS, geography, geography.geographical_feature_category, δ13C, Spatially resolved, Geophysics, chemistry, Greenhouse gas, General Earth and Planetary Sciences, Environmental science, Wetland methane emissions, Seasonal cycle
Abstract

We present the first spatially‐resolved wetland δ13C(CH4) source signature map based on data characterizing wetland ecosystems and demonstrate good agreement with wetland signatures derived from atmospheric observations. The source signature map resolves a latitudinal difference of ~10‰ between northern high‐latitude (mean ‐67.8‰) and tropical (mean ‐56.7‰) wetlands, and shows significant regional variations on top of the latitudinal gradient. We assess the errors in inverse modeling studies aiming to separate CH4 sources and sinks by comparing atmospheric δ13C(CH4) derived using our spatially‐resolved map against the common assumption of globally uniform wetland δ13C(CH4) signature. We find a larger interhemispheric gradient, a larger high‐latitude seasonal cycle and smaller trend over the period 2000‐2012. The implication is that erroneous CH4 fluxes would be derived to compensate for the biases imposed by not utilizing spatially‐resolved signatures for the largest source of CH4 emissions. These biases are significant when compared to the size of observed signals.Plain Language SummaryConcentrations of methane are increasing in the atmosphere. In order to understand the reasons behind such variations, carbon isotopes are used to help identify changes in emission sources and sinks. We present a new global map of the carbon isotope signature associated with wetland methane emissions, the largest global source of methane to the atmosphere. We show how this newly synthesized information can lead to more accurate understanding of the causes of variations in the amount and rate of increase of methane in the atmosphere.

Published
2018

21. Large loss of CO2 in winter observed across the northern permafrost region

Author

Gerardo Celis, Jack W. McFarland, David Olefeldt, Mathias Göckede, Jennifer D. Watts, Christian Wille, Torben R. Christensen, Gregory Starr, Casper T. Christiansen, S. Potter, Kevin Schaefer, Jordan P. Goodrich, N. Pirk, Benjamin W. Abbott, Patrick M. Crill, Elisabeth J. Cooper, Edward A. G. Schuur, Qianlai Zhuang, Zhihua Liu, Bang Yong Lee, Massimo Lupascu, Xiaofeng Xu, Kyle A. Arndt, Torsten Sachs, Walter C. Oechel, Donatella Zona, S. Ludwig, Jinyang Du, Brendan M. Rogers, Michael M. Loranty, Mark J. Lara, Yongwon Kim, Oliver Sonnentag, Zhen Zhang, Susan M. Natali, David Risk, Gaius R. Shaver, Aram Kalhori, A. David McGuire, Bo Elberling, Mats P. Björkman, Leah Birch, Roser Matamala, Philipp R. Semenchuk, Klaus Steenberg Larsen, Manuel Helbig, M. P. Waldrop, Frans-Jan W. Parmentier, Thomas Friborg, Yihui Wang, Julie D. Jastrow, Anders Michelsen, Hélène Genet, Roisin Commane, Fereidoun Rezanezhad, Claudia I. Czimczik, Elchin Jafarov, Lars Kutzbach, A. Anthony Bloom, Christina Minions, Jeffrey M. Welker, Claire C. Treat, Eugénie S. Euskirchen, Patrick F. Sullivan, Nima Madani, Magnus Lund, Jocelyn Egan, William L. Quinton, Paul Grogan, Niels Martin Schmidt, Avni Malhotra, Ben Poulter, S. P. Davydov, A. K. Selbmann, and John S. Kimball

Subjects
010504 meteorology & atmospheric sciences, Environmental Science and Management, Growing season, Environmental Science (miscellaneous), Atmospheric sciences, Permafrost, 01 natural sciences, Physical Geography and Environmental Geoscience, Atmospheric Sciences, 03 medical and health sciences, chemistry.chemical_compound, VDP::Mathematics and natural science: 400::Zoology and botany: 480, Ecosystem, 030304 developmental biology, 0105 earth and related environmental sciences, 0303 health sciences, Soil organic matter, 15. Life on land, Climate Action, chemistry, Arctic, Boreal, 13. Climate action, Carbon dioxide, Soil water, Environmental science, Social Sciences (miscellaneous), VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480
Abstract

Recent warming in the Arctic, which has been amplified during the winter1–3, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)4. However, the amount of CO2 released in winter is not known and has not been well represented by ecosystem models or empirically based estimates5,6. Here we synthesize regional in situ observations of CO2 flux from Arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1,662 TgC per year from the permafrost region during the winter season (October–April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (−1,032 TgC per year). Extending model predictions to warmer conditions up to 2100 indicates that winter CO2 emissions will increase 17% under a moderate mitigation scenario—Representative Concentration Pathway 4.5—and 41% under business-as-usual emissions scenario—Representative Concentration Pathway 8.5. Our results provide a baseline for winter CO2 emissions from northern terrestrial regions and indicate that enhanced soil CO2 loss due to winter warming may offset growing season carbon uptake under future climatic conditions. Winter warming in the Arctic will increase the CO2 flux from soils. A pan-Arctic analysis shows a current loss of 1,662 TgC per year over the winter, exceeding estimated carbon uptake in the growing season; projections suggest a 17% increase under RCP 4.5 and a 41% increase under RCP 8.5 by 2100.

Published
2019

22. Comment on 'The global tree restoration potential'

Author

Simon L. Lewis, Edward T. A. Mitchard, Colin Prentice, Mark Maslin, and Ben Poulter

Subjects
0106 biological sciences, Multidisciplinary, 010504 meteorology & atmospheric sciences, 13. Climate action, General Science & Technology, Climate Change, 15. Life on land, Forests, 010603 evolutionary biology, 01 natural sciences, Carbon, 0105 earth and related environmental sciences, Trees
Abstract

Bastin et al . (Reports, 5 July 2019, p. 76) state that the restoration potential of new forests globally is 205 gigatonnes of carbon, conclude that “global tree restoration is our most effective climate change solution to date,” and state that climate change will drive the loss of 450 million hectares of existing tropical forest by 2050. Here we show that these three statements are incorrect.

Published
2019

23. The importance of tree demography and root water uptake for modelling the carbon and water cycles of Amazonia

Author

Sebastiaan Luyssaert, Fabienne Maignan, Jérôme Chave, Ben Poulter, Jonathan Barichivich, Philippe Ciais, Isabelle Maréchaux, Emilie Joetzjer, Kim Naudts, Daniel S. Goll, Matthieu Guimberteau, Damien Bonal, Montana State University (MSU), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Evolution et Diversité Biologique (EDB), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, NASA Goddard Space Flight Center (GSFC), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD [France-Sud]), SILVA (SILVA), Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL)-AgroParisTech, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université de Lorraine (UL), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Canopy, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Vegetation, 15. Life on land, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 010603 evolutionary biology, 01 natural sciences, Carbon cycle, Carbon Cycle, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Amazonian forest, 13. Climate action, Evapotranspiration, Soil horizon, Environmental science, Spatial variability, Water cycle, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 0105 earth and related environmental sciences, Demography
Abstract

Amazonian forest plays a crucial role in regulating the carbon and water cycles in the global climate system. However, the representation of biogeochemical fluxes and forest structure in dynamic global vegetation models (DGVMs) remains challenging. This situation has considerable implications for modelling the state and dynamics of Amazonian forest. To address these limitations, we present an adaptation of the ORCHIDEE-CAN DGVM, a second-generation DGVM that explicitly models tree demography and canopy structure with an allometry-based carbon allocation scheme and accounts for hydraulic architecture in the soil-stem-leaf continuum. We use two versions of this DGVM: the first one (CAN) includes a new parameterization for Amazonian forest; the second one (CAN-RS) additionally includes a mechanistic root water uptake module, which models the hydraulic resistance of the water transfer from soil pores to roots. We compared the results with the simulation output of the big-leaf standard version of the ORCHIDEE DGVM (TRUNK) and with observations of turbulent energy and CO2 fluxes at flux tower locations, of carbon stocks and stand density at inventory plots and observation-based models of photosynthesis (GPP) and evapotranspiration (LE) across the Amazon basin. CAN-RS reproduced observed carbon and water fluxes and carbon stocks as well as TRUNK across Amazonia, both at local and at regional scales. In CAN-RS, water uptake by tree roots in the deepest soil layers during the dry season significantly improved the modelling of GPP and LE seasonal cycles, especially over the Guianan and Brazilian Shields. These results imply that explicit coupling of the water and carbon cycles improves the representation of biogeochemical cycles in Amazonia and their spatial variability. Representing the variation in the ecological functioning of Amazonia should be the next step to improve the performance and predictive ability of new generation DGVMs.

