Articles | Volume 18, issue 8
https://doi.org/10.5194/cp-18-1897-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-18-1897-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
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22 Aug 2022
Research article | Highlight paper |
| 22 Aug 2022
| 22 Aug 2022
Effects of orbital forcing, greenhouse gases and ice sheets on Saharan greening in past and future multi-millennia
Mateo Duque-Villegas
CORRESPONDING AUTHOR
Max Planck Institute for Meteorology, Hamburg, Germany
International Max Planck Research School on Earth System Modelling, Hamburg, Germany
Martin Claussen
Max Planck Institute for Meteorology, Hamburg, Germany
Center for Earth System Research and Sustainability (CEN), Universität Hamburg, Hamburg, Germany
Victor Brovkin
Max Planck Institute for Meteorology, Hamburg, Germany
Thomas Kleinen
Max Planck Institute for Meteorology, Hamburg, Germany
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Wetland methane responses to temperature and precipitation were studied in a boreal wetland-rich region in Northern Europe using ecosystem models, atmospheric inversions and up-scaled flux observations. The ecosystem models differed in their responses to temperature and precipitation and in their seasonality. However, multi-model means, inversions and up-scaled fluxes had similar seasonality, and they suggested co-limitation by temperature and precipitation.
István Dunkl, Nicole Lovenduski, Alessio Collalti, Vivek K. Arora, Tatiana Ilyina, and Victor Brovkin
Biogeosciences, 20, 3523–3538, https://doi.org/10.5194/bg-20-3523-2023, https://doi.org/10.5194/bg-20-3523-2023, 2023
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Despite differences in the reproduction of gross primary productivity (GPP) by Earth system models (ESMs), ESMs have similar predictability of the global carbon cycle. We found that, although GPP variability originates from different regions and is driven by different climatic variables across the ESMs, the ESMs rely on the same mechanisms to predict their own GPP. This shows that the predictability of the carbon cycle is limited by our understanding of variability rather than predictability.
Zoé Rehder, Thomas Kleinen, Lars Kutzbach, Victor Stepanenko, Moritz Langer, and Victor Brovkin
Biogeosciences, 20, 2837–2855, https://doi.org/10.5194/bg-20-2837-2023, https://doi.org/10.5194/bg-20-2837-2023, 2023
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Matteo Willeit, Tatiana Ilyina, Bo Liu, Christoph Heinze, Mahé Perrette, Malte Heinemann, Daniela Dalmonech, Victor Brovkin, Guy Munhoven, Janine Börker, Jens Hartmann, Gibran Romero-Mujalli, and Andrey Ganopolski
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Thomas Kleinen, Sergey Gromov, Benedikt Steil, and Victor Brovkin
Clim. Past, 19, 1081–1099, https://doi.org/10.5194/cp-19-1081-2023, https://doi.org/10.5194/cp-19-1081-2023, 2023
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We modelled atmospheric methane continuously from the last glacial maximum to the present using a state-of-the-art Earth system model. Our model results compare well with reconstructions from ice cores and improve our understanding of a very intriguing period of Earth system history, the deglaciation, when atmospheric methane changed quickly and strongly. Deglacial methane changes are driven by emissions from tropical wetlands, with wetlands in high northern latitudes being secondary.
Philipp de Vrese, Goran Georgievski, Jesus Fidel Gonzalez Rouco, Dirk Notz, Tobias Stacke, Norman Julius Steinert, Stiig Wilkenskjeld, and Victor Brovkin
The Cryosphere, 17, 2095–2118, https://doi.org/10.5194/tc-17-2095-2023, https://doi.org/10.5194/tc-17-2095-2023, 2023
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Leonore Jungandreas, Cathy Hohenegger, and Martin Claussen
Clim. Past, 19, 637–664, https://doi.org/10.5194/cp-19-637-2023, https://doi.org/10.5194/cp-19-637-2023, 2023
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Nora Farina Specht, Martin Claussen, and Thomas Kleinen
Clim. Past, 18, 1035–1046, https://doi.org/10.5194/cp-18-1035-2022, https://doi.org/10.5194/cp-18-1035-2022, 2022
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Palaeoenvironmental records only provide a fragmentary picture of the lake and wetland extent in North Africa during the mid-Holocene. Therefore, we investigate the possible range of mid-Holocene precipitation changes caused by an estimated small and maximum lake extent and a maximum wetland extent. Results show a particularly strong monsoon precipitation response to lakes and wetlands over the Western Sahara and an increased monsoon precipitation when replacing lakes with vegetated wetlands.
Stiig Wilkenskjeld, Frederieke Miesner, Paul P. Overduin, Matteo Puglini, and Victor Brovkin
The Cryosphere, 16, 1057–1069, https://doi.org/10.5194/tc-16-1057-2022, https://doi.org/10.5194/tc-16-1057-2022, 2022
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Thawing permafrost releases carbon to the atmosphere, enhancing global warming. Part of the permafrost soils have been flooded by rising sea levels since the last ice age, becoming subsea permafrost (SSPF). The SSPF is less studied than the part on land. In this study we use a global model to obtain rates of thawing of SSPF under different future climate scenarios until the year 3000. After the year 2100 the scenarios strongly diverge, closely connected to the eventual disappearance of sea ice.
Jooyeop Lee, Martin Claussen, Jeongwon Kim, Je-Woo Hong, In-Sun Song, and Jinkyu Hong
Clim. Past, 18, 313–326, https://doi.org/10.5194/cp-18-313-2022, https://doi.org/10.5194/cp-18-313-2022, 2022
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It is still a challenge to simulate the so–called Green Sahara (GS), which was a wet and vegetative Sahara region in the mid–Holocene, using current climate models. Our analysis shows that Holocene greening is simulated better if the amount of soil nitrogen and soil texture is properly modified for the humid and vegetative GS period. Future climate simulation needs to consider consequent changes in soil nitrogen and texture with changes in vegetation cover for proper climate simulations.
Anne Dallmeyer, Martin Claussen, Stephan J. Lorenz, Michael Sigl, Matthew Toohey, and Ulrike Herzschuh
Clim. Past, 17, 2481–2513, https://doi.org/10.5194/cp-17-2481-2021, https://doi.org/10.5194/cp-17-2481-2021, 2021
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Using the comprehensive Earth system model, MPI-ESM1.2, we explore the global Holocene vegetation changes and interpret them in terms of the Holocene climate change. The model results reveal that most of the Holocene vegetation transitions seen outside the high northern latitudes can be attributed to modifications in the intensity of the global summer monsoons.
István Dunkl, Aaron Spring, Pierre Friedlingstein, and Victor Brovkin
Earth Syst. Dynam., 12, 1413–1426, https://doi.org/10.5194/esd-12-1413-2021, https://doi.org/10.5194/esd-12-1413-2021, 2021
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The variability in atmospheric CO2 is largely controlled by terrestrial carbon fluxes. These land–atmosphere fluxes are predictable for around 2 years, but the mechanisms providing the predictability are not well understood. By decomposing the predictability of carbon fluxes into individual contributors we were able to explain the spatial and seasonal patterns and the interannual variability of CO2 flux predictability.
Aaron Spring, István Dunkl, Hongmei Li, Victor Brovkin, and Tatiana Ilyina
Earth Syst. Dynam., 12, 1139–1167, https://doi.org/10.5194/esd-12-1139-2021, https://doi.org/10.5194/esd-12-1139-2021, 2021
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Numerical carbon cycle prediction models usually do not start from observed carbon states due to sparse observations. Instead, only physical climate is reconstructed, assuming that the carbon cycle follows indirectly. Here, we test in an idealized framework how well this indirect and direct reconstruction with perfect observations works. We find that indirect reconstruction works quite well and that improvements from the direct method are limited, strengthening the current indirect use.
Alexander J. Winkler, Ranga B. Myneni, Alexis Hannart, Stephen Sitch, Vanessa Haverd, Danica Lombardozzi, Vivek K. Arora, Julia Pongratz, Julia E. M. S. Nabel, Daniel S. Goll, Etsushi Kato, Hanqin Tian, Almut Arneth, Pierre Friedlingstein, Atul K. Jain, Sönke Zaehle, and Victor Brovkin
Biogeosciences, 18, 4985–5010, https://doi.org/10.5194/bg-18-4985-2021, https://doi.org/10.5194/bg-18-4985-2021, 2021
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Satellite observations since the early 1980s show that Earth's greening trend is slowing down and that browning clusters have been emerging, especially in the last 2 decades. A collection of model simulations in conjunction with causal theory points at climatic changes as a key driver of vegetation changes in natural ecosystems. Most models underestimate the observed vegetation browning, especially in tropical rainforests, which could be due to an excessive CO2 fertilization effect in models.
Leonore Jungandreas, Cathy Hohenegger, and Martin Claussen
Clim. Past, 17, 1665–1684, https://doi.org/10.5194/cp-17-1665-2021, https://doi.org/10.5194/cp-17-1665-2021, 2021
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We investigate the impact of explicitly resolving convection on the mid-Holocene West African Monsoon rain belt by employing the ICON climate model in high resolution. While the spatial distribution and intensity of the precipitation are improved by this technique, the monsoon extents further north and the mean summer rainfall is higher in the simulation with parameterized convection.
