Weather and Climate Extremes: Changes, Variations and a Perspective from the Insurance Industry

341 Pages·1999·21.475 MB·English

by  Thomas Karl (auth.), Thomas R. Karl, Neville Nicholls, Anver Ghazi (eds.)

WEATHER AND CLIMATE EXTREMES
Changes, Variations and a Perspective from the Insurance Industry
WEATHER AND CLIMATE EXTREMES
Changes, Variations and a Perspective
from the Insurance Industry
Edited by
Thomas R. Karl
Neville Nicholls
and
Anver Ghazi
Reprinted from Climatic Change
Volume 42, No.1, 1999
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Sponsored by DG XII
Science Research and Development
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Springer-Science+Business Media, B.Y.
Library of Congress Cataloging-in-Publication Data
Weather and climate extremes: changes, variations, and a
perspective from the insurance industry / edited by Thomas R.
Karl, Neville Nicholls, and Anver Ghazi.
p. cm.
Includes Index.
ISBN 978-90-481-5223-0 ISBN 978-94-015-9265-9 (eBook)
DOI 10.1007/978-94-015-9265-9
1. Climatic extremes. 2. Climatic changes. 3. Insurance. ..
I. Karl, Thomas. II. Nicholls, N. (Neville) III. Ghazi, A.,
1940-
QC981.8.C53W4 1999
551 .6--dc21 99-25780
Printed on acid-free paper
All rights reserved
© 1999 Springer Science+Business Media Dordrecht
Originally published by Springer-Science+Business Media, B.Y. in 1999.
Softcover reprint of the hardcover I st edition 1999
No part of the material protected by this copyright notice may be reproduced or
utilised in any form or by any means, electronic or mechanical,
including photocopying, recording or by any information storage and
retrieval system, without written permission from the copyright owner
Contents
THOMAS R. KARL I Overview
Summary
THOMAS R. KARL, NEVILLE NICHOLLS and ANVER GHAZI
CLIVAR/GCOS/WMO Workshop on Indices and Indicators for Climate
Extremes - Workshop Summary 3
Editorials
KEVIN E. TRENBERTH and TIMOTHY W. OWEN I Workshop on Indices
and Indicators for Climate Extremes, Asheville, NC, USA, 3-6 June 1997
- Breakout Group A: Storms 9
NEVILLE NICHOLLS and WILLIAM MURRAY I Workshop on Indices
and Indicators for Climate Extremes: Asheville, NC, USA, 3-6 June
1997 - Breakout Group B: Precipitation 23
CK. FOLLAND, C MILLER, D. BADER, M. CROWE, P. JONES,
N. PLUMMER, M. RICHMAN, D.E. PARKER, 1. ROGERS and
P. SCHOLEFIELD I Workshop on Indices and Indicators for Climate
Extremes: Asheville, NC, USA, 3-6 June 1997 - Breakout Group C:
Temperature Indices for Climate Extremes 31
Climate Extremes and the Insurance Industry
FRANKLIN W. NUTTER I Global Climate Change: Why U.S. Insurers
C~ ~
STANLEY A. CHANGNON, E. RAY FOSSE and EUGENE L. LECOMTE I
Interactions between the Atmospheric Sciences and Insurers in the United
States 51
BRIAN D. SKINNER, DAVID CHANGNON, MICHAEL B. RICHMAN
and PETER 1. LAMB I Damaging Weather Conditions in the United
States: A Selection of Data Quality and Monitoring Issues 69
Observed Changes in Extremes
CHRISTOPHER W. LANDSEA, ROGER A. PIELKE, Jr., ALBERTO M.
MESTAS-NUNEZ and JOHN A. KNAFF I Atlantic Basin Hurricanes:
Indices of Climatic Changes 89
P.O. JONES, E.B. HORTON, CK. FOLLAND, M. HULME, D.E.