Published
2019

24. Supplementary material to 'The Global Methane Budget 2000–2017'

Author

Marielle Saunois, Ann R. Stavert, Ben Poulter, Philippe Bousquet, Joseph G. Canadell, Robert B. Jackson, Peter A. Raymond, Edward J. Dlugokencky, Sander Houweling, Prabir K. Patra, Philippe Ciais, Vivek K. Arora, David Bastviken, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Lori Bruhwiler, Kimberly M. Carlson, Mark Carrol, Simona Castaldi, Naveen Chandra, Cyril Crevoisier, Patrick M. Crill, Kristofer Covey, Charles L. Curry, Giuseppe Etiope, Christian Frankenberg, Nicola Gedney, Michaela I. Hegglin, Lena Höglund-Isaksson, Gustaf Hugelius, Misa Ishizawa, Akihiko Ito, Greet Janssens-Maenhout, Katherine M. Jensen, Fortunat Joos, Thomas Kleinen, Paul B. Krummel, Ray L. Langenfelds, Goulven G. Laruelle, Licheng Liu, Toshinobu Machida, Shamil Maksyutov, Kyle C. McDonald, Joe McNorton, Paul A. Miller, Joe R. Melton, Isamu Morino, Jureck Müller, Fabiola Murgia-Flores, Vaishali Naik, Yosuke Niwa, Sergio Noce, Simon O'Doherty, Robert J. Parker, Changhui Peng, Shushi Peng, Glen P. Peters, Catherine Prigent, Ronald Prinn, Michel Ramonet, Pierre Regnier, William J. Riley, Judith A. Rosentreter, Arjo Segers, Isobel J. Simpson, Hao Shi, Steven J. Smith, L. Paul Steele, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Francesco N. Tubiello, Aki Tsuruta, Nicolas Viovy, Apostolos Voulgarakis, Thomas S. Weber, Michiel van Weele, Guido R. van der Werf, Ray F. Weiss, Doug Worthy, Debra Wunch, Yi Yin, Yukio Yoshida, Wenxin Zhang, Zhen Zhang, Yuanhong Zhao, Bo Zheng, Qing Zhu, Qiuan Zhu, and Qianlai Zhuang

Published
2019

25. NASA's surface biology and geology designated observable: A perspective on surface imaging algorithms

Author

Daniel M. Griffith, Kimberly A. Casey, Florian M. Schwandner, Frank E. Muller-Karger, Vincent Realmuto, Christopher R. Hakkenberg, Qingyuan Zhang, Philip E. Dennison, J. L. Torres-Perez, Dar A. Roberts, Thomas R. H. Holmes, Alexey N. Shiklomanov, Robert Frouin, Maria Fabrizia Buongiorno, Nima Pahlevan, Hamid Dashti, Roberta E. Martin, Christine Lee, Fabian D. Schneider, Kyla M. Dahlin, Chuanmin Hu, Yi Qi, Pamela L. Blake, Ali M. Assiri, Yusri Yusup, Michael E. Schaepman, Kevin R. Turpie, Nimrod Carmon, Adam Erickson, David S. Schimel, Joseph D. Ortiz, Nancy F. Glenn, Michelle M. Gierach, Maria Tzortziou, Susan L. Ustin, Hamed Gholizadeh, Heidi M. Dierssen, David R. Thompson, E. Natasha Stavros, Joshua B. Fisher, Raymond F. Kokaly, D. B. Otis, Petya K. E. Campbell, Kerry Cawse-Nicholson, Philip A. Townsend, Raphael M. Kudela, James A. Goodman, Karl F. Huemmrich, Wesley J. Moses, T. H. Painter, Ben Poulter, Qian Yu, Glynn Hulley, Charles K. Gatebe, Eric J. Hochberg, Ryan Pavlick, Charles E. Miller, Shawn P. Serbin, Liane S. Guild, and Rosa Elvira Correa-Pabón

Subjects
medicine.medical_specialty, 010504 meteorology & atmospheric sciences, Land use, 0208 environmental biotechnology, Multispectral image, Marine habitats, Soil Science, Hyperspectral imaging, Geology, 02 engineering and technology, Vegetation, Albedo, Snow, 01 natural sciences, 020801 environmental engineering, Spectral imaging, medicine, Computers in Earth Sciences, Algorithm, 0105 earth and related environmental sciences, Remote sensing
Abstract

The 2017–2027 National Academies' Decadal Survey, Thriving on Our Changing Planet, recommended Surface Biology and Geology (SBG) as a “Designated Targeted Observable” (DO). The SBG DO is based on the need for capabilities to acquire global, high spatial resolution, visible to shortwave infrared (VSWIR; 380–2500 nm; ~30 m pixel resolution) hyperspectral (imaging spectroscopy) and multispectral midwave and thermal infrared (MWIR: 3–5 μm; TIR: 8–12 μm; ~60 m pixel resolution) measurements with sub-monthly temporal revisits over terrestrial, freshwater, and coastal marine habitats. To address the various mission design needs, an SBG Algorithms Working Group of multidisciplinary researchers has been formed to review and evaluate the algorithms applicable to the SBG DO across a wide range of Earth science disciplines, including terrestrial and aquatic ecology, atmospheric science, geology, and hydrology. Here, we summarize current state-of-the-practice VSWIR and TIR algorithms that use airborne or orbital spectral imaging observations to address the SBG DO priorities identified by the Decadal Survey: (i) terrestrial vegetation physiology, functional traits, and health; (ii) inland and coastal aquatic ecosystems physiology, functional traits, and health; (iii) snow and ice accumulation, melting, and albedo; (iv) active surface composition (eruptions, landslides, evolving landscapes, hazard risks); (v) effects of changing land use on surface energy, water, momentum, and carbon fluxes; and (vi) managing agriculture, natural habitats, water use/quality, and urban development. We review existing algorithms in the following categories: snow/ice, aquatic environments, geology, and terrestrial vegetation, and summarize the community-state-of-practice in each category. This effort synthesizes the findings of more than 130 scientists.

Published
2021

26. Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis

Author

Shijie Shu, Stephen Sitch, Pierre Friedlingstein, Andy Wiltshire, Fang Zhao, Rashid Rafique, Atul K. Jain, Sönke Zaehle, Nicolas Viovy, Ben Poulter, Ning Zeng, Charles D. Koven, Eugenia Kalnay, Beni Stocker, Etsushi Kato, Ghassem R. Asrar, and Akihiko Ito

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Carbon sink, Climate change, 15. Life on land, Seasonality, medicine.disease, Dynamic global vegetation model, 01 natural sciences, Carbon cycle, 13. Climate action, Climatology, Temperate climate, Spatial ecology, medicine, Environmental science, Terrestrial ecosystem, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

We examined the net terrestrial carbon flux to the atmosphere (FTA) simulated by nine models from the TRENDY dynamic global vegetation model project for its seasonal cycle and amplitude trend during 1961–2012. While some models exhibit similar phase and amplitude compared to atmospheric inversions, with spring drawdown and autumn rebound, others tend to rebound early in summer. The model ensemble mean underestimates the magnitude of the seasonal cycle by 40 % compared to atmospheric inversions. Global FTA amplitude increase (19 ± 8 %) and its decadal variability from the model ensemble are generally consistent with constraints from surface atmosphere observations. However, models disagree on attribution of this long-term amplitude increase, with factorial experiments attributing 83 ± 56 %, −3 ± 74 and 20 ± 30 % to rising CO2, climate change and land use/cover change, respectively. Seven out of the nine models suggest that CO2 fertilization is the strongest control – with the notable exception of VEGAS, which attributes approximately equally to the three factors. Generally, all models display an enhanced seasonality over the boreal region in response to high-latitude warming, but a negative climate contribution from part of the Northern Hemisphere temperate region, and the net result is a divergence over climate change effect. Six of the nine models show that land use/cover change amplifies the seasonal cycle of global FTA: some are due to forest regrowth, while others are caused by crop expansion or agricultural intensification, as revealed by their divergent spatial patterns. We also discovered a moderate cross-model correlation between FTA amplitude increase and increase in land carbon sink (R2 = 0.61). Our results suggest that models can show similar results in some benchmarks with different underlying mechanisms; therefore, the spatial traits of CO2 fertilization, climate change and land use/cover changes are crucial in determining the right mechanisms in seasonal carbon cycle change as well as mean sink change.

Published
2016

27. The relative importance of intrinsic and extrinsic factors in the decline of obligate seeder forests

Author

David M. J. S. Bowman, Grant J. Williamson, Lynda D. Prior, Brett P. Murphy, and Ben Poulter

Subjects
0106 biological sciences, Global and Planetary Change, 010504 meteorology & atmospheric sciences, Ecology, biology, Obligate, Climate oscillation, Climate change, 15. Life on land, biology.organism_classification, Seeder, 010603 evolutionary biology, 01 natural sciences, Eucalyptus, 13. Climate action, Alternative stable state, Local extinction, Eucalyptus delegatensis, Environmental science, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences
Abstract

Forests that regenerate exclusively from seed following high-severity fire are particularly vulnerable to local extinction if fire frequency leaves insufficient time for regenerating plants to reach sexual maturity. We evaluate the relative importance of extrinsic (such as fire weather and climate cycles) and intrinsic (such as proneness to fire due to stand age and structural development) factors in driving the decline of obligate seeder forests. We illustrate this using obligate seeding alpine ash (Eucalyptus delegatensis) forests in the montane regions of Victoria, Australia, that were burnt by megafires in 2003 (142,256 ha) or 2007 (79,902 ha), including some twice-burnt areas (11,599 ha). Geospatial analyses showed only a small effect of stand age on the remote sensing estimates of crown defoliation, but a substantial effect of forest fire weather, as measured by forest fire danger index (FFDI). Analysis of meteorological data over the last century showed that 5-year increases in FFDI precede cycle major fires in the E. delegatensis forests. Such strong extrinsic climate/weather driving of high-severity fires is consistent with the ‘interval squeeze model’ that postulates the vulnerability of obligate seeder forests to landscape-scale demographic collapse in response to worsening fire weather under climate change.

