Please see the attached pdf document.

In this study the authors provide mass changes for a large number of world glaciers from 1976 to 2023 by combining data sets based on in situ and space-based measurements. This new product, to be distributed by the Copernicus services will be of invaluable value for climate applications, including sea level rise and land hydrology. It will be definitely of hifg interest for the scientific community.

While I greatly appreciate the efforts made by the authors in combining different datasets,  in performing appropriate calibration and in providing product uncertainties, I find that the manuscript requires major improvements in terms of presentation. The paper is very difficult to read. First of all, it lacks a number of general information about the data used to be understandable to non-experts. Some sections are quite technical and poorly explained. A large number of variables are not defined and some important information is just provided in tables without explanation in the main text.

I recommend to the authors to consider my comments below and provide in a revised version a text clear enough to be appreciated by both experts and non experts. As it stands, it is not the case.

General comments:

• The abstract and introduction are too vague and lack useful information
• It is unclear in both the abstract and the introduction which data sets are considered and combined. How have they been obtained? The data section refers to the data sources given by their acronyms but no information is provided on the methods to obtain the data. What is the proportion of in situ data and remote sensing data? Are the latter only based on ASTER DEMs as described in Hugonnet et al. (2021)? What is the spatio-temporal coverage of each data set? It is insufficient to say (as written in the abstract and introduction) that geodetic and glaciological data are used. It is unclear whether in addition to the Hugonnet et al.’s data, other remote sensing data are considered.
• While the paper mentions the percentage of glaciers considered by Hugonnet et al (96%) and the total number of glaciers is never mentioned, neither the percentage of glaciers considered from in situ measurements.

I suggest to rewrite the abstract and introduction to clarify these issues and provide to the reader the missing information.

The figures are in general too busy. The figure captions need to be extended and provide the definition of the parameters appearing in the figure.

Line-by-line comments

• Abstract, line 14: the term ‘remote sensing’ is too generic. Mention how elevation measurements are obtained (in addition to streo images), laser altimetry and space gravimetry can be also used (the latter given rirectly mass changes).
• Abstract, line 15: ‘… resolved information’. What is this information?
• Abstract, line 16: how many world’s glaciers?
• Abstract, lines 19-20: sentence unclear. What do you mean by ‘leave-one-out cross validation’. This is a technical term. Should it appear in the abstract?
• Abstract: Estimated global glacier mass change and inferred sea level rise should appear in the abstract
• Introduction, line 54: What is FoG? Please define (in fact it is defined latter, line 74…)
• Introduction, line 74: Explain what is an ‘hydrological’ year.
• Introduction, line 78: ‘our methodology performs well…’. What is this methodology?
• Introduction, line 82: ‘leave-one-out cross validation’. Explain what this consists of.
• - Section 2.1.1, line 91: ‘to spatially locate glaciers’. Give some information on their size, number, distribution.
• Section 2.1.1, lines 96-97. Explain what GLIMS consists of.
• Section 2.1.1., line 108. Fog already defined
• Section 2.1.1, line 144. ‘96% of all world’s glaciers’. See comment above.
• Section 2.1.1, line 118: ‘more details on the glaciological methods…’. This sentence should appear earlier. Moreover, it would be useful for non experts to briefly explain what it consists of.
• Section 2.2, line 135. What is WGMS-id?
• Section 2.2, line 140. ‘low latitudes…’
• Figure 2. in the figure caption give the definitition of the parameters beta g, Y, beta cal,g, etc.
• Section 2.2.1, line 160. Give the definition of the variables.
• Section 2.2.1, line 168: What means a ‘threshold of 8 years’?
• Section 2.2.1, lines 171 to 174: Sentence unclear.
• Section 2.2.1: What means a ‘threshold of 1000 km’?
• Section 2.2.1, line 180: Give the definition of the variables.
• Section 2.2.1, lines 191 to 193: Give the definition of the variables.
• Table 2: Define the acronyms CAN, SjM, ALA, SCA, CEU, SAN…
• Section 2.2.2, line 219, 224, 229: what means ‘k-calibrated’
• Section 2.2.3, line 234. What is PoR?
• Section 2.2.4. This section is very technical. I would suggest to move the maths to an annex and explain in the main text the followed approach. As in the previous section, many variables are not defined…
• Section 2.2.4, line 295-296. Give a reference for C3S (https://climate.copernicus.eu/)
• Table 3: The content of Table 3 should be summarized in the main text.
• Table 4: same comment as above.
• Section 4. The ‘Results’ section should appear before the section on products
• Section 4, line 331: how much sea level rise?
• Figure 3: too busy. The panel on the global mass change should appear separately.
• Table 4, line 366: Should be Table 5.
• Section 5.2.1, line 406: Why Ba? Why such a notation for a mass change?
• Figure 7: define the acronyms appearing in the figure.
• Table 5, line 470: Should be Table 6. The content of the table should be summarized by a few sentences in the main text.
• Figure 8: the ‘global’ panel should be a separate figure. There is no discussion on the interannual variability? What is its origin? Some quasi periodicity is apparent? Could you provide a spectrum of the detrended time series?
• Section 5.3.1, line 560. What means ‘Hexagon corona’? Is it the name of a glacier? Where?
• Section 5.3.1, line 576: Instead of just quoting ‘gravimetry’, mention GRACE results and give references.
• Conclusions, lines 619-620. A reminder of the data used and methodology would be useful. A few sentences on the novelty of the study and the main results should also be added.
• Conclusions, line 640. Mention to ECVs and GCOS is too vague. Explain.