The Greenland Ice Sheet lost over 5 trillion tons of ice over the last three decades and the ice loss is projected to continue. This loss is driving global sea level rise and inducing a freshening of the North Atlantic with potential consequences for the global ocean circulation. Regionally, it is impacting marine ecosystems and communities at Greenland’s coastal margins. The rapidity of these changes came as a surprise, revealing our limited understanding of how ice sheets respond to a warming climate. Increased submarine melting of glaciers by warming ocean waters has emerged as a key trigger for ice loss and is amongst the poorly understood mechanisms that are also largely unaccounted for in projection models. The implication is that, to understand ongoing changes and project future ones, we need to account for processes that regulate the exchange of heat and mass between the ice sheet and the ocean. In Greenland, such exchanges occur at the head of hundreds of uncharted glacial fjords that glaciers flow into. These are remote, inaccessible, and challenging regions to survey and, not surprisingly, data from these regions is largely lacking. This lack of data, in turn, means that even a basic understanding of the basic processes was missing.

Working in Greenland’s glacial fjords, where drifting icebergs are hundreds of meters deep and calving glaciers pose a threat to humans and instrumentation, has required the development of novel technologies and approaches. Observations have been possible only through a close collaboration with local communities who have a unique knowledge of these regions. Our measurements have revealed that glacier melt in Greenland is associated with intrusions of warm, Gulf Stream water, and enhanced by turbulent plumes rising at the glacier fronts. Collaborations with modelers have complemented the limited picture gained from the scarce observations and led to including these dynamics in climate and ice sheet models, albeit in simplified terms. Finally, by partnering with scientists from the natural and social sciences and with local communities, we have built on the acquired physical understanding of these systems to identify conditions that support life in these regions and ask how these may evolve in the future. Cumulatively, this body of work exemplifies how addressing complex climate questions requires a concerted, multi-faceted, international, interdisciplinary, collaborative, and convergent approach.