Table Of Contentfrom Routledge
Drought
Past Problems and Future Scenarios
Justin Sheffield and Eric F. Wood
First published by Earthscan in the UK and USA in 2011
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Copyright © Justin Sheffield and Eric F. Wood 2011
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Plate 8.2, Figures 8.4–8.10 and Tables 8.2–8.3 are reproduced with kind permission from Springer
Science+Business Media: Climate Dynamics, ‘Projected changes in drought occurrence under future global
warming from multi-model, multi-scenario, IPCC AR4 simulations’, vol 13, no 1, pp79–105, J. Sheffield and
E. F. Wood.
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ISBN 978-1-84971-082-4 (hbk)
Typeset by Domex e-Data, India
Cover design by Adam Bohannon
A catalogue record for this book is available from the British Library
Library of Congress Cataloging-in-Publication Data
Sheffield, Justin.
Drought : past problems and future scenarios / Justin Sheffield and Eric F. Wood.
p. cm.
Includes bibliographical references and index.
ISBN 978-1-84971-082-4 (hardback)
1. Droughts–United States. 2. Drought relief–United States. 3. Water quality management. 4. Water-supply–
Management. I. Wood, Eric F. II. Title.
QC929.24.S54 2011
363.34'929–dc22
2010045894
Contents
Figures, tables, boxes and plates v
Preface xi
Acknowledgements xiii
Chapter 1 Introduction 1
Drought Today 1
Drought and Global Change 3
The Motivation for this Book 5
An Overview of the Book 6
Chapter 2 What is Drought? 9
The Hazard of Drought 9
Defining Drought 11
Chapter 3 The Science of Drought 17
Introduction 17
The Hydrological Cycle 17
Spatial and Temporal Patterns of Hydrology 18
What Causes Drought? 30
Summary 38
Chapter 4 Quantifying Drought 43
Introduction 43
Drought Data 44
Monitoring Drought from Space 45
Modelling Drought 50
Palaeoclimate Data: Reconstructing Drought over Millennia 54
Quantifying Drought: Characteristics and Indices 56
Summary 65
Chapter 5 Palaeo-drought: The Occurrence of Drought over Past Millennia 71
Introduction 71
Climate of the Holocene 73
Drought in the Holocene 77
The Last 2000 Years 79
The Last 1000 Years 81
Drought in Recent Centuries 88
Global Mechanisms and Connections 91
Summary 92
iv Drought
Chapter 6 Drought in the 20th Century 99
Introduction 99
Climate of the 20th Century 100
The Global Extent of 20th-Century Drought 102
Characteristics of Global Drought 106
Regional Drought over the 20th Century 107
Global Variability in Soil Moisture and Links with Large-Scale Climate Variability 112
Global Variability in Drought and Links with Large-Scale Climate Variability 114
Summary 119
Chapter 7 Major Drought Events of the 20th Century 123
Introduction 123
North America 123
South America 129
Europe 134
Africa 140
Asia 143
Oceania 151
The Most Severe Droughts of the 20th Century 155
Chapter 8 Drought in the 21st Century 165
Introduction 165
Mechanisms of Changes in Drought 169
Climate Models, Emission Scenarios and Future Projections 172
Drought Estimation 174
Projected Future Changes in Drought 177
Potential Impacts of Future Drought 185
Chapter 9 Summary and Recommendations 195
Conclusions 202
Index 203
Figures, Tables, Boxes and Plates
Figures
1.1 Time series of anthropogenic changes over the 20th century 4
2.1 Types of drought, their connections and impacts 12
3.1 The hydrological cycle 18
3.2 The global energy balance 21
3.3 General circulation of the atmosphere 22
3.4 Map of regions impacted by the ENSO 25
3.5 Map of regions impacted by the NAO 26
3.6 Map of regions impacted by the AMO 27
3.7 Time series of major modes of climate variability 28
3.8 Differences in hydrological regime between the southeast and western US in terms of
soil moisture 31
3.9 Propagation of drought through the hydrological system and the feedbacks to the
atmosphere 33
3.10 The propagation of wet and dry events through the hydrological system 34
3.11 Different hydrological regimes as depicted by daily streamflow time series for four
rivers across the US 36
4.1 Lake Victoria level variations as calculated from satellite radar altimeter data from the
TOPEX/Poseidon, Jason-1 and Jason-2/OSTM satellites 49
4.2 The VIC hydrological land surface model 52
4.3 Example of palaeoclimate data from tree-ring measurements at two sites in Mongolia. 56
4.4 The characteristics of drought 57
4.5 Example of identification and tracking of drought events using a clustering algorithm 63
4.6 Construction of severity–area–duration (SAD) curves 64
5.1 Antarctic temperature estimates for the past 800,000 and 25,000 years from the
EPICA Dome C Ice Core 74
5.2 Holocene temperature records from palaeoclimate proxy data from Antarctica,
Greenland and Africa 75
5.3 Temperature reconstructions for the northern hemisphere, southern hemisphere and
globally for the past 2000 years 76
5.4 Examples of major drought events in the past 2000 years 79
5.5 Time series of per cent calcite (CaCO) and sulphur from sediments of Lake Chichancanab
3
in the Yucatan Peninsula of Mexico as proxies for the climate of the region 81
