**5. Glacier retreat**

Glaciers are highly sensitive indicators of past and present climate change. Their current area and volume are a response to changes in both temperature and precipitation [13], as glaciers respond to slight but prolonged changes in climate. The study of glacier fluctuations is relevant to provide an understanding of climate change over temporal scales [13].

Most glaciers are currently retreating. According to the National Snow and Ice Data Center (NSIDC), the total glacier loss per year since 1994 is approximate 400 billion tons [40–46]. The retreat of glaciers is particularly concerning, since it represents hazards for human communities living near them such as outburst floods, landslides, debris flows, and debris avalanches. Additionally, glaciers contribute substantially to water resources, which can be substantially reduced in many areas of the world [47].