Published
2016

28. Evaluation of simulated soil carbon dynamics in Arctic-Boreal ecosystems

Author

Anna M. Michalak, Daniel J. Hayes, Atul K. Jain, Hannah Rose Kolus, Joshua B. Fisher, Hanqin Tian, Ben Poulter, Jianwu Tang, Yaxing Wei, Deborah H Huntzinger, Joanna C. Carey, Christopher R. Schwalm, Xiaoying Shi, Kevin Schaefer, Eric Stofferahn, and Jiafu Mao

Subjects
Soil respiration, Boreal, Arctic, Renewable Energy, Sustainability and the Environment, Public Health, Environmental and Occupational Health, Environmental science, Ecosystem, Soil carbon, Atmospheric sciences, General Environmental Science
Abstract

Given the magnitude of soil carbon stocks in northern ecosystems, and the vulnerability of these stocks to climate warming, land surface models must accurately represent soil carbon dynamics in these regions. We evaluate soil carbon stocks and turnover rates, and the relationship between soil carbon loss with soil temperature and moisture, from an ensemble of eleven global land surface models. We focus on the region of NASA’s Arctic-Boreal vulnerability experiment (ABoVE) in North America to inform data collection and model development efforts. Models exhibit an order of magnitude difference in estimates of current total soil carbon stocks, generally under- or overestimating the size of current soil carbon stocks by greater than 50 PgC. We find that a model’s soil carbon stock at steady-state in 1901 is the prime driver of its soil carbon stock a hundred years later—overwhelming the effect of environmental forcing factors like climate. The greatest divergence between modeled and observed soil carbon stocks is in regions dominated by peat and permafrost soils, suggesting that models are failing to capture the frozen soil carbon dynamics of permafrost regions. Using a set of functional benchmarks to test the simulated relationship of soil respiration to both soil temperature and moisture, we find that although models capture the observed shape of the soil moisture response of respiration, almost half of the models examined show temperature sensitivities, or Q10 values, that are half of observed. Significantly, models that perform better against observational constraints of respiration or carbon stock size do not necessarily perform well in terms of their functional response to key climatic factors like changing temperature. This suggests that models may be arriving at the right result, but for the wrong reason. The results of this work can help to bridge the gap between data and models by both pointing to the need to constrain initial carbon pool sizes, as well as highlighting the importance of incorporating functional benchmarks into ongoing, mechanistic modeling activities such as those included in ABoVE.

Published
2020

30. Land-use emissions play a critical role in land-based mitigation for Paris climate targets

Author

Stephen Sitch, Philippe Ciais, Andreas Krause, Peter M. Cox, Eddy Robertson, Atul K. Jain, William J. Collins, Garry Hayman, Lena Boysen, Christopher P. Webber, Timothy M. Lenton, Eleanor J. Burke, N. Devaraju, Jonathan C. Doelman, Edward Comyn-Platt, Sarah Chadburn, Anna B. Harper, Detlef P. van Vuuren, Vassilis Daioglou, Chris Huntingford, Ben Poulter, Ana Bastos, Joanna Isobel House, Andy Wiltshire, Tom Powell, Shijie Shu, College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, College of Life and Environmental Sciences, University of Exeter, School of Geographical Sciences [Bristol], University of Bristol [Bristol], Centre for Ecology and Hydrology [Wallingford] (CEH), Natural Environment Research Council (NERC), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], University of Leeds, Department of Meteorology [Reading], University of Reading (UOR), PBL Netherlands Environmental Assessment Agency, Department of Geography [München], Ludwig-Maximilians-Universität München (LMU), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Department of Atmospheric Sciences [Urbana], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, Institute of Nanotechnology [Karlsruhe] (INT), Karlsruhe Institute of Technology (KIT), NASA Goddard Space Flight Center (GSFC), European Project: 641816,H2020,H2020-SC5-2014-two-stage,CRESCENDO(2015), European Project: 603542,EC:FP7:ENV,FP7-ENV-2013-two-stage,LUC4C(2013), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Life on Land, Science, General Physics and Astronomy, Climate change, 010501 environmental sciences, Carbon sequestration, 01 natural sciences, 7. Clean energy, General Biochemistry, Genetics and Molecular Biology, Article, Meteorology and Climatology, Affordable and Clean Energy, Environmental protection, Deforestation, 11. Sustainability, Carbon capture and storage, ddc:550, lcsh:Science, 0105 earth and related environmental sciences, Multidisciplinary, Global warming, Reforestation, Bio-energy with carbon capture and storage, General Chemistry, Soil carbon, 15. Life on land, Climate Action, Earth sciences, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDE]Environmental Sciences, Environmental science, lcsh:Q
Abstract

Scenarios that limit global warming to below 2 °C by 2100 assume significant land-use change to support large-scale carbon dioxide (CO2) removal from the atmosphere by afforestation/reforestation, avoided deforestation, and Biomass Energy with Carbon Capture and Storage (BECCS). The more ambitious mitigation scenarios require even greater land area for mitigation and/or earlier adoption of CO2 removal strategies. Here we show that additional land-use change to meet a 1.5 °C climate change target could result in net losses of carbon from the land. The effectiveness of BECCS strongly depends on several assumptions related to the choice of biomass, the fate of initial above ground biomass, and the fossil-fuel emissions offset in the energy system. Depending on these factors, carbon removed from the atmosphere through BECCS could easily be offset by losses due to land-use change. If BECCS involves replacing high-carbon content ecosystems with crops, then forest-based mitigation could be more efficient for atmospheric CO2 removal than BECCS., Land-based mitigation for meeting the Paris climate target must consider the carbon cycle impacts of land-use change. Here the authors show that when bioenergy crops replace high carbon content ecosystems, forest-based mitigation could be more effective for CO2 removal than bioenergy crops with carbon capture and storage.

Published
2018

31. Change in terrestrial ecosystem water‐use efficiency over the last three decades

Author

Xiaoying Shi, Lei Cheng, Jiafu Mao, Mengtian Huang, Philippe Ciais, Shilong Piao, Yan Sun, Ben Poulter, Ying-Ping Wang, Zhenzhong Zeng, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University [Beijing], ICOS-ATC (ICOS-ATC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), CSIRO Land and Water, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Montana State University (MSU), Oceans and Atmosphere Flagship [Brisbane], and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nitrogen deposition, Nitrogen, Climate Change, Climate change, Carbon Cycle, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Environmental Chemistry, Photosynthesis, Water-use efficiency, China, Ecosystem, General Environmental Science, Hydrology, Global and Planetary Change, Ecology, business.industry, Environmental resource management, Water, Environmental research, Plant Transpiration, Carbon Dioxide, Models, Theoretical, Plants, 15. Life on land, 13. Climate action, Environmental science, Christian ministry, Terrestrial ecosystem, [SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology, business
Abstract

Defined as the ratio between gross primary productivity (GPP) and evapotranspiration (ET), ecosystem-scale water-use efficiency (EWUE) is an indicator of the adjustment of vegetation photosynthesis to water loss. The processes controlling EWUE are complex and reflect both a slow evolution of plants and plant communities as well as fast adjustments of ecosystem functioning to changes of limiting resources. In this study, we investigated EWUE trends from 1982 to 2008 using data-driven models derived from satellite observations and process-oriented carbon cycle models. Our findings suggest positive EWUE trends of 0.0056, 0.0007 and 0.0001 g C m(-2) mm(-1) yr(-1) under the single effect of rising CO2 ('CO2 '), climate change ('CLIM') and nitrogen deposition ('NDEP'), respectively. Global patterns of EWUE trends under different scenarios suggest that (i) EWUE-CO2 shows global increases, (ii) EWUE-CLIM increases in mainly high latitudes and decreases at middle and low latitudes, (iii) EWUE-NDEP displays slight increasing trends except in west Siberia, eastern Europe, parts of North America and central Amazonia. The data-driven MTE model, however, shows a slight decline of EWUE during the same period (-0.0005 g C m(-2) mm(-1) yr(-1) ), which differs from process-model (0.0064 g C m(-2) mm(-1) yr(-1) ) simulations with all drivers taken into account. We attribute this discrepancy to the fact that the nonmodeled physiological effects of elevated CO2 reducing stomatal conductance and transpiration (TR) in the MTE model. Partial correlation analysis between EWUE and climate drivers shows similar responses to climatic variables with the data-driven model and the process-oriented models across different ecosystems. Change in water-use efficiency defined from transpiration-based WUEt (GPP/TR) and inherent water-use efficiency (IWUEt , GPP×VPD/TR) in response to rising CO2 , climate change, and nitrogen deposition are also discussed. Our analyses will facilitate mechanistic understanding of the carbon-water interactions over terrestrial ecosystems under global change.