5.6 Reconstructions of hydroclimate for North America for the past 1200 years 83
5.7 Time series of various hydroclimate reconstructions across the globe for the past 1200 years 85
6.1 Annual anomalies of global land surface air temperature (°C), 1900–2009, relative to
the mean of 1961–1990 for the CRUTEM3 dataset of Brohan et al (2006) 100
6.2 Annual anomalies of global land precipitation, 1900–2008, relative to the mean
of 1961–1990 101
vi Drought
6.3 Global monthly time series of area-averaged soil moisture percentile, and percentage
area in drought 103
6.4 Monthly time series for 1901–2008 of area-averaged soil moisture percentile and
percentage area in drought for the world and the continents 104
6.5 Time series of globally averaged VIC soil moisture index and two PDSI datasets for
1950–2008 105
6.6 Time series of regionally averaged soil moisture percentile and extent of drought
for 1901–2008 108
6.7 Map of regions used in the analysis 109
6.8 Time series of regional spatial extent of short but intense drought periods 110
6.9 Smoothed time series of the first three principal components of monthly soil moisture
percentile for 1950–2000 in comparison to climate indices 113
6.10 Monthly smoothed time series of the number of global droughts for different areal
extent thresholds 115
6.11 Monthly time series of number of droughts of less than or equal to 24 months and
Nino3.4 SST anomalies 116
6.12 Composite average soil moisture, contiguous area in drought and the number of large
area droughts occurring globally for a 36-month window 117
6.13 Monthly time series of number of droughts longer than 12 months and the AMO
and PDO indices 119
7.1 Time series of monthly regional soil moisture index and the percentage area in drought
for the US and three sub-regions 124
7.2 Water storage of Lake Powell, 1963–2010, showing the long-term drought during
the late 1990s to early 2000s 127
7.3 Drought severity–area–duration curves for North America at 3-month and
12-month durations 129
7.4 River water level for 1903–1992 for the Rio Negro (a tributary of the
Amazon River) at Manaus 130
7.5 Soil moisture percentile and spatial extent of drought for 1901–2008 for the
Amazon River basin 131
7.6 Soil moisture percentile and spatial extent of drought over 1901–2008 for the
Parana River basin; and streamflow anomalies for the Parana River at the
Timbues gauging station 133
7.7 Drought severity–area–duration curves for South America at 3-month and
12-month durations 134
7.8 Soil moisture percentile and spatial extent of drought for 1901–2008 for Europe,
northern Europe and the Mediterranean region 135
7.9 Monthly streamflow anomalies for 1901–2008 of the Danube, Rhine, Thames and
Guadalquivir rivers 137
7.10 Drought severity–area–duration curves for Europe at 3-month and 12-month durations 140
7.11 Time series of soil moisture and drought extent for 1901–2008 for Africa
(excluding the Sahara Desert) 141
7.12 Time series of soil moisture and drought extent for 1901–2008 for Southern Africa;
also shown are streamflow anomalies for the Orange River in South Africa 141
7.13 Time series of soil moisture and drought extent for 1901–2008 for East Africa 142
List of Figures, Tables, Boxes and Plates vii
7.14 Time series of soil moisture and drought extent for 1901–2008 for West Africa 143
7.15 Drought severity–area–duration curves for Africa at 3-month and 12-month durations 144
7.16 Soil moisture and drought extent for East Asia 147
7.17 Time series of soil moisture and drought extent for Southeast Asia and a comparison
of ENSO and soil moisture 149
7.18 Drought severity–area–duration curves for Asia at three-month and 12-month durations 150
7.19 Annual time series of Australian precipitation for 1901–2008; time series of soil moisture
and drought extent for Australia, 1901–2008; and time series of soil moisture and drought
extent for the Murray-Darling River basin in southeast Australia 152
7.20 Drought severity–area–duration curves for Oceania at 3-month and 12-month durations 154
7.21 Major droughts of the 20th century 156
8.1 Time series of global average precipitation, surface air temperature, evapotranspiration,
soil moisture and drought extent for 1950–2008 166
8.2 Difference in 11-year moving window trends in soil moisture percentile between the
original and climatological temperature-driven VIC hydrological model simulations 168
8.3 Projected global CO emissions and changes in global surface air temperature for the
2
21st century for three SRES emissions scenarios 173
8.4 Regionally averaged short- and long-term drought frequencies for 1961–1990 from
20th century (20C3M) IPCC AR4 coupled model simulations and the VIC
off-line simulation 176
8.5 Regional time series of multimodel ensemble mean of frequency of short-term
droughts for the 21st century for the SRES B1, A1B and A2 scenarios 180
8.6 Regional time series of multimodel ensemble mean of frequency of long-term droughts
for the 21st century for the SRES B1, A1B and A2 scenarios 181
