Two Interglacials, Scientific Objective And

Total Page:16

File Type:pdf, Size:1020Kb

Two Interglacials, Scientific Objective And The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations Bette Otto-Bliesner, Pascale Braconnot, Sandy Harrison, Daniel Lunt, Ayako Abe-Ouchi, Samuel Albani, Patrick Bartlein, Emilie Capron, Anders Carlson, Andrea Dutton, et al. To cite this version: Bette Otto-Bliesner, Pascale Braconnot, Sandy Harrison, Daniel Lunt, Ayako Abe-Ouchi, et al.. The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations. Geoscientific Model Development, European Geosciences Union, 2017, 10 (11), pp.3979-4003. 10.5194/gmd-10-3979-2017. hal-02181006 HAL Id: hal-02181006 https://hal.archives-ouvertes.fr/hal-02181006 Submitted on 11 Jul 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Geosci. Model Dev., 10, 3979–4003, 2017 https://doi.org/10.5194/gmd-10-3979-2017 © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License. The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations Bette L. Otto-Bliesner1, Pascale Braconnot2, Sandy P. Harrison3, Daniel J. Lunt4, Ayako Abe-Ouchi5,6, Samuel Albani7, Patrick J. Bartlein8, Emilie Capron9,10, Anders E. Carlson11, Andrea Dutton12, Hubertus Fischer13, Heiko Goelzer14,15, Aline Govin2, Alan Haywood16, Fortunat Joos13, Allegra N. LeGrande17, William H. Lipscomb18, Gerrit Lohmann19, Natalie Mahowald20, Christoph Nehrbass-Ahles13, Francesco S. R. Pausata21, Jean-Yves Peterschmitt2, Steven J. Phipps22, Hans Renssen23,24, and Qiong Zhang25 1National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305, USA 2Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France 3Centre for Past Climate Change and School of Archaeology, Geography and Environmental Science (SAGES), University of Reading, Whiteknights, RG6 6AH, Reading, UK 4School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK 5Atmosphere Ocean Research Institute, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-20 8564, Japan 6Japan Agency for Marine-Earth Science and Technology, 3173-25 Showamachi, Kanazawa, Yokohama, Kanagawa, 236-0001, Japan 7Institute for Geophysics and Meteorology, University of Cologne, Cologne, Germany 8Department of Geography, University of Oregon, Eugene, OR 97403-1251, USA 9Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark 10British Antarctic Survey, High Cross Madingley Road, Cambridge CB3 0ET, UK 11College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA 12Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA 13Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland 14Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University, Princetonplein 5, 3584 CC Utrecht, the Netherlands 15Laboratoire de Glaciologie, Université Libre de Bruxelles, CP160/03, Av. F. Roosevelt 50, 1050 Brussels, Belgium 16School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, West Yorkshire, LS29JT, UK 17NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA 18Group T-3, Fluid Dynamics and Solid Mechanics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA 19Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research Bussestr. 24, 27570 Bremerhaven, Germany 20Earth and Atmospheric Sciences, Cornell University, Ithaca, NY 14850, USA 21Department of Earth and Atmospheric Sciences, University of Quebec in Montreal (UQAM), Montreal, QC, H3C 3P8, Canada 22Institute for Marine and Antarctic Studies, Uinversity of Tasmania, Hobart, Tasmania 7001, Australia 23Department of Earth Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands 24Department of Natural Sciences and Environmental Health, University College of Southeast Norway, 3800 Bø i Telemark, Norway Published by Copernicus Publications on behalf of the European Geosciences Union. 