ENERGY SOLUTIONS FOR A SUSTAINABLE WORLD SEPTEMBER 2006 WWW.SCIAM.COM How to Power the Economy and Still Fight Global Warming Energy’s Future Beyond Carbon ▼ Cleaning up Coal ▼ The Nuclear Option ▼ Hopes for Hydrogen ▼ Biofuels and Renewables ▼ Fusion and Other Dreams COPYRIGHT 2006 SCIENTIFIC AMERICAN, INC. september 2006 SCIENTIFIC AMERICAN Volume 295 Number 3 ENERGY’S FUTURE: BEYOND CARBON INTRODUCTION 46 A Climate Repair Manual BY GARY STIX Coping with global warming will take innovations in both energy technology and policy. STRATEGY Our energy choices 50 A Plan to Keep Carbon in Check shape the climate BY ROBERT H. SOCOLOW AND STEPHEN W. PACALA Multiple technologies, each taking a slice out of carbon dioxide emissions, ROLE FOR FISSION could slow warming. 76 The Nuclear Option BY JOHN M. DEUTCH AND ERNEST J. MONIZ AUTOMOTIVE ANSWERS Nuclear power could stave off more than a billion tons of carbon emissions annually. 60 Fueling Our Transportation Future BY JOHN B. HEYWOOD CLEAN POWER New technologies, lighter vehicles and 84 The Rise of Renewable Energy alternative fuels can lower greenhouse gas BY DANIEL M. KAMMEN releases from cars and trucks. Solar cells, wind turbines and biofuels are poised to become major energy sources. ENERGY EFFICIENCY 64 An Efficient Solution FUEL CELLS AND MORE BY EBERHARD K. JOCHEM 94 High Hopes for Hydrogen In buildings and in industrial processes, BY JOAN OGDEN using power more judiciously is the quickest, Hydrogen-fueled cars could slash carbon cheapest solution. emissions, but it won’t happen soon. CARBON CAPTURE AND STORAGE SPECULATIVE TECHNOLOGY 68 What to Do about Coal 102 Plan B for Energy BY DAVID G. HAWKINS, DANIEL A. LASHOF BY W. WAYT GIBBS AND ROBERT H. WILLIAMS Eventually, even more radical energy sources Coal is plentiful, but we must manage will be needed. Here are some possibilities its environmental dark side. under consideration. www.sciam.com SCIENTIFIC AMERICAN 3 COPYRIGHT 2006 SCIENTIFIC AMERICAN, INC. SCIENTIFIC AMERICAN Volume 295 Number 3 departments 8 SA Perspectives Cooling our heels. 10 How to Contact Us 10 On the Web 28 126 12 Letters 16 50, 100 & 150 Years Ago 18 News Scan 44 Forum: Tom Leighton The Net’s real security problem. ■ Ten years later: identifying victims in the former Yugoslavia. 116 Working Knowledge ■ Superconducting wires step toward A tall task for water towers. commercialization. 118 Reviews ■ New drug factories: chickens and goats. The Trouble with Physics and Not Even Wrong ■ Turbine engine for faster missiles. argue that it is time for string theory to give way. ■ Surprise: a net warming from contrails. ■ Mentally controlling robots with MRI. ■ By the Numbers: Illiteracy. ■ Data Points: C-sections on the rise. Mind over 30 (robot) matter columns 40 Skeptic BY MICHAEL SHERMER Economists have a shoot-out over the meaning of “replicate.” 42 Sustainable Developments BY JEFFREY D. SACHS Encouraging lower fertility in the developing world will pay off for everyone. 124 Anti Gravity BY STEVE MIRSKY R.I.P., Darwin’s tortoise. 126 Ask the Experts How do batteries store and discharge electricity? Does damp weather make arthritis pain worse? Cover image by Phil Saunders, Space Channel Ltd.; photograph at left by Honda Motor Company. Scientifi c American (ISSN 0036-8733), published monthly by Scientifi c American, Inc., 415 Madison Avenue, New York, N.Y. 10017-1111. Copyright © 2006 by Scientifi c American, Inc. All rights reserved. No part of this issue may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording for public or private use, or by any information storage or retrieval system, without the prior written permission of the publisher. Periodicals postage paid at New York, N.Y., and at additional mailing offi ces. Canada Post International Publications Mail (Canadian Distribution) Sales Agreement No. 40012504. Canadian BN No. 127387652RT; QST No. Q1015332537. Publication Mail Agreement #40012504. Return undeliverable mail to Scientifi c