Review Report: Glacier inventories reveal an acceleration of Heard Island glacier loss over recent decades

The study by Tielidze et al. presents a comprehensive analysis of glacier changes on Heard Island over multiple decades, utilizing historical topographical maps and satellite imagery. The study effectively highlights trends in glacier retreat, debris cover evolution, and climate influences. However, certain aspects require further clarification and refinement to strengthen the conclusions drawn.

My major concern is about Stephenson Glacier. Figure 7: The digitised boundaries showing retreat and advancement using three lines for 2005-08-09 needs to be confirmed with more data. For me, the area depicted by 2009 and 2008 is resultant of calving of icebergs. Can you recheck this with more data? The authors mention a rapid lagoon formation, but how does this compare with similar cases elsewhere? Could lake expansion and calving instability be primary retreat drivers rather than just air temperature increases? Stephenson Glacier has lost debris cover over time, which contradicts the general trend. Why is this the case? Does this suggest significant ice thinning or enhanced calving?

Line 25-27: The increase in debris cover from 7% to 12.8% is mentioned, but its implications for glacier mass balance should be briefly noted.

Line 30-31: The phrase "many questions about the behaviour of Heard Island glaciers remain unanswered" is too vague. Specify which key uncertainties remain.

Line 239: Manual mapping is stated to be “more suitable” than automated methods. However, this should be qualified—manual delineation is more appropriate for small regions with significant debris cover, but automated methods may be effective for clean ice surfaces.

Line 269: The uncertainty assessment should clarify whether multiple independent digitizations were conducted for validation.

Line 251: Terminus measurements are described, but the frequency of available images (e.g., annual vs. decadal) should be stated explicitly.

 Fig. 3: The authors highlight higher retreat rates on the eastern side of Heard Island. Would it be possible to overlay temperature or precipitation data to visually reinforce this finding?

Line 403: The impact of decreasing surface albedo is mentioned, but cloud cover over Heard Island is persistent. Would reduced albedo have the same effect under high cloud conditions?

Line 426: The discussion of human-induced warming should be carefully phrased. While anthropogenic climate change is a major factor, direct human interference on Heard Island is minimal.