Philipp de Vrese, Tobias Stacke, Thomas Kleinen, and Victor Brovkin
The Cryosphere, 15, 1097–1130, https://doi.org/10.5194/tc-15-1097-2021, https://doi.org/10.5194/tc-15-1097-2021, 2021
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With large amounts of carbon stored in frozen soils and a highly energy-limited vegetation the Arctic is very sensitive to changes in climate. Here our simulations with the land surface model JSBACH reveal a number of offsetting factors moderating the Arctic's net response to global warming. More importantly we find that the effects of climate change may not be fully reversible on decadal timescales, leading to substantially different CH4 emissions depending on whether the Arctic warms or cools.
Claudia Tebaldi, Kevin Debeire, Veronika Eyring, Erich Fischer, John Fyfe, Pierre Friedlingstein, Reto Knutti, Jason Lowe, Brian O'Neill, Benjamin Sanderson, Detlef van Vuuren, Keywan Riahi, Malte Meinshausen, Zebedee Nicholls, Katarzyna B. Tokarska, George Hurtt, Elmar Kriegler, Jean-Francois Lamarque, Gerald Meehl, Richard Moss, Susanne E. Bauer, Olivier Boucher, Victor Brovkin, Young-Hwa Byun, Martin Dix, Silvio Gualdi, Huan Guo, Jasmin G. John, Slava Kharin, YoungHo Kim, Tsuyoshi Koshiro, Libin Ma, Dirk Olivié, Swapna Panickal, Fangli Qiao, Xinyao Rong, Nan Rosenbloom, Martin Schupfner, Roland Séférian, Alistair Sellar, Tido Semmler, Xiaoying Shi, Zhenya Song, Christian Steger, Ronald Stouffer, Neil Swart, Kaoru Tachiiri, Qi Tang, Hiroaki Tatebe, Aurore Voldoire, Evgeny Volodin, Klaus Wyser, Xiaoge Xin, Shuting Yang, Yongqiang Yu, and Tilo Ziehn
Earth Syst. Dynam., 12, 253–293, https://doi.org/10.5194/esd-12-253-2021, https://doi.org/10.5194/esd-12-253-2021, 2021
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We present an overview of CMIP6 ScenarioMIP outcomes from up to 38 participating ESMs according to the new SSP-based scenarios. Average temperature and precipitation projections according to a wide range of forcings, spanning a wider range than the CMIP5 projections, are documented as global averages and geographic patterns. Times of crossing various warming levels are computed, together with benefits of mitigation for selected pairs of scenarios. Comparisons with CMIP5 are also discussed.
Lena R. Boysen, Victor Brovkin, Julia Pongratz, David M. Lawrence, Peter Lawrence, Nicolas Vuichard, Philippe Peylin, Spencer Liddicoat, Tomohiro Hajima, Yanwu Zhang, Matthias Rocher, Christine Delire, Roland Séférian, Vivek K. Arora, Lars Nieradzik, Peter Anthoni, Wim Thiery, Marysa M. Laguë, Deborah Lawrence, and Min-Hui Lo
Biogeosciences, 17, 5615–5638, https://doi.org/10.5194/bg-17-5615-2020, https://doi.org/10.5194/bg-17-5615-2020, 2020
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We find a biogeophysically induced global cooling with strong carbon losses in a 20 million square kilometre idealized deforestation experiment performed by nine CMIP6 Earth system models. It takes many decades for the temperature signal to emerge, with non-local effects playing an important role. Despite a consistent experimental setup, models diverge substantially in their climate responses. This study offers unprecedented insights for understanding land use change effects in CMIP6 models.
Taraka Davies-Barnard, Johannes Meyerholt, Sönke Zaehle, Pierre Friedlingstein, Victor Brovkin, Yuanchao Fan, Rosie A. Fisher, Chris D. Jones, Hanna Lee, Daniele Peano, Benjamin Smith, David Wårlind, and Andy J. Wiltshire
Biogeosciences, 17, 5129–5148, https://doi.org/10.5194/bg-17-5129-2020, https://doi.org/10.5194/bg-17-5129-2020, 2020
Vivek K. Arora, Anna Katavouta, Richard G. Williams, Chris D. Jones, Victor Brovkin, Pierre Friedlingstein, Jörg Schwinger, Laurent Bopp, Olivier Boucher, Patricia Cadule, Matthew A. Chamberlain, James R. Christian, Christine Delire, Rosie A. Fisher, Tomohiro Hajima, Tatiana Ilyina, Emilie Joetzjer, Michio Kawamiya, Charles D. Koven, John P. Krasting, Rachel M. Law, David M. Lawrence, Andrew Lenton, Keith Lindsay, Julia Pongratz, Thomas Raddatz, Roland Séférian, Kaoru Tachiiri, Jerry F. Tjiputra, Andy Wiltshire, Tongwen Wu, and Tilo Ziehn
Biogeosciences, 17, 4173–4222, https://doi.org/10.5194/bg-17-4173-2020, https://doi.org/10.5194/bg-17-4173-2020, 2020
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Since the preindustrial period, land and ocean have taken up about half of the carbon emitted into the atmosphere by humans. Comparison of different earth system models with the carbon cycle allows us to assess how carbon uptake by land and ocean differs among models. This yields an estimate of uncertainty in our understanding of how land and ocean respond to increasing atmospheric CO2. This paper summarizes results from two such model intercomparison projects that use an idealized scenario.
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 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, 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
Earth Syst. Sci. Data, 12, 1561–1623, https://doi.org/10.5194/essd-12-1561-2020, https://doi.org/10.5194/essd-12-1561-2020, 2020
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Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. 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. This is the second version of the review dedicated to the decadal methane budget, integrating results of top-down and bottom-up estimates.
Matteo Puglini, Victor Brovkin, Pierre Regnier, and Sandra Arndt
Biogeosciences, 17, 3247–3275, https://doi.org/10.5194/bg-17-3247-2020, https://doi.org/10.5194/bg-17-3247-2020, 2020
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A reaction-transport model to assess the potential non-turbulent methane flux from the East Siberian Arctic sediments to water columns is applied here. We show that anaerobic oxidation of methane (AOM) is an efficient filter except for high values of sedimentation rate and advective flow, which enable considerable non-turbulent steady-state methane fluxes. Significant transient methane fluxes can also occur during the building-up phase of the AOM-performing biomass microbial community.
Andrew H. MacDougall, Thomas L. Frölicher, Chris D. Jones, Joeri Rogelj, H. Damon Matthews, Kirsten Zickfeld, Vivek K. Arora, Noah J. Barrett, Victor Brovkin, Friedrich A. Burger, Micheal Eby, Alexey V. Eliseev, Tomohiro Hajima, Philip B. Holden, Aurich Jeltsch-Thömmes, Charles Koven, Nadine Mengis, Laurie Menviel, Martine Michou, Igor I. Mokhov, Akira Oka, Jörg Schwinger, Roland Séférian, Gary Shaffer, Andrei Sokolov, Kaoru Tachiiri, Jerry Tjiputra, Andrew Wiltshire, and Tilo Ziehn
Biogeosciences, 17, 2987–3016, https://doi.org/10.5194/bg-17-2987-2020, https://doi.org/10.5194/bg-17-2987-2020, 2020
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The Zero Emissions Commitment (ZEC) is the change in global temperature expected to occur following the complete cessation of CO2 emissions. Here we use 18 climate models to assess the value of ZEC. For our experiment we find that ZEC 50 years after emissions cease is between −0.36 to +0.29 °C. The most likely value of ZEC is assessed to be close to zero. However, substantial continued warming for decades or centuries following cessation of CO2 emission cannot be ruled out.
Thomas Kleinen, Uwe Mikolajewicz, and Victor Brovkin
Clim. Past, 16, 575–595, https://doi.org/10.5194/cp-16-575-2020, https://doi.org/10.5194/cp-16-575-2020, 2020
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We investigate the changes in natural methane emissions between the Last Glacial Maximum and preindustrial periods with a methane-enabled version of MPI-ESM. We consider all natural sources of methane except for emissions from wild animals and geological sources. Changes are dominated by changes in tropical wetland emissions, high-latitude wetlands play a secondary role, and all other natural sources are of minor importance. We explain the changes in ice core methane by methane emissions only.
Anne Dallmeyer, Martin Claussen, Stephan J. Lorenz, and Timothy Shanahan
Clim. Past, 16, 117–140, https://doi.org/10.5194/cp-16-117-2020, https://doi.org/10.5194/cp-16-117-2020, 2020
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We analyse the end of the African humid period (AHP) in a transient Holocene simulation performed with the comprehensive Earth system model MPI-ESM1.2. The model reproduces the time-transgressive end of the AHP evident in proxy data and indicates that changes in moisture can be attributed to the retreat of the summer monsoon and to changes in the extratropical troughs. The spatially varying impact of these systems imposes regionally different responses to the Holocene insolation change.
Georgii A. Alexandrov, Victor A. Brovkin, Thomas Kleinen, and Zicheng Yu
Biogeosciences, 17, 47–54, https://doi.org/10.5194/bg-17-47-2020, https://doi.org/10.5194/bg-17-47-2020, 2020
Mateo Duque-Villegas, Juan Fernando Salazar, and Angela Maria Rendón
Earth Syst. Dynam., 10, 631–650, https://doi.org/10.5194/esd-10-631-2019, https://doi.org/10.5194/esd-10-631-2019, 2019
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Earth's climate can be studied as a system with different components that can be strongly altered by human influence. One possibility is that the El Niño phenomenon becomes more frequent. We investigated the potential impacts of the most frequent El Niño: a permanent one. The most noticeable impacts include variations in global water availability and vegetation productivity, potential dieback of the Amazon rainforest, greening of western North America, and further aridification of Australia.
