| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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Counterpoints in science The Future Fights Back In Franz Kafka's story "The Burrow," a delving animal sets out to dig himself a cozy and safe underground home, with secret entrances and exits. Like all of Kafka's central characters, though, he's a worrier. Despite his precautions, he fears that some predator will sneak in and trap him in his hideout. To avoid this fate, he energetically digs an extensive labyrinth of passages with hidden escape hatches. Then, to his alarm, he realizes that by expanding his system of tunnels he has increased the probability that a natural enemy will stumble onto one of the entrances or accidentally dig its way into the network and track him down. All the things he does to make himself more secure just add to his anxiety and sense of vulnerability. That's the situation we find ourselves in today, according to Edward Tenner, author of the book Why Things Bite Back: Technology and the Revenge of Unintended Consequences (Alfred A. Knopf 1996). Our modern devices, our medical and scientific breakthroughs, have made us healthier and wealthier but not necessarily happier. We seem to be doing better but feeling worse. Every technical advance that solves one problem carries with it what Tenner calls "revenge effects" that create new problems. These effects are particularly vengeful in our dealings with disease, the environment, and recreation. Tenner gives many examples, some of which I have excerpted here. Take antibiotics, for instance. The U.S. Surgeon General predicted 20 years ago that antibiotics were going to "close the books on infectious disease." Instead, the liberal prescribing of antibiotics has spawned resistant varieties of bacteria that sometimes make hospitals dangerous places for sick people. Among AIDS patients, a new variety of tuberculosis is thriving that's resistant to all three of the available anti-Tb drugs. Thanks to angioplasty and clot-busters, we're surviving acute heart attacks and strokes in unprecedented numbers. The consequence of all this success, of people living longer, is an exponential increase in chronic conditions like arthritis, emphysema, and degenerative brain diseases such as Parkinson's and Alzheimer's. Malaria is still the big killer in the underdeveloped world where most of humanity resides. One of our great public health triumphs in the industrial North has been the elimination of malaria and the creepy menagerie of parasitic worms that infest millions in Africa, South America, and Asia. What could possibly be wrong with that? The sickle cell trait that partially protects red blood cells of Africans against endemic malaria can also cause lethal sickle cell disease when both parents have the trait. The benefits are clearly greater than the cost for Africans in Africa, since the sickle cell trait saves far more lives than are lost to the disease. For African-Americans, however, the situation is reversed. There's no malaria here any more, but sickle cell disease still cripples and kills those who suffer from this evolutionary hangover. The IgE story is less well known. Immunoglobulin E is a specialized antibody that has evolved over eons of time to defend us against parasites like malaria, flukes, and hookworm. Deprived of these natural adversaries that have lived in all primate and human bodies for millions of years, our IgE is behaving like a large well-armed militia that doesn't have enough to do. Lacking real enemies, IgE has taken on pseudo-enemies like pollens, dust mites, and animal danders. These antibody-antigen reactions set off allergies like hay fever, asthma, and dermatitis that afflict the populations of "advanced" nations. According to a recent issue of Science (January 3, 1997), "The prevalence of asthma in Westernized society has risen steadily this century, doubling in the last 20 years. Asthma now affects one child in seven in Great Britain, and in the United States it causes one-third of pediatric emergency-room visits." Asthma is much less common in crowded and polluted Eastern block countries, where respiratory and other infections are much more frequent than they are in the West. Ironically, these infections, by tying up the IgE, seem to protect people against asthma. Our "success" in eliminating many epidemic diseases has unleashed our IgE to trigger an epidemic of asthma and allergies. Our environment, like our bloodstream, is replete with defensive measures that have gone awry. The most productive soil for agriculture lies in alluvial plains and deltas that used to flood predictably on a seasonal basis. In recent decades, though, dams and elaborate flood-control systems have encouraged people to settle in river valleys. Floods still occur, of course, not in predictable cycles as before, but when rainfall is excessive or dams and levees fail. The population of Bangladesh (formerly East Pakistan) was massively settled on land reclaimed from the rivers and marshes by the wonders of engineering. When the cyclone of 1970 struck, about half a million people died. Every few years the six o'clock news shows beleaguered folks on the Great Plains, and recently here in California, piling up sandbags on banks of rising rivers, being evacuated from homes with several inches of water over the wall-to-wall carpets, or sitting on their roofs waiting for rescue. As soon as the water level drops, they move back into the floodplain. Dry weather has its revenge effects, too. Disk plows were efficient in ripping up grassland and increasing crop yields in the Midwest. Drought then turned the Great Plains into a dust bowl in the "dirty thirties" and again in the "filthy fifties." In California we have a fire ecology, where conflagrations have swept through the forests periodically, cleaning out accumulated deadwood, debris, and undergrowth. Nature lovers want to live in or near the woods, though, and growth-minded boosters in the Sierra foothills, for instance, have obliged by easing restrictions on building