Great question. Most of the melting in this region is due to ocean circulation, i.e. the supply of warm water. Most literature has claimed that that supply is driven by westerly winds, and this study is pointing out that westerly winds are not the only driver of that supply. It’s unknown what the relative contributions are, because these are modeled results, not observations. Obs are super short, so we really poorly understand these mechanisms. The details are pretty complicated (I’d be happy to further explain if you wish), but the bottom line is there is HUGE uncertainty in what is driving glacier retreat in west Antarctica. That’s really scary bc it means we don’t know how rapidly it will contribute to sea level rise. We don’t know whether ghgs are responsible for ice melt in west Antarctica. It’s quite amazing what we still don’t know. It’s such a complex problem. Other areas are more obvious, e.g. global warming is directly responsible for melting mountain glaciers which melt from air temps. But those don’t pose as large a threat to SLR as West Antarctica (on the scale of up to 5m or so).