April 2004
| R E V I E W |
Heat Exchange
The global warming debate mixes daunting complexity with
high political stakes, a toxic brew that continues to test dispassionate science.
By Robert Ehrlich
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THE COMPLEX MIX OF SCIENCE AND POLITICS bundled together under the label “global warming” usually prompts one of two generic responses in books for the general public. One is a call to action, as in Al Gore’s Earth in the Balance. The second is a call to inaction, as in the wittily titled The Satanic Gases, by Patrick J. Michaels and Robert C. Balling Jr. In The Discovery of Global Warming, Spencer R. Weart brings a welcome third perspective to the subject: the historical point of view..
Weart, as it happens, is both a physicist and a historian of science, and his diverse activities make him well qualified for the task he sets out to do (and accomplishes!) in his book. His aim is to describe the many converging strands of science that led to the “discovery” of global warming—by which he means the emerging scientific consensus that people are discernibly (and probably quite significantly) affecting Earth’s climate through the greenhouse effect.
As Weart makes clear, the “discovery” announced in his title is quite different from the usual discoveries in physics. The latter can often be traced to a particular moment in time and to the work of a particular person or group. But the consensus among scientists about the effects of global warming developed gradually, Weart tells us. And by “connecting the dots among roughly a thousand of the most important papers in the science of climate change,” he shows how that happened. (The Web site that supplements Weart’s published volume, hosted by the American Institute of Physics at www.aip.org/history/climate/, includes roughly three times more material than the book does, but it is both clearly organized and surprisingly easy to navigate.) In some places the book does indeed read almost like an elaborate mystery story, with all the attendant false clues and twists of plot.
Some of the plot thickeners are quite instructive. Take for instance the view that emerged during the 1960s and early 1970s, according to which the planet was probably facing a new ice age. That view was embraced by some of the same investigators who today are quite certain the Earth is headed for some serious warming. To be fair, however, that shift is by no means just a reversal of opinion. Rather, it represents a refinement of a still-evolving climate theory—an outcome that should come as no surprise to anyone familiar with the way science really works. In fact, the current understanding among most climate scientists is that both views (warming and cooling) are right. We are facing both near-term global warming, because of a buildup of greenhouse gases, and an eventual serious cooling (another ice age), probably as a consequence of small shifts in the Earth’s axis of rotation. Weart’s approach, then, gives just the kind of treatment that places the history of ideas in the context they demand.
Weart is probably correct in asserting that the consensus today is more reliable and more robust than the ice-age predictions of thirty years ago. The belief in a human-induced warming trend is more widely held within the scientific community than the belief in a coming ice age ever was. The evidence for an anthropogenic cause of recent warming also rests on firmer foundations, given that climate-modeling tools are far more sophisticated now than they were in the 1970s. Still, science is not an enterprise in which “majority rules.” And Weart reports that though nearly all the computer models now agree in “predicting” the present climate—that is, taking into account conditions and trends in the past, their computational results are in accord with today’s climate—the critics of global warming point out that the models have been “laboriously ‘tuned’ to match [current climate] by adjusting a variety of arbitrary parameters.”
None of these caveats imply that the climate modelers are wrong; science generally makes gradual progress toward the truth. But the caveats ought to remind people that when climate models are projected into the future, their predictions should be viewed with some degree of caution, particularly when it comes to the assumptions built into the models. In most places Weart is appropriately cautious in his assertions, reminding his readers that
scientists rarely label a proposed answer to a scientific question “true” or “false,” but rather consider how likely it is to be true. Normally a new body of data will shift opinion only in part, making the idea seem a bit more likely or less likely.
Weart also is forthcoming about the many uncertainties about global warming that remain, despite the present consensus.
Weart’s decision to write from the historical perspective—understandable as that is for a historian of science—does present some structural problems for the reader. For one thing, information on specific topics is spread throughout the book. Readers who want to know about the role of aerosols in the global climate, for instance, have to read about the subject in dribs and drabs. They won’t find out whether, on balance, aerosols tend to warm or to cool the planet until they are three-quarters of the way through the book. That’s a more serious shortcoming than it may at first appear, because aerosols are one example of what global-warming skeptics call a “fudge factor”: one whose effects can be arbitrarily adjusted in the computer models.
Another quibble I have is that, though The Discovery of Global Warming is intriguing and well written, its readability suffers from the author’s attempt to weave together so many different threads of the story.