Published
2015

32. Detection and attribution of vegetation greening trend in China over the last 30 years

Author

Ying-Ping Wang, Ronggao Liu, Ranga B. Myneni, Shushi Peng, Lei Cheng, Mengtian Huang, Shilong Piao, Ning Zeng, Xiaoying Shi, Guodong Yin, Jiafu Mao, Jianguang Tan, Ben Poulter, Zhenzhong Zeng, Zhiqiang Xiao, and Yue Li

Subjects
China, Conservation of Natural Resources, Nitrogen, Climate Change, Plant Development, Climate change, Forests, Greening, Effects of global warming, Environmental Chemistry, Ecosystem, Spacecraft, Leaf area index, General Environmental Science, Global and Planetary Change, Ecology, Temperature, Primary production, Vegetation, Carbon Dioxide, Models, Theoretical, Geography, Climatology, Remote Sensing Technology, Spatial ecology, Environmental Monitoring
Abstract

The reliable detection and attribution of changes in vegetation growth is a prerequisite for the development of strategies for the sustainable management of ecosystems. This is an extraordinary challenge. To our knowledge, this study is the first to comprehensively detect and attribute a greening trend in China over the last three decades. We use three different satellite-derived Leaf Area Index (LAI) datasets for detection as well as five different process-based ecosystem models for attribution. Rising atmospheric CO2 concentration and nitrogen deposition are identified as the most likely causes of the greening trend in China, explaining 85% and 41% of the average growing-season LAI trend (LAIGS) estimated by satellite datasets (average trend of 0.0070 yr(-1), ranging from 0.0035 yr(-1) to 0.0127 yr(-1)), respectively. The contribution of nitrogen deposition is more clearly seen in southern China than in the north of the country. Models disagree about the contribution of climate change alone to the trend in LAIGS at the country scale (one model shows a significant increasing trend, whereas two others show significant decreasing trends). However, the models generally agree on the negative impacts of climate change in north China and Inner Mongolia and the positive impact in the Qinghai-Xizang plateau. Provincial forest area change tends to be significantly correlated with the trend of LAIGS (P < 0.05), and marginally significantly (P = 0.07) correlated with the residual of LAIGS trend, calculated as the trend observed by satellite minus that estimated by models through considering the effects of climate change, rising CO2 concentration and nitrogen deposition, across different provinces. This result highlights the important role of China's afforestation program in explaining the spatial patterns of trend in vegetation growth.

Published
2015

33. Higher temperature variability reduces temperature sensitivity of vegetation growth in Northern Hemisphere

Author

Xiao-Yan Li, Xiuchen Wu, Yi Yin, Nicolas Vuichard, Pei Wang, Weichao Guo, Yongmei Huang, Shilong Piao, Hongyan Liu, Ben Poulter, Changhui Peng, Philippe Ciais, Nicolas Viovy, Beijing Normal University (BNU), College of Urban and Environmental Sciences [Beijing], Peking University [Beijing], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Montana State University (MSU), Université du Québec à Montréal = University of Québec in Montréal (UQAM), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
0301 basic medicine, 010504 meteorology & atmospheric sciences, ved/biology.organism_classification_rank.species, Climate change, 01 natural sciences, Shrub, Normalized Difference Vegetation Index, Latitude, 03 medical and health sciences, Ecosystem model, medicine, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ved/biology, Global warming, Northern Hemisphere, 15. Life on land, 030104 developmental biology, Geophysics, 13. Climate action, Climatology, General Earth and Planetary Sciences, Environmental science, medicine.symptom, Vegetation (pathology)
Abstract

Interannual air temperature variability has changed over some regions in Northern Hemisphere (NH), accompanying with climate warming. However, whether and to what extent it regulates the interannual sensitivity of vegetation growth to temperature variability (i.e., interannual temperature sensitivity)—one central issue in understanding and predicting the responses of vegetation growth to changing climate—still remains poorly quantified and understood. Here we quantify the relationships between the interannual temperature sensitivity of mean growing-season (April–October) normalized difference vegetation index (NDVI) and ecosystem model simulations of gross primary productivity (GPP), and variability in mean growing-season temperature for forest, shrub, and grass over NH. We find that higher interannual variability in mean growing-season temperature leads to consistent decrease in interannual temperature sensitivity of mean growing-season NDVI among all vegetation types but not in model simulations of GPP. Drier condition associates with ~130 ± 150% further decrease in interannual temperature sensitivity of mean growing-season NDVI by temperature variability in forest and shrub. These results illustrate that varying temperature variability can significantly regulate the interannual temperature sensitivity of vegetation growth over NH, interacted with drought variability and nonlinear responses of photosynthesis to temperature. Our findings call for an improved characterization of the nonlinear effects of temperature variability on vegetation growth within global ecosystem models.

Published
2017

34. Variability and quasi-decadal changes in the methane budget over the period 2000–2012

Author

Marielle Saunois, Philippe Bousquet, Ben Poulter, Anna Peregon, Philippe Ciais, Josep G. Canadell, Edward J. Dlugokencky, Giuseppe Etiope, David Bastviken, Sander Houweling, Greet Janssens-Maenhout, Francesco N. Tubiello, Simona Castaldi, Robert B. Jackson, Mihai Alexe, Vivek K. Arora, David J. Beerling, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Lori Bruhwiler, Cyril Crevoisier, and Patri

Published
2017
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35. Spatial variability and temporal trends in water-use efficiency of European forests

Author

Tom Levanič, Ben Poulter, John S. Waterhouse, Emilia Gutiérrez, David Frank, Danny McCarroll, Iain Robertson, Laia Andreu-Hayles, Håkan Grudd, Tatjana Boettger, Fortunat Joos, Gerd Helle, Peter M. Wynn, Ingo Heinrich, Isabel Dorado Liñán, Markus Leuenberger, Emmi Hilasvuori, Giles H.F. Young, Eloni Sonninen, Matthias Saurer, Kerstin Treydte, Ewan J. Woodley, Ian J. Fairchild, Rolf T. W. Siegwolf, Mary Gagen, Risto Jalkanen, Hans W. Linderholm, Renato Spahni, Michael Friedrich, Marika Haupt, Neil J. Loader, Paul Scherrer Institute, Villigen, Oeschger Centre for Climate Change Research (OCCR), University of Bern, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Department of Geography [Swansea], Swansea University, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ), Universitat de Barcelona (UB), University of Birmingham [Birmingham], University of Hohenheim, Finnish Museum of Natural History (LUOMUS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Bolin Centre for Climate Research, Stockholm University, Finnish Forest Research Institute (METLA), Natural Resources Institute Finland (LUKE), Slovenian Forestry Institute, University of Gothenburg (GU), Anglia Ruskin University (ARU), Lancaster Environment Centre, Lancaster University, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University of Helsinki, and Universitat de Barcelona

Subjects
0106 biological sciences, Stomatal conductance, Time Factors, Dendrochronology, 010504 meteorology & atmospheric sciences, Climate Change, ta1171, Climate change, Forests, Atmospheric sciences, 01 natural sciences, Carbon Cycle, Trees, Water Cycle, Canvi climàtic, Environmental Chemistry, Ecosystem, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Dendrocronologia, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Hydrology, Climatology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Carbon Isotopes, Global and Planetary Change, Geography, Ecology, Boscos, Vegetation, Carbon Dioxide, Models, Theoretical, 15. Life on land, Climatic changes, ta4112, Climatic change, Europe, 13. Climate action, Climatologia, Spatial ecology, Common spatial pattern, Spatial variability, Europa, Temperate rainforest, 010606 plant biology & botany, Canvis climàtics
Abstract

The increasing carbon dioxide (CO2) concentration in the atmosphere in combination with climatic changes throughout the last century are likely to have had a profound effect on the physiology of trees: altering the carbon and water fluxes passing through the stomatal pores. However, the magnitude and spatial patterns of such changes in natural forests remain highly uncertain. Here, stable carbon isotope ratios from a network of 35 tree-ring sites located across Europe are investigated to determine the intrinsic water-use efficiency (iWUE), the ratio of photosynthesis to stomatal conductance from 19012000. The results were compared with simulations of a dynamic vegetation model (LPX-Bern 1.0) that integrates numerous ecosystem and landatmosphere exchange processes in a theoretical framework. The spatial pattern of tree-ring derived iWUE of the investigated coniferous and deciduous species and the model results agreed significantly with a clear south-to-north gradient, as well as a general increase in iWUE over the 20th century. The magnitude of the iWUE increase was not spatially uniform, with the strongest increase observed and modelled for temperate forests in Central Europe, a region where summer soil-water availability decreased over the last century. We were able to demonstrate that the combined effects of increasing CO2 and climate change leading to soil drying have resulted in an accelerated increase of iWUE. These findings will help to reduce uncertainties in the land surface schemes of global climate models, where vegetationclimate feedbacks are currently still poorly constrained by observational data.

