On December 27, 2004, while the world was focused on the Indian Ocean tsunami, a few astronomers were contemplating the possibility of an even deadlier disaster: that of a massive asteroid striking Earth. A fifth of a mile wide—heftier than the space rock that leveled a vast swath of Siberian forest in 1908—Near-Earth Asteroid 2004 MN4 had grabbed the attention of NASA scientists just before Christmas. They put the chance of an April 13, 2029, collision at 1 in 2,700 and two days later upped the odds to 1 in 165. On the morning of the 27th the astronomers elevated their assessment again, this time to an alarming 1 in 38. On the Torino scale, which measures the likelihood and potential severity1 of an asteroid impact, they gave the asteroid a 4, the highest alert ever issued. Like most people, I was oblivious to this maybe menace. These days, it can be hard to keep your hazards straight. There are the usual suspects—car crashes, crime, cancer—and a seemingly endless parade of new threats. Breakneck global warming, bioengineered smallpox, gray goo? Sometimes my worst fear is not knowing what I should fear most.
Assessing and avoiding risk is a Darwinian imperative; mitigating risks that can’t be dodged is ancient as well.2 With current science, medicine and technology, we know more and can do more about risk than ever before, and in the past century, American life expectancy has jumped from 47 to 77 years. Somehow, though, the good news hasn’t gotten out. A recent study showed that nearly 80 percent of us think the world is more dangerous than it used to be, not less. Earlier this year, I launched a risk-research study with a subject pool of one: me. First I kept a diary, recording and ranking every hazard I encountered for two weeks. Then I submerged myself in accident, mortality, epidemiological and toxicological data; purchased a small library of scholarly books; and interviewed the country’s foremost risk experts. I sent them a copy of my diary for review. The key questions: How accurate was I at rating risks, and how could I do better? Sure, I’ll never live risk-free, but maybe I could learn to live risk-smart. Did I? Let’s take a look.
JANUARY 23, 2005
Biking the Urban Snowstorm
Yesterday, New York was slammed by one of the worst January blizzards in a century, a frigid nor’easter that dumped a foot and a half of snow. After such an onslaught, there’s really only one sensible activity: sledding. Friends of mine are meeting in Brooklyn’s Prospect Park, and I’m running late. I decide to bike. “I’ll wear my helmet,” I promise my girlfriend, Anne, as I rush out the door.
In my diary, I record biking as being highly risky. But riding very carefully, I reason, offsets the danger. When the risk experts review my journal, however, they cry foul at this rationalization.3 “Sometimes we decide how we want to live our lives and then invent reasons why certain things do or don’t worry us,” says George Gray, executive director of the Harvard Center for Risk Analysis. It seems that I’ve fallen prey to a couple common perceptual traps. Canadian psychologist Gerald Wilde might see my actions as an example of the risk-balancing process he calls homeostasis—the helmet makes me feel safe, so I engage in a more dangerous behavior than I would have otherwise.4 Other researchers have demonstrated that feeling in control—as you do at the handlebars of a bike—provides a false sense of security. In a 1989 study, Hofstra University psychologist William Sanderson had panic-prone patients breathe air that was 5.5 percent carbon dioxide, which is known to provoke panic attacks. Half of them were informed that they could lower the carbon dioxide concentration by twisting a dial, and this group reported fewer and milder attacks—even though the dial was a dummy.
Flatbush Avenue, my primary route to the park, is only partially plowed. I ride over slush, a foot or two from buses and cars, with slipping tires. The good news: I’m not drunk. A recent Johns Hopkins University study found that one in three fatal bicycle accidents in Maryland was linked to alcohol; a blood-alcohol level of 0.08 or higher was found to increase the risk of serious or fatal injury by 2,000 percent. The bad news: I’m a man. Of the 800 bicyclists killed in accidents with cars each year, 90 percent are male; 80 percent of the 500,000 injured are men. Male cyclists do slightly outnumber female ones, and men tend to bike more often, but these factors alone don’t account for the elevated death and injury rates. Men, it seems, simply take more risks. For anyone, though, bikes can be dangerous: Traveling a mile by bike is almost 14 times as likely to be fatal as a mile by car.5
In the park, it’s a full Norman Rockwell scene, with kids in mittens and scarves towing sleds across sparkling snow. I meet my friends, and we head to a crowded bunny slope. Some 33,000 Americans a year are injured while sledding, but the sport registered little concern in my diary. This time, the facts are with me—after all, millions of people go sledding every winter and don’t get hurt.
Risk assessors rip their hair out at the general public’s innumeracy; many people jump to conclusions based only on absolute numbers and don’t consider ratios as well. For example, the average number of people killed each year in hot-air balloon accidents is 2.6, while the number killed in hunting accidents is 600. But there are two million hunters in the U.S. and just 3,000 hot-air balloonists, which makes ballooning’s death rate 30 times as high as that of hunting.