11. From the Andes to the Alps, mountain glaciers are retreating. 12. The Yangtze River is derived from the mountain glacier . 13. Mountain glaciers , he noted, are a key water source in some regions, particularly in summer.14. Mountain glaciers in otherwise unglaciated areas extend to lower elevations due to a lower snow line.15. Antarctic mountain glaciers contribute 28 % of this. 16. The drainage of supraglacial lakes on mountain glaciers can disrupt the internal plumbing structure of the glacier. 17. Glaciologists have documented large-scale shrinkage of mountain glaciers throughout North and South America, Europe, Asia and Africa. 18. However, geomorphological evidence in the form of moraines and cirques indicates the former presence of mountain glaciers . 19. Mountain glaciers have receded in many areas.20. Increasing temperatures cause mountain glaciers to melt.
