Arctic Palaeoclimate and its EXtremes (APEX)

What do we mean by EXtremes? Conditions that represent the end points of magnitude / frequency behaviour (e.g. maximum ice sheet extent, very fast ice flow, maximum air temperatures, rapid changes in palaeoceanography) Their definitions are spatially and temporally specific (e.g. Eurasian ice sheet versus an individual ice stream, or ice extent during the Last Glacial Maximum versus the Little Ice Age) They may be defined by dimensions or with respect to process Their definition requires understanding of the background, or “steady state” of a particular system

Why do EXtremes matter? They establish boundary conditions that constrain our understanding of the Arctic and the role of the Arctic in global climate change They are relevant to predictions of future climate change They provide excellent modelling targets

APEX themes Cold Extremes: Arctic marine and terrestrial glacial maxima, sea level minima and maxima, Arctic Ocean palaeoceanography, ice shelf extent, palaeoatmospheric circulation Warm Extremes: interglacial environments, sea level maximum, sea-ice minimum, Arctic Ocean palaeoceanography, ice shelf extent Hydrological extremes: Fluvial-marine interaction, freshwater budget and ice-dammed lakes Permafrost extremes: Maximum and minimum extent, rates of change, response to climate change Glacio-dynamical extremes: Ice sheet instability, palaeo-ice stream dynamics and feedback mechanisms

Some APEX scientific challenges What were the dimensions, age and palaeoglaciology of the Arctic ice sheets during glacial maxima? Was there a large Arctic Ocean ice-shelf during glacial maxima, and how did coastal ice shelves respond to Holocene climate change? How large were the MIS 6 ice sheets and what were its climate impacts? How large was the Greenland ice sheet during interglacials? How fast can an ice sheet develop? How does the Eemian compare to the Holocene in the Arctic? How warm can Arctic interglacials be? How did palaeo-ice streams operate within the Eurasian, Iceland and Greenland ice sheets and effect their stability? Can we develop a chronology for the Eemian? Was there influx of Atlantic Water into the central Arctic Ocean during glacial maxima? What caused the development of extreme cold and dry climatic conditions in eastern Siberia?

APEX Methodology Builds on PONAM and QUEEN legacy Strong integration between land and ocean investigations Strong integration between modeling and field data Emphasis on both patterns and processes

How are we going to promote this? The role of the Arctic in the global climate system Emphasis on the extremes Analogues for future climate change, e.g. Greenland Ice Sheet mass balance and sea ice thickness and extent Multi- and interdisciplinary Proven track record from PONAM and QUEEN Embrace new EU member states into APEX

APEX and the International Polar Year 2007 – Status: to determine the present environmental status of the polar regions 2.Change: to quantify, and understand, past and present natural environmental and social change in the polar regions; and to improve projections of future change 3.Global Linkages: to advance understanding on all scales of the links and interactions between polar regions and the rest of the globe, and of the processes controlling these 4.New Frontiers: to investigate the frontiers of science in the polar regions 5.Vantage Point: to use the unique vantage point of the polar regions to develop and enhance observatories from the interior of the Earth to the Sun and the cosmos beyond 6.Human Dimension: to investigate the cultural, historical, and social processes that shape the sustainability of circumpolar human societies, and to identify their unique contributions to global cultural diversity and citizenship Concept of IPY as defined in “A framework for the International Polar Year”, www,ipy.org

APEX planned field activities

2005: Beringia 2005, Icebreaker Oden/ USCGC Healy “A pan-Arctic transect for linking Eurasian and Amerasian records to constrain the paleoenvironmental evolution of the Arctic Ocean” IPY : 07/08-1. Lomonosov/Greenland, Icebreaker Oden “Geological coring and geophysical seafloor mapping using an Autonomous Underwater Vehicle (AUV) under the pack ice to study the glacial history of the Arctic Ocean” 07/ Southampton Oceanography Centre Scott Polar Research Institute

Polarstern Polarstern “Variability of water mass exchange during interglacials in the Arctic” 2. Polarstern “High-resolution marine records of Late Quaternary Eurasian ice sheets” IFM-GEOMAR

Field campaign North and NE Greenland ice sheet / ocean interactions 2: Field campaign West Greenland LGM and Holocene ice sheet and palaeoceanography 3: Field campaign Iceland ice sheet dimensions and palaeoglaciology

Bristol Glaciology Centre University of Bristol Integration between modeling and field data