But the book’s biggest problems are some conspicuous omissions, and a certain lack of balance. Take the discussion of feedback. Seven scattered passages in the book address feedback, yet one never gets a hint that feedbacks can be negative as well as positive. Positive feedbacks tend to amplify initial disturbances that warm or cool the planet; negative feedbacks tend to damp them down. Negative feedbacks, whether they operate in the presence of heating or cooling factors, drive a perturbed global climate back to the state it was in before the perturbation in question; they are a force for equilibrium rather than instability.
There are many examples of negative feedback. Atmospheric carbon dioxide (CO2), for instance, stimulates the growth of plants, and the plants absorb more CO2 from the atmosphere. Another example is the cloud-evaporation cycle: low-altitude clouds formed by temperature-driven evaporation block the sunlight. The blockage cools the planet, which leads to reduced evaporation. But not only does the book shortchange its discussion of negative feedbacks; it also usually describes the action of positive feedbacks in unnecessarily ominous terms. Feedbacks that simply amplify planetary temperature changes—perhaps only modestly—become changes that “[switch] the climate system to a drastically different state.”
Some of Weart’s other omissions are equally disturbing. Why, for example, does he leave out any discussion of satellite data on global temperatures, and the degree to which they deviate from readings at weather stations on Earth’s surface? The disagreement deserves attention on its merits, but to ignore it entirely arouses suspicion about Weart’s objectivity. Satellite data show a much smaller increase in global warming than do measurements at ground stations or projections based on computer climate models. The satellite data have been repeatedly cited by some skeptics of global warming as a major objection to the mainstream consensus. Because they are averaged over larger areas, satellite data are less subject to bias than data from ground stations, so skeptics argue that satellites yield the more reliable data set.
Although the book is certainly no polemic—there is no call for action to avert catastrophic global warming—the reader can find many instances in which Weart’s biases color his presentation. (Bias, of course, like beauty, is in the eye of the beholder; it is entirely possible that some of the imbalance discussed here may belong to the reviewer rather than to the book’s author.)
Weart’s discussion about global-warming skeptics and their arguments is probably where he strays furthest from his otherwise reasonable tone. In several brief passages he treats two of the more vocal among them: the atmospheric physicist S. Fred Singer and the physicist Frederick Seitz. Weart’s discussion, though not disrespectful, focuses more on their sources of funding, methods of publication, and backing by politically conservative groups than it does on their actual arguments.
Weart notes that “the most outspoken scientific critiques of global warming predictions rarely appeared in the standard scientific publications”—but instead, with few exceptions, in venues backed by industrial, business, or conservative policy interests. The point is true, but one wonders why Weart regards it as relevant. Attacking the “most outspoken” skeptics is really attacking a straw man. Would Weart offer up a similar assertion—equally true—about the “most outspoken” believers in an imminent global-warming catastrophe? They, too, rarely publish such dire appraisals in scientific journals, but instead, with few exceptions, in venues backed by liberal, anti-industry groups.
Further on in his narrative, Weart belatedly acknowledges that some skeptics, such as the meteorologist Richard S. Lindzen of the Massachusetts Institute of Technology, are highly respected climate scientists who have published their findings in the peer-reviewed literature. But for the reader, the impression has already been created that most of the skepticism about global warming is based on ideology, not on science.
Another part of Weart’s narrative that might have benefitted from a more evenhanded approach is his detailed discussion of the Intergovernmental Panel on Climate Change (IPCC). The body of hundreds of scientists and government representatives arrived at its own conclusions about global warming in its first report, issued in 1990, and, through its subsequent reports, played a major role in forging the present consensus. “Because they were under a mandate to make only statements that virtually every knowledgeable scientist could endorse,” Weart writes, “IPCC’s consensus statements were highly qualified and cautious.”
What he fails to mention is that, unlike the IPCC reports themselves, the executive summaries for policy makers have been anything but cautious about the way they highlight certain points in their presentation of the global-warming problem. He also fails to note that some major contributors to the IPCC reports have been highly critical of their contents. Lindzen, for instance, has said that “the possibility of large warming, while not disproven, is also without a scientific basis.”
So just what does the IPCC project for the next hundred years? The third and latest report, issued in 2001, notes that during the twenty-first century, average global temperatures could rise by between 2.5 and 10.4 degrees Fahrenheit (between 1.4 and 5.8 degrees Celsius). What is notable about the latest IPCC projection is its high upper limit and its significant uncertainty: a factor of four between the upper and lower limits. How does the IPCC arrive at those numbers?
