WP3: Greenhouse - Icehouse fluctuations in the Arctic Ocean and their role in the global climate system - integrating marine and terrestrial geological records

Work package leaders: Astrid Lyså (NGU) and Matthias Forwick (UiT)
Contributions from: Jochen Knies (NGU), Katrine Husum (NPI), Tom Arne Rydningen (UiT), Lena Håkansson (UNIS), Jan Sverre Laberg (UiT), Nele Meckler (UiB), Bjørg Risebrobakken (UniResearch), Riko Noormets (UNIS)

Introduction

The Arctic Ocean belongs to the region on Earth that is currently exposed to the most dramatic climatic and environmental changes (IPCC 2014). Also in the geological past, i.e. during Cenozoic times, the Arctic Ocean was an area where marked changes from “Greenhouse Climate” with surface-water temperatures of up to 25 °C to perennial sea-ice cover occurred (e.g. Moran et al. 2006; Sluijs et al. 2006; Backman and Moran 2008). In addition to the orbitally driven climatic changes, the Arctic Ocean transformed due to tectonic changes from a lake to an ocean, thus obtaining an essential role in the global ocean circulation. The timing and nature of this development is closely linked to the opening of the Fram Strait, the only deep-water gateway linking the Arctic Ocean to the global ocean circulation, and an important prerequisite for the development of the modern ocean circulation system (Kristoffersen 1990; Jakobsson et al. 2007; Engen et al. 2008).

Thus far, long-term reconstructions of Cenozoic climatic change in the Arctic are based on very few and incomplete marine records from the Lomonosov Ridge (IODP Expedition 302; ACEX; e.g. Backman et al. 2008) and the Yermak Plateau (ODP Leg 151; e.g. Thiede et al. 1996). This is due to the difficulty of accessing the area because of sea ice, but also because post-depositional modifications have in many cases altered the sediment packages. Furthermore, limited onshore and offshore studies reveal only the youngest part of a generally fragmentary Quaternary record (Ingolfsson and Landvik 2013). The sparse knowledge about the environmental development of the Arctic Ocean requires additional investigation and the integration of terrestrial and marine records as proposed in this work package.

Main objective

Improve the understanding of the Cenozoic geological, climatological and oceanographic evolution of the Arctic Ocean and, thereby, enhance the understanding of natural climate variability at high northern latitudes, as well as to infer the role of the Arctic in the global climatic and oceanographic system. The success of the work package will depend on the integration of marine and terrestrial records, as well as Earth System Modelling, to get a comprehensive understanding of the geological, climatological and oceanographic evolution of the Arctic Ocean.