Ice Sheets And Climate

Climate modelling is a field in rapid development, and the fltudy of cryospheric processes has become an important part of it. On smaller time scales, the effect of snow cover and sea ice on the atmospheric circulation is of concern for long-range weather forecasting. Thinking in decades or centuries, the effect of a C02 climatic warming on the present-day ice sheets, and the resulting changes in global sea level, has drawn a lot of attention. In particular, the dynamics of marine ice sheets (ice sheets on a bed that would be below sea level after removal of ice and full isostatic rebound) is a subject of continuous research. This interest stems from the fact that the West Antarctic Ice Sheet is a marine ice sheet which, according to some workers, may be close to a complete collapse. The Pleistocene ice ages, or glacial cycles, are best characterized by total ice volume on earth, indicating that on 4 5 large time scales (10 to 10 yr) ice sheets are a dominant component of the climate system. The enormous amount of paleoclimatic information obtained from deep-sea sediments in the last few decades has led to a complete revival of iriterest in the physical aspects of the Pleistocene climatic evolution.

Our realisation of how profoundly glaciers and ice sheets respond to climate change and impact sea level and the environment has propelled their study to the forefront of Earth system science. Aspects of this multidisciplinary endeavour now constitute major areas of research. This book is named after the international summer school held annually in the beautiful alpine village of Karthaus, Northern Italy, and consists of twenty chapters based on lectures from the school. They cover theory, methods, and observations, and introduce readers to essential glaciological topics such as ice-flow dynamics, polar meteorology, mass balance, ice-core analysis, paleoclimatology, remote sensing and geophysical methods, glacial isostatic adjustment, modern and past glacial fluctuations, and ice sheet reconstruction. The chapters were written by thirty-four contributing authors who are leading international authorities in their fields. The book can be used as a graduate-level textbook for a university course, and as a valuable reference guide for practising glaciologists and climate scientists.

Written by more than 70 scientists from around the world, this publication assesses the state of the environment and the trends in ice and snow-covered regions (the cryosphere). It looks at the significance of climate changes for ecosystems and human well-being, both now and in the years to come, given that changes in ice and snow alter the distribution of the earth's heat and water, and influence regional and global ocean circulation. This publication is an official project of the International Polar Year 2007-2008.

According to my latest model for the last glacial maximum (LGM) (Grosswald 1988), the Arctic continental margin of Eurasia was glaciated by the Eurasian ice sheet, which consisted of three interconnected ice domes --the Scandinavian, Kara, and East Siberian. The Kara Sea glacier was largely a marine ice dome grounded on the sea's continental shelf. The ice dome discharged its ice in all directions, northward into the deep Arctic Basin, southward and westward onto the mainland of west-central North Siberia, the northern Russian Plain, and over the Barents shelf into the Norwegian-Greenland Sea On the Barents shelf, the Kara ice dome merged with the Scandinavian ice dome. In the Arctic Basin the discharged ice floated and eventually coalesced with the floating glacier ice of the North-American provenance giving rise to the Central-Arctic ice shelf. Along its southern margin, the Kara ice dome impounded the northward flowing rivers, causing the formation of large proglaciallakes and their integration into a transcontinental meltwater drainage system. Despite the constant increase in corroborating evidence, the concept of a Kara ice dome is still considered debatable, and the ice dome itself problematic. As a result, a paleogeographic uncertainty takes place, which is aggravated by the fact that a great deal of existing knowledge, no matter how broadly accepted, is based on ambiguous interpretations of the data, most of which are published in Russian and, therefore, not easily available to western scientists.

Chapter 1 focuses on the science to understand the physical processes and projections of mass loss of the major ice sheets in Greenland and Antarctica, as well as of mountain and other land-based glaciers. The chapter reports on current projections of glacier mass loss due to anthropogenic climate change, and in turn how that will affect sea level.The diminishment of Arctic sea ice has led to increased human activities in the Arctic, and has heightened interest in, and concerns about, the region's future as reported in chapter 2. Issues such as Arctic territorial disputes; commercial shipping through the Arctic; Arctic oil, gas, and mineral exploration; endangered Arctic species; and increased military operations in the Arctic could cause the region in coming years to become an arena of international cooperation, tension, or competition.

The Arctic is thawing. In summer, cruise ships sail through the once ice-clogged Northwest Passage, lakes form on top of the Greenland Ice Sheet, and polar bears swim farther and farther in search of waning ice floes. At the opposite end of the world, floating Antarctic ice shelves are shrinking. Mountain glaciers are in retreat worldwide, unleashing flash floods and avalanches. We are on thin ice—and with melting permafrost’s potential to let loose still more greenhouse gases, these changes may be just the beginning. Vanishing Ice is a powerful depiction of the dramatic transformation of the cryosphere—the world of ice and snow—and its consequences for the human world. Delving into the major components of the cryosphere, including ice sheets, valley glaciers, permafrost, and floating ice, Vivien Gornitz gives an up-to-date explanation of key current trends in the decline of ice mass. Drawing on a long-term perspective gained by examining changes in the cryosphere and corresponding variations in sea level over millions of years, she demonstrates the link between thawing ice and sea-level rise to point to the social and economic challenges on the horizon. Gornitz highlights the widespread repercussions of ice loss, which will affect countless people far removed from frozen regions, to explain why the big meltdown matters to us all. Written for all readers and students interested in the science of our changing climate, Vanishing Ice is an accessible and lucid warning of the coming thaw.

Proceedings of a workshop on the possibility of a rapid rise in sea level following the response of the West Antarctic ice sheet to global warming, and outline of a project to study the phenomenon, called SEARISE : Sea Level Response to Ice Sheet Evolution.