Abstract
Over the last 15 years glaciers that discharge directly into the ocean have shown pronounced increases in flow speed, thinning, and retreat. The resulting increased discharge of ice contributes to an increased rate of sea level rise; in Greenland this has put the ice sheet tens of percent out of balance. While the changes in these tidewater outlet glaciers are large, understanding their direct cause remains elusive. I will present observations of glacier-ocean interaction that range from half-gigaton calving events to tidal and seasonal variations in flow speed from radar interferometry and time-lapse photography. In addition, I will summarize some recent work on the relationship between fjord circulation and melting on an Alaskan tidewater glacier, to introduce the problem of energy exchange between warming sea water and a rapidly flowing glacier, and to highlight a little appreciated tie between increased surface melt on the ice and the stability of a glacier terminus.