R-08-79 Fennoscandian paleo-environment and ice sheet dynamics during Marine Isotope Stage (MIS) 3 Report of a workshop held September 20–21, 2007 in Stockholm, Sweden Jens-Ove Näslund (ed), Svensk Kärnbränslehantering AB Barbara Wohlfarth (ed), Helena Alexanderson, Karin Helmens, Marina Hättestrand, Peter Jansson, Johan Kleman, Jan Lundqvist Stockholm University, Sweden Jenny Brandefelt, Royal Institute of Technology, Sweden Michael Houmark-Nielsen, University of Copenhagen, Denmark Erik Kjellström, Gustav Strandberg Rossby Centre, Swedish Meteorological and Hydrological Institute, Sweden Karen Luise Knudsen, University of Aarhus, Denmark Nicolaj Krog Larsen, Pirkko Ukkonen Lund University, Sweden Jan Mangerud, University of Bergen, Norway October 2008 Svensk Kärnbränslehantering AB Swedish Nuclear Fuel and Waste Management Co Box 250, SE-101 24 Stockholm Tel +46 8 459 84 00 CM Gruppen AB, Bromma, 2008 ISSN 1402-3091 Tänd ett lager: SKB Rapport R-08-79 P, R eller TR. Fennoscandian paleo-environment and ice sheet dynamics during Marine Isotope Stage (MIS) 3 Report of a workshop held September 20–21, 2007 in Stockholm, Sweden Jens-Ove Näslund (ed), Svensk Kärnbränslehantering AB Barbara Wohlfarth (ed), Helena Alexanderson, Karin Helmens, Marina Hättestrand, Peter Jansson, Johan Kleman, Jan Lundqvist Stockholm University, Sweden Jenny Brandefelt, Royal Institute of Technology, Sweden Michael Houmark-Nielsen, University of Copenhagen, Denmark Erik Kjellström, Gustav Strandberg Rossby Centre, Swedish Meteorological and Hydrological Institute, Sweden Karen Luise Knudsen, University of Aarhus, Denmark Nicolaj Krog Larsen, Pirkko Ukkonen Lund University, Sweden Jan Mangerud, University of Bergen, Norway October 2008 A pdf version of this document can be downloaded from www.skb.se. Preface This document compiles information on the paleoenvironment for a specific part of the last glacial cycle. The information is relevant for the analysis of climate and climate related processes in the safety assessment SR-Site. In particular, the information was used in setting up climate model simulations performed for SR-Site. The aim of the report is to summarize the state of knowledge on a selected period during the Weichselian glaciation, as presented and discussed during a workshop arranged by SKB in September 2007. The participants of the workshop comprised most of the researches working on this period in Fennoscandia. In the report, the workshop participants have written their own abstracts and also directly contributed to the discussion and conclusions. Considering this aim and content of the report, it was not useful for this document to undergo the SR-Site review process. Stockholm, September 2008 Jens-Ove Näslund Person in charge of the SKB climate research programme 3 Contents 1 Introduction 7 1.1 Background 7 1.2 The 100,000 year climate conditions project 9 1.3 Purpose of the workshop 9 1.4 Workshop participant list 10 2 MIS 3 – modelling: abstracts and presentations 13 2.1 Näslund J O: Introduction with background on SKB’s assessments of nuclear repository long-term safety 13 2.2 Kjellström E: Climate conditions in Sweden in a 100,000 year time perspective – project overview 14 2.3 Näslund J O: Examples of ice sheet configurations for MIS 3 from numerical ice sheet modelling 15 2.4 Brandefelt J: Simulations of global climate within the 100,000 year project 17 2.5 Strandberg G: Simulation of the European regional climate within the 100,000-year project 18 3 MIS 3 – information from geological observations: abstracts and presentations 19 3.1 Kleman J: The elusive MIS 3 ice sheet extents – geomorphological constraints, glaciological reasoning and research strategies 19 3.2 Houmark-Nielsen M: MIS 3 ice streams and interstadial episodes in the south-western Baltic Basin 20 3.3 Knudsen K L and Krog Larsen N: Fennoscandian ice sheet fluctuations during MIS 3 in Northern Denmark, Kattegat and Skagerrak: marine and non-marine environments 23 3.4 Mangerud J J, Løvlie R, Gulliksen S, Hufthammer A-K, Larsen E and Valen V: Correlations between Fennoscandian Ice-Sheet fluctuations and Greenland Dansgaard-Oeschger Events, 45,000–25,000 years BP 24 3.5 Mangerud J: Were Svalbard, the Barents Sea and Novaya Zemlya ice-free during MIS 3? 