Published
2014
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36. The global methane budget 2000-2012

Author

Akihiko Ito, Philippe Ciais, Peter Bergamaschi, Greet Janssens-Maenhout, David J. Beerling, Cyril Crevoisier, Philippe Bousquet, Julia Marshall, Simona Castaldi, Isabelle Pison, Heon Sook Kim, Yasunori Tohjima, Jean-Francois Lamarque, Atsushi Takizawa, Charles L. Curry, Debra Wunch, Kyle C. McDonald, Michel Ramonet, David Bastviken, Simon O'Doherty, Josep G. Canadell, Robin Locatelli, Francesco N. Tubiello, Prabir K. Patra, P. Steele, Brett F. Thornton, Catherine Prigent, Sander Houweling, Toshinobu Machida, David J. Wilton, Joe R. Melton, Ronald G. Prinn, William J. Riley, Edward J. Dlugokencky, Monia Santini, Giuseppe Etiope, Doug Worthy, Guido R. van der Werf, Christian Frankenberg, Shushi Peng, Vivek K. Arora, Patrick M. Crill, Ray F. Weiss, Nicolas Viovy, Michiel van Weele, Anna Peregon, Shamil Maksyutov, Vaishali Naik, Zhen Zhang, Thomas Kleinen, Lori Bruhwiler, Yukio Yoshida, Lena Höglund-Isaksson, Kristofer R. Covey, Fortunat Joos, Misa Ishizawa, Bowen Zhang, Christine Wiedinmyer, Ronny Schroeder, Nicola Gedney, Hanqin Tian, Changhui Peng, Apostolos Voulgarakis, Mihai Alexe, Victor Brovkin, Ray L. Langenfelds, Isamu Morino, Glen P. Peters, Xiyan Xu, Andy Wiltshire, Isobel J. Simpson, Ben Poulter, Marielle Saunois, Qiuan Zhu, Donald R. Blake, Paul B. Krummel, Frans-Jan W. Parmentier, Makoto Saito, Gordon Brailsford, Robert B. Jackson, Renato Spahni, Earth and Climate, Hydrology and Geo-environmental sciences, Faculty of Earth and Life Sciences, Saunois, Marielle, Bousquet, Philippe, Poulter, Ben, Peregon, Anna, Ciais, Philippe, Canadell Josep, G, Dlugokencky Edward, J., Etiope, Giuseppe, Bastviken, David, Houweling, Sander, Janssens Maenhout, Greet, Tubiello Francesco, N., Castaldi, Simona, Jackson Robert, B., Alexe, Mihai, Arora Vivek, K., Beerling David, J., Bergamaschi, Peter, Blake Donald, R., Brailsford, Gordon, Brovkin, Victor, Bruhwiler, Lori, Crevoisier, Cyril, Crill, Patrick, Covey, Kristofer, Curry, Charle, Frankenberg, Christian, Gedney, Nicola, Höglund Isaksson, Lena, Ishizawa, Misa, Ito, Akihiko, Joos, Fortunat, Kim Heon, Sook, Kleinen, Thoma, Krummel, Paul, Lamarque Jean, Françoi, Langenfelds, Ray, Locatelli, Robin, Machida, Toshinobu, Maksyutov, Shamil, McDonald Kyle, C., Marshall, Julia, Melton Joe, R., Morino, Isamu, Naik Vaishali, Oapo, Doherty, Simon, Parmentier Frans Jan, W., Patra Prabir, K., Peng, Changhui, Peng, Shushi, Peters Glen, P., Pison, Isabelle, Prigent, Catherine, Prinn, Ronald, Ramonet, Michel, Riley William, J., Saito, Makoto, Santini, Monia, Schroeder, Ronny, Simpson Isobel, J., Spahni, Renato, Steele, Paul, Takizawa, Atsushi, Thornton Brett, F., Tian, Hanqin, Tohjima, Yasunori, Viovy, Nicola, Voulgarakis, Apostolo, van Weele, Michiel, van der Werf Guido, R., Weiss, Ray, Wiedinmyer, Christine, Wilton David, J., Wiltshire, Andy, Worthy, Doug, Wunch, Debra, Xu, Xiyan, Yoshida, Yukio, Zhang, Bowen, Zhang, Zhen, Zhu, Qiuan, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), ICOS-ATC (ICOS-ATC), Istituto Nazionale di Geofisica e Vulcanologia, The Department of Thematic Studies - Water and Environmental Studies, Linköping University (LIU), SRON Netherlands Institute for Space Research (SRON), European Commission - Joint Research Centre [Ispra] (JRC), LM, Canadian Centre for Climate Modelling and Analysis (CCCma), Environment and Climate Change Canada, Department of Animal and Plant Sciences, University of Sheffield [Sheffield], JRC Institute for Environment and Sustainability (IES), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-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), Tropospheric sounding, assimilation, and modeling group [JPL], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH)-NASA-California Institute of Technology (CALTECH), National Institute for Environmental Studies (NIES), Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), Atmospheric Chemistry Division [Boulder], National Center for Atmospheric Research [Boulder] (NCAR), Oceans and Atmosphere, CSIRO, Strathom Energie, Centre Européen de Réalité Virtuelle (CERV), École Nationale d'Ingénieurs de Brest (ENIB), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Université du Québec à Trois-Rivières (UQTR), ICOS-RAMCES (ICOS-RAMCES), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Shandong Agricultural University (SDAU), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Department of Physics [Imperial College London], Imperial College London, Royal Netherlands Meteorological Institute (KNMI), Faculty of Earth and Life Sciences [Amsterdam] (FALW), Vrije Universiteit Amsterdam [Amsterdam] (VU), Scripps Institution of Oceanography (SIO - UC San Diego), University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Climate Research Division [Toronto], California Institute of Technology (CALTECH), Laboratoire de Physique et d'Etude des Matériaux (UMR 8213) (LPEM), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), USC Viterbi School of Engineering, University of Southern California (USC), Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Prinn, Ronald G, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universität Bern [Bern]-Universität Bern [Bern], Scripps Institution of Oceanography (SIO), and University of California-University of California

Subjects
010504 meteorology & atmospheric sciences, Naturgeografi, TRACE GASES, 010501 environmental sciences, Atmospheric sciences, 7. Clean energy, 01 natural sciences, Physical Geography and Environmental Geoscience, Methane, chemistry.chemical_compound, Natural gas, 11. Sustainability, SDG 13 - Climate Action, Meteorology & Atmospheric Sciences, Geosciences, Multidisciplinary, Greenhouse effect, lcsh:Environmental sciences, ComputingMilieux_MISCELLANEOUS, lcsh:GE1-350, [PHYS]Physics [physics], GREENHOUSE-GAS EMISSIONS, methane, lcsh:QE1-996.5, Geology, PAST 2 DECADES, Carbon project, Atmospheric chemistry, Physical Sciences, hydroxyl, Earth and Related Environmental Sciences, Wetland methane emissions, BIOMASS BURNING EMISSIONS, NATURAL-GAS, PROCESS-BASED MODEL, TROPOSPHERIC METHANE, 530 Physics, methane sources, Climate change, Atmospheric Sciences, ATMOSPHERIC HYDROXYL RADICALS, SDG 14 - Life Below Water, ISOTOPIC COMPOSITION, 550 Earth sciences & geology, 0105 earth and related environmental sciences, global model, Science & Technology, business.industry, Environmental engineering, Geovetenskap och miljövetenskap, 15. Life on land, methane budget, lcsh:Geology, Climate Action, Geochemistry, chemistry, Physical Geography, 13. Climate action, Greenhouse gas, General Earth and Planetary Sciences, Environmental science, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], INTERCOMPARISON PROJECT ACCMIP
Abstract

The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (similar to biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 TgCH(4) yr(-1), range 540-568. About 60% of global emissions are anthropogenic (range 50-65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios. Bottom-up approaches suggest larger global emissions (736 TgCH(4) yr(-1), range 596-884) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the top-down budget, it is likely that some of the individual emissions reported by the bottom-up approaches are overestimated, leading to too large global emissions. Latitudinal data from top-down emissions indicate a predominance of tropical emissions (similar to 64% of the global budget, amp;lt;30 degrees N) as compared to mid (similar to 32 %, 30-60 degrees N) and high northern latitudes (similar to 4 %, 60-90 degrees N). Top-down inversions consistently infer lower emissions in China (similar to 58 TgCH(4) yr(-1), range 51-72, -14 %) and higher emissions in Africa (86 TgCH(4) yr(-1), range 73-108, + 19 %) than bottom-up values used as prior estimates. Overall, uncertainties for anthropogenic emissions appear smaller than those from natural sources, and the uncertainties on source categories appear larger for top-down inversions than for bottom-up inventories and models. The most important source of uncertainty on the methane budget is attributable to emissions from wetland and other inland waters. We show that the wetland extent could contribute 30-40% on the estimated range for wetland emissions. Other priorities for improving the methane budget include the following: (i) the development of process-based models for inland-water emissions, (ii) the intensification of methane observations at local scale (flux measurements) to constrain bottom-up land surface models, and at regional scale (surface networks and satellites) to constrain top-down inversions, (iii) improvements in the estimation of atmospheric loss by OH, and (iv) improvements of the transport models integrated in top-down inversions. The data presented here can be downloaded from the Carbon Dioxide Information Analysis Center (http://doi.org/10.3334/CDIAC/GLOBAL_METHANE_BUDGET_2016_V1.1) and the Global Carbon Project. Funding Agencies|Swiss National Science Foundation; NASA [NNX14AF93G, NNX14AO73G]; National Environmental Science Program - Earth Systems and Climate Change Hub; European Commission [283576, 633080]; ESA Climate Change Initiative Greenhouse Gases Phase 2 project; US Department of Energy, BER [DE-AC02-05CH11231]; FAO member countries; Environment Research and Technology Development Fund of the Ministry of the Environment, Japan [2-1502]; ERC [322998]; NERC [NE/J00748X/1]; Swedish Research Council VR; Research Council of Norway [244074]; NSF [1243232, 1243220]; National Science and Engineering Research Council of Canada (NSERC); Chinas QianRen Program; CSIRO Australia; Australian Bureau of Meteorology; Australian Institute of Marine Science; Australian Antarctic Division; NOAA USA; Meteorological Service of Canada; National Aeronautic and Space Administration (NASA) [NAG5-12669, NNX07AE89G, NNX11AF17G, NNX07AE87G, NNX07AF09G, NNX11AF15G, NNX11AF16G]; Department of Energy and Climate Change (DECC, UK) [GA01081]; Commonwealth Scientific and Industrial Research Organization (CSIRO Australia); Bureau of Meteorology (Australia); Joint DECC/Defra Met Office Hadley Centre Climate Programme [GA01101]