PARKER and T.A. BASNETT I The Use of Indices to Identify Changes
in Climatic Extremes 131
VI CONTENTS
R. HEINO, R. BRAzDIL, E. F0RLAND, H. TUOMENVIRTA, H.
ALEXANDERSSON, M. BENISTON, C. PFISTER, M. REBETEZ,
G. ROSENHAGEN, S. ROSNER and 1. WIBIG / Progress in the Study
of Climatic Extremes in Northern and Central Europe 151
NEIL PLUMMER, M. JAMES SALINGER, NEVILLE NICHOLLS,
RAMASAMY SUPPIAH, KEVIN 1. HENNESSY, ROBERT M.
LEIGHTON, BLAIR TREWIN, CHER M. PAGE and JANICE M.
LOUGH / Changes in Climate Extremes over the Australian Region and
New Zealand during the Twentieth Century 183
PANMAO ZHAI, ANJIAN SUN, FUMIN REN, XIAONIN LIU, BO GAO
and QIANG ZHANG / Changes of Climate Extremes in China 203
G. GRUZA, E. RANKOVA, V. RAZUVAEVand O. BULYGINA / Indica-
tors of Climate Change for the Russian Federation 219
PAVEL VA. GROISMAN, THOMAS R. KARL, DAVID R. EASTERLING,
RICHARD W. KNIGHT, PAUL F. JAMASON, KEVIN 1. HENNESSY,
RAMASAMY SUPPIAH, CHER M. PAGE, JOANNA WIBIG,
KRZYSZTOF FORTUNIAK, VYACHESLAV N. RAZUVAEV,
ARTHUR DOUGLAS, EIRIK F0RLAND and PAN-MAO ZHAI /
Changes in the Probability of Heavy Precipitation: Important Indicators
of Climatic Change 243
DAVID R. EASTERLING, HENRY F. DIAZ, ARTHUR V. DOUGLAS,
WILLIAM D. HOGG, KENNETH E. KUNKEL, JEFFRY C. ROGERS
and JAIME F. WILKINSON / Long-Term Observations for Monitoring
Extremes in the Americas 285
THOMAS R. KARL and DAVID R. EASTERLING / Climate Extremes:
Selected Review and Future Research Directions 309
Some Critical Aspects of Extreme Events
KEVIN E. TRENBERTH / Conceptual Framework for Changes of Extremes
of the Hydrological Cycle with Climate Change 327
ANDREW R. SOLOW / On Testing for Change in Extreme Events 341
OVERVIEW
In recent years, more climate data has become available to enable climatologists to
analyze these data for trends and variations related to extreme weather and climate
events. At the same time, the insurance industry has experienced a significant
increase in weather and climate related insurance claims. The set of papers in this
volume represent a major step toward developing a comprehensive set of information
about worldwide changes in climate extremes. Nonetheless, there are still many
difficulties in analysis, data availability, data quality and consistency that make it
difficult to derive a clear picture of changes in worldwide extreme weather and
climate events. Clearly, in some areas we know much more than in other areas. For
example, analysis oft emperature extremes are much more comprehensive than other
variables, although there is now emerging a number of new analyses related to
precipitation extremes. What is more striking, however, is the complexity oflinking
current information about climate extremes to the needs of the insurance industry.
As the reader of this volume will quickly learn, however, there are many
opportunities for clever scientists and insurance industry analysts to leverage various
types of information from both fields to develop better statistics on climate variability
that have a direct effect on insurance claims and rates.
On average, as the climate has warmed, there has been a reduced frequency of
extremely cold days leading to a reduction in frost and freeze frequency, although
this general trend can be temporally reversed, as described in two separate analyses
of severe freezes that have affected Florida and the southeast United States as global
temperatures warmed during the 1980s. The reduction in the number of freezes and
frosts is exaggerated by the fact that the minimum temperature is rising faster than
the daily maximum temperature. There has also been an tendency toward an increase
in the frequency of extremely warm days, but a strong trend has yet to emerge.
