The Role of the Sun in Climate Change Douglas V. Hoyt Kenneth H. Schatten Oxford University Press The ROLE of the SUN in CLIMATE CHANGE THE SUN ON JULY 6, 1979. FROM W. J. LIVINGSTON. The ROLE of the SUN in CLIMATE CHANGE Douglas V Hoyt Kenneth H. Schatten New York Oxford • Oxford University Press 1997 Oxford University Press Oxford New York Athens Auckland Bangkok Bogota Bombay Buenos Aires Calcutta Cape Town Dar es Salaam Delhi Florence Hong Kong Istanbul Karachi Kuala Lumpur Madras Madrid Melbourne Mexico City Nairobi Paris Singapore Taipei Tokyo Toronto and associated companies in Berlin Ibadan Copyright © 1997 by Oxford University Press, Inc. Published by Oxford University Press, Inc., 198 Madison Avenue, New York, New York 10016 Oxford is a registered trademark of Oxford University Press All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging-in-Publication Data Hoyt, Douglas V. The role of the sun in climate change / Douglas V. Hoyt, Kenneth H. Schalten. p. cm. Includes bibliographical references and index. 1SBN 0-19-509413-1; ISBN 0-19-509414-X (pbk.) 1. Solar activity. 2. Climatic changes. I. Schatten, Kenneth H. II. Title. QC883.2.S6H69 1997 551.6—dc20 96-10848 987654321 Printed in the United States of America on acid-free paper Acknowledgments We would like to thank Tom Bryant, Richard A. Goldberg, and O. R. White for reviewing a draft of this book. Their comments helped improve the book. Dr. Elena Gavryuseva and Dr. Ron Gilliland sent us the neutrino-flux calculations. Dr. Eugene Parker gave us an estimate of the energy-storage requirements in the solar convection zone associated with long-term changes in solar luminos- ity. Ruth Freitag of the Library of Congress aided in tracking down some bio- graphical information. Any errors are solely the responsibility of the authors, and any views expressed here do not reflect any organizational viewpoints. Finally, one reviewer of this book, who wishes to remain anonymous, receives our heartfelt thanks for greatly improving the readability of the text. This book is dedicated to all the pioneers of sun/climate studies. This page intentionally left blank Contents 1. Introduction 3 I. THE SUN 2. Observations of the Sun 9 3. Variations in Solar Brightness 48 II. THE CLIMATE 4. Climate Measurement and Modeling 83 5. Temperature 105 6. Rainfall 125 7. Storms 143 8. Biota 153 9. Cyclomania 165 III. THE LONGER TERM SUN/CLIMATE CONNECTION 10. Solar and Climate Changes 173 11. Alternative Climate-Change Theories 203 viii CONTENTS 12. Gaia or Athena? The Early Faint-Sun Paradox 216 13. Final Thoughts 222 IV. APPENDICES 1. Glossaries 229 2. Solar and Terrestrial Data 235 3. A Technical Discussion of Some Statistical Techniques used in Sun/Climate Studies 240 Bibliography 245 Index 275 The ROLE of the SUN in CLIMATE CHANGE [...]... that the sun is a driving force behind climatic change To place the solar connection within the context of other ideas, we examine various competing climate theories and explain how climatic change may be deduced by combining several theories We explore the problem of the early faint sun and the paradox that climate has remained stable for billions of years despite a dramatic increase in the sun' s... morning he discerned specks on the face of the sun, the culmination of many such blemishes in recent years On a hunch, Meton began examining his more than 20 years of solar records These seemed to confirm his belief: when the sun has spots, the weather tends to be wetter and rainier Theophrastus reported these findings in the fourth century B.C Other ancient accounts concerning the sun and weather... were not located in Earth's atmosphere, but rather were real bodies in or near the sun Yet if they were in the sun, this would indicate that the sun rotates, contradicting the Aristotelian viewpoint Apelles then logically concluded that the spots were bodies revolving around the sun In the second letter, he argued that as Venus revolved around the sun, so did the spots In the third and final letter, dated... description of present-day solar theories We will then examine why the sun varies and place the sun' s variation within the context of other stars FIGURE 1.2 The approximate number of sun/ weather /climate publications each year from 1850 to 1992 arc shown (1,908 total) Note the initial surge of publications after 1870 followed by a decline around 1900 Since then, the increase in publications has remained almost... a single sphere and like the stars are carried around the Sun, or that they are in the body of the Sun itself which revolves in its place and carries them with it Of the suppositions, the second appears to me to be true, the other false All Galileo's conclusions about sunspots remain true today The sun rotates in about 27 days, and the sunspots are carried along in this rotation Sunspots occur in two... copy of the cover of Johann Fabricus's pamphlet covering the first published account of sunspots (From Mitchell, 1915.) of the University of Pennsylvania for Walter M Mitchell) appeared in Popular Astronomy in 1915: While observing these things [i.e., the sun] carefully, a blackish spot suddenly presented itself, on one side indeed rather thin and faint, of no little size compared to the disk of the sun. .. standards the sun remained subdued From 1672 to 1705 all the sunspots were in the southern hemisphere Then in April 1705 a spot appeared in the sun' s northern hemisphere These solar changes generated widespread interest In the first decade of the 1700s, at least 25 people started to make and subsequently record or publish their sunspot observations No previous decade had created such curiosity Many other individuals... of the sun' s internal structure Dynamo processes in the sun' s outer layers, or convection zone, create a magnetic field This results in sunspots, flares, coronal mass ejections, and other types of "magnetic activity," as well as "the solar cycle." Solar cycles are the periodic variations of the sun' s activity and inactivity, varying within an 11- FIGURE 2.1 A cross-section of the sun, showing the interior... believed the sun to be a perfect sphere To the surprise of many, roughly a half-dozen dark blotches blemished the sun What were these dark spots? Some thought there were defects in the telescope Nevertheless, when Galileo rotated the telescope, the sun' s image remained unaltered, proving the telescope was not the culprit Others wondered if the spots were swarms of planets or objects passing in front of the. .. entered the Renaissance The 1600s reveal perhaps half a dozen scattered references to changes in the sun and their effect on weather After a few more references in the 1700s, scientific interest in the sun waned Following Sir William Herschel's comments on sunspots and climate in 1796 and 1801, about 10 scientific papers touched on the sun' s influence on climate and weather The next two decades contain . The Role of the Sun in Climate Change Douglas V. Hoyt Kenneth H. Schatten Oxford University Press The ROLE of the SUN in CLIMATE CHANGE THE SUN ON JULY 6, 1979. FROM W. J. LIVINGSTON. The . the sun has spots, the weather tends to be wetter and rainier. Theophrastus reported these findings in the fourth century B.C. Other an- cient accounts concerning the sun and weather . increase in the number of sun/ climate studies has appeared in the twentieth century. Unfortunately, none of these new studies is definitive in either proving or disproving the sun/ climate