High arctic polynyas in a changing climate
The Arctic is undergoing a profound transformation. The striking increase in observed Greenland Ice Sheet melt and sea-ice retreat are two symptoms of the multiple impacts of climate change at high latitudes. In the sea-ice covered oceans surrounding northern Greenland however, large areas of year-round open water, termed polynyas, have been present since historical times. Located at two major Arctic-Atlantic gateways, these biological productivity hotspots support not only large mammals and birds but are a vital natural and cultural resource for indigenous Arctic communities. Polynyas also act as a potentially significant carbon sink. Three large polynyas recurrently form around northern Greenland. Paleoceanographic reconstructions of the largest, the North Water Polynya, indicate that the polynya and its associated ecosystem are extremely sensitive to rapid climatic fluctuations during the Holocene. Taking advantage of new, readily available marine sediment cores, I propose to reconstruct, for the first time, ocean circulation and sea-ice dynamics at the two main polynyas in the Greenland Sea (North East Water and Sirius Water). This action will target key climatic intervals in the early (Holocene Climatic Optimum) and late (Little Ice Age, Medieval Warm Period) Holocene and provide direct input to a fully-coupled earth system model to evaluate past and, more vitally, predict future dynamics under different greenhouse gas concentration pathways defined by the IPCC. This action provides a unique opportunity for me to learn a new proxy for Arctic paleoclimate reconstructions, skills in the applicability of paleo-data to modelling and a number of essential transferable skills such as scientific writing and mentorship, coupled with an extensive new network of expert collaborators. Through this action, I believe I can contribute to bringing this field of research forward, while gaining invaluable assets for my career development as an independent Arctic researcher.