Abstract
During a 2016 field expedition to the West Greenland Ice Sheet, a striking observation of significantly elevated CH(4) concentrations of up to 15 times the background atmospheric concentration were measured directly in the air expelled with meltwater at a subglacial discharge point from the Greenland Ice Sheet. The range of hourly subglacial CH(4) flux rate through the discharge point was estimated to be 3.1 to 134 g CH(4) hr(-1). These measurements are the first observations of direct emissions of CH(4) from the subglacial environment under the Greenlandic Ice Sheet to the atmosphere and indicate a novel emission pathway of CH(4) that is currently a non-quantified component of the Arctic CH(4) budget.