The United Nations University is an organ of the United Nations established by the General Assembly in 1972 to be an international community of scholars engaged in research, advanced training, and the dissemination of knowledge related to the pressing global problems of human survival, development, and welfare. Its activities focus mainly on the areas of peace and gover- nance, environment and sustainable development, and science and technology in relation to human welfare. The University operates through a worldwide network of research and post- graduate training centres, with its planning and coordinating headquarters in Tokyo. The United Nations University Press, the publishing division of the UNU, publishes scholarly and policy-oriented books and periodicals in areas related to the University’s research. The Basin of Mexico UNU Studies on Critical Environmental Regions Edited by Jeanne X. Kasperson, Roger E. Kasperson, and B.L. Turner II Note from the editors This book is the fourth in a series from the United Nations University (UNU) research project, Critical Zones in Global Environmental Change, itself part of the UNU programme on the Human and Policy Dimensions of Global Change. Both endeavours explore the complex linkages between human activities and the environment. The project views the human causes of and responses to major changes in bio- chemical systems – global environmental change broadly defined – as consequences of cumulative and synergistic actions (or inactions) of individuals, groups, and states, occurring in their local and regional settings. The study examines and compares nine regional cases in which large-scale, human-induced environmental changes portend to threaten the sustainability of an existing system. The aim is to define common lessons about regional trajectories and dynamics of change as well as the types of human actions that breed environmental criticality and endangerment, thereby con- tributing to global environmental change. The overall results of the comparative analysis are found in Regions at Risk, the initial volume in this series. Titles currently available: . Regions at Risk: Comparisons of Threatened Environments . In Place of the Forest: Environmental and Socio-economic Transformation in Borneo and the Eastern Malay Peninsula . Amazonia: Resiliency and Dynamism of the Land and its People . The Basin of Mexico: Critical Environmental Issues and Sustainability . The Ordos Plateau of China: An Endangered Environment The Basin of Mexico: Critical environmental issues and sustainability Exequiel Ezcurra, Marisa Mazari-Hiriart, Irene Pisanty, and Adria´n Guillermo Aguilar United Nations a University Press TOKYO u NEW YORK u PARIS ( The United Nations University, 1999 The views expressed in this publication are those of the authors and do not necessarily reflect the views of the United Nations University. United Nations University Press The United Nations University, 53-70, Jingumae 5-chome, Shibuya-ku, Tokyo, 150-8925, Japan Tel: þ81-3-3499-2811 Fax: þ81-3-3406-7345 E-mail: [email protected] http://www.unu.edu United Nations University Office in North America 2 United Nations Plaza, Room DC2-1462-70, New York, NY 10017, USA Tel: þ1-212-963-6387 Fax: þ1-212-371-9454 E-mail: [email protected] United Nations University Press is the publishing division of the United Nations University. Cover design by Joyce C. Weston Printed in the United States of America UNUP-1021 ISBN 92-808-1021-9 Library of Congress Cataloging-in-Publication Data The Basin of Mexico : critical environmental issues and sustainability / Exequiel Ezcurra p. cm. Includes bibliographical references (p. ) and index. 1. Mexico City Metropolitan Area (Mexico) – Environmental conditions. I. Ezcurra, Exequiel. GE160.M6 B38 1999 363.7’00972’53 – dc21 99-6695 CIP Contents Acknowledgements vii List of tables and figures viii Preface xiii 1 Introduction 1 2 The environmental history of the basin 7 The ecological transformations of the Basin of Mexico 7 The environmental setting 9 Demographic and resource changes in the Basin of Mexico 29 3 The socio-economy of the Basin of Mexico 39 Urban growth and social distribution 40 The economy of the basin 55 Socio-economic pre-eminence 59 v Contents 4 Recent changes in the environmental situation of the basin 61 Vegetation changes in the Basin of Mexico 61 The environmental impact of urbanization patterns 70 Water resources 77 Waste 91 Air quality 98 5 The driving forces of environmental change 112 Population change 115 Governmental policies 119 The distribution of wealth and resources 123 Technological capacity 129 Economic development and environmental degradation 134 6 The vulnerability of the basin 136 Vegetation and open space 136 Water quantity and quality 143 Waste 149 Air