3980 B. L. Otto-Bliesner et al.: PMIP4-CMIP6 interglacial simulations 25Department of Physical Geography, Stockholm University, 10691 Stockholm, Sweden Correspondence to: Bette L. Otto-Bliesner ([email protected]) Received: 3 November 2016 – Discussion started: 28 November 2016 Revised: 20 July 2017 – Accepted: 21 August 2017 – Published: 7 November 2017 Abstract. Two interglacial epochs are included in the suite 2015; Schmidt et al., 2014). The Paleoclimate Modelling In- of Paleoclimate Modeling Intercomparison Project (PMIP4) tercomparison Project (PMIP) has served to coordinate pale- simulations in the Coupled Model Intercomparison Project oclimate experiments and data–model comparisons for sev- (CMIP6). The experimental protocols for simulations of the eral decades (Braconnot et al., 2007a, b, 2012; Joussaume mid-Holocene (midHolocene, 6000 years before present) and and Taylor, 1995; Joussaume et al., 1999), and now spear- the Last Interglacial (lig127k, 127 000 years before present) heads the paleoclimate contribution to the current phase of are described here. These equilibrium simulations are de- the Coupled Model Intercomparison Project (CMIP6, Eyring signed to examine the impact of changes in orbital forcing et al., 2016). at times when atmospheric greenhouse gas levels were sim- This paper is part of a suite of five documenting the ilar to those of the preindustrial period and the continental PMIP4 contributions to CMIP6. Kageyama et al. (2016) configurations were almost identical to modern ones. These provide an overview of the five selected time periods and simulations test our understanding of the interplay between the experiments. More specific information is given in the radiative forcing and atmospheric circulation, and the con- contributions for the last millennium (past1000) by Jung- nections among large-scale and regional climate changes giv- claus et al. (2017), for the last glacial maximum (lgm) by ing rise to phenomena such as land–sea contrast and high- Kageyama et al. (2017), for the mid-Pliocene warm period latitude amplification in temperature changes, and responses (midPliocene-eoi400) by Haywood et al. (2016), and the of the monsoons, as compared to today. They also provide an present paper the mid-Holocene (midHolocene) and the pre- opportunity, through carefully designed additional sensitivity vious interglacial (lig127k). PMIP4 has adopted the CMIP6 experiments, to quantify the strength of atmosphere, ocean, categorization where the highest-priority experiments are cryosphere, and land-surface feedbacks. Sensitivity experi- classified as Tier 1, whereas additional sensitivity experi- ments are proposed to investigate the role of freshwater forc- ments or dedicated studies are Tier 2 or Tier 3. The stan- ing in triggering abrupt climate changes within interglacial dard experiments for the five periods are all ranked Tier 1. epochs. These feedback experiments naturally lead to a fo- Tier 2 and 3 experiments absolutely require the correspond- cus on climate evolution during interglacial periods, which ing Tier 1 experiment for their analysis, so the groups must will be examined through transient experiments. Analyses perform the Tier 1 experiment first. Modeling groups are not of the sensitivity simulations will also focus on interactions obliged to run all PMIP4-CMIP6 experiments. It is manda- between extratropical and tropical circulation, and the rela- tory, however, for all participating groups to run at least one tionship between changes in mean climate state and climate of the experiments that were run in previous phases of PMIP variability on annual to multi-decadal timescales. The com- (i.e., midHolocene or lgm). parative abundance of paleoenvironmental data and of quan- The two experiments described here focus on comparing titative climate reconstructions for the Holocene and Last In- the most recent interglacial epochs and specifically the cur- terglacial make these two epochs ideal candidates for system- rent interglacial (the Holocene) and the previous interglacial atic evaluation of model performance, and such comparisons (the Last Interglacial, LIG) periods (Fig. 1). These two ex- will shed new light on the importance of external feedbacks periments are of interest because they examine the response (e.g., vegetation, dust) and the ability of state-of-the-art mod- of the climate system to relatively simple changes in forcing els to simulate climate changes realistically. compared to present. The main difference in forcing from present was in the latitudinal and seasonal distribution of in- coming solar radiation (insolation) caused by known changes in the Earth’s orbit; greenhouse gas (GHG) concentrations
