The headlines were extraordinary: “Japan Weighed Evacuating Tokyo in Nuclear Crisis,” the New York Times wrote a few days ago. “Tokyo Evacuation ‘Was Considered’,” said the Sydney Morning Herald. “Japan Urged Calm While It Mulled Tokyo Evacuation,” wrote … hey, TIME magazine. The stories detailed the Rebuild Japan report, a deep and independent investigation of the events surrounding the Fukushima nuclear meltdown that occurred nearly a year ago. And the takeaway was alarming: at one point Japanese officials feared that radiation levels at the stricken plant would become so high that workers would be forced to abandon the facility — and that in turn could create a chain reaction that would force other Japanese nuclear plants to be abandoned as radiation spread. The report quotes then Chief Cabinet Secretary Yukio Edano as saying that “it was only logical to conclude that we would also lose Tokyo itself.”
Considering that some 30 million people live in the vast metropolitan area of Tokyo — about a quarter of Japan’s total population — the idea of evacuating the capital city is, frankly, unimaginable. But then, so is a full-scale nuclear meltdown in one of the most crowded countries in the world — a country that at the time was still reeling from a tsunami that had wiped out much of the northeastern coast and killed nearly 20,000 people. (TIME subscribers should check out these amazing photos of Fukushima by James Nachtwey.) Still, nearly a year after the event, the question remains: Was the Fukushima meltdown that dangerous?
(MORE: Japan, One Year Later)
There are some dissenting voices. Over at Slate, Michael Shellenberger and Ted Nordhaus of the Breakthrough Institute — an energy-and-innovation think tank — raise some doubts about whether Tokyo was really in danger during the Fukushima crisis. They note that then Prime Minister Naoto Kan told the PBS Frontline crew producing a documentary on Fukushima that he asked his team to outline a number of scenarios, including worse-case ones, but “it didn’t mean that it seemed likely to happen.”
Yet there’s something about nuclear power that seems to make the media and others go straight to the worst-case scenario — without pausing to evaluate how likely it really is. Shellenberger and Nordhaus write:
“In any field of endeavor,” wrote physicist Bernard Cohen in his classic 1990 study, The Nuclear Energy Option, “it is easy to concoct a possible accident scenario that is worse than anything that has been previously proposed.” Cohen goes on to spin a scenario of a gasoline spill resulting in out-of-control fires, a disease epidemic, and, eventually, nuclear war.
Cohen concludes his fantastical thought experiment by saying, “I have frequently been told that the probability doesn’t matter — the very fact that such an accident is possible makes nuclear power unacceptable. According to that way of thinking, we have shown that the use of gasoline is not acceptable, and almost any human activity can similarly be shown to be unacceptable. If probability didn’t matter, we would all die tomorrow from any one of thousands of dangers we live with constantly.”
Of course, probability does matter to us most of the time — that’s why we can work up the courage to do dangerous things like walking across the street or driving. We’ve internalized the risks of those everyday behaviors, and, if anything, we probably underrate some of them. (I shouldn’t have to tell you that your chance of dying in an auto accident — motorized transport kills 1.2 million people around the world each year — or even from heart disease worsened by coal pollution is far greater than the risk posed to you by nuclear power.) But we don’t look at nuclear power that way, as the risk expert David Ropeik wrote last year:
Nuclear radiation is human-made, which is scarier than natural risks, like radiation from the sun (which kills 8,000 Americans per year from skin cancer). And radiation can cause cancer, a particularly painful way to go, and anything that involves more pain and suffering understandably causes more concern.
So nuclear radiation, in addition to being actually physically hazardous, has some psychological characteristics that make it particularly frightening, and a frightening history, and as a result, the worst case scenarios get played up, and magnified in the scream-a-thon that 24/7 global communication creates around events like those in Japan. Fear of nuclear energy is reinforced, fear that unquestionably in the coming weeks and months will infect the ongoing debate over what kind of energy future we should have.
(MORE: A Nuke Scare in San Diego)
As it happens, scientists have begun to compile early assessments of the health impacts of Fukushima — and the conclusions are less than catastrophic. Researchers speaking at a conference for the Health Physics Society said the health threat to Japanese from radiation exposure looks to be extremely low. Even the brave workers who stayed behind at the plant had radiation exposure that was more than 10 times lower than the levels received by the half-million people who helped entomb the Chernobyl reaction more than two decades ago. They estimated that the risk of getting cancer for those exposed would increase 0.002%, and the risk of dying from cancer would rise by 0.001%. “I received more radiation on my transcontinental flights from Tokyo to Washington than I did at the reactor site,” said John Boice, a professor at Vanderbilt University and the incoming president of the National Council on Radiation Protection & Measurements.
Obviously there’s uncertainty to those estimates, in part because it’s hard for researchers to know exactly how much radiation workers and others near the plant may have received. But it’s almost certain that it will be impossible to distinguish cancer cases that may be connected to Fukushima to the background rate of cancer, which eventually hits 41 out of every 100 people. Indeed, the greater risk may be to the psychological health of residents around Fukushima, who risk being seen as outcasts — just as the hibakusha, the survivors of the atomic bombings in Japan, faced years of discrimination from the rest of Japanese society.
What the Rebuild Japan report and other investigations show is that the Japanese response to Fukushima was the real disaster. Communication between the government and the Tokyo Electric Power Co. was full of mistakes and misunderstandings that turned a difficult situation into a near catastrophe. As Evan Osnos writes for the New Yorker, we are lucky that Fukushima didn’t turn out to be worse than it was. But the more we learn about it, the more it seems that the odds were always in our favor.