Analyses of changes in precipitation extremes suggest that for some regions and
times of the year there is clear evidence of an increase in extreme and heavy
precipitation events, e.g., USA, PRC, and during summer in Australia, Canada,
Norway, Mexico, Poland, and the former Soviet Union. There is now a solid
foundation to expect increases in these types of events as the climate warms and
precipitation increases. There are some areas, however, where differences in the way
in which the data have been analyzed make it difficult to interpret the results, e.g.,
Canada, and can lead to apparent contradictions. Another difficulty relates to the
inability of scientists to get access to data that is residing within national archives.
The analysis of changes in tropical storms reveal intriguing relationships between
large-scale climate variables and the number of storms that march across the oceans
each year. Although there are important decadal variations evident in the data, no
clear trends emerge, except for some regional changes noted in the Austral-Australian
region. Changes in extratropical storms have important consequences related to wind
,~ Climatic Change 42: 1-2, 1999.
2 THOMAS R. KARL
damage and other factors, but little evidence is available to suggest a real increase
in damaging winds, although the record is woefully underanalyzed.
Finally, there are some regions where local severe weather events such as hail
frequency have been analyzed. For some parts oft he world, existing insurance claims
provide a means to cross-validate weather and climate data for consistency of trends
and variations. This is a potentially fruitful area of research in regions of the world
that have a history of insurance claims.
NOAA, Us. Department ojCommercelNOAA THOMAS KARL
National Climatic Data Center
151 Patton Avenue,Room 120
Asheville, NC 28801-5001, US.A.
CLIVA RlGCOSIWMO WORKSHOP ON INDICES AND
INDICATORS FOR CLIMATE EXTREMES
WORKSHOP SUMMARY
THOMAS R. KARL
National Climatic Data Center, 151 Patton Ave., Asheville, NC 28801-5001, U.S.A.
NEVILLE NICHOLLS
Bureau ofM eteorology Research Center, GPO Box 1289K, Melbourne Vic 3001, Australia
ANVERGHAZI
European Commission, 200, rue de la Loi, Brussels B-1049, Belgium
There is general agreement that changes in the frequency or intensity of extreme
weather and climate events are likely to have profound impacts on society and
the environment (Karl et aI., 1997). A Workshop on Indices and Indicators for
Climate Extremes was held in Asheville, North Carolina, 3-6 June 1997, to
encourage the development of data sets, and analysis techniques, to determine
whether such extreme events are becoming more extreme or variable. Over 100
participants, from 23 countries, including representatives from 15 insurance and
re-insurance countries (which have a clear interest in extreme weather and
climate), examined the following questions:
• What needs to be done to improve data sets and analyses for extreme
weather monitoring?
• Can we establish priorities for specific data set development and
improvement?
• Can we establish indices and indicators of extreme weather and climate?
• What are the impediments to improving the monitoring of climate extremes?
The incentive for holding this workshop came largely from the difficulties
the Intergovernmental Panel on Climate Change (IPCC) has had in answering
the question: Has the climate become more variable or extreme? The Second
Assessment Report (SAR) of the IPCC was completed in 1995 and determined
that (Nicholls et aI., 1996):
Overall, there is no evidence that extreme weather events, or climate
variability, has increased, in a global sense, through the 20th century,
although data and analyses are poor and not comprehensive. On regional
scales there is clear evidence of changes in some extremes and climate
variability indicators. Some of these changes have been toward greater
variability; some have been toward lower variability.
.... Climatic Change 42: 3-7, 1999.
,~ © 1999 Kluwer Academic Publishers.
4 THOMAS R. KARL
The SAR further noted:
• The data on climate extremes and variability are inadequate to say anything
about global changes, but in some regions, where data are available, there
have been decreases or increases in extreme weather events and variability.
• Other than the few areas with longer term trends to lower rainfall (eg., the
Sahel), little evidence is available of changes in drought frequency or
intensity.