Alexander J. Winkler, Ranga B. Myneni, and Victor Brovkin
Earth Syst. Dynam., 10, 501–523, https://doi.org/10.5194/esd-10-501-2019, https://doi.org/10.5194/esd-10-501-2019, 2019
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The concept of
emergent constraintsis a key method to reduce uncertainty in multi-model climate projections using historical simulations and observations. Here, we present an in-depth analysis of the applicability of the method and uncover possible limitations. Key limitations are a lack of comparability (temporal, spatial, and conceptual) between models and observations and the disagreement between models on system dynamics throughout different levels of atmospheric CO2 concentration.
Victor Brovkin, Stephan Lorenz, Thomas Raddatz, Tatiana Ilyina, Irene Stemmler, Matthew Toohey, and Martin Claussen
Biogeosciences, 16, 2543–2555, https://doi.org/10.5194/bg-16-2543-2019, https://doi.org/10.5194/bg-16-2543-2019, 2019
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Mechanisms of atmospheric CO2 growth by 20 ppm from 6000 BCE to the pre-industrial period are still uncertain. We apply the Earth system model MPI-ESM-LR for two transient simulations of the climate–carbon cycle. An additional process, e.g. carbonate accumulation on shelves, is required for consistency with ice-core CO2 data. Our simulations support the hypothesis that the ocean was a source of CO2 until the late Holocene when anthropogenic CO2 sources started to affect atmospheric CO2.
Anne Dallmeyer, Martin Claussen, and Victor Brovkin
Clim. Past, 15, 335–366, https://doi.org/10.5194/cp-15-335-2019, https://doi.org/10.5194/cp-15-335-2019, 2019
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A simple but powerful method for the biomisation of plant functional type distributions is introduced and tested for six different dynamic global vegetation models based on pre-industrial and palaeo-simulations. The method facilitates the direct comparison between vegetation distributions simulated by different Earth system models and between model results and the pollen-based biome reconstructions. It is therefore a powerful tool for the evaluation of Earth system models.
Thomas Schneider von Deimling, Thomas Kleinen, Gustaf Hugelius, Christian Knoblauch, Christian Beer, and Victor Brovkin
Clim. Past, 14, 2011–2036, https://doi.org/10.5194/cp-14-2011-2018, https://doi.org/10.5194/cp-14-2011-2018, 2018
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Past cold ice age temperatures and the subsequent warming towards the Holocene had large consequences for soil organic carbon (SOC) stored in perennially frozen grounds. Using an Earth system model we show how the spread in areas affected by permafrost have changed under deglacial warming, along with changes in SOC accumulation. Our model simulations suggest phases of circum-Arctic permafrost SOC gain and losses, with a net increase in SOC between the last glacial maximum and the pre-industrial.
Thomas Riddick, Victor Brovkin, Stefan Hagemann, and Uwe Mikolajewicz
Geosci. Model Dev., 11, 4291–4316, https://doi.org/10.5194/gmd-11-4291-2018, https://doi.org/10.5194/gmd-11-4291-2018, 2018
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During the Last Glacial Maximum, many rivers were blocked by the presence of large ice sheets and thus found new routes to the sea. This resulted in changes in the pattern of freshwater discharge into the oceans and thus would have significantly affected ocean circulation. Also, rivers found routes across the vast exposed continental shelves to the lower coastlines of that time. We propose a model for such changes in river routing suitable for use in wider models of the last glacial cycle.
Uwe Mikolajewicz, Florian Ziemen, Guido Cioni, Martin Claussen, Klaus Fraedrich, Marvin Heidkamp, Cathy Hohenegger, Diego Jimenez de la Cuesta, Marie-Luise Kapsch, Alexander Lemburg, Thorsten Mauritsen, Katharina Meraner, Niklas Röber, Hauke Schmidt, Katharina D. Six, Irene Stemmler, Talia Tamarin-Brodsky, Alexander Winkler, Xiuhua Zhu, and Bjorn Stevens
Earth Syst. Dynam., 9, 1191–1215, https://doi.org/10.5194/esd-9-1191-2018, https://doi.org/10.5194/esd-9-1191-2018, 2018
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Model experiments show that changing the sense of Earth's rotation has relatively little impact on the globally and zonally averaged energy budgets but leads to large shifts in continental climates and patterns of precipitation. The retrograde world is greener as the desert area shrinks. Deep water formation shifts from the North Atlantic to the North Pacific with subsequent changes in ocean overturning. Over large areas of the Indian Ocean, cyanobacteria dominate over bulk phytoplankton.
Sabine Egerer, Martin Claussen, and Christian Reick
Clim. Past, 14, 1051–1066, https://doi.org/10.5194/cp-14-1051-2018, https://doi.org/10.5194/cp-14-1051-2018, 2018
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We find a rapid increase in simulated dust deposition between 6 and
4 ka BP that is fairly consistent with an abrupt change in dust deposition that was observed in marine sediment records at around 5 ka BP. This rapid change is caused by a rapid increase in simulated dust emissions in the western Sahara due to a fast decline in vegetation cover and a locally strong reduction of lake area. Our study identifies spatial and temporal heterogeneity in the transition of the North African landscape.
Sirisha Kalidindi, Christian H. Reick, Thomas Raddatz, and Martin Claussen
Earth Syst. Dynam., 9, 739–756, https://doi.org/10.5194/esd-9-739-2018, https://doi.org/10.5194/esd-9-739-2018, 2018
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Using climate simulations, we investigate the role of water recycling in shaping the climate of low-obliquity Earth-like terra-planets. By such a mechanism feeding water back from the extra-tropics to the tropics, the planet can assume two drastically different climate states differing by more than 35 K in global temperature. We describe the bifurcation between the two states occurring upon changes in surface albedo and argue that the bistability hints at a wider habitable zone for such planets.
Sandy P. Harrison, Patrick J. Bartlein, Victor Brovkin, Sander Houweling, Silvia Kloster, and I. Colin Prentice
Earth Syst. Dynam., 9, 663–677, https://doi.org/10.5194/esd-9-663-2018, https://doi.org/10.5194/esd-9-663-2018, 2018
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Temperature affects fire occurrence and severity. Warming will increase fire-related carbon emissions and thus atmospheric CO2. The size of this feedback is not known. We use charcoal records to estimate pre-industrial fire emissions and a simple land–biosphere model to quantify the feedback. We infer a feedback strength of 5.6 3.2 ppm CO2 per degree of warming and a gain of 0.09 ± 0.05 for a climate sensitivity of 2.8 K. Thus, fire feedback is a large part of the climate–carbon-cycle feedback.
Karel Castro-Morales, Thomas Kleinen, Sonja Kaiser, Sönke Zaehle, Fanny Kittler, Min Jung Kwon, Christian Beer, and Mathias Göckede
Biogeosciences, 15, 2691–2722, https://doi.org/10.5194/bg-15-2691-2018, https://doi.org/10.5194/bg-15-2691-2018, 2018
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We present year-round methane emissions from wetlands in Northeast Siberia that were simulated with a land surface model. Ground-based flux measurements from the same area were used for evaluation of the model results, finding a best agreement with the observations in the summertime emissions that take place in this region predominantly through plants. During winter, methane emissions through the snow contribute 4 % of the total annual methane budget, but these are still underestimated.
Markus Adloff, Christian H. Reick, and Martin Claussen
Earth Syst. Dynam., 9, 413–425, https://doi.org/10.5194/esd-9-413-2018, https://doi.org/10.5194/esd-9-413-2018, 2018
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Computer simulations show that during an ice age a strong atmospheric CO2 increase would have resulted in stronger carbon uptake of the continents than today. Causes are the larger potential of glacial vegetation to increase its photosynthetic efficiency under increasing CO2 and the smaller amount of carbon in extratropical soils during an ice age that can be released under greenhouse warming. Hence, for different climates the Earth system is differently sensitive to carbon cycle perturbations.
Vivienne P. Groner, Thomas Raddatz, Christian H. Reick, and Martin Claussen
Biogeosciences, 15, 1947–1968, https://doi.org/10.5194/bg-15-1947-2018, https://doi.org/10.5194/bg-15-1947-2018, 2018
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We show that plant functional diversity significantly affects climate–vegetation interaction and the climate–vegetation system stability in response to external forcing using a series of coupled land–atmosphere simulation. Our findings raise the question of how realistically Earth system models can actually represent climate–vegetation interaction, considering the incomplete representation of plant functional diversity in the current generation of land surface models.
Maarit Raivonen, Sampo Smolander, Leif Backman, Jouni Susiluoto, Tuula Aalto, Tiina Markkanen, Jarmo Mäkelä, Janne Rinne, Olli Peltola, Mika Aurela, Annalea Lohila, Marin Tomasic, Xuefei Li, Tuula Larmola, Sari Juutinen, Eeva-Stiina Tuittila, Martin Heimann, Sanna Sevanto, Thomas Kleinen, Victor Brovkin, and Timo Vesala
Geosci. Model Dev., 10, 4665–4691, https://doi.org/10.5194/gmd-10-4665-2017, https://doi.org/10.5194/gmd-10-4665-2017, 2017
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Wetlands are one of the most significant natural sources of the strong greenhouse gas methane. We developed a model that can be used within a larger wetland carbon model to simulate the methane emissions. In this study, we present the model and results of its testing. We found that the model works well with different settings and that the results depend primarily on the rate of input anoxic soil respiration and also on factors that affect the simulated oxygen concentrations in the wetland soil.