The answer comes not so much from the global-climate models themselves, but from inputs to those models. The inputs depend in turn on projections of future worldwide economic growth, and the extent of its dependence on fossil fuels. To arrive at temperature increases by the year 2100 anywhere near the IPCC’s upper limit, you have to assume that developing nations will soon catch up with the West, and that when they do, they will be just as wasteful about energy as Americans are today. All that seems fairly improbable, though a governmental organization such as the IPCC is unlikely to admit as much. As for the lower limit to the IPCC’s projection, which assumes much less future reliance on fossil fuels, an increase of that magnitude in the next century is probably something to which the world can adjust.
At the end of the book, Weart implicitly acknowledges that the magnitude of any future climate warming is largely unpredictable. “The biggest source of uncertainty now,” he writes, “is not in the science.” True, the predicted climate changes caused by greenhouse gases, emissions of aerosols and smoke, and the management of crops and forests, among other things, can be calculated, he writes. But “these changes depend less on geochemistry and biology than on human actions.” The skeptic Lindzen might put the matter much the same way.
So what is the global warming debate really all about? It’s not about whether global warming is real or not—nearly everyone agrees that it is, at least to some degree. What is ultimately at stake is how best to react to a threat whose severity and impact are so uncertain. And one of the most pressing questions is whether the cost of remediation outweighs the cost of inaction.
It’s also worth pointing out that global warming may not be entirely negative. Weart is far too dismissive of that possibility; he gives it only one short paragraph in the entire book. Yet if the temperature increase in the coming century remains in the lower half of the range projected by the IPCC (that is, less than 5.4 degrees Fahrenheit, or 3 degrees Celsius), there could be numerous benefits both locally and globally, particularly in regions of severe cold.
In part, the benefits would stem from the expected patterns of warming: the warming should be much greater in winter than in summer, and greater in very cold regions than in the more temperate or tropical regions. Hence in most places warming would benefit agriculture—or, at worst, shift it poleward. Higher CO2 levels and fewer killing frosts should also benefit crops, and higher temperatures would make it feasible to grow valuable crops such as citrus in regions that were once too cold. As for the direct effects of warmer temperatures on human mortality, they should, on balance, be positive in most regions, because the reduction in extremely cold days should more than offset the increase in the number of extremely hot days. Storms and droughts might become more frequent in some places, but not necessarily worldwide, as Weart suggests.
Some consequences of global warming, of course, will be far more negative than positive. A rising sea level would inundate many coastal cities and communities, and both inundation and rapid temperature increases would almost certainly damage natural ecosystems. The latter consequence is particularly worrisome; one recent study has suggested that between 15 percent and 37 percent of all living species could be driven toward extinction by 2050 by global warming. No one can put a dollar value on such terrible loses, should they occur.
But among the impacts that can be calculated, the overall picture is far from clear. Some economists estimate that, on the whole, the effect of a warming up to 5 degrees Celsius could be economically positive for the United States and other developed nations. The effect on developing nations is less likely to be benign. Yet if the scenarios that yield the largest temperature increases are correct in assuming that those nations will soon catch up economically, maybe they, too, will have enough resources to be able to cope with the situation.
On the other side of the ledger, suppose you concede that the overall effect of global warming would probably be negative. Then you might ask, What would it cost to prevent it? Here Weart does not have a great deal to say. He does note that “more and more experts were confident that they could find practical ways to keep climate change within tolerable limits without harming industrial efficiency.” Most of the remedies he cites, however, would lead to only modest reductions in greenhouse gases. That isn’t to argue against some of Weart’s pay-for-themselves ideas for conserving energy and reducing the consumption of fossil fuels. No one who wants to reduce U.S. dependence on foreign oil can dismiss them, just because they do not go very far toward solving the problem of global warming.
Some other ideas of Weart’s, however, seem well outside the bounds of what is politically possible—or desirable. For example, he suggests that the United States emulate Europe and add several dollars in tax to gasoline prices. That is simply not going to happen—nor should it. A sizable gasoline tax is regressive, and it would have a drastic economic impact on the nation if imposed suddenly.