8.7 Regional time series of multimodel ensemble mean of spatial extent of monthly drought
for the 21st century for the SRES B1, A1B and A2 scenarios 182
8.8 Regionally averaged drought statistics for 1961–1990 (20C3M) and three future
climate scenarios for 2070–2099 (SRES B1, A1B, A2) 183
8.9 Multimodel regional average of frequency of monthly soil moisture deficits for the
20C3M, SRES B1, A1B and A2 scenarios, relative to the tenth percentile of the
20C3M simulations 186
8.10 Mean seasonal cycle of air temperature and the main components of the terrestrial
hydrological cycle for the Mediterranean, central North American and northern Asia
regions for the 20C3M (1961–1990) and SRES A2 (2070–2099) scenarios 187
Tables
2.1 Summary of US weather-related disasters, 1980–2009 10
2.2 Losses and affected population for drought and other natural hazards globally, 1900–2004 11
3.1 Climate zones of the world based on the Köppen-Geiger classification 19
4.1 Popular drought indices, their rationale and advantages/disadvantages 59
6.1 List of regions used in this study, their total area and the maximum spatial extent of
drought and when it occurred 109
6.2 Summary of large-scale drought occurrence for the six continents during 1901–2008 114
viii Drought
6.3 Summary of global drought events for 1900–2004 and impacts 115
6.4 Top ranked global drought years based on the number of months with a drought
extent of more than 500,000 km2 116
7.1 List of top five ranked drought events for each continent in terms of duration and
maximum spatial extent 128
7.2 List of top ten ranked drought events for the world in terms of duration and maximum
spatial extent 155
8.1 Models used in this study, which have monthly soil moisture data available for
20C3M and SRES B1, A1B and A2 scenarios 174
8.2 Summary of multimodel global mean soil moisture and drought characteristics for the
20C3M and future climate SRES B1, A1B and A2 scenarios 179
8.3 Regionally averaged, multimodel mean values of short-term and long-term drought
frequencies and spatial extent of drought, for the 20C3M (1961–1990) (20C)
and SRES B1, A1B, A2 (2070–2099) scenarios 184
Boxes
3.1 Climate oscillations and teleconnections 24
4.1 Global hydrological modelling 52
4.2 Quantifying drought 61
Plates
1.1 The global impacts of drought in 2008–2009
3.1 Climate classification of the world, based on the Köppen-Geiger system
3.2 (a) The ratio of precipitation derived from land evaporation to total precipitation
for April–September averaged over 1979–2009; (b) the source of moisture for the
Ohio River basin in the US
4.1 Examples of remote-sensing data used to assess large-scale drought and changes in
the hydrological cycle
5.1 Location of land palaeoclimate records that have been used to reconstruct climate over
the past hundred to several thousand years
5.2 Global status of lakes during the Holocene at 3ky intervals
5.3 North American drought during the peak of the series of megadroughts in the 14–15th
centuries, as quantified by the PDSI
5.4 Examples of droughts in Asia during the monsoon (July–August)
5.5 North American drought during the peak of the severe drought events of the late
1700s to 1890s
6.1 Annual trends in air temperature, precipitation, run-off, evapotranspiration, soil
moisture and snow water equivalent for 1950–2000
6.2 Average annual precipitation and annual coefficient of variation for 1950–2000
6.3 Correlation between the VIC soil moisture index and the PDSI at monthly, annual
and seasonal timescales
List of Figures, Tables, Boxes and Plates ix
6.4 Global variation, 1950–2000, of frequency of droughts, mean drought duration,
frequency of occurrence of very short, short, medium and long-term droughts,
mean drought intensity and mean accumulated deficit/severity
6.5 Spatial loadings of the first three principal components of annual soil moisture
percentile for 1950–2000
7.1 Maps of the peak extent of major droughts of North America during the 20th and
early 21st centuries
7.2 Continental and global drought severity–area–duration (SAD) envelope curves for 3-month,
12-month and 24-month durations
7.3. Maps of the peak extent of major droughts of the Amazon and northern South America
during the 20th and early 21st centuries
7.4 Maps of the peak extent of major droughts of Europe during the 20th and early 21st centuries
7.5 Maps of the peak extent of major droughts of Africa during the 20th century
7.6 Maps of the peak extent of major droughts in Asia during the 20th and early 21st centuries
7.7 Maps of the peak extent of major drought events for Australia
8.1 Trends in precipitation, soil moisture and evapotranspiration for 1998–2008
8.2 Global average time series of soil moisture and various drought statistics for the
21st century for the SRES B1, A1B and A2 scenarios
8.3 Multimodel ensemble mean of frequency of D droughts in the 20C3M (1961–1990)
4-6
simulation and for 2070–2099 in the SRES B1, A1B and A2 future climate scenarios
8.4 As for Plate 8.3, but for frequency of D droughts
12+
