Climate models typically do not include meltwater entering the Southern Ocean due to Antarctic ice sheet mass loss. Previous work shows this meltwater drives sea ice growth, but the varying responses have been difficult to compare across models. We ran 11 climate models using the same meltwater input and found a wide range of sea ice responses depending on the background state in each model. Understanding this uncertainty in response is important for future projections of Antarctic sea ice.

Antarctic meltwater affects ocean stratification and temperature, which in turn influences the rate of ice shelf melting – a coupling missing in most climate models. We analyze a suite of climate models with added meltwater to explore this feedback in different regions. While meltwater generally enhances ocean warming and melt, in West Antarctica most models simulate coastal cooling, suggesting a negative feedback that could slow future ice loss there.

Warm ocean water causes rapid melting of Antarctic glaciers. The circulation and mixing of warm water in ice shelf cavities is mostly unknown. We observed ocean currents and mixing under Dotson Ice Shelf. Mixing is low, with patches of higher mixing associated with stronger currents and vertical current shear. The levels of turbulent mixing will lead to negligible heat loss during the path of the warm water to the grounding line, leaving plenty of heat available to melt the ice shelf there.

The state of sea ice strongly affects its absorption of solar energy. In May 2019, we flew uncrewed aerial vehicles (UAVs) equipped with sensors designed to quantify the sunlight that is reflected by sea ice at each wavelength over the sea ice of Kotzebue Sound, Alaska. We found that snow patches get darker (up to ~ 20 %) as they get smaller, while bare patches get darker (up to ~ 20 %) as they get larger. We believe that this difference is due to melting around the edges of small features.

Current climate models typically do not include full representation of ice sheets. As the climate warms and the ice sheets melt, they add freshwater to the ocean. This freshwater can influence climate change, for example by causing more sea ice to form. In this paper we propose a set of experiments to test the influence of this missing meltwater from Antarctica using multiple different climate models.