25 3.6 Helmens K F: Environment conditions in the Sokli region (NE Finland) during an early MIS 3 interstadial based on multi-proxy evidence 27 3.7 Ukkonen P: Mammoth dates from Fennoscandia and the Baltic States related to MIS 3 28 3.8 Alexanderson H: New interstadial OSL- and 14C-dates in Sweden 30 3.9 Wohlfarth B: The paleodata contribution to the 100,000 year project 31 4 Discussion 33 4.1 Problem of time available for building up and melting of ice sheets during MIS 3 stadial/interstadials 33 4.2 Dating methods 34 4.3 Model setup for MIS 3: Selection of period 34 4.4 Model setup for MIS 3: Ice sheet configurations 35 4.5 Model setup for MIS 3: Coast lines/isostacy 36 4.6 Model setup for MIS 3: Vegetation 37 4.7 Climate seasonality/LGM climate from GCM simulation 37 4.8 Regional climate modeling 37 4.9 Poster presentation 37 5 Summary and conclusions 39 5 6 Publication and documentation of the workshop 41 7 References 43 Appendix A Circular 2 – workshop on Fennoscandian paleo-environment and ice sheet dynamics during MIS 3 Sept 20–21 2007 47 Appendix B Model forcing conditions to be used for the permafrost case (a cold stadial in MIS 3) in the project “Climate conditions in Sweden in a 100,000-year time perspective” 51 6 1 Introduction 1.1 Background This report is a documentation of the two day workshop on Fennoscandian paleo-environment and ice sheet dynamics during Marine Isotope Stage 3 (MIS 3) arranged by the Swedish Nuclear Fuel and Waste Management Company (SKB), together with the Rossby Centre at the Swedish Meteorological and Hydrological Institute and Stockholm University. The organizing committee of the workshop consisted of Jens-Ove Näslund (SKB), Barbara Wohlfarth (Stockholm University), Erik Kjellström (Rossby Centre), Jenny Brandefelt (Royal Institute of Technology, Stockholm) and Gustav Strandberg (Rossby Centre). The workshop was held at Villa Söderås on Lidingö, Stockholm. SKB is responsible for the management of spent nuclear fuel and radioactive waste generated within the Swedish nuclear power program. Detailed site investigations for a deep geological repository for spent nuclear fuel have been carried out in the Forsmark and Oskarshamn regions along the Swedish Baltic Sea coast (Figure 1-1). Within the coming years, SKB will submit an application to build a deep geological repository at one of these sites. An important document in this application is a detailed assessment of long-term repository safety. The deep geological repository will keep radiotoxic material separated from humans and the surface environment for 100,000 years and more. It is not possible to predict climate development in a 100,000 year time perspective. However, the extremes within which climate in Sweden may vary can be estimated with reasonable confidence. Within the limits defined by glacial and interglacial states, a number of characteristic climate conditions can be identified. Figure 1-1. Location of the two candidate sites for a Swedish geological repository for spent nuclear fuel, Forsmark and Laxemar, and the Finnish repository site Olkiluoto. 7 These climate conditions can be represented as climate domains /SKB 2006a/, and are defined as climatically determined environments in which a set of characteristic processes of impor- tance for repository safety appear together. Three such climate domains have been identified and defined; i) a temperate climate domain, ii) a permafrost climate domain, and iii) a glacial climate domain (Figure 1-2). The purpose of identifying these domains is to create a framework for the assessment of issues which are of importance for repository safety associated with particular, climatically determined environments that may occur in Sweden. It is likely that all three climate domains will appear during the next 100,000 years, i.e. all reasonable climate evolutions included in the safety assessment will have to cover these domains. For a more detailed description of the climate domains and how they are used to construct site specific climate developments for the safety assessment, see /SKB 2006ab/. In SKB:s last safety assessment, SR-Can, a reference climate evolution based on a reconstruc- tion of conditions during the last glacial cycle was constructed using the above climate domains /SKB 2006b/ (see also section 2.1). This reference scenario represents a conceivable evolution and covers climate-related conditions and sequences of importance for repository safety that may be expected in a 100,000 year time perspective. Here it is important to note that there may be other climate developments which may have a stronger influence on repository performance than those reconstructed for the last glacial cycle. Therefore a number of additional climate evolutions are also analyzed in the safety assessment in order to cover the whole range of climate variations expected in the coming 100,000 years. These additional climate developments include e.g. a climate evolution with a warmer climate caused by an increased greenhouse effect, and an evolution dominated by cold and dry climates favouring permafrost growth /SKB 2006b/. Figure 1-2. Simplified picture exemplifying an areal distribution of the glacial, permafrost and temperate climate domains mentioned in the text. 8 1.2 The 100,000 year climate conditions project In 2006 a project was initiated with the aim of identifying and describing climatic extremes within which climate may vary in Sweden over a 100,000 year time span (see section 2.2, 2.4, 2.5, /Kjellström et al. 2008, Strandberg et al. 2008/). Based on forcing conditions which yielded extreme climate conditions during the last glacial-interglacial cycle, climate models are applied to produce climate variables for those climate situations.