Sydney, Australia

SIX weeks ago, when I first heard about the reactor damage at the Fukushima Daiichi plant in Japan, I knew the prognosis: If any of the containment vessels or fuel pools exploded, it would mean millions of new cases of cancer in the Northern Hemisphere.

Many advocates of nuclear power would deny this. During the 25th anniversary last week of the Chernobyl disaster, some commentators asserted that few people died in the aftermath, and that there have been relatively few genetic abnormalities in survivors’ offspring. It’s an easy leap from there to arguments about the safety of nuclear energy compared to alternatives like coal, and optimistic predictions about the health of the people living near Fukushima.

But this is dangerously ill informed and short-sighted; if anyone knows better, it’s doctors like me. There’s great debate about the number of fatalities following Chernobyl; the International Atomic Energy Agency has predicted that there will be only about 4,000 deaths from cancer, but a 2009 report published by the New York Academy of Sciences says that almost one million people have already perished from cancer and other diseases. The high doses of radiation caused so many miscarriages that we will never know the number of genetically damaged fetuses that did not come to term. (And both Belarus and Ukraine have group homes full of deformed children.)

Nuclear accidents never cease. We’re decades if not generations away from seeing the full effects of the radioactive emissions from Chernobyl.