Recommended publications
  • Understanding and Attributing Climate Change
    9 Understanding and Attributing Climate Change Coordinating Lead Authors: Gabriele C. Hegerl (USA, Germany), Francis W. Zwiers (Canada) Lead Authors: Pascale Braconnot (France), Nathan P. Gillett (UK), Yong Luo (China), Jose A. Marengo Orsini (Brazil, Peru), Neville Nicholls (Australia), Joyce E. Penner (USA), Peter A. Stott (UK) Contributing Authors: M. Allen (UK), C. Ammann (USA), N. Andronova (USA), R.A. Betts (UK), A. Clement (USA), W.D. Collins (USA), S. Crooks (UK), T.L. Delworth (USA), C. Forest (USA), P. Forster (UK), H. Goosse (Belgium), J.M. Gregory (UK), D. Harvey (Canada), G.S. Jones (UK), F. Joos (Switzerland), J. Kenyon (USA), J. Kettleborough (UK), V. Kharin (Canada), R. Knutti (Switzerland), F.H. Lambert (UK), M. Lavine (USA), T.C.K. Lee (Canada), D. Levinson (USA), V. Masson-Delmotte (France), T. Nozawa (Japan), B. Otto-Bliesner (USA), D. Pierce (USA), S. Power (Australia), D. Rind (USA), L. Rotstayn (Australia), B. D. Santer (USA), C. Senior (UK), D. Sexton (UK), S. Stark (UK), D.A. Stone (UK), S. Tett (UK), P. Thorne (UK), R. van Dorland (The Netherlands), M. Wang (USA), B. Wielicki (USA), T. Wong (USA), L. Xu (USA, China), X. Zhang (Canada), E. Zorita (Germany, Spain) Review Editors: David J. Karoly (USA, Australia), Laban Ogallo (Kenya), Serge Planton (France) This chapter should be cited as: Hegerl, G.C., F. W. Zwiers, P. Braconnot, N.P. Gillett, Y. Luo, J.A. Marengo Orsini, N. Nicholls, J.E. Penner and P.A. Stott, 2007: Under- standing and Attributing Climate Change. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D.
    [Show full text]
  • Shortwave Forcing and Feedbacks in Last Glacial
    Downloaded from http://rsta.royalsocietypublishing.org/ on October 12, 2015 Shortwave forcing and feedbacks in Last Glacial rsta.royalsocietypublishing.org Maximum and Mid-Holocene PMIP3 simulations Research Pascale Braconnot and Masa Kageyama Cite this article: Braconnot P,Kageyama M. Laboratoire des Siences du climat et de l’Environnement, 2015 Shortwave forcing and feedbacks in Last Orme des Merisiers, bât. 712, Gif-sur-Yvette Cedex 91191, France Glacial Maximum and Mid-Holocene PMIP3 simulations. Phil.Trans.R.Soc.A373: Simulations of the climates of the Last Glacial 20140424. Maximum (LGM), 21 000 years ago, and of the http://dx.doi.org/10.1098/rsta.2014.0424 Mid-Holocene (MH), 6000 years ago, allow an analysis of climate feedbacks in climate states that Accepted: 29 June 2015 are radically different from today. The analyses of cloud and surface albedo feedbacks show that the shortwave cloud feedback is a major driver of One contribution of 12 to a discussion meeting differences between model results. Similar behaviours issue ‘Feedbacks on climate in the Earth appear when comparing the LGM and MH simulated system’. changes, highlighting the fingerprint of model physics. Even though the different feedbacks show Subject Areas: similarities between the different climate periods, climatology the fact that their relative strength differs from one climate to the other prevents a direct comparison of past and future climate sensitivity. The land- Keywords: surface feedback also shows large disparities among Last Glacial Maximum and Mid-Holocene models even though they all produce positive climates, ice-sheet and insolation forcing, sea-ice and snow feedbacks. Models have very cloud and surface albedo feedbacks different sensitivities when considering the vegetation feedback.
