Cold Region Hazards and Risks E-Book

Colin A. Whiteman

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 583

Veröffentlichungsjahr: 2011

Beschreibung

This is a unique, timely and engaging text with wide ranging geographical coverage. The text brings together, for the first time, information about a vast array of hazards associated with ice and snow, spanning both well known phenomenon (e.g. avalanches) and the less familiar (e.g. river ice jams and ice storms) using, in many cases, material which is rarely seen outside advanced academic research books and journals. The range of ice-related hazards will be introduced and the significance of the current global warming context discussed. Broad physical models of glacial, periglacial and atmospheric cold environments are presented to provide a scientific context for discussion of the human issues of risk, vulnerability impact and mitigation. Key Features: * Wide ranging geographical coverage (the Americas, Asia, Australasia, Antarctic & Europe) * Localised hazards (avalanches, life storms, landslides) contrasted to those with wider reaching effects (arctic ice loss, ice sheet retreat and wide spread permafrost decay) * Includes the latest developments in the field * Each chapter includes hazards overview, summery, conclusions, potential projects exercise and key references * Includes a supplementary website with figures from the text and further references * Each chapter includes a hazards overview, summary, conclusions, potential projects exercise and key references

Leseprobe

Contents

Preface

1 Introduction

1.1 Concept and rationale

1.2 Scope and classification of the hazards

1.3 Hazard awareness

1.4 Physical properties of ice

1.5 Hazard and risk

1.6 Summary

2 Arctic Sea Ice

2.1 Introduction

2.2 The Arctic Ocean

2.3 Sea ice

2.4 Impacts

2.5 Direct impacts

2.6 Indirect impacts

2.7 Mitigation

2.8 Summary

3 Ice Sheets – Antarctica and Greenland

3.1 Introduction

3.2 Ice sheet systems

3.3 Greenland

3.4 Antarctica

3.5 Impacts of ice sheet loss

3.6 Mitigation

3.7 Summary

4 Icebergs

4.1 Introduction

4.2 Iceberg characteristics

4.3 Iceberg impact and risk

4.4 Iceberg mitigation

4.5 Summary

5 Glaciers

5.1 Introduction

5.2 Inherent glacier hazards

5.3 Glacier mass balance changes

5.4 Mitigation measures

5.5 Summary

6 Glacial Lake Outburst Floods (GLOFs)

6.1 Introduction

6.2 The glacial meltwater system

6.3 GLOFs

6.4 Trigger mechanisms

6.5 Risk

6.6 Mitigation

6.7 Summary

7 Permafrost

7.1 Introduction

7.2 Permafrost distribution and characteristics

7.3 Permafrost hazardousness

7.4 Lowland permafrost hazards

7.5 Mountain permafrost hazards

7.6 Summary

8 Snow Avalanches

8.1 Introduction

8.2 Definition, classification and motion

8.3 Factors promoting avalanches

8.4 Impacts of avalanches

8.5 Mitigation methods

8.6 Summary

9 River Ice – Ice Jams and Ice Roads

9.1 Introduction

9.2 Ice jams

9.3 Ice roads

9.4 Summary

10 Winter Storms – Ice Storms and Blizzards

10.1 Introduction

10.2 Definitions

10.3 Weather systems and processes

10.4 Impacts

10.5 Mitigation

10.6 Summary

11 Conclusions – The Future

References

Glossary

Acronyms

Index

This edition first published 2011, © 2011 by John Wiley & Sons, Ltd

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Library of Congress Cataloguing-in-Publication Data

Whiteman, C. A. (Colin A.)

Cold region hazards and risks/Colin Whiteman. p. cm.

Includes bibliographical references and index.

ISBN 978-0-470-02927-5 (cloth) — ISBN 978-0-470-02928-2 (pbk.)

1. Cold regions. 2. Environmental risk assessment-Cold regions. I. Title.

GB642.W45 2010

363.700911—dc22

2010028090

Dedication

To Mother and Father

Preface

Sometimes, in the Arctic, you just have to sit and wait. It is the nature of tundra travel that the weather plays a key role. If the fog is down the Cessna doesn't fly; but then there is time to sit and think, or catch up with reading, which is how I came to be in the library of the Aurora Research Centre, in Inuvik, NWT, Canada. A thick volume on Arctic contaminants (not actually included in this text) sparked a train of thought that led to cold hazards and risk, and the idea that this would make an attractive subject for undergraduate students. However, with the exception of avalanches, ice-related hazards very rarely feature in existing geohazards texts. There may be some geomorphological coverage of particular topics in specialist glacial and periglacial books but nothing that brings the full range of cryogenic hazards together within one cover. At the same time as this idea arose, climate change was receiving wide coverage in the media and the subject of environmental hazards was gaining popularity amongst students. Polar and alpine regions appeared to be most vulnerable to climatic warming and ice- related events were attracting more media coverage. Dramatic pictures of disintegrating Antarctic ice shelves were projected into our living rooms for the first time, an Alpine glacier received an insulating blanket to preserve it for skiing, and stirring tales of the 'Northwest Passage' were revived as Arctic sea ice retreated. With popular coverage of these issues growing, it seemed an appropriate moment to provide a broad physical and human geographical background to these and related cold region hazards.

