The Arctic is currently undergoing the most dramatic climatic changes on Earth, with the Arctic Ocean rapidly moving towards a “blue” (summer sea ice free) state. To assess how a “blue” Arctic will respond to and drive an increasingly warmer future, in the absence of observational records, requires robust archives from greenhouse periods in the geological past when the Arctic was “blue”. Such conditions existed during the Pleistocene interglacials of Marine Isotope Stage (MIS) 5e (~125.000 years ago) and MIS 11c, (~410.000 years ago), when geological and oceanographic conditions were comparable to today, yet substantial insolation changes led to pronounced high northern latitude warming, associated with reduced or absent summer Arctic sea ice, smaller-than-present ice sheets, and an expansion of boreal forests to the Arctic Ocean shoreline. Such periods represent valuable analogues to a potential future “blue” Arctic, yet despite the recovery of 100+ sedimentary records from the Arctic Ocean covering these time periods, empirical and numerical studies remain scares, and the research community is currently unable to adequately characterize these “greenhouse climate states”, due to severe stratigraphic uncertainties.
These “past greenhouse climate states” archive crucial analogous processes that must be understood to study the mechanisms underlying the rapid modern transition to a “blue” Arctic in response to global warming, yet unlocking this potential is limited by our current inability to date and correlate these archives across the Arctic. To solve this potential requires an open discussion during a dedicated conference (ArcSTRAT) on (1) the current status of the stratigraphic framework for the Arctic Ocean, (2) recent methodological advances to overcome the existing constraints, and (3) a road map to create synergies between expert groups and laboratories to solve all obstacles in Arctic Ocean stratigraphy during the Pleistocene and beyond.