If your hypothesis is correct, we would predict there shouldn't be any global pattern. If this isn't caused by global climate change, there's no reason to expect correlation between glaciers in distant places.
Looked at their data. There is no pattern, or even correlation to pollution or to CO2. They did a lot of funny math to make it look like it does but it's remarkably constant and not variable. Take the Alaska data from 41586_2021_3436_MOESM4_ESM.xlsx for their first figure. You can take the area to get the percentage change each year and you get about 0.489% which very minimal variation after 4 decimals and only 8 unique values when there should be 19 or 20 if you want to include the first year which would be 0% or undefined since the prior year for the first year doesn't exist.
The lack of unique values is concerning but may just be a result of the limit of their measures and rounding. However, constant melting would contradict our CO2 emissions and give anyone reason to ether toss out the study because all those values should be unique, or toss out global warming because it should correlate to the CO2 emissions and not be Constant.
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