The Arctic ocean is warmed by North Atlantic surface waters, which allows for effective heat transport into the far northern latitudes. Upon cooling these same waters also provide the most oxygen rich deep waters into the global oceans. However, sea ice and fresh water have the potential to modulate or interrupt these processes, which is relevant for past slow and abrupt climatic changes, but also for the current warming.

In this presentation I synthesise the current workings of Arctic deep water formation and the extensive literature about past changes in these mechanisms. I will show that deep water formation in the Arctic during cold climate stages is generally thought to be suppressed. However, based on compiled data from the last glacial cycle and a “new” mechanistic understanding I argue that Arctic deep water formation was different but still contributed to deep ocean ventilation through the formation of spicy – that is warm and very salty – dense waters. While these results are currently preliminary, the potential of warm glacial deep water formation can have significant implications on our understanding of glacial climatology.