Arctic Sea Ice Loss: A Bellwether Challenge to Interdisciplinary Science (Invited Presentation)

The recent retreat of Arctic sea ice has been viewed as a bellwether of global change. By historical standards, the loss of sea ice during the first decades of this Century has far exceeded the magnitude and rates of loss documented by observational data or reconstructions. However, attribution of this trend and predictions the future rates of loss have posed interdisciplinary challenges to the earth science community. Factors contributing to the ice loss include the atmosphere’s temperature and winds, fluxes of oceanic heat into the Arctic from the Atlantic and Pacific, and poorly quantified feedbacks within the Arctic system. Even the terrestrial component has been invoked through fluxes of heat and freshwater from land. The key attributional question is: What is the relative importance of these factors? Internal variability is a key consideration in attributional efforts, and Walter Roberts’ legacy institution, the National Center for Atmospheric Research, has been a leader in placing the recent ice loss into a framework of internal variability. We will synthesize interdisciplinary research activities into an assessment of future scenarios of Arctic sea ice, including the timeline for an ice-free summer Arctic.