Andrey Ganopolski and Victor Brovkin
Clim. Past, 13, 1695–1716, https://doi.org/10.5194/cp-13-1695-2017, https://doi.org/10.5194/cp-13-1695-2017, 2017
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Ice cores reveal that atmospheric CO2 concentration varied synchronously with the global ice volume. Explaining the mechanism of glacial–interglacial variations of atmospheric CO2 concentrations and the link between CO2 and ice sheets evolution still remains a challenge. Here using the Earth system model of intermediate complexity we performed for the first time simulations of co-evolution of climate, ice sheets and carbon cycle using the astronomical forcing as the only external forcing.
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, Patrick Crill, Kristofer Covey, 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, Joe R. Melton, Isamu Morino, Vaishali Naik, Simon O'Doherty, Frans-Jan W. Parmentier, Prabir K. Patra, Changhui Peng, Shushi Peng, Glen P. Peters, Isabelle Pison, Ronald Prinn, Michel Ramonet, William J. Riley, Makoto Saito, Monia Santini, Ronny Schroeder, Isobel J. Simpson, Renato Spahni, Atsushi Takizawa, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Nicolas Viovy, Apostolos Voulgarakis, Ray Weiss, David J. Wilton, Andy Wiltshire, Doug Worthy, Debra Wunch, Xiyan Xu, Yukio Yoshida, Bowen Zhang, Zhen Zhang, and Qiuan Zhu
Atmos. Chem. Phys., 17, 11135–11161, https://doi.org/10.5194/acp-17-11135-2017, https://doi.org/10.5194/acp-17-11135-2017, 2017
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Following the Global Methane Budget 2000–2012 published in Saunois et al. (2016), we use the same dataset of bottom-up and top-down approaches to discuss the variations in methane emissions over the period 2000–2012. The changes in emissions are discussed both in terms of trends and quasi-decadal changes. The ensemble gathered here allows us to synthesise the robust changes in terms of regional and sectorial contributions to the increasing methane emissions.
Daniel S. Goll, Alexander J. Winkler, Thomas Raddatz, Ning Dong, Ian Colin Prentice, Philippe Ciais, and Victor Brovkin
Geosci. Model Dev., 10, 2009–2030, https://doi.org/10.5194/gmd-10-2009-2017, https://doi.org/10.5194/gmd-10-2009-2017, 2017
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The response of soil organic carbon decomposition to warming and the interactions between nitrogen and carbon cycling affect the feedbacks between the land carbon cycle and the climate. In the model JSBACH carbon–nitrogen interactions have only a small effect on the feedbacks, whereas modifications of soil organic carbon decomposition have a large effect. The carbon cycle in the improved model is more resilient to climatic changes than in previous version of the model.
Anne Dallmeyer, Martin Claussen, Jian Ni, Xianyong Cao, Yongbo Wang, Nils Fischer, Madlene Pfeiffer, Liya Jin, Vyacheslav Khon, Sebastian Wagner, Kerstin Haberkorn, and Ulrike Herzschuh
Clim. Past, 13, 107–134, https://doi.org/10.5194/cp-13-107-2017, https://doi.org/10.5194/cp-13-107-2017, 2017
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The vegetation distribution in eastern Asia is supposed to be very sensitive to climate change. Since proxy records are scarce, hitherto a mechanistic understanding of the past spatio-temporal climate–vegetation relationship is lacking. To assess the Holocene vegetation change, we forced the diagnostic biome model BIOME4 with climate anomalies of different transient climate simulations.
Beniamino Abis and Victor Brovkin
Biogeosciences, 14, 511–527, https://doi.org/10.5194/bg-14-511-2017, https://doi.org/10.5194/bg-14-511-2017, 2017
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We study the link between the boreal tree-cover fraction distribution and eight globally observed environmental factors. We find that they exert a strong control over the tree-cover distribution, generally uniquely determining its state. Furthermore, we show the location of areas with potentially alternative tree-cover states under the same environmental conditions. These areas represent transition zones with reduced resilience, where the forest can shift between different vegetation states.
Sonja Kaiser, Mathias Göckede, Karel Castro-Morales, Christian Knoblauch, Altug Ekici, Thomas Kleinen, Sebastian Zubrzycki, Torsten Sachs, Christian Wille, and Christian Beer
Geosci. Model Dev., 10, 333–358, https://doi.org/10.5194/gmd-10-333-2017, https://doi.org/10.5194/gmd-10-333-2017, 2017
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A new consistent, process-based methane module that is integrated with permafrost processes is presented. It was developed within a global land surface scheme and evaluated at a polygonal tundra site in Samoylov, Russia. The calculated methane emissions show fair agreement with field data and capture detailed differences between the explicitly modelled gas transport processes and in the gas dynamics under varying soil water and temperature conditions during seasons and on different microsites.
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, Kristofer Covey, 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, Vaishali Naik, 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, Monia Santini, 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 R. van der Werf, Ray Weiss, Christine Wiedinmyer, David J. Wilton, Andy Wiltshire, Doug Worthy, Debra Wunch, Xiyan Xu, Yukio Yoshida, Bowen Zhang, Zhen Zhang, and Qiuan Zhu
Earth Syst. Sci. Data, 8, 697–751, https://doi.org/10.5194/essd-8-697-2016, https://doi.org/10.5194/essd-8-697-2016, 2016
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An accurate assessment of the methane budget is important to understand the atmospheric methane concentrations and trends and to provide realistic pathways for climate change mitigation. The various and diffuse sources of methane as well and its oxidation by a very short lifetime radical challenge this assessment. We quantify the methane sources and sinks as well as their uncertainties based on both bottom-up and top-down approaches provided by a broad international scientific community.
Thomas Kleinen, Victor Brovkin, and Guy Munhoven
Clim. Past, 12, 2145–2160, https://doi.org/10.5194/cp-12-2145-2016, https://doi.org/10.5194/cp-12-2145-2016, 2016
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We investigate trends in atmospheric CO2 during three recent interglacials – the Holocene, the Eemian and MIS 11 – using an earth system model of intermediate complexity. Our model experiments show a considerable improvement in the modelled CO2 trends for all three interglacials if peat accumulation and shallow water CaCO3 sedimentation are included, forcing the model only with orbital and sea level changes. The Holocene CO2 trend requires anthropogenic emissions of CO2 only after 3 ka BP.
Sylvia S. Nyawira, Julia E. M. S. Nabel, Axel Don, Victor Brovkin, and Julia Pongratz
Biogeosciences, 13, 5661–5675, https://doi.org/10.5194/bg-13-5661-2016, https://doi.org/10.5194/bg-13-5661-2016, 2016
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We introduce an approach applicable to dynamic global vegetation models for evaluating simulated soil carbon changes from land-use changes against meta-analyses. The approach makes use of the large spatial coverage of the observations, and accounts for different ages of the sampled land-use transitions. The evaluation offers an opportunity for identifying causes of model–data discrepancies. Applied to the model JSBACH, we find that introducing crop harvest substantially improves the results.
Ana Bastos, Philippe Ciais, Jonathan Barichivich, Laurent Bopp, Victor Brovkin, Thomas Gasser, Shushi Peng, Julia Pongratz, Nicolas Viovy, and Cathy M. Trudinger
Biogeosciences, 13, 4877–4897, https://doi.org/10.5194/bg-13-4877-2016, https://doi.org/10.5194/bg-13-4877-2016, 2016
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The ice-core record shows a stabilisation of atmospheric CO2 in the 1940s, despite continued emissions from fossil fuel burning and land-use change (LUC). We use up-to-date reconstructions of the CO2 sources and sinks over the 20th century to evaluate whether these capture the CO2 plateau and to test the previously proposed hypothesis. Both strong terrestrial sink, possibly due to LUC not fully accounted for in the records, and enhanced oceanic uptake are necessary to explain this stall.
David M. Lawrence, George C. Hurtt, Almut Arneth, Victor Brovkin, Kate V. Calvin, Andrew D. Jones, Chris D. Jones, Peter J. Lawrence, Nathalie de Noblet-Ducoudré, Julia Pongratz, Sonia I. Seneviratne, and Elena Shevliakova
Geosci. Model Dev., 9, 2973–2998, https://doi.org/10.5194/gmd-9-2973-2016, https://doi.org/10.5194/gmd-9-2973-2016, 2016
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Human land-use activities have resulted in large changes to the Earth's surface, with resulting implications for climate. In the future, land-use activities are likely to expand and intensify further to meet growing demands for food, fiber, and energy. The goal of LUMIP is to take the next steps in land-use change science, and enable, coordinate, and ultimately address the most important land-use science questions in more depth and sophistication than possible in a multi-model context to date.
Chris D. Jones, Vivek Arora, Pierre Friedlingstein, Laurent Bopp, Victor Brovkin, John Dunne, Heather Graven, Forrest Hoffman, Tatiana Ilyina, Jasmin G. John, Martin Jung, Michio Kawamiya, Charlie Koven, Julia Pongratz, Thomas Raddatz, James T. Randerson, and Sönke Zaehle
Geosci. Model Dev., 9, 2853–2880, https://doi.org/10.5194/gmd-9-2853-2016, https://doi.org/10.5194/gmd-9-2853-2016, 2016
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How the carbon cycle interacts with climate will affect future climate change and how society plans emissions reductions to achieve climate targets. The Coupled Climate Carbon Cycle Model Intercomparison Project (C4MIP) is an endorsed activity of CMIP6 and aims to quantify these interactions and feedbacks in state-of-the-art climate models. This paper lays out the experimental protocol for modelling groups to follow to contribute to C4MIP. It is a contribution to the CMIP6 GMD Special Issue.
