Sea level rise contribution from Ryder Glacier in northern Greenland varies by an order of magnitude by 2300 depending on future emissions

Abstract

The northern sector of the Greenland Ice Sheet contains some of the ice sheet's last remaining glaciers with floating ice tongues. One of these glaciers is Ryder Glacier, which has been relatively stable in recent decades, in contrast to the neighbouring Petermann and C.H. Ostenfeld glaciers. Understanding Ryder Glacier's future behaviour is important as ice-tongue loss could lead to acceleration and increased ice discharge. Meanwhile, it is unclear whether Greenland-wide modelling attempts are able to accurately resolve the influence of fjord and bedrock topography and small-scale variations in ice dynamics for a glacier like Ryder. To fill these gaps, here we conduct targeted high-resolution modelling of Ryder Glacier until the year 2300. We find that mass loss is dominated by discharge under a low-emissions scenario all the way to 2300, leading to a sea level contribution of between 0.8 and 2 mm depending on the amount of ocean warming. Discharge also plays a key role under a high-emissions scenario up until 2100, after which a strongly negative surface mass balance becomes the dominant driver of mass loss. This negative surface mass balance leads to a much higher sea level rise contribution by 2300 of between 44 and 52 mm, with little sensitivity to the range of ocean warming scenarios used in this study.