This has not proved to be an easy task. At the same time as popular coverage was rising, scientists in all areas have been exceptionally busy seeking answers to these accelerating environmental changes in an effort to understand what is happening and provide some advice on ways to reduce the potential impacts. Consequently the amount of literature on most topics is daunting. While adopting a global outlook in terms of the scope of examples, it has been necessary to be selective and apologies are due to those who feel that their work has been overlooked or inadequately handled. Nevertheless, I hope that there is sufficient scope and detail in each area to provide an understanding of the nature of the hazard, its potential impacts and the different approaches that have been taken to mitigate the hazard and limit risk.

For many reasons I must acknowledge a number of individuals and groups. Jim Rose is responsible for my interest in cold region geomorphology and geology. Julian Murton invited me to spend research time in the Arctic and, through our Inuvialuit assistants, Fred Wolki, Enoch Pokiak and Raymond Cockney, enabled me to gain a deeper understanding of Arctic life and environments. My colleagues in the Geography Division of the School of Environment and Technology at the University of Brighton kindly supported the cold region hazards module proposal, and some have even raised my awareness of human issues behind the physical environment. Their friendly rivalry provided a stimulating working environment under Roger Smith's able leadership. I have also received willing support from technical staff in the School and research assistant, Margaret Allen, has spent many hours in the search for appropriate material, as well as arranging two successful popular conferences related to polar environments which have raised the profile of cold environments within the School. At Wiley, I am grateful to Rachel Ballard for inviting me to submit the initial proposal and to unnamed colleagues who either reviewed the proposal or, subsequently, parts of the completed text, though I am responsible for any remaining errors. Also at Wiley, I am indebted to Izzy Canning, Chelsea Cheh, Aparajita Srivastava and, especially, to my project editor, Fiona Woods, who has provided encouragement and the necessary drive to see this project to completion. Finally, I thank Jill for her patience and long-suffering support.

Colin A. Whiteman

2

Arctic Sea Ice

2.1 Introduction

Under long-term, north-polar-average conditions, Arctic Ocean water is cold enough to freeze. In winter the ocean is largely covered by at least 2–4 m of ice (Figure 2.1), except for the region north of Scandinavia which is warmed by the Gulf Stream (North Atlantic Drift) (Figure 2.2). The area covered by sea ice contracts during the summer to a minimum around mid-September, as the Arctic warms, and then expands again during the winter to a maximum in March. In the past, and still today, Arctic sea ice presents a hazard to shipping and other off-shore activities as its mass and movement is capable of crushing vessels. However, in 2007 Arctic sea ice made headlines in newspapers around the world for a different reason (BBC NEWS, 2007). A dramatic reduction in the area of ice on the Arctic Ocean, at its annual September minimum, produced speculation by Wieslaw Maslowski that an ice-less Arctic Ocean would occur as early as the summer of 2013. More realistic estimates by Peter Wadham (“earlier than 2040”) and Mark Serreze (“2030”) are not unreasonable following three more years when the summer ice minimum has failed to reach the 1979–2000 average (Figure 2.3). As will become clear, sea ice can be a hazard when it is present, and also when it is not present.

Many expeditions, some searching for the elusive ‘Northwest Passage’ as a short cut between Europe or north eastern North America and Asia, have become trapped and sometimes crushed by the build-up of sea ice in winter (Fleming, 1998). Indigenous communities, adapted to a marine-based subsistence culture, have lost property and occasionally there have been fatalities due to override of sea ice onto the coast (in Alaska a process referred to as ‘ivu’). The surface relief of sea ice can hinder movement but generally, from the Inuit perspective, sea ice is seen as an asset for travel purposes. However, in recent years the hazards traditionally associated with Arctic sea ice have begun to change. Instead of excess sea ice hazards are now more likely to arise from a paucity of ice, either its complete loss or a significant thinning. The ice that used to provide the Inuit and polar bears with a reliable travelling platform now sometimes fails to support skidoos or to accumulate sufficiently early to provide an adequate hunting season for both humans and polar bears. Thinning of the ice cover alters light transmission to the ocean beneath the ice and melting freshwater ice changes the salinity of marine ecological systems. Reduction of albedo, as the ocean surface transforms from light-coloured, reflective ice and snow to dark, solar radiation-absorbing ocean water, leads to a warmer ocean which enhances the rate of sea ice loss. The exposed ocean releases more heat to the atmosphere which in turn melts more ice in a positive feedback. It is too early to be certain exactly how the widespread loss of Arctic sea ice will impact on regional and global climates, but what is certain is that climate and weather patterns will be altered under a regime of severely reduced or even absent Arctic sea ice. One can only speculate on the impacts of the increased access for shipping, mineral exploration and ecotourism, on an ice-free Arctic Ocean.