Alexander Lemburg, Martin Claussen, and Felix Ament
Clim. Past Discuss., https://doi.org/10.5194/cp-2016-68, https://doi.org/10.5194/cp-2016-68, 2016
Manuscript not accepted for further review
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The deforestation of Easter Island several hundred years ago might have influenced its local near-surface climate. With a series of numerical model experiments we investigate the impact of deforestation on precipitation and near-surface climate. We find that a deforested Easter Island appears to be significantly less resistant to drought than a forested island and thus, deforestation has probably exacerbated the effects of past climate drought spells on Easter Island's socio-ecological systems.
Ulrike Port, Martin Claussen, and Victor Brovkin
Earth Syst. Dynam., 7, 535–547, https://doi.org/10.5194/esd-7-535-2016, https://doi.org/10.5194/esd-7-535-2016, 2016
Sabine Egerer, Martin Claussen, Christian Reick, and Tanja Stanelle
Clim. Past, 12, 1009–1027, https://doi.org/10.5194/cp-12-1009-2016, https://doi.org/10.5194/cp-12-1009-2016, 2016
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We demonstrate for the first time the direct link between dust accumulation in marine sediment cores and Saharan land surface by simulating the mid-Holocene and pre-industrial dust cycle as a function of Saharan land surface cover and atmosphere-ocean conditions using the coupled atmosphere-aerosol model ECHAM6-HAM2.1. Mid-Holocene surface characteristics, including vegetation cover and lake surface area, are derived from proxy data and simulations.
Fabio Cresto Aleina, Benjamin R. K. Runkle, Tim Brücher, Thomas Kleinen, and Victor Brovkin
Geosci. Model Dev., 9, 915–926, https://doi.org/10.5194/gmd-9-915-2016, https://doi.org/10.5194/gmd-9-915-2016, 2016
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This study presents the hotspot parameterization, a novel approach to upscaling methane emissions in a boreal peatland from the micro-topographic scale to the landscape scale. We based this new parameterization on the analysis of water table patterns generated by the Hummock–Hollow (HH) model. We show how the hotspot parameterization successfully upscales the micro-topographic controls on methane emissions for both present-day conditions and for the next century under three different scenarios.
T. Brücher, M. Claussen, and T. Raddatz
Earth Syst. Dynam., 6, 769–780, https://doi.org/10.5194/esd-6-769-2015, https://doi.org/10.5194/esd-6-769-2015, 2015
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A major link between climate and humans in northern Africa, and the Sahel in particular, is land use. We assess possible feedbacks between the type of land use and harvest intensity and climate by analysing a series of idealized GCM experiments using the MPI-ESM. Our study suggests marginal feedback between land use changes and climate changes triggered by strong greenhouse gas emissions.
U. Port and M. Claussen
Clim. Past, 11, 1563–1574, https://doi.org/10.5194/cp-11-1563-2015, https://doi.org/10.5194/cp-11-1563-2015, 2015
V. P. Groner, M. Claussen, and C. Reick
Clim. Past, 11, 1361–1374, https://doi.org/10.5194/cp-11-1361-2015, https://doi.org/10.5194/cp-11-1361-2015, 2015
F. Cresto Aleina, B. R. K. Runkle, T. Kleinen, L. Kutzbach, J. Schneider, and V. Brovkin
Biogeosciences, 12, 5689–5704, https://doi.org/10.5194/bg-12-5689-2015, https://doi.org/10.5194/bg-12-5689-2015, 2015
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We developed a process-based model for peatland micro-topography and hydrology, the Hummock-Hollow (HH) model, which explicitly represents small-scale surface elevation changes. By coupling the HH model with a model for soil methane processes, we are able to model the effects of micro-topography on hydrology and methane emissions in a typical boreal peatland. We also identify potential biases that models without a micro-topographic representation can introduce in large-scale models.
C. D. Koven, J. Q. Chambers, K. Georgiou, R. Knox, R. Negron-Juarez, W. J. Riley, V. K. Arora, V. Brovkin, P. Friedlingstein, and C. D. Jones
Biogeosciences, 12, 5211–5228, https://doi.org/10.5194/bg-12-5211-2015, https://doi.org/10.5194/bg-12-5211-2015, 2015
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Terrestrial carbon feedbacks are a large uncertainty in climate change. We separate modeled feedback responses into those governed by changed carbon inputs (productivity) and changed outputs (turnover). The disaggregated responses show that both are important in controlling inter-model uncertainty. Interactions between productivity and turnover are also important, and research must focus on these interactions for more accurate projections of carbon cycle feedbacks.
T. J. Bohn, J. R. Melton, A. Ito, T. Kleinen, R. Spahni, B. D. Stocker, B. Zhang, X. Zhu, R. Schroeder, M. V. Glagolev, S. Maksyutov, V. Brovkin, G. Chen, S. N. Denisov, A. V. Eliseev, A. Gallego-Sala, K. C. McDonald, M.A. Rawlins, W. J. Riley, Z. M. Subin, H. Tian, Q. Zhuang, and J. O. Kaplan
Biogeosciences, 12, 3321–3349, https://doi.org/10.5194/bg-12-3321-2015, https://doi.org/10.5194/bg-12-3321-2015, 2015
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We evaluated 21 forward models and 5 inversions over western Siberia in terms of CH4 emissions and simulated wetland areas and compared these results to an intensive in situ CH4 flux data set, several wetland maps, and two satellite inundation products. In addition to assembling a definitive collection of methane emissions estimates for the region, we were able to identify the types of wetland maps and model features necessary for accurate simulations of high-latitude wetlands.
S. Kloster, T. Brücher, V. Brovkin, and S. Wilkenskjeld
Clim. Past, 11, 781–788, https://doi.org/10.5194/cp-11-781-2015, https://doi.org/10.5194/cp-11-781-2015, 2015
U. Port, M. Claussen, and V. Brovkin
Clim. Past Discuss., https://doi.org/10.5194/cpd-11-997-2015, https://doi.org/10.5194/cpd-11-997-2015, 2015
Revised manuscript not accepted
A. Dallmeyer, M. Claussen, N. Fischer, K. Haberkorn, S. Wagner, M. Pfeiffer, L. Jin, V. Khon, Y. Wang, and U. Herzschuh
Clim. Past, 11, 305–326, https://doi.org/10.5194/cp-11-305-2015, https://doi.org/10.5194/cp-11-305-2015, 2015
F. S. E. Vamborg, V. Brovkin, and M. Claussen
Earth Syst. Dynam., 5, 89–101, https://doi.org/10.5194/esd-5-89-2014, https://doi.org/10.5194/esd-5-89-2014, 2014
P. Dass, C. Müller, V. Brovkin, and W. Cramer
Earth Syst. Dynam., 4, 409–424, https://doi.org/10.5194/esd-4-409-2013, https://doi.org/10.5194/esd-4-409-2013, 2013
L. M. Verheijen, V. Brovkin, R. Aerts, G. Bönisch, J. H. C. Cornelissen, J. Kattge, P. B. Reich, I. J. Wright, and P. M. van Bodegom
Biogeosciences, 10, 5497–5515, https://doi.org/10.5194/bg-10-5497-2013, https://doi.org/10.5194/bg-10-5497-2013, 2013
M. Claussen, K. Selent, V. Brovkin, T. Raddatz, and V. Gayler
Biogeosciences, 10, 3593–3604, https://doi.org/10.5194/bg-10-3593-2013, https://doi.org/10.5194/bg-10-3593-2013, 2013
R. Wania, J. R. Melton, E. L. Hodson, B. Poulter, B. Ringeval, R. Spahni, T. Bohn, C. A. Avis, G. Chen, A. V. Eliseev, P. O. Hopcroft, W. J. Riley, Z. M. Subin, H. Tian, P. M. van Bodegom, T. Kleinen, Z. C. Yu, J. S. Singarayer, S. Zürcher, D. P. Lettenmaier, D. J. Beerling, S. N. Denisov, C. Prigent, F. Papa, and J. O. Kaplan
Geosci. Model Dev., 6, 617–641, https://doi.org/10.5194/gmd-6-617-2013, https://doi.org/10.5194/gmd-6-617-2013, 2013
F. Joos, R. Roth, J. S. Fuglestvedt, G. P. Peters, I. G. Enting, W. von Bloh, V. Brovkin, E. J. Burke, M. Eby, N. R. Edwards, T. Friedrich, T. L. Frölicher, P. R. Halloran, P. B. Holden, C. Jones, T. Kleinen, F. T. Mackenzie, K. Matsumoto, M. Meinshausen, G.-K. Plattner, A. Reisinger, J. Segschneider, G. Shaffer, M. Steinacher, K. Strassmann, K. Tanaka, A. Timmermann, and A. J. Weaver
Atmos. Chem. Phys., 13, 2793–2825, https://doi.org/10.5194/acp-13-2793-2013, https://doi.org/10.5194/acp-13-2793-2013, 2013
J. R. Melton, R. Wania, E. L. Hodson, B. Poulter, B. Ringeval, R. Spahni, T. Bohn, C. A. Avis, D. J. Beerling, G. Chen, A. V. Eliseev, S. N. Denisov, P. O. Hopcroft, D. P. Lettenmaier, W. J. Riley, J. S. Singarayer, Z. M. Subin, H. Tian, S. Zürcher, V. Brovkin, P. M. van Bodegom, T. Kleinen, Z. C. Yu, and J. O. Kaplan
Biogeosciences, 10, 753–788, https://doi.org/10.5194/bg-10-753-2013, https://doi.org/10.5194/bg-10-753-2013, 2013
J. Segschneider, A. Beitsch, C. Timmreck, V. Brovkin, T. Ilyina, J. Jungclaus, S. J. Lorenz, K. D. Six, and D. Zanchettin
Biogeosciences, 10, 669–687, https://doi.org/10.5194/bg-10-669-2013, https://doi.org/10.5194/bg-10-669-2013, 2013
Related subject area
Subject: Climate Modelling | Archive: Marine Archives | Timescale: Pleistocene
Assessment of the southern polar and subpolar warming in the PMIP4 Last Interglacial simulations using paleoclimate data syntheses
A new global surface temperature reconstruction for the Last Glacial Maximum
Evaluating seasonal sea-ice cover over the Southern Ocean at the Last Glacial Maximum
A multi-model CMIP6-PMIP4 study of Arctic sea ice at 127 ka: sea ice data compilation and model differences
From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates
Oxygen stable isotopes during the Last Glacial Maximum climate: perspectives from data–model (iLOVECLIM) comparison
Last Glacial Maximum world ocean simulations at eddy-permitting and coarse resolutions: do eddies contribute to a better consistency between models and palaeoproxies?
