The life, times, and demise of the world's largest lake
During the last ice age, sea levels fell more than 100 meters. The ocean water didn't disappear, of course. It just ended up someplace else. A significant decrease in global temperatures permitted snow in some places to accumulate faster than it melted. Glaciers formed at high altitudes and scoured mountain valleys. Existing ice masses, like those in Greenland and Antarctica, thickened. In the higher latitudes of Asia, North America, and Europe, ice sheets hundreds of meters thick grew to smother vast regions.