American, P.O. Box 819, Stn Main, Markham, ON L3P 8A2. Subscription rates: one year $34.97, Canada $49 USD, International $55 USD. Postmaster: Send address changes to Scientifi c American, Box 3187, Harlan, Iowa 51537. Reprints available: write Reprint Department, Scientifi c American, Inc., 415 Madison Avenue, New York, N.Y. 10017-1111; (212) 451-8877; fax: (212) 355-0408. Subscription inquiries: U.S. and Canada (800) 333-1199; other (515) 248-7684. Send e-mail to [email protected] Printed in U.S.A. 6 SCIENTIFIC AMERICAN SEPTEMBER 2006 COPYRIGHT 2006 SCIENTIFIC AMERICAN, INC. SA Perspectives Cooling Our Heels From Christmas Day in 1991, when the white, blue needed to achieve the concurrent objectives of and red Russian fl ag rose over the Kremlin, symbol- growth and sustainability. Decades may pass before izing the end of the Soviet Union, the U.S. assumed hydrogen-powered trucks and cars relegate gasoline- a dominant presence in world affairs the likes of and diesel-fueled vehicles to antique auto shows. In which has not been witnessed since the Imperium the interim, conservation and better effi ciencies in Romanum. Yet the nation that endorsed the idea of both transportation and electricity generation and preemptive military action has acted with remark- usage will allow us to muddle through. Yet for even able passivity when it that to happen, the world’s leading economy—and comes to an energy poli- emitter of almost one quarter of human-generated cy that deals with cli- carbon emissions—will have to assume the leader- mate change. ship role that it has so far largely shirked. In a recent scholarly Regaining a modicum of credibility will itself article, economist Jef- prove an immense undertaking. Both the president frey D. Sachs and geo- and Congress need to endorse the ever expanding physicist Klaus S. Lack- body of evidence that points to the reality of warm- ner of Columbia Univer- ing and listen to, rather than harass, scientists who sity noted that the Bush arrive bearing bad news. administration’s impulse Funding for energy research must be accorded on global warming has the privileged status usually reserved for health care DARK SHADOW: U.S. leadership void been to wait for “some- and defense. Yet rhetoric needs to go beyond the impairs progress on climate change. thing to turn up”—say, mantra that before taking action, more research is the discovery of a plenti- needed to eliminate uncertainties surrounding cli- ful, noncarbon fuel or a technique to eliminate mate science. A ceiling on greenhouse emissions greenhouse emissions at low cost. Global warming should be set, and then the market should decide has never been the priority it should be. how to achieve that target through sales and pur- The reasons are not hard to fathom. People worry chases of emissions allowances. Other measures that that the consumerist way of life that Americans have must be adopted include stiffened fuel economy come to accept as a birthright will have to be scaled standards, carbon taxes and requirements that the back. After all, on average, each U.S. citizen has more largest producers of greenhouse gases report their than twice the energy consumption of a western Eu- emissions publicly. ropean, according to statistics for 2003, and almost The U.S. should lead by example. An aggressive 10 times that of a Chinese. To narrow this gap, the domestic program would enable this country to in- U.S. will have to alter its energy-intensive habits. But fl uence China, India and other fast-growing devel- that doesn’t mean we must all live in cardboard box- oping nations to control emissions. Without the U.S. es. In every plan to tackle warming, Americans will at the head of the table, the prospects for any mean- still be better off in 2050 than they are today. ingful action on a global scale will gradually recede Both technical and policy farsightedness will be along with the Arctic glaciers. 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