Terminations VI and VIII (∼ 530 and ∼ 720 kyr BP) tell us the importance of obliquity and precession in the triggering of deglaciations
Are paleoclimate model ensembles consistent with the MARGO data synthesis?
Qinggang Gao, Emilie Capron, Louise C. Sime, Rachael H. Rhodes, Rahul Sivankutty, Xu Zhang, Bette L. Otto-Bliesner, and Martin Werner
EGUsphere, https://doi.org/10.5194/egusphere-2024-1261, https://doi.org/10.5194/egusphere-2024-1261, 2024
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Marine sediment and ice core records suggest a warmer Southern Ocean and Antarctica at the early last interglacial, ~127 thousand years ago. However, when only forced by orbital parameters and greenhouse gas concentrations during that period, state-of-the-art climate models do not reproduce the magnitude of warming. Here we show that much of the warming at southern mid-to-high latitudes can be reproduced by a UK climate model HadCM3 with a 3000-year freshwater forcing over the North Atlantic.
James D. Annan, Julia C. Hargreaves, and Thorsten Mauritsen
Clim. Past, 18, 1883–1896, https://doi.org/10.5194/cp-18-1883-2022, https://doi.org/10.5194/cp-18-1883-2022, 2022
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We have created a new global surface temperature reconstruction of the climate of the Last Glacial Maximum, representing the period 19–23 000 years before the present day. We find that the globally averaged mean temperature was roughly 4.5 °C colder than it was in pre-industrial times, albeit there is significant uncertainty on this value.
Ryan A. Green, Laurie Menviel, Katrin J. Meissner, Xavier Crosta, Deepak Chandan, Gerrit Lohmann, W. Richard Peltier, Xiaoxu Shi, and Jiang Zhu
Clim. Past, 18, 845–862, https://doi.org/10.5194/cp-18-845-2022, https://doi.org/10.5194/cp-18-845-2022, 2022
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Climate models are used to predict future climate changes and as such, it is important to assess their performance in simulating past climate changes. We analyze seasonal sea-ice cover over the Southern Ocean simulated from numerical PMIP3, PMIP4 and LOVECLIM simulations during the Last Glacial Maximum (LGM). Comparing these simulations to proxy data, we provide improved estimates of LGM seasonal sea-ice cover. Our estimate of summer sea-ice extent is 20 %–30 % larger than previous estimates.
Masa Kageyama, Louise C. Sime, Marie Sicard, Maria-Vittoria Guarino, Anne de Vernal, Ruediger Stein, David Schroeder, Irene Malmierca-Vallet, Ayako Abe-Ouchi, Cecilia Bitz, Pascale Braconnot, Esther C. Brady, Jian Cao, Matthew A. Chamberlain, Danny Feltham, Chuncheng Guo, Allegra N. LeGrande, Gerrit Lohmann, Katrin J. Meissner, Laurie Menviel, Polina Morozova, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, Ryouta O'ishi, Silvana Ramos Buarque, David Salas y Melia, Sam Sherriff-Tadano, Julienne Stroeve, Xiaoxu Shi, Bo Sun, Robert A. Tomas, Evgeny Volodin, Nicholas K. H. Yeung, Qiong Zhang, Zhongshi Zhang, Weipeng Zheng, and Tilo Ziehn
Clim. Past, 17, 37–62, https://doi.org/10.5194/cp-17-37-2021, https://doi.org/10.5194/cp-17-37-2021, 2021
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The Last interglacial (ca. 127 000 years ago) is a period with increased summer insolation at high northern latitudes, resulting in a strong reduction in Arctic sea ice. The latest PMIP4-CMIP6 models all simulate this decrease, consistent with reconstructions. However, neither the models nor the reconstructions agree on the possibility of a seasonally ice-free Arctic. Work to clarify the reasons for this model divergence and the conflicting interpretations of the records will thus be needed.
Priscilla Le Mézo, Luc Beaufort, Laurent Bopp, Pascale Braconnot, and Masa Kageyama
Clim. Past, 13, 759–778, https://doi.org/10.5194/cp-13-759-2017, https://doi.org/10.5194/cp-13-759-2017, 2017
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This paper focuses on the relationship between Arabian Sea biological productivity and the Indian summer monsoon in climates of the last 72 kyr. A general circulation model coupled to a biogeochemistry model simulates the changes in productivity and monsoon intensity and pattern. The paradigm stating that a stronger summer monsoon enhances productivity is not always verified in our simulations. This work highlights the importance of considering the monsoon pattern in addition to its intensity.
T. Caley, D. M. Roche, C. Waelbroeck, and E. Michel
Clim. Past, 10, 1939–1955, https://doi.org/10.5194/cp-10-1939-2014, https://doi.org/10.5194/cp-10-1939-2014, 2014
M. Ballarotta, L. Brodeau, J. Brandefelt, P. Lundberg, and K. Döös
Clim. Past, 9, 2669–2686, https://doi.org/10.5194/cp-9-2669-2013, https://doi.org/10.5194/cp-9-2669-2013, 2013
F. Parrenin and D. Paillard
Clim. Past, 8, 2031–2037, https://doi.org/10.5194/cp-8-2031-2012, https://doi.org/10.5194/cp-8-2031-2012, 2012
J. C. Hargreaves, A. Paul, R. Ohgaito, A. Abe-Ouchi, and J. D. Annan
Clim. Past, 7, 917–933, https://doi.org/10.5194/cp-7-917-2011, https://doi.org/10.5194/cp-7-917-2011, 2011
Cited articles
Archer, D. and Brovkin, V.: The millennial atmospheric lifetime of
anthropogenic CO2, Clim. Change, 90, 283–297,
https://doi.org/10.1007/s10584-008-9413-1, 2008. a
Bartlein, P. J., Harrison, S. P., Brewer, S., Connor, S., Davis, B. A. S.,
Gajewski, K., Guiot, J., Harrison-Prentice, T. I., Henderson, A., Peyron, O.,
Prentice, I. C., Scholze, M., Seppä, H., Shuman, B., Sugita, S.,
Thompson, R. S., Viau, A. E., Williams, J., and Wu, H.: Pollen-based
continental climate reconstructions at 6 and 21 ka: a global synthesis,
Clim. Dynam., 37, 775–802, https://doi.org/10.1007/s00382-010-0904-1, 2011. a, b
Bathiany, S., Claussen, M., and Fraedrich, K.: Implications of climate
variability for the detection of multiple equilibria and for rapid
transitions in the atmosphere-vegetation system, Clim. Dynam., 38,
1775–1790, https://doi.org/10.1007/s00382-011-1037-x, 2012. a
Bauer, E. and Ganopolski, A.: Aeolian dust modeling over the past four glacial
cycles with CLIMBER-2, Global Planet. Change, 74, 49–60,
https://doi.org/10.1016/j.gloplacha.2010.07.009, 2010. a
Bauer, E. and Ganopolski, A.: Sensitivity simulations with direct shortwave radiative forcing by aeolian dust during glacial cycles, Clim. Past, 10, 1333–1348, https://doi.org/10.5194/cp-10-1333-2014, 2014. a
Braconnot, P., Harrison, S. P., Kageyama, M., Bartlein, P. J., Masson-Delmotte,
V., Abe-Ouchi, A., Otto-Bliesner, B., and Zhao, Y.: Evaluation of climate
models using palaeoclimatic data, Nat. Clim. Change, 2, 417–424,
https://doi.org/10.1038/nclimate1456, 2012. a, b
Brierley, C., Manning, K., and Maslin, M.: Pastoralism may have delayed the end
of the green Sahara, Nat. Commun., 9, 1–9,
https://doi.org/10.1038/s41467-018-06321-y, 2018. a
Brovkin, V., Ganopolski, A., and Svirezhev, Y.: A continuous climate-vegetation
classification for use in climate-biosphere studies, Ecol. Modell.,
101, 251–261, https://doi.org/10.1016/S0304-3800(97)00049-5, 1997. a, b
Brovkin, V., Claussen, M., Petoukhov, V., and Ganopolski, A.: On the stability
of the atmosphere-vegetation system in the Sahara/Sahel region, J.