    [Show full text]
  • 1 Chapter 9: Evaluation of Climate Models
    Zero Order Draft Chapter 9 IPCC WGI Fifth Assessment Report 1 2 Chapter 9: Evaluation of Climate Models 3 4 Coordinating Lead Authors: Gregory Flato (Canada), Jochem Marotzke (Germany) 5 6 Lead Authors: Babatunde Abiodun (South Africa), Pascale Braconnot (France), Sin Chan Chou (Brazil), 7 William Collins (USA), Peter Cox (UK), Fatima Driouech (Morocco), Seita Emori (Japan), Veronika Eyring 8 (Germany), Chris Forest (USA), Peter Gleckler (USA), Eric Guilyardi (France), Christian Jakob (Australia), 9 Vladimir Kattsov (Russia), Chris Reason (South Africa), Markku Rummukainen (Sweden) 10 11 Contributing Authors: Johanna Baehr, Alejandro Bodas-Salcedo, Bode Gbobaniyi, Stephen Griffies, 12 Elizabeth Hunke, Tatiana Ilyina, Stephen A. Klein, Reto Knutti, Felix Landerer, Florian Rauser, Mark 13 Rodwell, Adam A. Scaife, John Scinocca, Hideo Shiogama, Ken Sperber, Bjorn Stevens, Keith Williams, 14 Tim Woollings 15 16 Review Editors: Isaac Held (USA), Andy Pitman (Australia), Serge Planton (France), Zong-Ci Zhao 17 (China) 18 19 Date of Draft: 15 April 2011 20 21 Notes: TSU Compiled Version 22 23 24 Table of Contents 25 26 Executive Summary..........................................................................................................................................3 27 9.1 Climate Models and their Characteristics..............................................................................................4 28 9.1.1 Introduction.....................................................................................................................................4
    [Show full text]
  • Chapter 9 IPCC WGI Fifth Assessment Report
    First Order Draft Chapter 9 IPCC WGI Fifth Assessment Report 1 2 Chapter 9: Evaluation of Climate Models 3 4 Coordinating Lead Authors: Gregory Flato (Canada), Jochem Marotzke (Germany) 5 6 Lead Authors: Babatunde Abiodun (South Africa), Pascale Braconnot (France), Sin Chan Chou (Brazil), 7 William Collins (USA), Peter Cox (UK), Fatima Driouech (Morocco), Seita Emori (Japan), Veronika Eyring 8 (Germany), Chris Forest (USA), Peter Gleckler (USA), Eric Guilyardi (France), Christian Jakob (Australia), 9 Vladimir Kattsov (Russia), Chris Reason (South Africa), Markku Rummukainen (Sweden) 10 11 Contributing Authors: Alessandro Anav, Timothy Andrews, Johanna Baehr, Alejandro Bodas-Salcedo, 12 Ping Chang, Aiguo Dai, Clara Deser, Bode Gbobaniyi, Fidel Gonzales-Rouco, Stephen Griffies, Alex Hall, 13 Elizabeth Hunke, Tatiana Ilyina, Viatcheslav Kharin, Stephen A. Klein, Jeff Knight, Reto Knutti, Felix 14 Landerer, Tatiana Pavlova, Florian Rauser, Mark Rodwell, Adam A. Scaife, John Scinocca, Hideo 15 Shiogama, Jana Sillmann, Ken Sperber, David Stephenson, Bjorn Stevens, Mark Webb, Keith Williams, Tim 16 Woollings, Shang-Ping Xie 17 18 Review Editors: Isaac Held (USA), Andy Pitman (Australia), Serge Planton (France), Zong-Ci Zhao 19 (China) 20 21 Date of Draft: 16 December 2011 22 23 Notes: TSU Compiled Version 24 25 26 Table of Contents 27 28 Executive Summary ......................................................................................................................................... 3 29 9.1 Climate Models and their Characteristics ...........................................................................................