Whenever one thinks about the likelihood of a catastrophic impact from global warming, the so-called precautionary principle comes into play. As Weart puts it, “If there is even a small risk that your house will burn down, you will take care to install smoke alarms and buy insurance.” So, given all the uncertainties, why shouldn’t humanity do whatever it can to eliminate even the smallest risk of a catastrophic warming? My response to that question is: “Smoke alarms, sure, but insurance, maybe not.”
The decision to buy insurance can depend on many factors: its cost, how fireproof your house is, the amount to be paid in the event of a claim, the limitations of the policy, the likelihood that a better policy might be available in the short term. As an insurance policy, for instance, the Kyoto Treaty (which Weart discusses mainly to demonstrate how isolated the U.S. is from world opinion) appears to have little to recommend it. It offers only insignificant reimbursement—in terms of the warming effects it would prevent—in return for what could be a very high cost. A fully implemented Kyoto Treaty would make almost no difference to either the rise in sea level or the probable loss of species. Yet it might divert huge amounts of capital for replacing fossil fuels rapidly with alternative energy sources.
If the dimensions of the global warming problem should turn out to be as severe as many people claim, action far more painful than what is required by the Kyoto Treaty could become necessary. For now, however, the picture is not at all clear—as Weart notes, it may never become completely clear. Nations should certainly adopt prudent, “no-regrets” actions that make sense no matter what the future levels of global warming. Energy conservation and the promotion of nonfossil-fuel energy sources, including nuclear energy, fall in that category. Market forces, including the end of cheap oil and the exploitation of less expensive renewable sources of energy, as well as possible technical fixes for the global-warming problem, such as extracting CO2 during fossil-fuel combustion, may make any remedial action that much easier in the future. In the meantime, then, why not just stick with “no-regrets” actions?
Robert Ehrlich is a professor of physics at George Mason University in Fairfax, Virginia, and the author most recently of Eight Preposterous Propositions: From the Genetics of Homosexuality to the Benefits of Global Warming (Princeton University Press, 2003), a series of case studies in how to evaluate evidence for and against controversial questions.
| B O O K S H E L F |
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By Laurence A. Marschall |
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In August 1911 newspapers nationwide reported the discovery of a starving man crouching in the backyard of a slaughterhouse near the northern California town of Oroville. He wore only a tattered denim shirt, carried a rough sack with some manzanita berries and dried meat inside, and spoke a language no one understood. The anthropologist Alfred Lewis Kroeber, suspecting that Ishi was a cultural fossil, had him brought to San Francisco. Kroeber settled Ishi at the newly opened Museum of Anthropology and saw to it that he was hired as a part-time janitor.
Ishi ultimately adapted well, even to his duties as a “living exhibit,” putting on Sunday demonstrations of arrowhead making and other native arts for eager crowds of visitors. He learned to converse in broken English and developed a taste for doughnuts and ice-cream sodas. Professors came west to interview him, take down his utterances, and make wax cylinders of his chants. When he died of tuberculosis in March 1916, the San Francisco Examiner reported that he had been cremated “according to the customs of the California tribes,” along with his bow and arrows, some acorn meal, and a pouch of tobacco.
But Ishi’s story had only begun. Over the years, Californians transformed him into an icon of an unspoiled past they’d never known, the one that existed before the missions, the forty-niners, the farmers, and the freeways turned the state’s promised land into a nightmare. In 1961 Kroeber’s widow Theodora wrote a best seller portraying Ishi as a noble savage; the book became a favorite of the 1960s flower children.
In the 1980s and 1990s, newly empowered Native Americans began to retell Ishi’s story as a case study in cultural imperialism. In 1997 Art Angle, a political activist and a descendent of the Maidu, neighbors of Ishi’s Yahi kinfolk, organized an effort to rebury Ishi in the old Yahi territory near Mount Lassen. Rumors circulated among some of the Maidu that Ishi’s brain had been removed for scientific study just after his death, though it was not clear what had happened to it after that.
Starn, a cultural anthropologist at Duke University in Durham, North Carolina, played a role in finding the brain, which had been preserved in a jar and sent to the Smithsonian Institution in Washington, D.C., and he writes with undisguised empathy for the California tribespeople who brought Ishi home. But he’s too much of a scholar not to note the cultural ironies of the case. Little is known of Ishi’s Yahi ancestors, and practically nothing of Ishi himself. But even before he set foot in San Francisco, Ishi was no unspoiled innocent. He wore garments of factory-made cloth, foraged for food near homesteads and general stores, and even spoke a few words in the language of his neighbors (Maidu and perhaps Spanish).