Geophys. Res.-Atmos., 103, 31613–31624,
https://doi.org/10.1029/1998JD200006, 1998. a
Brovkin, V., Bendtsen, J., Claussen, M., Ganopolski, A., Kubatzki, C.,
Petoukhov, V., and Andreev, A.: Carbon cycle, vegetation, and climate
dynamics in the Holocene: Experiments with the CLIMBER-2 model, Global
Biogeochem. Cy., 16, 86–1, https://doi.org/10.1029/2001GB001662, 2002. a, b
Brovkin, V., Ganopolski, A., Archer, D., and Rahmstorf, S.: Lowering of glacial
atmospheric CO2 in response to changes in oceanic circulation and
marine biogeochemistry, Paleoceanography, 22, PA4202,
https://doi.org/10.1029/2006PA001380, 2007. a
Chandan, D. and Peltier, W. R.: African humid period precipitation sustained by
robust vegetation, soil, and lake feedbacks, Geophys. Res. Lett.,
47, e2020GL088728, https://doi.org/10.1029/2020GL088728, 2020. a
Cheddadi, R., Carré, M., Nourelbait, M., François, L., Rhoujjati, A.,
Manay, R., Ochoa, D., and Schefuß, E.: Early Holocene greening of the
Sahara requires Mediterranean winter rainfall, P. Natl.
Acad. Sci., 118, e2024898118, https://doi.org/10.1073/pnas.2024898118, 2021. a
Claussen, M., Brovkin, V., Ganopolski, A., Kubatzki, C., Petoukhov, V., and
Rahmstorf, S.: A new model for climate system analysis: Outline of the model
and application to palaeoclimate simulations, Environ. Model.
Assess., 4, 209–216, https://doi.org/10.1023/A:1019016418068, 1999a. a
Claussen, M., Kubatzki, C., Brovkin, V., Ganopolski, A., Hoelzmann, P., and
Pachur, H. J.: Simulation of an abrupt change in Saharan vegetation in the
mid-Holocene, Geophys. Res. Lett., 26, 2037–2040,
https://doi.org/10.1029/1999GL900494, 1999b. a, b, c, d
Claussen, M., Mysak, L., Weaver, A., Crucifix, M., Fichefet, T., Loutre, M.-F.,
Weber, S., Alcamo, J., Alexeev, V., Berger, A., Calov, R., Ganopolski, A.,
Goosse, H., Lohmann, G., Lunkeit, F., Mokhov, I., Petoukhov, V., Stone, P.,
and Wang, Z.: Earth system models of intermediate complexity: closing the gap
in the spectrum of climate system models, Clim. Dynam., 18, 579–586,
https://doi.org/10.1007/s00382-001-0200-1, 2002. a
Claussen, M., Dallmeyer, A., and Bader, J.: Theory and modeling of the
African Humid Period and the Green Sahara, in: Oxford Research
Encyclopedia of Climate Science, 1–39 pp., Oxford University Press,
https://doi.org/10.1093/acrefore/9780190228620.013.532, 2017. a, b
D’Agostino, R., Bader, J., Bordoni, S., Ferreira, D., and Jungclaus, J.:
Northern Hemisphere monsoon response to mid-Holocene orbital forcing and
greenhouse gas-induced global warming, Geophys. Res. Lett., 46,
1591–1601, https://doi.org/10.1029/2018GL081589, 2019. a
Dallmeyer, A., Claussen, M., Lorenz, S. J., and Shanahan, T.: The end of the African humid period as seen by a transient comprehensive Earth system model simulation of the last 8000 years, Clim. Past, 16, 117–140, https://doi.org/10.5194/cp-16-117-2020, 2020. a, b
deMenocal, P. B., Ortiz, J., Guilderson, T., Adkins, J., Sarnthein, M.,
Baker, L., and Yarusinsky, M.: Abrupt onset and termination of the African
Humid Period: rapid climate responses to gradual insolation forcing,
Quaternary Sci. Rev., 19, 347–361,
https://doi.org/10.1016/S0277-3791(99)00081-5, 2000. a
Dickinson, R. E., Henderson-Sellers, A., and Kennedy, P. J.:
Biosphere-Atmosphere Transfer Scheme (BATS) version 1e as coupled to
the NCAR Community Climate Model, NCAR Tech. Note TH-387+STR,
1–72 pp., https://doi.org/10.5065/D67W6959, 1993. a
Ehrmann, W. and Schmiedl, G.: Nature and dynamics of North African humid
and dry periods during the last 200,000 years documented in the clay fraction
of Eastern Mediterranean deep-sea sediments, Quaternary Sci. Rev.,
260, 106925, https://doi.org/10.1016/j.quascirev.2021.106925, 2021. a, b, c, d, e, f, g
Ehrmann, W., Schmiedl, G., Beuscher, S., and Krüger, S.: Intensity of
African Humid Periods estimated from Saharan dust fluxes, PloS One,
12, e0170989, https://doi.org/10.1371/journal.pone.0170989, 2017. a
EPICA Community Members: Eight glacial cycles from an Antarctic ice core,
Nature, 429, 623–628, https://doi.org/10.1038/nature02599, 2004. a, b
Ganopolski, A. and Brovkin, V.: Simulation of climate, ice sheets and CO2 evolution during the last four glacial cycles with an Earth system model of intermediate complexity, Clim. Past, 13, 1695–1716, https://doi.org/10.5194/cp-13-1695-2017, 2017. a, b
Ganopolski, A. and Calov, R.: The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles, Clim. Past, 7, 1415–1425, https://doi.org/10.5194/cp-7-1415-2011, 2011. a, b, c
Ganopolski, A. and Rahmstorf, S.: Rapid changes of glacial climate simulated in
a coupled climate model, Nature, 409, 153–158, https://doi.org/10.1038/35051500, 2001. a
Ganopolski, A., Rahmstorf, S., Petoukhov, V., and Claussen, M.: Simulation of
modern and glacial climates with a coupled global model of intermediate
complexity, Nature, 391, 351–356, https://doi.org/10.1038/34839, 1998. a
Ganopolski, A., Petoukhov, V., Rahmstorf, S., Brovkin, V., Claussen, M.,
Eliseev, A., and Kubatzki, C.: CLIMBER-2: a climate system model of
intermediate complexity. Part II: model sensitivity, Clim. Dynam.,
17, 735–751, https://doi.org/10.1007/s003820000144, 2001. a, b
Ganopolski, A., Calov, R., and Claussen, M.: Simulation of the last glacial cycle with a coupled climate ice-sheet model of intermediate complexity, Clim. Past, 6, 229–244, https://doi.org/10.5194/cp-6-229-2010, 2010. a, b
Ganopolski, A., Winkelmann, R., and Schellnhuber, H. J.: Critical
insolation–CO2 relation for diagnosing past and future glacial
inception, Nature, 529, 200–203, https://doi.org/10.1038/nature16494, 2016. a, b
Grant, K. M., Grimm, R., Mikolajewicz, U., Marino, G., Ziegler, M., and
Rohling, E. J.: The timing of Mediterranean sapropel deposition relative to
insolation, sea-level and African monsoon changes, Quaternary Sci.
Rev., 140, 125–141, https://doi.org/10.1016/j.quascirev.2016.03.026, 2016. a
Grant, K. M., Rohling, E. J., Westerhold, T., Zabel, M., Heslop, D.,
Konijnendijk, T., and Lourens, L.: A 3 million year index for North
African humidity/aridity and the implication of potential pan-African
Humid periods, Quaternary Sci. Rev., 171, 100–118,
https://doi.org/10.1016/j.quascirev.2017.07.005, 2017. a
Greve, R.: A continuum–mechanical formulation for shallow polythermal ice
sheets, Philos. Trans. Roy. Soc. London A, 355, 921–974,
https://doi.org/10.1098/rsta.1997.0050, 1997. a, b
Harrison, S. P., Bartlein, P. J., Izumi, K., Li, G., Annan, J., Hargreaves, J.,
Braconnot, P., and Kageyama, M.: Evaluation of CMIP5 palaeo-simulations to
improve climate projections, Nat. Clim. Change, 5, 735–743,
https://doi.org/10.1038/nclimate2649, 2015. a
Hopcroft, P. O. and Valdes, P. J.: Paleoclimate-conditioning reveals a North
Africa land–atmosphere tipping point, P. Natl. Acad.
Sci. USA, 118, 1–7, https://doi.org/10.1073/pnas.2108783118, 2021. a
Jungandreas, L., Hohenegger, C., and Claussen, M.: Influence of the representation of convection on the mid-Holocene West African Monsoon, Clim. Past, 17, 1665–1684, https://doi.org/10.5194/cp-17-1665-2021, 2021. a
Killick, R., Fearnhead, P., and Eckley, I. A.: Optimal detection of
changepoints with a linear computational cost, J. Am.