Published
2016

37. Supplementary material to 'The Global Methane Budget: 2000–2012'

Author

Marielle Saunois, Philippe Bousquet, Ben Poulter, Anna Peregon, Philippe Ciais, Josep G. Canadell, Edward J. Dlugokencky, Giuseppe Etiope, David Bastviken, Sander Houweling, Greet Janssens-Maenhout, Francesco N. Tubiello, Simona Castaldi, Robert B. Jackson, Mihai Alexe, Vivek K. Arora, David J. Beerling, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Victor Brovkin, Lori Bruhwiler, Cyril Crevoisier, Patrick Crill, Charles Curry, Christian Frankenberg, Nicola Gedney, Lena Höglund-Isaksson, Misa Ishizawa, Akihiko Ito, Fortunat Joos, Heon-Sook Kim, Thomas Kleinen, Paul Krummel, Jean-François Lamarque, Ray Langenfelds, Robin Locatelli, Toshinobu Machida, Shamil Maksyutov, Kyle C. McDonald, Julia Marshall, Joe R. Melton, Isamu Morino, Simon O'Doherty, Frans-Jan W. Parmentier, Prabir K. Patra, Changhui Peng, Shushi Peng, Glen P. Peters, Isabelle Pison, Catherine Prigent, Ronald Prinn, Michel Ramonet, William J. Riley, Makoto Saito, Ronny Schroeder, Isobel J. Simpson, Renato Spahni, Paul Steele, Atsushi Takizawa, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Nicolas Viovy, Apostolos Voulgarakis, Michiel van Weele, Guido van der Werf, Ray Weiss, Christine Wiedinmyer, David J. Wilton, Andy Wiltshire, Doug Worthy, Debra B. Wunch, Xiyan Xu, Yukio Yoshida, Bowen Zhang, Zhen Zhang, and Qiuan Zhu

Published
2016

39. Role of CO2, climate and land use in regulating the seasonal amplitude increase of carbon fluxes in terrestrial ecosystems: a multimodel analysis

Author

Fang Zhao, Ning Zeng, Ito Akihiko, Ghassam Asrar, Pierre Friedlingstein, Atul Jain, Eugenia Kalnay, Etsushi Kato, Charles D. Koven, Ben Poulter, Rashid Rafique, Stephen Sitch, Shijie Shu, Beni Stocker, Nicolas Viovy, Andy Wiltshire, and Sonke Zaehle

Abstract

We examined the net terrestrial carbon flux to the atmosphere (FTA) simulated by nine models from the TRENDY dynamic global vegetation model project during 1961–2012 for its seasonal cycle and amplitude trend. While some models exhibit similar phase and amplitude compared to atmospheric inversions, with spring drawdown and autumn rebound, others tend to rebound early in summer. The model ensemble mean underestimates the magnitude of the seasonal cycle by 40 % compared to atmospheric inversions. Global FTA amplitude increase (19 ± 8 %) and its decadal variability from the model ensemble are generally consistent with constraints from surface atmosphere observations. However, models disagree on attribution of this long-term amplitude increase, with factorial experiments attributing 83 ± 56 %, −3 ± 74 % and 20 ± 30 % to rising CO2, climate change and land use/cover change, respectively. Seven out of the nine models suggest that CO2 fertilization is a stronger control — with the notable exception of VEGAS, which attributes approximately equally to the three factors. Generally, all models display an enhanced seasonality over the boreal region in response to high-latitude warming, but a negative climate contribution from part of the Northern Hemisphere temperate region, and the net result is a divergence over climate change effect. Six of the nine models show land use/cover change amplifies the seasonal cycle of global FTA: some are due to forest regrowth while others are caused by crop expansion or agricultural intensification, as revealed by their divergent spatial patterns. We also discovered a moderate cross-model correlation between FTA amplitude increase and increase in land carbon sink (R2 = 0.61). Our results suggest that models can show similar results in some benchmarks with different underlying mechanisms, therefore the spatial traits of CO2 fertilization, climate change, and land use/cover changes are crucial in determining the right mechanisms in seasonal carbon cycle change as well as mean sink change.

Published
2016

40. Compensatory water effects link yearly global land CO

Author

Martin, Jung, Markus, Reichstein, Christopher R, Schwalm, Chris, Huntingford, Stephen, Sitch, Anders, Ahlström, Almut, Arneth, Gustau, Camps-Valls, Philippe, Ciais, Pierre, Friedlingstein, Fabian, Gans, Kazuhito, Ichii, Atul K, Jain, Etsushi, Kato, Dario, Papale, Ben, Poulter, Botond, Raduly, Christian, Rödenbeck, Gianluca, Tramontana, Nicolas, Viovy, Ying-Ping, Wang, Ulrich, Weber, Sönke, Zaehle, and Ning, Zeng

Subjects
Machine Learning, Atmosphere, Cell Respiration, Temperature, Water, Carbon Dioxide, Photosynthesis, Ecosystem, Carbon Cycle
Abstract

Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO

Published
2015

41. MEASURING THE IMPACT OF SEA-LEVEL RISE ON COASTAL REAL ESTATE: A HEDONIC PROPERTY MODEL APPROACH*

Author

Okmyung Bin, Christopher F. Dumas, John C. Whitehead, and Ben Poulter

Subjects
Economic growth, Discounting, Geospatial analysis, business.industry, IPCC Fourth Assessment Report, Property (programming), Distribution (economics), Real estate, Environmental Science (miscellaneous), Development, computer.software_genre, Lidar, Geography, Range (statistics), Physical geography, business, computer
Abstract

This study estimates the impact of sea-level rise on coastal real estate in North Carolina using a unique integration of geospatial and hedonic property data. With rates of sea- level rise approximately double the global average, North Carolina has one of the most vulnerable coastlines in the United States. A range of modest sea-level rise scenarios based on the IPCC Fourth Assessment Report projections (2007) are considered for four counties of North Carolina—New Hanover, Dare, Carteret, and Bertie—which represent a cross-section of the state’s coastline in geographical distribution and economic development. High-resolution topographic LIDAR (light detection and ranging) data are used to provide accurate inundation maps for the properties that will be at risk under six different sea-level rise scenarios. A simulation approach based on spatial hedonic models is used to provide consistent estimates of the property value losses. Considering just four coastal counties in North Carolina, the value of residential property loss without discounting in 2030 (2080) is estimated to be about $179 ($526) million for the mid-range sea-level rise scenarios. Low-lying and heavily developed areas in the northern coastline are comparatively more vulnerable to the effect of sea-level rise than the other areas.

Published
2010

42. Measuring the economic effects of sea level rise on shore fishing

Author

Okmyung Bin, John C. Whitehead, Ben Poulter, and Christopher F. Dumas

Subjects
Shore, Global and Planetary Change, geography, geography.geographical_feature_category, Ecology, Fishing, Climate change, Fishery, Recreational fishing, Oceanography, Sea level rise, Environmental science, Economic impact analysis, Empirical relationship, Recreation
Abstract

In this paper we develop estimates of the economic effects of sea level rise on marine recreational shore fishing in North Carolina, USA. The relationship between angler behavior and spatial differences in beach width is estimated using the Marine Recreational Fishing Statistics Survey and geospatial data. We exploit the empirical relationship between beach width and fishing site choice by simulating the effects of sea level rise on angler site choice. We find that reductions in beach width negatively affect the quality and number of fishing trips even as anglers adapt by using piers and bridges. Welfare losses are potentially substantial, ranging up 39% of the total value of marine shore fishing in North Carolina.