• There have been few studies of variations in extreme rainfall events and
flood frequency. In some areas with available data there is evidence of
increase in the intensity of extreme rainfall events, but no clear large-scale
pattern has emerged.
• There is some evidence of recent (since 1988) increases in extreme extra
tropical cyclones over the North Atlantic. Intense tropical cyclone activity in
the Atlantic has decreased over the past few decades although the 1995
season was more active than recent years. Elsewhere, changes in observing
systems and analysis methods confound the detection of trends in the
intensity or frequency of extreme synoptic systems.
• There has been a clear trend to fewer extremely low minimum temperatures
in several widely separated areas in recent decades. Widespread significant
changes in extreme high temperature events have not been observed.
• There have been decreases in daily temperature variability in recent decades,
in the Northern Hemisphere mid-latitudes.
Despite the difficulties in assessing whether there had been recent trends in
climate extremes and variability, the SAR examined model projections, to assess
the likelihood of future changes in extremes and variability (Kattenberg et al.,
1996) and concluded that:
• A general warming would tend to lead to an increase in extremely high
temperature events and a decrease in winter days with extremely low
temperatures (eg., frost days in some areas).
• With increasing greenhouse gas concentration, many models suggest an
increase in the probability of intense precipitation. A number of simulations
also show an increase in the probability of dry days and the length of dry spells
(consecutive days without precipitation).
• New results reinforce the view that variability associated with the enhanced
hydrological cycle translates into prospects for more severe droughts and/or
floods in some places and less severe droughts and/or floods in other places.
• In the few analyses available, there is little agreement between models on
changes in storminess that might occur in a warmer world. Conclusions
regarding extreme storm events are obviously even more uncertain. The
formation of tropical cyclones depend not only on sea surface temperature
WORKSHOP SUMMARY 5
(SST) but also on a number of atmospheric factors. Although some models
now represent tropical storms with some realism for present day climate, the
state of the science does not allow assessment of future changes.
The lack of certainty with regard to past and future extremes evident in the
SAR indicates that further work is necessary to develop data bases capable of
monitoring changes in climate extremes and variability, and to develop systems
for such monitoring. This will require daily weather data to be made available
over long periods, and for problems arising from changes in instrumentation,
exposure, siting, and even analysis and meteorological interpretation, to be
overcome. The Third Assessment Report (TAR) of the IPCC will be completed
at the end of this century. Considerable efforts are needed before then, to ensure
that the data and analyses are available to allow the TAR to provide a more
complete answer to the question: Has the climate become more variable or
extreme? CLIVA R provides a mechanism to coordinate studies aimed at
answering questions raised by IPCC assessments. The WCRP CLIV AR program
(CLIVAR, 1995) includes amongst its objectives:
• To extend the record of climate variability over the time-scales of interest
through the assembly of quality-controlled paleoclimatic and instrumental
data sets.
• To understand and predict the response of the climate system to increases of
radiatively active gases and aerosols and to compare these predictions to the
observed climate record in order to detect the anthropogenic modification of
the natural climate signal.
These objectives will be pursued through one of the 12 Principal Research
Areas of CLIV AR: Climate Change Detection and Attribution. Detection of
climate change is the process of demonstrating that an observed variation in
climate is highly unusual in a statistical sense. Detection of climate change
requires demonstrating that the observed change is larger than would be
expected to occur by natural internal fluctuations. Attribution of change to
human activity requires showing that the observed change cannot be explained
by natural causes, forced or unforced. It is the process of establishing cause and
effect relations, including the testing of competing hypotheses. CLIV AR will
aim to improve the current state of studies of climate change detection and
attribution through, inter alia, encouraging the development of historical time
series of relevant climate data, with the Global Climate Observing System
(GCOS).
The first step in the detection/attribution of climate change is the assembly
of high-quality time-series of key variables. We need to ensure that credible
historical time-series are available, through the correction for time-varying
biases caused by changes in observing practices, instrumentation, and location.