quality 150 7 The response to the environmental problem 155 The construction of an environmental conscience 155 Trends in governmental institutions 156 Trends in non-governmental institutions 169 Environmental networks 181 Appendix: List of acronyms and abbreviations 182 8 Conclusions 184 Bibliography 188 Index 207 vi Acknowledgements The authors thank Roma´nA´ lvarez Be´jar, Roberto Bonifaz, and Alma Luz Cabrera from the Instituto de Geografı´a, Universidad Nacional Auto´ noma de Me´xico (UNAM), for processing the imag- ery, and Lucero Rodrı´guez, Jorge Ortega, J. L. Pe´rez-Damian, and J. Gabriel for assistance in drawing and digitizing the figures. Marisa Mazari-Hiriart acknowledges financial support from the Direccio´ n General de Asuntos del Personal Acade´mico, UNAM. Adria´n Guil- lermo Aguilar acknowledges the invaluable help of Irma Escamilla in the search for references and management of data bases. Exequiel Ezcurra thanks very especially Gonzalo Halffter and Jose´ Sarukha´n, two outstanding Mexican ecologists who aroused his interest in the environmental future and sustainability of the Basin of Mexico. Finally, the authors thank the research group at the Center for Tech- nology, Environment, and Development (CENTED) at Clark Univer- sity, especially Jeanne Kasperson, Roger Kasperson, and Billie Turner. It was their interest in critically endangered environmental regions that first brought the group together, and it was their enthusiasm that kept us going throughout the project. Thanks to their interest and support we learned to see with the eyes of a natural history researcher what pre- viously had seemed to us only the city in which we lived. They brought a whole new perspective to our research, and we are grateful for it. vii List of tables and figures Tables 1.1 The 21 megacities whose population is expected to exceed 10 million by the year 2000, and their 1980–1990 growth rate 2 2.1 Vegetation zones in the Basin of Mexico 14 2.2 Species richness of mammals in the Basin of Mexico in the early 1980s 23 2.3 Mammals present in the Basin of Mexico in pre- Hispanic times 24 3.1 Population in the Basin of Mexico, 1940–1990 41 3.2 Population growth rates in the Basin of Mexico, 1940– 1990 43 3.3 Population growth in the Metropolitan Area of Mexico City, 1970–1990 46 3.4 Evolution of the Metropolitan Area of Mexico City, by municipality, 1950–1990 52 3.5 The municipalization of the Metropolitan Area of Mexico City, 1950–1990 53 3.6 Population distribution in the Metropolitan Area of Mexico City, by metropolitan rings, 1940–1990 54 List of tables and figures 3.7 Population growth rates in the Metropolitan Area of Mexico City, by metropolitan rings, 1940–1990 54 3.8 Mexico City’s contribution to the country’s gross domestic product, by economic sector, 1970–1990 56 3.9 The industrial structure of Mexico City according to aggregated value, 1950–1970 57 4.1 Total urban area of Mexico City estimated from aerial photographs, 1953–1990, and estimated rates of growth of the city 71 4.2 Rate of change of green areas within the Metropolitan Area of Mexico City, 1950–1980 74 4.3 Rate of change of green areas within different sectors of the Metropolitan Area of Mexico City, 1950–1980 74 4.4 Population, urban area, and water use in Mexico City, 1910–1990, and projected values for 2000 80 4.5 Water supply systems for the Federal District and the State of Mexico, 1988 81 4.6 Distribution and consumption of water in the Federal District 83 4.7 Wastewater treatment plants in the Metropolitan Area of Mexico City 92 4.8 Concentration of industries and production of industrial waste in the different municipalities within Mexico City 95 4.9 Mean composition and production of domestic waste per inhabitant in Mexico City and in the United States 97 4.10 Atmospheric emissions estimated for the Metropolitan Area of Mexico City, 1994 98 4.11 Number of vehicles in Mexico City, 1978–2000 99 4.12 Average concentration of lead in the atmosphere of Mexico City in 1970, compared with some cities in the United States 100 4.13 Concentration of lead tetra-ethyl in Mexican gasolines, 1978–1991 102 4.14 Maximum allowable standards for the six main air pollutants in Mexico City 109 5.1 Energy consumption in the Mexican Republic and in the Basin of Mexico, 1970–1975 113 5.2 Changes in the 10 highest causes of mortality in Mexico between 1955–57 and 1980 114 5.3 Population in Mexico City, 1519–1990 115 ix List of tables and figures 5.4 Evolution of the quality-of-life indicators for the Basin of Mexico, 1950–1980 118 5.5 Comparison of the Mexican air quality index (IMECA) against Ott and Thom’s index and the National Ambient Air Quality Standard (NAAQS) of the United States, for similar pollution levels 124 5.6 Employed population in Mexico City by income