    [Show full text]
  • Otto-Bliesner, B. L., Braconnot, P., Harrison, S. P., Lunt, D. J., Abe- Ouchi, A., Albani, S., Bartlein, P
    Otto-Bliesner, B. L., Braconnot, P., Harrison, S. P., Lunt, D. J., Abe- Ouchi, A., Albani, S., Bartlein, P. J., Capron, E., Carlson, A. E., Dutton, A., Fischer, H., Goelzer, H., Govin, A., Haywood, A., Joos, F., Legrande, A. N., Lipscomb, W. H., Lohmann, G., Mahowald, N., ... Zhang, Q. (2017). The PMIP4 contribution to CMIP6 - Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations. Geoscientific Model Development, 10(11), 3979-4003. https://doi.org/10.5194/gmd-10-3979-2017 Publisher's PDF, also known as Version of record License (if available): CC BY Link to published version (if available): 10.5194/gmd-10-3979-2017 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Copernicus at https://www.geosci-model-dev.net/10/3979/2017/ . Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ Geosci. Model Dev., 10, 3979–4003, 2017 https://doi.org/10.5194/gmd-10-3979-2017 © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License. The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations Bette L.
    [Show full text]
  • Understanding and Attributing Climate Change
    9 Understanding and Attributing Climate Change Coordinating Lead Authors: Gabriele C. Hegerl (USA, Germany), Francis W. Zwiers (Canada) Lead Authors: Pascale Braconnot (France), Nathan P. Gillett (UK), Yong Luo (China), Jose A. Marengo Orsini (Brazil, Peru), Neville Nicholls (Australia), Joyce E. Penner (USA), Peter A. Stott (UK) Contributing Authors: M. Allen (UK), C. Ammann (USA), N. Andronova (USA), R.A. Betts (UK), A. Clement (USA), W.D. Collins (USA), S. Crooks (UK), T.L. Delworth (USA), C. Forest (USA), P. Forster (UK), H. Goosse (Belgium), J.M. Gregory (UK), D. Harvey (Canada), G.S. Jones (UK), F. Joos (Switzerland), J. Kenyon (USA), J. Kettleborough (UK), V. Kharin (Canada), R. Knutti (Switzerland), F.H. Lambert (UK), M. Lavine (USA), T.C.K. Lee (Canada), D. Levinson (USA), V. Masson-Delmotte (France), T. Nozawa (Japan), B. Otto-Bliesner (USA), D. Pierce (USA), S. Power (Australia), D. Rind (USA), L. Rotstayn (Australia), B. D. Santer (USA), C. Senior (UK), D. Sexton (UK), S. Stark (UK), D.A. Stone (UK), S. Tett (UK), P. Thorne (UK), R. van Dorland (The Netherlands), M. Wang (USA), B. Wielicki (USA), T. Wong (USA), L. Xu (USA, China), X. Zhang (Canada), E. Zorita (Germany, Spain) Review Editors: David J. Karoly (USA, Australia), Laban Ogallo (Kenya), Serge Planton (France) This chapter should be cited as: Hegerl, G.C., F. W. Zwiers, P. Braconnot, N.P. Gillett, Y. Luo, J.A. Marengo Orsini, N. Nicholls, J.E. Penner and P.A. Stott, 2007: Under- standing and Attributing Climate Change. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D.