Published
2009

43. Assessing carbon dynamics in Amazonia with the Dynamic Global Vegetation Model LPJmL — discharge evaluation

Author

Stefanie Rost, Fanny Langerwisch, Ben Poulter, Heike Zimmermann-Timm, and Wolfgang Cramer

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Amazon rainforest, 010604 marine biology & hydrobiology, chemistry.chemical_element, Dynamic global vegetation model, Atmospheric sciences, 01 natural sciences, Atmosphere, chemistry, Climatology, Environmental science, Carbon flow, Ecosystem, Carbon, 0105 earth and related environmental sciences, Amazon basin
Abstract

et al. 2006).A substantial, globally significant carbon flow exists be-tween the atmosphere, land ecosystems, and aquatic ecosys-tems in the Amazon basin, probably leading to a major, yet poorly constrained carbon export to the Tropical Atlantic. One estimate of the annual export of carbon to the ocean is 40 Tg C/yr (M

Published
2008

44. Multicriteria evaluation of discharge simulation in Dynamic Global Vegetation Models

Author

Mark R. Lomas, Yue Li, Soenke Zaehle, Yi Yin, Stephen Sitch, Samuel Levis, Matthieu Guimberteau, Shilong Piao, Fang Zhao, Zhenzhong Zeng, Philippe Ciais, Anders Ahlström, Xiran Li, Lei Wang, Ning Zeng, Hui Yang, Nicolas Viovy, Pierre Friedlingstein, Ben Poulter, Chris Huntingford, Philippe Peylin, Mengtian Huang, Peter Levy, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University [Beijing], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), University of Exeter, Stanford EARTH, Stanford University, Centre for Ecology and Hydrology [Wallingford] (CEH), Natural Environment Research Council (NERC), National Center for Atmospheric Research [Boulder] (NCAR), Centre for Ecology and Hydrology (CEH), University of Sheffield [Sheffield], Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Montana State University (MSU), Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft, University of Maryland [College Park], University of Maryland System, Chinese Academy of Sciences [Beijing] (CAS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, geography, geography.geographical_feature_category, Discharge, Drainage basin, Climate change, Forecast skill, Vegetation, 15. Life on land, Snow, Geophysics, Meteorology and Climatology, 13. Climate action, Space and Planetary Science, Climatology, Middle latitudes, Earth and Planetary Sciences (miscellaneous), Environmental science, Hydrology, Surface runoff, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; In this study, we assessed the performance of discharge simulations by coupling the runoff from seven Dynamic Global Vegetation Models (DGVMs; LPJ, ORCHIDEE, Sheffield-DGVM, TRIFFID, LPJ-GUESS, CLM4CN, and OCN) to one river routing model for 16 large river basins. The results show that the seasonal cycle of river discharge is generally modeled well in the low and middle latitudes but not in the high latitudes, where the peak discharge (due to snow and ice melting) is underestimated. For the annual mean discharge, the DGVMs chained with the routing model show an underestimation. Furthermore, the 30 year trend of discharge is also underestimated. For the interannual variability of discharge, a skill score based on overlapping of probability density functions (PDFs) suggests that most models correctly reproduce the observed variability (correlation coefficient higher than 0.5; i.e., models account for 50% of observed interannual variability) except for the Lena, Yenisei, Yukon, and the Congo river basins. In addition, we compared the simulated runoff from different simulations where models were forced with either fixed or varying land use. This suggests that both seasonal and annual mean runoff has been little affected by land use change but that the trend itself of runoff is sensitive to land use change. None of the models when considered individually show significantly better performances than any other and in all basins. This suggests that based on current modeling capability, a regional-weighted average of multimodel ensemble projections might be appropriate to reduce the bias in future projection of global river discharge.

Published
2015

45. Plant functional type classification for earth system models: Results from the European Space Agency's Land Cover Climate Change Initiative

Author

Natasha MacBean, Andrew Hartley, Martin Herold, Richard Betts, Carsten Brockmann, Catherine Ottlé, Céline Lamarche, Iryna Khlystova, Sophie Bontemps, Martin Boettcher, Pierre Defourny, Ben Poulter, Stefan Hagemann, Philippe Peylin, Olivier Arino, Dimitri Lederer, Grit Kirches, Marco Peters, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Montana, Institute of Environmental Physics [Bremen] (IUP), University of Bremen, Earth and Life Institute [Louvain-La-Neuve] (ELI), Université Catholique de Louvain = Catholic University of Louvain (UCL), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Modélisation des Surfaces et Interfaces Continentales (MOSAIC), International Center for Tropical Agriculture, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
Cover (telecommunications), Meteorology, 010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, Climate change, Land cover, 02 engineering and technology, 01 natural sciences, phenology, Laboratory of Geo-information Science and Remote Sensing, Laboratorium voor Geo-informatiekunde en Remote Sensing, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, database, ComputingMilieux_MISCELLANEOUS, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, forests, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, business.industry, cycle, Environmental resource management, lcsh:QE1-996.5, resolution, Vegetation, Plant functional type, 15. Life on land, PE&RC, uncertainties, world map, Earth system science, lcsh:Geology, global vegetation model, Thematic map, 13. Climate action, Environmental science, business, ecosystems, World map, feedbacks
Abstract

Global land cover is a key variable in the earth system with feedbacks on climate, biodiversity and natural resources. However, global land cover data sets presently fall short of user needs in providing detailed spatial and thematic information that is consistently mapped over time and easily transferable to the requirements of earth system models. In 2009, the European Space Agency launched the Climate Change Initiative (CCI), with land cover (LC_CCI) as 1 of 13 essential climate variables targeted for research development. The LC_CCI was implemented in three phases: first responding to a survey of user needs; developing a global, moderate-resolution land cover data set for three time periods, or epochs (2000, 2005, and 2010); and the last phase resulting in a user tool for converting land cover to plant functional type equivalents. Here we present the results of the LC_CCI project with a focus on the mapping approach used to convert the United Nations Land Cover Classification System to plant functional types (PFTs). The translation was performed as part of consultative process among map producers and users, and resulted in an open-source conversion tool. A comparison with existing PFT maps used by three earth system modeling teams shows significant differences between the LC_CCI PFT data set and those currently used in earth system models with likely consequences for modeling terrestrial biogeochemistry and land–atmosphere interactions. The main difference between the new LC_CCI product and PFT data sets used currently by three different dynamic global vegetation modeling teams is a reduction in high-latitude grassland cover, a reduction in tropical tree cover and an expansion in temperate forest cover in Europe. The LC_CCI tool is flexible for users to modify land cover to PFT conversions and will evolve as phase 2 of the European Space Agency CCI program continues.

Published
2015

47. Fire regimes and variability in aboveground woody biomass in miombo woodland

Author

Makoto Saito, Patricia Cadule, Valentin Bellassen, Casey M. Ryan, Philippe Ciais, Sebastiaan Luyssaert, Philippe Peylin, Mathew Williams, Chao Yue, Ben Poulter, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Institute for Environmental Studies (NIES), Montana State University (MSU), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre d'Economie et de Sociologie Rurales Appliquées à l'Agriculture et aux Espaces Ruraux (CESAER), AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Institut National de la Recherche Agronomique (INRA), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, and Systems Ecology

Subjects
Atmospheric Science, [SDV]Life Sciences [q-bio], Soil Science, Aquatic Science, chemistry.chemical_compound, Ecosystem model, SDG 13 - Climate Action, Fire ecology, Water Science and Technology, Flammable liquid, Climate pattern, Biomass (ecology), topkill, Fire regime, Ecology, biomass, Palaeontology, Paleontology, Forestry, 15. Life on land, resprouting, Miombo woodland, savanna, self-thinning, chemistry, 13. Climate action, Environmental science, fire regime, Woody plant
Abstract

This study combined a process-based ecosystem model with a fire regime model to understand the effect of changes in fire regime and climate pattern on woody plants of miombo woodland in African savanna. Miombo woodland covers wide areas in Africa and is subject to frequent anthropogenic fires. The model was developed based on observations of tree topkill rates in individual tree size classes for fire intensity and resprouting. Using current and near-future climate patterns, the model simulated the dynamics of miombo woodland for various fire return intervals and grass cover fractions, allowing fire intensity to be estimated. There was a significant relationship between aboveground woody biomass and long-term fire regimes. An abrupt increase in fire intensity and/or fire frequency applied as a model forcing led to reduced long-term average aboveground woody biomass and mean tree size. Fire intensity increased with increasing living grass biomass (which provides increased flammable fuel), thereby affecting the relationship between fire regime and tree size, creating a demographic bottleneck on the route to tree maturity. For the current fire regime in miombo woodland, with a fire return interval of about 1.6-3 years, the model-predicted fire intensity lower than 930-1700 kW m-1 is necessary to maintain today's aboveground woody biomass under current climate conditions. Future climate change was predicted to have a significant positive effect on woody plants in miombo woodland associated with elevated CO 2 concentration and warming, allowing woody plants to survive more effectively against periodic fires. Key Points Aboveground biomass is controlled by fire regimes Current fire management results in degradation of miombo woodland Future climate change has a positive effect on biomass of miombo woodland

Published
2014

48. Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity

Author

Zhenzhong Zeng, Huijuan Nan, Lingli Liu, Shushi Peng, Anping Chen, Ben Poulter, Philippe Ciais, Ranga B. Myneni, Tao Wang, Peter Levy, Xiaoying Shi, Pierre Friedlingstein, Xuhui Wang, Guodong Yin, Chris Huntingford, Mark R. Lomas, Philippe Peylin, Anders Ahlström, Soenke Zaehle, Josep G. Canadell, Ning Zeng, Stephen Sitch, Samuel Levis, Nicolas Viovy, Nan Cong, Shilong Piao, Jiafu Mao, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University [Beijing], Centre for Ecology and Hydrology [Wallingford] (CEH), Natural Environment Research Council (NERC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Exeter, College of Life and Environmental Sciences [Exeter], Lund University [Lund], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Chinese Academy of Sciences [Beijing] (CAS), National Center for Atmospheric Research [Boulder] (NCAR), UK Centre for Ecology & Hydrology, University of Sheffield [Sheffield], Environmental Sciences Division [Oak Ridge], Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC-UT-Battelle, LLC, Boston University [Boston] (BU), Modélisation des Surfaces et Interfaces Continentales (MOSAIC), Montana State University (MSU), Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft, Institute of Atmospheric Physics [Beijing] (IAP), National Engineering Research Center for Information Technology in Agriculture [Beijing] (NERCITA), Princeton University, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
Satellite Imagery, Climate, ved/biology.organism_classification_rank.species, General Physics and Astronomy, Growing season, Atmospheric sciences, Poaceae, Shrub, Global Warming, General Biochemistry, Genetics and Molecular Biology, Normalized Difference Vegetation Index, Atmospheric Sciences, Soil, Meteorology and Climatology, Ecosystem model, Temperate climate, Ecosystem, Computer Simulation, Photosynthesis, Plant Physiological Phenomena, Multidisciplinary, Geography, Ecology, ved/biology, Arctic Regions, Temperature, Biogeochemistry, General Chemistry, 15. Life on land, Plants, Tundra, Droughts, 13. Climate action, Environmental science, Seasons, Hydrology, [SDV.EE.BIO]Life Sciences [q-bio]/Ecology, environment/Bioclimatology, Environmental Monitoring
Abstract