The various tribes of native Americans who contributed to bringing about his reinterment have more culture in common with each other—and with the residents of Brooklyn—than they do with Ishi’s ancestors. They drive gasoline-powered vehicles, watch the NFL on the tube, and pay more heed to Arnold Schwarzenegger than to the spirits of the hills and woodlands. In the end, the lessons of Ishi’s story have more to do with managing cultural identity in the modern era than with returning to Ishi’s way of life.
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Was it? In 1970, when Owen Gingerich, then an astrophysicist at Harvard, had a chance to examine a copy of the first edition of De revolutionibus, he was impressed by its extensive annotations. Someone had taken the time to examine all of Copernicus’s arguments, even the most turgid mathematical sections. Someone clearly felt the book was worthy of a reading as close as any reading of the Bible or the Talmud. The commentator was unidentified, but the possibility that others might have made such an intensive study of Copernicus was too strong to ignore.
Fascinated by the marginal notes as well as the antiquarian texts themselves, Gingerich became a full-time historian of science. His thirty-year quest to locate, identify, and study all the early editions of Copernicus’s magnum opus, with a particular emphasis on annotated copies, became “The Great Copernicus Chase.” The chase turned up a rich collection of marginalia, which has led to a deepening understanding of Copernicus’s influence and of the intellectual climate of the era. And it culminated, two years ago, in Gingerich’s weighty An Annotated Census of Copernicus’ De Revolutionibus.
Few people are likely to read Gingerich’s census, but anyone who appreciates the printed word will gallop through his new account of how it came to be. The Book Nobody Read moves around the world like an espionage thriller—from federal courtrooms in Washington (where Gingerich was an expert witness in the prosecution of a book thief), to Beijing, Australia, Soviet-era Leningrad, and the Vatican. Using investigative techniques worthy of Sherlock Holmes, Gingerich has identified the personal copies owned by such figures as Johannes Kepler and Adam Smith. Many, pace Koestler, bought the book to read it; others became buyers just because it was rare and important.
Gingerich describes their lives so vividly that it seems he’s met them in the flesh. Yet whenever the reader begins to tire of historical minutiae, Gingerich throws in charming tidbits of bibliophilic lore. Attentive readers will learn how many books a sixteenth-century printing press could produce in a day, which insects bore round holes through the pages of old books, and how a German library once sold off a copy of Newton’s Principia because it was too heavily annotated, only to discover that the notations were made by Newton’s contemporary and archrival Gottfried Wilhelm Leibniz.
Now that its first editions bring as much as $800,000 at rare-book auctions, De revolutionibus has truly become a book that few can read, at least in its original editions. Spend a few hours, then, with The Book Nobody Read, which, title notwithstanding, is a book to be read by everybody.
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Bats, I now recognize, are victims of bad PR. In the countryside of Mexico and in rural Central America, reports Theodore Fleming, it is common to assume all bats are vampires. But few bats are actually bloodsuckers. Most bats, if they eat meat at all, eat insects, small rodents, and lizards; several insect-eating species consume half their own body weight (and sometimes more) in insects on each night’s foraging raid. Bats are therefore not to be feared but conserved, not only for their control of insect populations, but also for their pollination and seed dispersal of many highly valued plants, including such delicacies as mangoes and figs.
A good deal of credit for dispelling misinformation about bats goes to Fleming, one of the rare humans for whom bats are a passion. Among bat mammalogists, he’s something of a gray eminence. Fleming can identify species by their smell, their sound, or their droppings. He’s perfectly at home sitting in a pitch-dark cavern while tens of thousands of web-winged creatures flap around him. He even knows which bats urinate while hanging upside down, and which turn themselves upright beforehand (the smaller species do it upside down).
Fleming’s account of his studies is notable not just for war stories and bat lore, but also for his instructive account of the variety of investigative techniques required to practice good biology. In the 1970s he began to attach small radio transmitters to the backs of bats (they didn’t seem to mind). By day, the radio signals would guide him to hidden sleeping places in hollow trees and in hillside caves in the Costa Rican rainforest. By night, as the bats emerged from their roosts, he and a small group of volunteers and graduate students would track the beeps, patiently mapping out the bats’ activity patterns and favorite foraging places.