    [Show full text]
  • Annex I Glossary Editor: A.P.M
    Annex I Glossary Editor: A.P.M. Baede (Netherlands) Notes: This glossary defines some specific terms as the lead authors intend them to be interpreted in the context of this report. Red, italicised words indicate that the term is defined in the Glossary. 8.2ka event Following the last post-glacial warming, a rapid Albedo The fraction of solar radiation reflected by a surface or climate oscillation with a cooling lasting about 400 years occurred object, often expressed as a percentage. Snow-covered surfaces have about 8.2 ka. This event is also referred to as the 8.2kyr event. a high albedo, the surface albedo of soils ranges from high to low, and vegetation-covered surfaces and oceans have a low albedo. The Abrupt climate change The nonlinearity of the climate system Earth’s planetary albedo varies mainly through varying cloudiness, may lead to abrupt climate change, sometimes called rapid climate snow, ice, leaf area and land cover changes. change, abrupt events or even surprises. The term abrupt often refers to time scales faster than the typical time scale of the responsible Albedo feedback A climate feedback involving changes in the forcing. However, not all abrupt climate changes need be externally Earth’s albedo. It usually refers to changes in the cryosphere, which forced. Some possible abrupt events that have been proposed has an albedo much larger (~0.8) than the average planetary albedo include a dramatic reorganisation of the thermohaline circulation, (~0.3). In a warming climate, it is anticipated that the cryosphere rapid deglaciation and massive melting of permafrost or increases in would shrink, the Earth’s overall albedo would decrease and more soil respiration leading to fast changes in the carbon cycle.
    [Show full text]
  • Comment Response 5-1 5 0 0 0 0 the Coverage of the Chapter Seems a Bit Too Limited and Selective Although I Understand the Number of Pages Taken Into Account
    Expert Review Comments on the IPCC WGI AR5 First Order Draft -- Chapter 5 Comment Chapter From From To To No Page Line Page Line Comment Response 5-1 5 0 0 0 0 The coverage of the chapter seems a bit too limited and selective although I understand the number of pages Taken into account. Covered in new section 5.5 are limited. For example, why abrupt climate change in the Holocene is not covered only those in the glacial? (Holocene regional changes) within space limitations. Some of the topics probably are dealt in earlier reports, but because of its importance for future implications coverage of the Holocene climate change should be increased. [Takuro Kobashi, Japan] 5-2 5 0 Too many references in the text will distract the attention of the readers [Muhammad Amjad, Pakistan] Noted 5-3 5 0 This chapter is generally difficult to read for non specialists. The style has to be corrected as well as the Taken into account. Sections reorganised and logics numerous typos and spelling mistakes. The content needs to be "simplified" and better organised. To my better explained. opinion, there is still some work to do on this chapter. [CATHERINE BELTRAN, France] 5-4 5 0 In general it is difficult to get the main message. It would be easier if the main results were highlighted and if Noted "what's left to do" was clearly assigned. [CATHERINE BELTRAN, France] 5-5 5 0 general comment. I found the material included in this chapter quite convincing. The overall organisation of the Noted; Revised introduction should give better chapter is fine, except that the exact place of some pieces of information should be reconsidered.
    [Show full text]
  • Annex I FINAL.Indd
    Annex I Glossary Editor: A.P.M. Baede (Netherlands) Notes: This glossary defi nes some specifi c terms as the lead authors intend them to be interpreted in the context of this report. Red, italicised words indicate that the term is defi ned in the Glossary. 8.2ka event Following the last post-glacial warming, a rapid Albedo The fraction of solar radiation refl ected by a surface or climate oscillation with a cooling lasting about 400 years occurred object, often expressed as a percentage. Snow-covered surfaces have about 8.2 ka. This event is also referred to as the 8.2kyr event. a high albedo, the surface albedo of soils ranges from high to low, and vegetation-covered surfaces and oceans have a low albedo. The Abrupt climate change The nonlinearity of the climate system Earth’s planetary albedo varies mainly through varying cloudiness, may lead to abrupt climate change, sometimes called rapid climate snow, ice, leaf area and land cover changes. change, abrupt events or even surprises. The term abrupt often refers to time scales faster than the typical time scale of the responsible Albedo feedback A climate feedback involving changes in the forcing. However, not all abrupt climate changes need be externally Earth’s albedo. It usually refers to changes in the cryosphere, which forced. Some possible abrupt events that have been proposed has an albedo much larger (~0.8) than the average planetary albedo include a dramatic reorganisation of the thermohaline circulation, (~0.3). In a warming climate, it is anticipated that the cryosphere rapid deglaciation and massive melting of permafrost or increases in would shrink, the Earth’s overall albedo would decrease and more soil respiration leading to fast changes in the carbon cycle.