in fire hazard zones. "House-shading trees, rustic shakes and shingles, and winding and leafy driveways all invite wildfire to make fatal moves--and obstruct firefighters," Tenner writes. Environmental writer Charles Little calls events like these Smokey's Revenge. The 1991 Oakland hills fire was one of many predictable disasters resulting from this flouting of California history. For most fire-zone residents there was no advance warning. A radiologist colleague of mine happened to look out his window, saw the flames roaring toward him, and was lucky to get out with the clothes on his back. Our interactions with the animal world have fared no better than our encounters with flood and forest. Benefiting from protective legislation, sea lions on the West Coast have multiplied sixfold in the past two decades--and have decimated the steelhead population. Furthermore, tiny parasitic nematode worms that infest the GI tracts of sea lions have spread through their feces to crustaceans and fish that are eaten by people as uncooked sushi and sashimi, creating a small epidemic. This boomerang of a well-meaning policy is putting our underused IgE back to work. Some of the biggest fiascoes stem from efforts to eradicate the smallest pests. The fire ant, Solenopsis invicta, devours seedling trees, kills young calves and fawns, and its venomous bite has an effect on human victims somewhere between a mosquito bite and a bee sting. The species originated in Paraguay and made it to Mobile, Alabama, in 1930, where its mounds obstructed and damaged farm equipment and its taste for electric insulation disabled traffic signals. The Agricultural Research Service (ARS) declared war on the fire ant and in a campaign that Tenner calls "the Vietnam of entomology" launched an all-out chemical assault with dieldrin, heptachlor, mirex, and other insecticides. Unfortunately, these poisons were much more effective against the fire ant's natural enemies than they were against the ant. Thanks to ARS, the fire ant's share of the resident ant population of the Mobile area has increased from one to 99 percent. Solenopsis not only remains invicta (unconquered), but new colonies are now appearing in southern California and working their way up the West Coast. Even our attempts to make sports and other recreational activities safer for the participants have unexpected backlashes. Protective devices for skiers and football- players have encouraged those athletes to take more and bigger chances and so incur more serious injuries. In skiing, new materials and techniques are constantly changing the sport. Wood has been replaced by plastics. Rigid lightweight boots and bindings release quickly. Sidecuts increase maneuverability. The result should be easier, faster, and safer runs, and for many careful skiers that's the way it is. You don't win championships, though, by being careful. In World Cup downhill skiing, men's speeds have gone from 75 to 90 miles per hour, women's from 60 to 75. It's easy to lose control at those speeds and have a fatal spill, as Australian skier Ulrike Maier did in the 1994 World Cup race at Garmisch-Partenkirchen. Older skiers and young novices are encouraged by the "safer" equipment to take bigger risks. New resorts like Crested Butte, Colorado, offer slopes as steep as 55 degrees. Catastrophic injuries have jumped from 35 per season in the 1980s to 75 in 1992. The new equipment does accomplish much of what it was intended to do. Injuries to the lower leg, foot, and ankle have decreased a lot. What has changed is that annually there are now, nationwide, 100,000 sprains of the anterior cruciate ligament of the knee. These injuries are painful, difficult, and expensive to repair, and long term can lead to cartilage breakdown and arthritis. Like the new boots and skis, modern high-tech football helmets were intended to protect the athletes from serious trauma. And again the competitive spirit found a way of converting safety into hazard. The more aggressive players quickly discovered that these hard plastic crests make excellent battering rams. "Spearing" an opponent with a helmet to knock him down is now officially banned, but of course it still goes on. The result is an epidemic of serious injuries not only to the target, but to the cervical spine of the rammer, leading to broken necks and paralysis. What message can we take home from all these lost skirmishes and Pyrrhic victories? It's still true that we in the industrial world are living on average much longer than our grandparents did and have a higher standard of living. We are much less likely to be struck down by childhood infections, by heart attacks in early middle age, or by natural disasters. Why are we then, like Kafka's frantic rodent, such unhappy campers? Tenner's diagnosis is that the safer life imposes an ever-increasing burden of attention. We're so busy patrolling and protecting the borders of our expanded lifestyle that we may not have much time or energy left to enjoy it. Change itself, though a challenge to some, is disconcerting to many more, especially to those who were comfortable with the old ways. Computers are transforming American industry, but a lot of CEOs over 50 are afraid to use them. Our early human ancestors in Africa used the same stone tool technology for more than a million years, that is, for thousands of generations, while we have to deal with a major technical innovation at least once a decade. These shiny new helmets enfold the same old brain, and our paleolithic cerebral software struggles with the new hardware and speed of change. The anxiety we experience in our compulsive burrowing into new and unfamiliar psychic territory may be the ultimate revenge effect, the future's payback for our restless refusal to be content with things as they are. Jerold M. Lowenstein is a professor of medicine at the University of California at San Francisco and chairman of the Department of Nuclear Medicine at California Pacific Medical Center in San Francisco. |
Spring 1997
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