Read about the glaciers that swept over north america
The Melting World: A Journey Across America’s Vanishing Glaciers by Christopher WhiteGlobal warming usually seems to happen far away, but one catastrophic effect of climate change is underway right now in the Rocky Mountains. In The Melting World, Chris White travels to Montana to chronicle the work of Dan Fagre, a climate scientist and ecologist, whose work shows that alpine glaciers are vanishing rapidly close to home. For years, Fagre has monitored the ice sheets in Glacier National Park proving that they—and by extension all Rocky Mountain ice—will melt far faster than previously imagined. How long will the ice fields survive? What are the consequences on our environment? The Melting World chronicles the first extinction of a mountain ecosystem in what is expected to be a series of such global calamities as humanity faces the prospect of a world without alpine ice.
Last Glacial Period
Alpine glaciers form on mountainsides and move downward through valleys. Ice sheets, unlike alpine glaciers, are not limited to mountainous areas. As ice sheets spread, they cover everything around them with a thick blanket of ice, including valleys, plains, and even entire mountains. Today, continental glaciers cover most of Antarctica and the island of Greenland. Ice sheets reached their greatest size about 18, years ago. How Glaciers Form Glaciers begin forming in places where more snow piles up each year than melts.
The glacier that covered most of North America scarred the land, turned rivers in their courses, and deeply influenced our history. A narrow band of very low, very gentle hills extends across the northern states from Cape Cod to the Rocky Mountains in Montana. In places the winds and rains of thousands of years have worn them down to insignificant undulations; in other places they may be a hundred feet high or more. The glacier that stood on that line would have been a spectacular sight had there been anyone to see it: a great palisade of green and white ice many hundreds of feet high and stretching to the horizon cast and west. For the most part, it probably loomed silently menacing, but from time to time huge sections crumbled off in awesome avalanches. Forests grew, and herds of woolly mammoths and other, less lordly creatures grazed almost up to the ice face, but to the north, atop the glacier, there was only a barren expanse of blizzard-swept ice stretching in absolute desolation toward the Arctic Circle. The glacier was the last cataclysmic event that helped shape the face of the continent.
The world was a much different place 14, years ago. Global temperatures were significantly colder than they are today, with northern oceans an average of 4 to 8 degrees colder than modern temperatures. Huge stretches of ice covered most of northern Europe and all but the southern tip of the British Isles. Sea levels were also dramatically different during the LGM due to the twin pressures of eustacy and isostacy. Today, glaciers are found only in the polar regions and in high mountainous areas; however, in the past, they covered vast areas of the Earth's surface and shaped much of the landscape that we see today.
jackson j spielvogel western civilization 9th edition
Cold and warm glaciers - Crash Course Cryosphere #6
This most recent glacial period is part of a larger pattern of glacial and interglacial periods known as the Quaternary glaciation extending from c. The Antarctic ice sheet began to form earlier, at about 34 Ma, in the mid- Cenozoic Eocene—Oligocene extinction event. The term Late Cenozoic Ice Age is used to include this early phase. During this last glacial period there were alternating episodes of glacier advance and retreat. Within the last glacial period the Last Glacial Maximum was approximately 22, years ago. While the general pattern of global cooling and glacier advance was similar, local differences in the development of glacier advance and retreat make it difficult to compare the details from continent to continent see picture of ice core data below for differences. Approximately 13, years ago, the Late Glacial Maximum began.