Later, in studies of the lesser long-nosed bat (Leptonycteris curasoae), which pollinates cactus flowers in the Sonoran Desert of Mexico, Fleming attached small vials of luminous chemicals to the backs of the bats. Then, taking advantage of the open terrain, he simply watched the moving “fireflies” through binoculars from a high vantage point to see which cactuses best attracted the bats. When he discovered that some species migrate hundreds of miles a year, he began snipping minute samples of wing tissue from bats he caught in mist nets. He could then track a migrating population by analyzing the samples for their mitochondrial DNA.
For the future, Fleming has both good news and bad news. Bat species may be more resilient to habitat loss than other wild mammals because their diets are more adaptable and because they can fly. And public appreciation of bats is beginning to work in their favor too, thanks to some enlightened efforts at environmental education. But during his three decades in the field, Fleming has seen so many dirt roads become paved highways, and so many forests turned to cropland, that he cannot be certain how much longer his beloved creatures will continue to rule the night.
Laurence A. Marschall, author of The Supernova Story, is W.K.T. Sahm Professor of Physics at Gettysburg College in Pennsylvania, and director of Project CLEA, which produces widely used simulation software for education in astronomy.
| n a t u r e . n e t |
The Good Earth |
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Not surprisingly, perhaps, the process that greens the planet also protects it. Photosynthesis helps cool the atmosphere by absorbing carbon dioxide, a greenhouse gas, and it is a critical factor to consider in forecasting climate change and global warming. I found a remarkable, fresh perspective on photosynthesis at NASA’s “Earth Observatory” site, in an animation that accompanies an article on Earth’s carbon “metabolism” (earthobservatory.nasa.gov/Newsroom/NPP/npp.html).
Every eight days for the years 2001 and 2002, NASA combined land-based data with data from Terra and Aqua, two Earth-orbiting satellites, to generate composite maps of the world’s “net primary production” of carbon dioxide—the amount absorbed during photosynthesis, minus the amount given off during respiration. Scroll down the “Earth Observatory” site to “animations,” on the right, where you’ll find the composite maps compressed into a short film (download the larger, twenty-megabyte version if you have a fast Internet connection). In the film, tides of photosynthesis ebb and flow with the seasons across the oceans and continents of our planet.
NASA also keeps track of the abundance of aquatic life by measuring the chlorophyll in the microscopic marine plants known as phytoplankton. At eob.gsfc.nasa.gov/Observatory/Datasets/chloro.ocean.html you can use data sets obtained by satellites to “build” your own animated illustrations of the shifting concentrations of chlorophyll.
If you want to start your acquaintance with photosynthesis with some history and a simple explanation, go to www.chm.bris.ac.uk/motm/chlorophyll/chlorophyll_h.htm, a site run by Paul May, a chemist at the University of Bristol in England. Another approach—one my children prefer—is through well-illustrated pages, such as the ones at David Watson’s “Flying Turtle” site (www.ftexploring.com/photosyn/photosynth.html).
Devens Gust, a biochemist at Arizona State University in Tempe, offers a good introduction to the importance of photosynthesis for life on Earth (go to photoscience.la.asu.edu/photosyn, scroll down to “Educational Resources,” and click on “Why Study Photosynthesis?”). Gust works at the university’s Center for the Study of Early Events in Photosynthesis, which has become a Web clearing house for information on the subject. In the same resources list, you’ll also find a long, well-organized directory of related sites (click on “Photosynthesis and the Web”).
As the name implies, photosynthesis is powered by electromagnetic radiation. Even a cursory glance at a diagram of the chain of events needed to convert photons into food hints at what a complex process it is. (See, for instance, the diagram at www.uqtr.ca/labcarpentier/eng/home_frames.htm of “Electron transport in the photosynthetic membrane,” by Robert Carpentier, a biochemist at the University of Quebec at Trois-Rivières.) For more information about how the photosynthetic process got under way on Earth, you can try www.ucmp.berkeley.edu/bacteria/cyanointro.html, a site run by UCLA’s Museum of Paleontology.
Perhaps the most intriguing aspect of the study of photosynthesis, however, is the promise it holds for a sustainable future. The world’s hunger for fossil fuels is rapidly depleting the photosynthetic bonanza that took hundreds of millions of years to store as coal and oil. But biochemists may soon figure out how to duplicate nature’s most important chemical reaction, and harness it more directly to make our fuel from scratch.
Robert Anderson is a freelance science writer living in Los Angeles.
Copyright © Natural History Magazine, Inc., 2004