Global Warming Cycles: Ice Ages and Glacial Retreat

223 Pages·2009·13.404 MB·English

by  Julie Kerr Casper

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Global Warming
Cycles

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Global Warming
Cycles
Ice Ages and Glacial Retreat
Julie Kerr Casper, Ph.D.
GLOBAL WARMING CYCLES: Ice Ages and Glacial Retreat
Copyright © 2010 by Julie Kerr Casper, Ph.D.

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Facts On File, Inc.
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Library of Congress Cataloging-in-Publication Data
Casper, Julie Kerr.
Global warming cycles : ice ages and glacial retreat / Julie Kerr Casper.
p. cm.—(Global warming)
Includes bibliographical references and index.
ISBN 978-0-8160-7262-0
1. Global warming. I. Title.
QC981.8.G56C37 2010
551.6—dc22 2008053347
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Text design by Erik Lindstrom
Illustrations by Melissa Ericksen and Sholto Ainslie
Photo research by the author
Printed in the United States of America
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This book is printed on acid-free paper.
Contents
Preface viii
Acknowledgments xii
Introduction xiv
1 
Ice Ages 1
Ice Ages—What They Are and Why They Occur 1
Sources of Information 12
Climate Cycles 16
Prominent Cooling Events 19
The Hockey Stick Theory 22
Will There Be Another Ice Age? 24
Changes Today Because of Warmer Temperatures 25
The Phenomenon Called Global Dimming 26
2 
Glacial Retreat and Meltdown 28
Glacial Morphology 29
Past Glacial Evidence 33
How Ice Melts 34
How Glaciers Reflect Climate Change 37
Evidence of Global Warming 40
Glacial Retreat 42
Impacts of Glacial Retreat 52
Computer Modeling Applications 54
3 
The Cryosphere and Isostasy 57
The Water Cycle—The Earth’s Water Stored in Ice and Snow 58
Ice Shelves and Ice Sheets 60
Cryospheric Facts 71
Ice Caps 72
Glacial Isostasy 76
4 
Ocean Currents and Climate 78
Understanding the Role of Oceans in Regulating Climate 78
The Role of Oceans in Climate Change 81
Cyclic Ocean Circulation That Influences Climate 88
5 
Rising Sea Levels 92
Sea-Level Rise 93
Measuring Sea Level 95
A Historical Perspective 99
Variations in Sea Level 100
Effects of Sea-Level Rise 106
Future Projections 109
6 
Abrupt Climate Change 111
Abrupt Changes in Climate 112
Evidence of Past Abrupt Climate Change 113
Causes of Abrupt Climate Change 114
Using Paleo Evidence to Predict the Future 118
Warning Signs Today 119
Global Warming as a Trigger 120
The Day after Tomorrow 124
Misconceptions about Abrupt Climate Change 126
7 
Tropical Cyclones and Other Severe Weather 129
Hurricanes and Global Warming 129
Storm Surge Prediction and Simulation 134
How Hurricanes Are Named 135
Global Warming and the Hurricanes of 2004–2005 137
Cyclic Theory 139
Hurricanes of the Past 144
Hurricane Katrina and Global Warming 144
The Costliest U.S. Hurricanes 149
Hurricane Research 151
Tornado and Thunderstorm Research 152
The Ten Worst Places for an Extreme Hurricane to Strike 153
8 
Climate Research—What the Experts Say 157
Tracking the Ocean’s Circulation 158
CO Sequestration 160
2
Large-scale Salinity Changes 162
Locating 64°F Water 163
Atlantic Freshwater 164
Southern Ocean Currents 165
Trade Wind Changes 166
Past Warmer Oceans 168
Breaking the Temperature Record 168
Arctic Melt 169
9 
Conclusions and a Glance into the Future 171
Water Resources 172
Sea-Level Rise 174
Research 177
Chronology 180
Links to Global Warming Sites 186
Glossary 189
Further Resources 195
Index 201
PrefaCe
We do not inherit the Earth from our ancestors—
we borrow it from our children.
T
his ancient Native American proverb and what it implies resonates
today as it has become increasingly obvious that people’s actions
and interactions with the environment affect not only living condi-
tions now, but also those of many generations to follow. Humans must
address the effect they have on the Earth’s climate and how their choices
today will have an impact on future generations.
Many years ago, Mark Twain joked that “Everyone talks about the
weather, but no one does anything about it.” That is not true anymore.
Humans are changing the world’s climate and with it the local, regional,
and global weather. Scientists tell us that “climate is what we expect,
and weather is what we get.” Climate change occurs when that average
weather shifts over the long term in a specific location, a region, or the
entire planet.
Global warming and climate change are urgent topics. They are
discussed on the news, in conversations, and are even the subjects of
horror movies. How much is fact? What does global warming mean to
individuals? What should it mean?
The readers of this multivolume set—most of whom are today’s
middle and high school students—will be tomorrow’s leaders and sci-
entists. Global warming and its threats are real. As scientists unlock the
mysteries of the past and analyze today’s activities, they warn that future
viii
Preface ix
generations may be in jeopardy. There is now overwhelming evidence
that human activities are changing the world’s climate. For thousands of
years, the Earth’s atmosphere has changed very little; but today, there are
problems in keeping the balance. Greenhouse gases are being added to
the atmosphere at an alarming rate. Since the Industrial Revolution (late
18th, early 19th centuries), human activities from transportation, agricul-
ture, fossil fuels, waste disposal and treatment, deforestation, power sta-
tions, land use, biomass burning, and industrial processes, among other
things, have added to the concentrations of greenhouse gases.
These activities are changing the atmosphere more rapidly than
humans have ever experienced before. Some people think that warm-
ing the Earth’s atmosphere by a few degrees is harmless and could have
no effect on them; but global warming is more than just a warming—or
cooling—trend. Global warming could have far-reaching and unpredict-
able environmental, social, and economic consequences. The following
demonstrates what a few degrees’ change in the temperature can do.
The Earth experienced an ice age 13,000 years ago. Global tempera-
tures then warmed up 8.3°F (5°C) and melted the vast ice sheets that cov-
ered much of the North American continent. Scientists today predict that
average temperatures could rise 11.7°F (7°C) during this century alone.
What will happen to the remaining glaciers and ice caps?
If the temperatures rise as leading scientists have predicted, less fresh-
water will be available—and already one-third of the world’s population
(about 2 billion people) suffer from a shortage of water. Lack of water will
keep farmers from growing food. It will also permanently destroy sensitive
fish and wildlife habitat. As the ocean levels rise, coastal lands and islands
will be flooded and destroyed. Heat waves could kill tens of thousands
of people. With warmer temperatures, outbreaks of diseases will spread
and intensify. Plant pollen mold spores in the air will increase, affecting
those with allergies. An increase in severe weather could result in hur-
ricanes similar or even stronger than Katrina in 2005, which destroyed
large areas of the southeastern United States.
Higher temperatures will cause other areas to dry out and become
tinder for larger and more devastating wildfires that threaten forests,
wildlife, and homes. If drought destroys the rain forests, the Earth’s