Stat. Assoc., 107, 1590–1598, https://doi.org/10.1080/01621459.2012.737745,
2012. a
Kutzbach, J. E.: Monsoon climate of the early Holocene: climate experiment
with the earth's orbital parameters for 9000 years ago, Science, 214, 59–61,
https://doi.org/10.1126/science.214.4516.59, 1981. a
Kutzbach, J. E., Guan, J., He, F., Cohen, A. S., Orland, I. J., and Chen, G.:
African climate response to orbital and glacial forcing in 140,000-y
simulation with implications for early modern human environments, P. Natl. Acad. Sci. USA, 117, 2255–2264,
https://doi.org/10.1073/pnas.1917673117, 2020. a, b, c, d
Larrasoaña, J. C., Roberts, A. P., and Rohling, E. J.: Dynamics of green
Sahara periods and their role in hominin evolution, PloS ONE, 8,
e76514, https://doi.org/10.1371/journal.pone.0076514, 2013. a, b
Lézine, A.-M., Hély, C., Grenier, C., Braconnot, P., and Krinner, G.:
Sahara and Sahel vulnerability to climate changes, lessons from Holocene
hydrological data, Quaternary Sci. Rev., 30, 3001–3012,
https://doi.org/10.1016/j.quascirev.2011.07.006, 2011. a, b
Lisiecki, L. E. and Raymo, M. E.: A Pliocene-Pleistocene stack of 57
globally distributed benthic δ18O records, Paleoceanography, 20,
PA1003, https://doi.org/10.1029/2004PA001071, 2005. a, b, c
Liu, Z., Wang, Y., Gallimore, R., Notaro, M., and Prentice, I. C.: On the cause
of abrupt vegetation collapse in North Africa during the Holocene: climate
variability vs. vegetation feedback, Geophys. Res. Lett., 33,
L22709, https://doi.org/10.1029/2006GL028062, 2006. a
Lourens, L. J., Wehausen, R., and Brumsack, H. J.: Geological constraints on
tidal dissipation and dynamical ellipticity of the Earth over the past
three million years, Nature, 409, 1029–1033, https://doi.org/10.1038/35059062, 2001. a
Marzin, C., Braconnot, P., and Kageyama, M.: Relative impacts of insolation
changes, meltwater fluxes and ice sheets on African and Asian monsoons
during the Holocene, Clim. Dynam., 41, 2267–2286,
https://doi.org/10.1007/s00382-013-1948-9, 2013. a, b
Milankovitch, M.: Kanon der Erdbestrahlung und seine Anwendung auf das
Eiszeitenproblem, vol. 83, Königlich Serbische Akademie, Belgrad, 1941. a
MPG.PuRe: Effects of orbital forcing, greenhouse gases and ice sheets on Saharan greening in past and future multi-millennia, Max Planck Digital Library, https://pure.mpg.de/pubman/faces/ViewItemOverviewPage.jspitemId=item_3371030, last access: 16 August 2022. a
Pausata, F. S. R., Messori, G., and Zhang, Q.: Impacts of dust reduction on the
northward expansion of the African monsoon during the Green Sahara
period, Earth Planet. Sci. Lett., 434, 298–307,
https://doi.org/10.1016/j.epsl.2015.11.049, 2016. a
Pausata, F. S. R., Gaetani, M., Messori, G., Berg, A., de Souza, D. M., Sage,
R. F., and deMenocal, P. B.: The Greening of the Sahara: Past Changes
and Future Implications, One Earth, 2, 235–250,
https://doi.org/10.1016/j.oneear.2020.03.002, 2020. a
Peltier, W. R.: Ice age paleotopography, Science, 265, 195–201,
https://doi.org/10.1126/science.265.5169.195, 1994. a, b
Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N. I., Barnola, J. M., Basile,
I., Bender, M., Chappellaz, J., Davis, M., Delaygue, G., et al.: Climate and
atmospheric history of the past 420000 years from the Vostok ice core,
Antarctica, Nature, 399, 429, https://doi.org/10.1038/20859, 1999. a, b
Petoukhov, V., Ganopolski, A., Brovkin, V., Claussen, M., Eliseev, A.,
Kubatzki, C., and Rahmstorf, S.: CLIMBER-2: a climate system model of
intermediate complexity. Part I: model description and performance for
present climate, Clim. Dynam., 16, 1–17, https://doi.org/10.1007/PL00007919, 2000. a, b
Railsback, L. B., Gibbard, P. L., Head, M. J., Voarintsoa, N. R. G., and
Toucanne, S.: An optimized scheme of lettered marine isotope substages for
the last 1.0 million years, and the climatostratigraphic nature of isotope
stages and substages, Quaternary Sci. Rev., 111, 94–106,
https://doi.org/10.1016/j.quascirev.2015.01.012, 2015. a, b, c
Shanahan, T. M., McKay, N. P., Hughen, K. A., Overpeck, J. T., Otto-Bliesner,
B., Heil, C. W., King, J., Scholz, C. A., and Peck, J.: The
time-transgressive termination of the African Humid Period, Nat.
Geosci., 8, 140–144, https://doi.org/10.1038/ngeo2329, 2015. a, b
Skonieczny, C., McGee, D., Winckler, G., Bory, A., Bradtmiller, L. I., Kinsley,
C. W., Polissar, P. J., De Pol-Holz, R., Rossignol, L., and Malaizé, B.:
Monsoon-driven Saharan dust variability over the past 240,000 years,
Sci. Adv., 5, eaav1887, https://doi.org/10.1126/sciadv.aav1887, 2019.
a, b
Stein, U. and Alpert, P.: Factor separation in numerical simulations, J. Atmos. Sci., 50, 2107–2115,
https://doi.org/10.1175/1520-0469(1993)050<2107:FSINS>2.0.CO;2, 1993. a, b, c, d
Stocker, T. F., Wright, D. G., and Mysak, L. A.: A zonally averaged, coupled
ocean-atmosphere model for paleoclimate studies, J. Climate, 5,
773–797, https://www.jstor.org/stable/26197126 (last access: 16 August 2022), 1992. a
Thompson, A. J., Skinner, C. B., Poulsen, C. J., and Zhu, J.: Modulation of
mid-Holocene African rainfall by dust aerosol direct and indirect effects,
Geophys. Res. Lett., 46, 3917–3926, https://doi.org/10.1029/2018GL081225,
2019. a
Tierney, J. E., deMenocal, P. B., and Zander, P. D.: A climatic context for the
out-of-Africa migration, Geology, 45, 1023–1026, https://doi.org/10.1130/G39457.1,
2017a. a, b
Tierney, J. E., Pausata, F. S. R., and deMenocal, P. B.: Rainfall regimes of
the Green Sahara, Sci. Adv., 3, e1601503,
https://doi.org/10.1126/sciadv.1601503, 2017b. a
Tjallingii, R., Claussen, M., Stuut, J.-B. W., Fohlmeister, J., Jahn, A.,
Bickert, T., Lamy, F., and Röhl, U.: Coherent high-and low-latitude
control of the northwest African hydrological balance, Nat. Geosci.,
1, 670–675, https://doi.org/10.1038/ngeo289, 2008. a, b, c
Tuenter, E., Weber, S. L., Hilgen, F. J., and Lourens, L. J.: The response of
the African summer monsoon to remote and local forcing due to precession
and obliquity, Global Planet. Change, 36, 219–235,
https://doi.org/10.1016/S0921-8181(02)00196-0, 2003. a, b, c
Tuenter, E., Weber, S. L., Hilgen, F. J., Lourens, L. J., and Ganopolski, A.:
Simulation of climate phase lags in response to precession and obliquity
forcing and the role of vegetation, Clim. Dynam., 24, 279–295,
https://doi.org/10.1007/s00382-004-0490-1, 2005. a, b, c
Vernekar, A. D.: Long-period global variations of incoming solar radiation,
Meteorol. Monogr., 12, 1–128, https://doi.org/10.1007/978-1-935704-34-8_1,
1972. a
Waelbroeck, C., Labeyrie, L., Michel, E., Duplessy, J. C., McManus, J. F.,
Lambeck, K., Balbon, E., and Labracherie, M.: Sea-level and deep water
temperature changes derived from benthic foraminifera isotopic records,
Quaternary Sci. Rev., 21, 295–305,
https://doi.org/10.1016/S0277-3791(01)00101-9, 2002. a, b
Weber, S. L. and Tuenter, E.: The impact of varying ice sheets and greenhouse
gases on the intensity and timing of boreal summer monsoons, Quaternary
Sci. Rev., 30, 469–479, https://doi.org/10.1016/j.quascirev.2010.12.009, 2011. a
Ziegler, M., Tuenter, E., and Lourens, L. J.: The precession phase of the
boreal summer monsoon as viewed from the eastern Mediterranean (ODP Site
968), Quaternary Sci. Rev., 29, 1481–1490,
https://doi.org/10.1016/j.quascirev.2010.03.011, 2010. a
Co-editor-in-chief
The alternation of vegetated and arid Sahara has long attracted wide interest in paleoclimate field. This study presents a suite of highly interesting simulations of the past 190,000 years with a state-of-the-art Earth system model of intermediate complexity. This set of experiments are rigorously designed and analyzed, which allow the authors to make an important discovery of what controls the onset of African Humid Period: i.e. a threshold in orbital forcing, which decreases at elevated CO2 concentration. Moreover, maximum rates of change in simulated vegetation extent during the onset and termination of African Humid Period correlate strongly with the rates of change of the orbital forcing. A factor separation analysis further confirms the dominant role of the orbital forcing in driving the amplitude of precipitation and vegetation extent for past African Humid Period. These results have broad implications to future variability of Sahara climate in response to orbital forcing changes and non-linear earth system feedbacks.
The alternation of vegetated and arid Sahara has long attracted wide interest in paleoclimate...
Short summary
Using an Earth system model of intermediate complexity, we quantify contributions of the Earth's orbit, greenhouse gases (GHGs) and ice sheets to the strength of Saharan greening during late Quaternary African humid periods (AHPs). Orbital forcing is found as the dominant factor, having a critical threshold and accounting for most of the changes in the vegetation response. However, results suggest that GHGs may influence the orbital threshold and thus may play a pivotal role for future AHPs.
Using an Earth system model of intermediate complexity, we quantify contributions of the Earth's...