International audience; Satellite-derived Normalized Difference Vegetation Index (NDVI), a proxy of vegetation productivity, is known to be correlated with temperature in northern ecosystems. This relationship, however, may change over time following alternations in other environmental factors. Here we show that above 30°N, the strength of the relationship between the interannual variability of growing season NDVI and temperature (partial correlation coefficient R NDVI-GT) declined substantially between 1982 and 2011. This decrease in R NDVI-GT is mainly observed in temperate and arctic ecosystems, and is also partly reproduced by process-based ecosystem model results. In the temperate ecosystem, the decrease in R NDVI-GT coincides with an increase in drought. In the arctic ecosystem, it may be related to a nonlinear response of photosynthesis to temperature, increase of hot extreme days and shrub expansion over grass-dominated tundra. Our results caution the use of results from interannual time scales to constrain the decadal response of plants to ongoing warming.

Published
2014

49. Mechanisms of water supply and vegetation demand govern the seasonality and magnitude of evapotranspiration in Amazonia and Cerrado

Author

Hans Verbeeck, David W. Galbraith, Gonzalo Miguez-Macho, Humberto Ribeiro da Rocha, Ben Poulter, Zong-Liang Yang, Ian Baker, Scott R. Saleska, Mingjie Shi, Lindsey E. Gulden, Bart Kruijt, Natalia Restrepo-Coupe, Xubin Zeng, Bart van den Hurk, Naomi M. Levine, Bradley O. Christoffersen, Kazuhito Ichii, Phillippe Ciais, Luis Gustavo Gonçalves de Gonçalves, A. K. Sahoo, Xiaodan Guan, Bruno Paraluppi Cestaro, Joshua B. Fisher, Atul K. Jain, Alessandro Araújo, Jordan Borak, Michel Nobre Muza, Koichi Sakaguchi, Hewlley Maria Acioli Imbuzeiro, Débora Regina Roberti, Kevin Schaefer, M. Altaf Arain, Antonio O. Manzi, Celso von Randow, Marcos Heil Costa, University of Arizona, McMaster University [Hamilton, Ontario], Colorado State University [Fort Collins] (CSU), Universidade Federal de São Paulo, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University of Oxford [Oxford], University of Edinburgh, Royal Netherlands Meteorological Institute (KNMI), Chiba University, Department of Atmospheric Sciences [Urbana], University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, University of Southern California (USC), Montana State University (MSU), Pacific Northwest National Laboratory (PNNL), University of California [Los Angeles] (UCLA), University of California, Alterra [Wageningen] (ESS-CC), Centre for Water and Climate [Wageningen], Universidade de São Paulo (USP), Instituto Nacional de Pesquisas Espaciais (INPE), Ministério da Ciência, Tecnologia e Inovação, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Oxford, University of California (UC), and Universidade de São Paulo = University of São Paulo (USP)

Subjects
Biosphere model, Atmospheric Science, Stomatal conductance, 010504 meteorology & atmospheric sciences, environment simulator jules, 0207 environmental engineering, Eddy covariance, 02 engineering and technology, climate model, 01 natural sciences, Earth System Science, Hydrology (agriculture), Evapotranspiration, Dry season, Meteorology & Atmospheric Sciences, Water-use efficiency, 020701 environmental engineering, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, AMAZÔNIA, 0105 earth and related environmental sciences, Hydrology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, regional evapotranspiration, biosphere model, Forestry, boundary-layer, Vegetation, 15. Life on land, land-surface scheme, Climate Resilience, atmosphere interactions, 13. Climate action, Klimaatbestendigheid, stomatal conductance, model description, carbon-cycle feedbacks, Environmental science, Leerstoelgroep Aardsysteemkunde, Agronomy and Crop Science
Abstract

Evapotranspiration (E) in the Amazon connects forest function and regional climate via its role in precipitation recycling However, the mechanisms regulating water supply to vegetation and its demand for water remain poorly understood, especially during periods of seasonal water deficits In this study, we address two main questions: First, how do mechanisms of water supply (indicated by rooting depth and groundwater) and vegetation water demand (indicated by stomatal conductance and intrinsic water use efficiency) control evapotranspiration (E) along broad gradients of climate and vegetation from equatorial Amazonia to Cerrado, and second, how do these inferred mechanisms of supply and demand compare to those employed by a suite of ecosystem models? We used a network of eddy covariance towers in Brazil coupled with ancillary measurements to address these questions With respect to the magnitude and seasonality of E, models have much improved in equatorial tropical forests by eliminating most dry season water limitation, diverge in performance in transitional forests where seasonal water deficits are greater, and mostly capture the observed seasonal depressions in E at Cerrado However, many models depended universally on either deep roots or groundwater to mitigate dry season water deficits, the relative importance of which we found does not vary as a simple function of climate or vegetation In addition, canopy stomatal conductance (gs) regulates dry season vegetation demand for water at all except the wettest sites even as the seasonal cycle of E follows that of net radiation In contrast, some models simulated no seasonality in gs, even while matching the observed seasonal cycle of E. We suggest that canopy dynamics mediated by leaf phenology may play a significant role in such seasonality, a process poorly represented in models Model bias in gs and E, in turn, was related to biases arising from the simulated light response (gross primary productivity, GPP) or the intrinsic water use efficiency of photosynthesis (iWUE). We identified deficiencies in models which would not otherwise be apparent based on a simple comparison of simulated and observed rates of E. While some deficiencies can be remedied by parameter tuning, in most models they highlight the need for continued process development of belowground hydrology and in particular, the biological processes of root dynamics and leaf phenology, which via their controls on E, mediate vegetation-climate feedbacks in the tropics. © 2014 Elsevier B.V.

Published
2014

50. Inter-annual variability of carbon and water fluxes in Amazonian forest, Cerrado and pasture sites, as simulated by terrestrial biosphere models

Author

Gonzalo Miguez-Macho, Luis Gustavo Gonçalves de Gonçalves, Kevin Schaefer, Antonio O. Manzi, Natalia Restrepo-Coupe, Bart van den Hurk, David W. Galbraith, Bruno Paraluppi Cestaro, Xiaodan Guan, Philippe Ciais, Joshua B. Fisher, Hans Verbeeck, Marcos Heil Costa, Hewlley Maria Acioli Imbuzeiro, Marcelo Zeri, Michel Nobre Muza, M. Alaf Arain, A. K. Sahoo, Zong-Liang Yang, Alessandro Araújo, Scott R. Saleska, Mingjie Shi, Ian Baker, Bradley O. Christoffersen, Kazuhito Ichii, Naomi M. Levine, Atul K. Jain, Humberto Ribeiro da Rocha, Débora Regina Roberti, Hanqin Tian, Ben Poulter, Celso von Randow, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Eddy covariance, Climate change, Rainforest, 010603 evolutionary biology, 01 natural sciences, Pasture, Evapotranspiration, Meteorology & Atmospheric Sciences, Precipitation, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, AMAZÔNIA, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, geography, geography.geographical_feature_category, Biosphere, Forestry, Ecotone, 15. Life on land, 13. Climate action, Climatology, Environmental science, Agronomy and Crop Science
Abstract

This study analyzes the inter-annual variability (IAV) of simulations of 21 different land surface model formulations, driven by meteorological conditions measured at 8 flux towers, located in rain forest, forest-savanna ecotone and pasture sites in Amazonia, and one in savanna site in Southeastern Brazil. Annual totals of net ecosystem exchange (NEE) of carbon and evapotranspiration (ET), measured and simulated by each model for each site-year, were compared in terms of year-to-year variability and possible relation to climate drivers. Results have shown that most of models simulations for annual totals of NEE and ET, and IAV of these fluxes, are frequently different from measurements. The average of the model simulations of annual fluxes tend to respond to climatic drivers similarly to the observations, but with noticeable discrepancies. Annual measurements of NEE are negatively correlated to annual rainfall in the forest sites group. Although the ensemble of all models yields a similar result, only three model formulations reproduce a significant negative correlation of simulated NEE with rainfall. For the IAV of ET, tower measurements are controlled by annual variations of radiation and this feature is captured by the ensemble of the models, both at individual sites and when all forest sites are grouped. However, simulated ET values are also significantly correlated to the amount of precipitation in many models and in the model ensemble, while there is no significant correlation in the observations. In general, the surface models are able to reproduce the responses of fluxes to climatic drivers, but improvements are still needed to better capture their inter-annual variability. © 2013 Elsevier B.V..

Published
2013

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