    [Show full text]
  • Assessing the Reliability of Climate Models, CMIP5
    Assessing the Reliability of Climate Models, CMIP5 Bart van den Hurk , Pascale Braconnot , Veronika Eyring , Pierre Friedlingstein , Peter Gleckler , Reto Knutti , and Joao Teixeira Abstract In spite of the yet incomplete subsample of the 5th phase of the Coupled Model Intercomparison Project (CMIP5) model ensemble to date, evaluation of these models is underway. Novel diagnostics and analysis methods are being utilized in order to explore the skill of particular processes, the degree to which models have improved since CMIP3, and particular features of the hindcasts, decadal and centennial projections. These assessments strongly benefi t from the increasing availability of state-of-the-art data sets and model output processing techniques. Also paleo-climate analysis proves to be useful for demonstrating the ability of models to simulate climate conditions that are different from present day. The existence of an increasingly wide ensemble of model simulations re-emphasizes the need to carefully consider the implications of model spread. Disparity between projected results does imply that model uncertainty exists, but not necessarily refl ects a true estimate of this uncertainty. B. van den Hurk (*) Royal Netherlands Meteorological Institute (KNMI) , AE De Bilt , Post Box 201 NL-3730 , The Netherlands e-mail: [email protected] P. Braconnot Insitut Pierre Simon Laplace/Laboratoire des Sciences du Climat et de l’Environnement , unité mixte de recherches CEA-CNRS-UVSQ , Bât.712, Orme des Merisiers CE-Saclay , Gif sur Yvette Cedex F-91191 , France e-mail: [email protected] V. Eyring Deutsches Zentrum fuer Luft- und Raumfahrt (DLR) , Institut für Physik der Atmosphäre (IPA) , Oberpfaffenhofen, Wessling 82234 , Germany e-mail: [email protected] P.
    [Show full text]
  • The PMIP4 Contribution to CMIP6 – Part 2: Two Interglacials, Scientific Objective and Experimental Design for Holocene and Last Interglacial Simulations
    The PMIP4 contribution to CMIP6 – Part 2: two interglacials, scientific objective and experimental design for Holocene and last interglacial simulations Article Published Version Creative Commons: Attribution 3.0 (CC-BY) Open Access ( Final Version ) Otto-Bleisner, B. L., Braconnot, P., Harrison, S. P., Lunt, D. J., Abe-Ouchi, A., Albani, S., Bartlein, P. J., Capron, E., Carlson, A. E., Dutton, A., Fischer, H., Goelzer, H., Govin, A., Haywood, A., Joos, F., Legrande, A. N., Lipscomb, W. H., Lohmann, G., Mahowald, N., Nehrbass-Ahles, C., Pausata, F. S.-R., Peterschmidt, J.-Y., Phipps, S. and Renssen, H. (2017) The PMIP4 contribution to CMIP6 – Part 2: two interglacials, scientific objective and experimental design for Holocene and last interglacial simulations. Geoscientific Model Development, 10 (11). pp. 3979-4003. ISSN 1991-9603 doi: https://doi.org/10.5194/gmd-10-3979-2017 Available at http://centaur.reading.ac.uk/68688/ It is advisable to refer to the publisher’s version if you intend to cite from the work. See Guidance on citing . To link to this article DOI: http://dx.doi.org/10.5194/gmd-10-3979-2017 Publisher: European Geosciences Union All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law. Copyright and IPR is retained by the creators or other copyright holders. Terms and conditions for use of this material are defined in the End User Agreement . www.reading.ac.uk/centaur CentAUR Central Archive at the University of Reading Reading’s research outputs online Geosci. Model Dev., 10, 3979–4003, 2017 https://doi.org/10.5194/gmd-10-3979-2017 © Author(s) 2017.
    [Show full text]